ROTATION MONITORING MODULES AND ROTATION MONITORING METHOD FOR A TOOL TO BE ROTATED IN OPERATION

Description

Technical area

[0001] This document describes a runout monitoring module, a runout monitoring tool holder module, and a runout monitoring tool module for a tool to be rotated during operation. Furthermore, a machine tool / machining center and a runout monitoring signal interface are described, which operatively interact with the runout monitoring module / the runout monitoring tool holder module / the runout monitoring tool module to monitor the runout of the tool to be rotated during operation. A runout monitoring method for a tool to be rotated in a machine tool / machining center is also described, which is carried out by the runout monitoring module / the runout monitoring tool holder module / the runout monitoring tool module, optionally through interaction with the machine tool / machining center and / or with the runout monitoring signal interface.A computer program product comprises instructions that cause the execution of the method steps of the runout monitoring method. background

[0002] This document describes individual monitoring modules for monitoring the concentricity of a rotating tool during operation. The tool is mounted in a workpiece processing machine. The workpiece processing machine can be, for example, a (numerically controlled) machine tool (NC machine), a (multi-axis) machining center, a (multi-axis) milling machine, a flexible manufacturing cell, or the like. The terms "machine tool" and "machining center" are also used below for these or similar machines.

[0003] Such a machine tool has a (main) spindle into which the tools to be used in machining a workpiece, such as drills, milling cutters, etc., or the workpieces themselves, are inserted. The spindle can be fixed in position or, for example, can be moved in three orthogonal directions X, Y, Z within the machine tool's working space. The spindle can also be driven to rotate about the X, Y, and Z axes. In modern machining centers, tools often have to be changed during the machining of a single workpiece. This is usually done by automatically changing the tools, whereby a tool in the spindle is replaced by another tool located in a tool magazine in the machine tool. During the tool change, a clamping device on the spindle for holding the tools is exposed in the machine's working space. The same can apply to the tools and any pre-mounted tool holders.This results in deposits of chips and other contaminants on the spindle clamping device and / or on the tools. On modern machine tools, the clamping device is usually designed as a taper interface, and steep tapers (SK) or hollow shank tapers (HSK) are used to insert the tools. If, for example, chips build up at the taper interface and / or on the HSK / SK during a tool change, a faultless face contact / complete retraction of the tool or its holder can no longer be guaranteed because the chips become trapped between the taper interface and the holder. If the tool subsequently rotates with the spindle, a type of wobbling motion occurs, which results from an imbalance caused by the lack of face contact / incomplete retraction. If the wobbling motion exceeds a permissible level, this is referred to as a radial runout of the tool.If the runout error goes unnoticed and no countermeasures are taken, radial runout will occur in the rotating tool during workpiece machining, which will lead to dimensionally inaccurate machining results, inadequate surface quality, and tool imbalance. Furthermore, a runout error puts a strain on the tool itself, as it can lead to increased wear and, as a result, to tool damage (even tool breakage). Runout errors can occur even if the tools and spindle are cleaned during tool changes, e.g., by supplying (cooling) lubricant or compressed air. Another reason for a runout error can be existing damage to the spindle itself. It is therefore important to quickly detect and accurately evaluate runout errors during operation of rotating tools in order to ensure satisfactory machining results and a stable machining environment. State of the art

[0004] One way to detect a tool's incorrect face contact in the spindle of a machine tool is to monitor the face contact using compressed air. Compressed air is applied to the taper interface of the machine tool in such a way that, in the event of a faulty face contact, compressed air escapes between the spindle and the tool holder. The detection of this pressure loss allows us to determine whether the face contact is faulty.

[0005] The Planko sensor system from OTT-JAKOB Spanntechnik GmbH, D-87663 Lengenwang, determines the flatness of a tool on a machine tool by querying several ceramic sensors (resonators). The system is based on a compact, passive electronic module consisting of a resonator, cable, and connector, which is integrated into the spindle nose. The flatness is determined by sequentially querying the resonators during rotation. In the read head, the current measurement results are compared with a previously defined reference value stored in the internal memory. If there is a deviation from the reference value, the measurement data is recorded via a comparator signal and passed on to the machine control system. In addition, measuring systems for flatness monitoring are at least partially integrated into the spindle of a machine tool and use, for example, force sensors, electromagnetic signals, or laser light for evaluation.In this context, reference is made to, for example, DE 10 2013 201 328 A1, DE 10 2018 201 427 A1, DE 103 51 347 A1, EP 3 360 642 A1, DE 10 2013 100 975 B3 and EP 3 581 328 A1.

[0006] Another option for monitoring runout errors on rotating tools is laser measuring systems such as the LC50-DIGILOG from Blum-Novotest GmbH, DE-88287 Grünkraut. This system detects runout errors on rotating tools caused, for example, by a contaminated contact surface on the tool holder. Specific tool data is required for each tool, and the measurement depends on the desired measuring point. In a learning process, a basic runout error is first determined; this represents the difference between the longest and the shortest cutting edge of the tool. A statement about the runout error caused by contamination on the contact surface can then be made by measuring the cylindrical shank of the tool in comparison to the effects on the cutting edges, as to whether a currently measured runout error is larger or smaller than the stored basic runout error.Calculations are carried out by NC programs, with particular attention being paid to radius changes of the longest cutting edges as wear values.

[0007] Furthermore, intelligent tools exist for monitoring various process variables during machining. For example, in WO 2021 / 029 404 A1, the vibration of a rotating tool is determined using several acceleration sensors mounted symmetrically on the tool shank with respect to the tool's rotational axis. Similarly, according to WO 2021 / 029 099 A1, vibrations are determined from signals from acceleration sensors and strain gauges mounted externally on the shank (e.g., a rolling or milling tool). WO 2019 / 122 375 A1 describes a sensor module for a rotating tool holder, e.g., for cutting tools, to enable reliable recording of operating or system states in real time.For this purpose, a sensor module containing sensors for detecting force introduction, temperature, and acceleration (vibrations) is conveniently positioned in the tool holder along the rotational axis, and a coolant flow is structurally directed around this position. This positioning of the sensor module serves to minimize imbalances and simplify insertion of the sensor module. Recorded measurement signals are transmitted, preferably wirelessly, via a transmitter and antenna to a receiver on a machine tool. A control arrangement in the machine tool enables an ad-hoc response to instability states that have not yet stabilized. This is achieved through real-time adaptation of machining parameters such as feed rate, speed, etc., with this adaptation being implemented depending on the process states, such as vibration or the force applied to the tool.Tool systems with monitoring of process variables are also disclosed in WO 2021 / 033 670 A1, EP 2 103 379 A1, US 10 828 740 B2, US 10 828 739 B2, EP 3 808 503 A1, US 2021 / 026 322 A1 and JP 5 089 342 B2.

[0008] Conventionally, the tool systems mentioned are operated using batteries, for example. However, some tool systems have devices for generating energy in the sense of energy harvesting in order to supply the tool system itself, including the integrated electronics, with energy. For example, EP 3 539 717 A1 describes a machining tool with a generator unit. A first component is fixedly connected to the body of the machining tool and a second component is movably connected to the body. When there is a fluid flow to the second component, electrical energy is generated by its relative movement to the first component. EP 2 112 461 B1 describes a measuring probe with a power generator, wherein a flywheel is rotatably connected to the measuring probe. A rotor of the power generator has permanent magnets and is connected to the flywheel, while a stator with induction windings is fastened inside the housing of the measuring probe.When a rotary movement of the probe housing is accelerated, the flywheel, due to its high moment of inertia, does not immediately follow the housing movement. This difference in movement – ​​as long as it exists – converts kinetic energy into electrical energy. The flywheel is equipped with a freewheel. While it follows the housing rotation in a first direction of rotation, it can only rotate freely in a second direction opposite to the first direction, thus generating electrical energy. Further tool systems using the energy harvesting principle are also disclosed in DE 10 2016 223 199 A1, US 2015 / 0 125 230 A1, EP 1 742 011 B1, and TW I491463 B.

[0009] Although the aforementioned devices and methods for tool runout monitoring operate according to different detection principles, there are still opportunities to improve the reliability and speed of detection of the flat contact surface, particularly for tools used for runout monitoring. Improvements also exist with regard to reducing system costs.

[0010] For example, with the initially described flat contact monitoring using compressed air, the pressure does not remain constant if the flat contact is faulty, but rather more air escapes over time. Monitoring using compressed air therefore only provides limited results. Furthermore, this system is not able to detect a faulty flat contact if chips adhere directly to the air outlet on the flat contact and thus block this air outlet. The Planko sensor system from OTT-JAKOB Spanntechnik GmbH, D-87663 Lengenwang, must be integrated into the spindle nose in a complex manner, which entails high system costs. Furthermore, according to this sensor system, the correct flat contact is determined by querying several ceramic sensors. In particular, ground and / or crushed aluminum chips can adhere to the ceramic sensors.This leads to a total failure of the sensor system, which subsequently no longer detects concentricity errors, resulting in a complex and expensive sensor replacement. Even if force sensors are integrated into the spindle nose, as in accordance with EP 3 360 342 A1, this involves complex integration and therefore high system costs. Furthermore, data acquisition and data analysis with these systems are complex.

[0011] In the case of concentricity monitoring devices that work with laser measuring systems, determining the concentricity is generally time-consuming because - regardless of the comparatively long measurement time - exact spindle positioning in the measuring room or at the measuring point is necessary.

[0012] Although tools equipped with various sensors are now available, such as temperature sensors, force sensors, and acceleration sensors, these tools are used to record process parameters such as vibrations or cutting forces. However, none of these tools is capable of detecting a clamping error; there is still no integrated runout monitoring system in a rotating tool. EP 2 208 017 A2 relates to a technology for controlling the transmission power of a transmit / receive device in a machine's position measuring system, which enables robust and time-critical data transmission and rapid connection establishment with low energy consumption.This involves sending a first transmission power message with a first transmission power and sending a second transmission power message with a second transmission power, the latter being lower than the first transmission power if a transmission power confirmation message was received in response to the transmitted first transmission power message, and the second transmission power being higher than the first transmission power if no transmission power confirmation message was received in response to the transmitted first transmission power message. The transmission power messages are used to determine whether functional communication between the transmitting / receiving device and a base station is possible with the current transmission power. Depending on the transmission conditions via the air interface, i.e., in the event of interference with other signals, the transmission power of the transmitting / receiving device is adjusted.This allows the lower transmission power limit to be determined to avoid continuous transmission at excessive transmission power. This saves energy in the transmitting / receiving device. The transmitting / receiving device sends the transmission power messages to a base station connected to the transmitting / receiving device. After transmitting the transmission power message, the transmitting / receiving device waits to receive a transmission power confirmation message. If the transmission power message is received by a base station connected to the transmitting / receiving device, the base station sends a transmission power confirmation message. Depending on the receipt of the transmission power confirmation message, the transmitting / receiving device knows whether a radio connection between the transmitting / receiving device and the base station is possible.Depending on this information, the transmit / receive device can increase or decrease the transmit power for a subsequent transmit power message.

[0013] After the second transmission power message, a third transmission power message with a third transmission power can be sent. If the transmission power of the second transmission power message was lower than the transmission power of the first transmission power message and a transmission power confirmation message is received for the second transmission power message, the third transmission power is lower than the second transmission power. If the transmission power of the second transmission power message was lower than the transmission power of the first transmission power message and no transmission power confirmation message is received for the second transmission power message, the third transmission power is higher than the second transmission power. If the transmission power of the second transmission power message was higher than the transmission power of the first transmission power message and a transmission power confirmation message is received for the second transmission power message, the third transmission power is equal to the second transmission power.If the transmission power of the second transmission power message was greater than the transmission power of the first transmission power message and no transmission power confirmation message is received in response to the second transmission power message, the third transmission power is greater than the second transmission power. Problem to be solved

[0014] The aim of the solution presented here is to provide a methodology and devices for monitoring the concentricity of a rotating tool (during operation). Solution presented here

[0015] One of these devices is a machine-tool-independent runout monitoring module with an integrated tool, capable of determining the runout error (or underlying data) during rotation and, if necessary, sending one or more corresponding status and / or measurement signals, particularly via a communication interface, to the control of a (runout monitoring) signal interface or a machine tool. The devices and methods improve existing solutions in terms of the accuracy and speed of detecting the planar contact (and subsequently checking the runout) and are quick, easy, and cost-effective to manufacture (even significantly more cost-effective than spindle-integrated systems). They also enable easy integration into existing machine tools or simple combination with available tools or tool systems.This makes it possible to assemble task-specific tools with a concentricity monitoring function according to requirements with little effort.

[0016] This object is achieved according to a first aspect by a runout monitoring module for a tool to be rotated during operation. The runout monitoring module comprises a tool interface, configured to receive the tool to be rotated, and a tool holder interface, configured for insertion into a tool holder, in particular of a machine tool or a machining center. In addition, the runout monitoring module comprises a sensor unit, which is assigned to the runout monitoring module such that a rotational axis of the runout monitoring module runs through the sensor unit, wherein the sensor unit is configured to detect variables representative of an acceleration in a plane oriented substantially normal to the rotational axis of the runout monitoring module when the runout monitoring module, in particular together with the tool to be rotated and / or with the tool holder,rotates. A computing unit of the concentricity monitoring module is configured to receive the acceleration-representative variables detected by the sensor unit, to determine a total acceleration based on the detected acceleration-representative variables, to compare the total acceleration with a threshold value dependent on a rotational speed of the concentricity monitoring module during the detection of the acceleration-representative variables, and to determine that a concentricity error of the tool to be rotated, of the concentricity monitoring module, and / or of the tool holder exists if the total acceleration is greater than the threshold value. A communication unit of the concentricity monitoring module is communicatively connected to the computing unit and configured to signal to the machine tool / machining center whether a concentricity error of the tool to be rotated,of the concentricity monitoring module and / or the tool holder is present or not.

[0017] The tool interface can be, for example, an ABS holder (ABS system) or an ABS adapter (ABS connection), into which the tool to be rotated or a corresponding ABS adapter of the tool to be rotated can be inserted. This ABS system can be, for example, an ABS system from Ceratizit SA. Alternatively, the tool interface can be equipped with a collet holder into which the tool to be rotated can be inserted. Finally, the tool interface can be connected to the tool to be rotated in any other suitable manner, ensuring a stable and concentric connection.

[0018] Similarly, the tool holder interface can be designed as an ABS adapter for insertion into the tool holder, which is also designed as an ABS holder, for example. This tool holder can be pre-assembled on the machine tool / machining center or can be inserted into the machine tool together with the runout monitoring module between the runout monitoring module and the spindle. Alternatively, the tool holder interface can be securely and concentrically connected to the tool holder in any other suitable manner.

[0019] The runout monitoring module thus establishes a customizable connection with a runout monitoring function between the spindle of a machine tool and the rotating tool. This provides a modular runout monitoring module structure that is suitable for any common machine tool interface, such as SK, SK-FC, BT, BT-FC, HSK-A, PSC, and HSK-E. It thus offers maximum flexibility without loss of the runout monitoring function, as different tools with different spindle interfaces can be combined to machine workpieces.

[0020] A second aspect relates to a runout monitoring tool holder module for a tool to be rotated during operation. The runout monitoring tool holder module comprises a tool interface configured to receive the tool to be rotated and a tool holder configured for insertion into a spindle of a machine tool or a machining center.The concentricity monitoring tool holder module also comprises a sensor unit which is assigned to the concentricity monitoring tool holder module in such a way that a rotational axis of the concentricity monitoring tool holder module runs through the sensor unit, wherein the sensor unit is configured to detect variables representative of an acceleration in a plane oriented substantially normal to the rotational axis of the concentricity monitoring tool holder module when the concentricity monitoring tool holder module rotates, in particular together with the tool to be rotated and / or with the spindle.A computing unit of the concentricity monitoring tool holder module is configured to receive the acceleration-representative variables detected by the sensor unit, to determine a total acceleration based on the detected acceleration-representative variables, to compare the total acceleration with a threshold value dependent on a rotational speed of the concentricity monitoring tool holder module during the detection of the acceleration-representative variables, and to determine that a concentricity error of the tool to be rotated and / or the tool holder exists if the total acceleration is greater than the threshold value.A communication unit of the concentricity monitoring tool holder module is communicatively connected to the computing unit and is configured to signal to the machine tool / machining center whether or not there is a concentricity error of the tool to be rotated and / or the tool holder.

[0021] The tool interface can be, for example, an ABS holder (ABS system) or an ABS adapter (ABS connection), into which the tool to be rotated or a corresponding ABS adapter of the tool to be rotated can be inserted. Alternatively, the tool interface can be equipped with a collet holder into which the tool to be rotated can be inserted.

[0022] The tool holder can be designed as an ABS holder and in particular as an HSK or as an SK, which serves to insert the concentricity monitoring tool holder module into the spindle of the machine tool / machining center.

[0023] The runout monitoring tool holder module can therefore consist of a central housing housing the sensor unit, the processing unit, and the communication unit, which is permanently connected to the tool holder. Thus, the runout monitoring tool holder module, which establishes a connection between the spindle and the rotating tool, offers the possibility of flexibly using different tools for machining workpieces without losing the runout monitoring function.

[0024] A third aspect relates to a runout monitoring tool module. The runout monitoring tool module comprises a tool to be rotated during operation and a tool holder configured for insertion into a spindle of a machine tool or a machining center. The runout monitoring tool module further comprises a sensor unit assigned to the runout monitoring tool module such that a rotational axis of the runout monitoring tool module extends through the sensor unit. The sensor unit is configured to detect variables representative of acceleration in a plane oriented substantially perpendicular to the rotational axis of the runout monitoring tool module when the runout monitoring tool module rotates, in particular together with the spindle.A computing unit of the runout monitoring tool module is configured to receive the acceleration-representative variables detected by the sensor unit, determine a total acceleration based on the detected acceleration-representative variables, compare the total acceleration with a threshold value dependent on a rotational speed of the runout monitoring tool module during the detection of the acceleration-representative variables, and determine that a runout error of the runout monitoring tool module exists if the total acceleration is greater than the threshold value. A communication unit of the runout monitoring tool module is communicatively connected to the computing unit and configured to signal to the machine tool / machining center whether or not a runout error of the runout monitoring tool module exists.

[0025] The tool holder can therefore be a mechanical interface between the rotating tool and the machine tool spindle. The tool holder can be designed as an ABS holder and, in particular, as an HSK or SK, which serves to insert the concentricity monitoring tool module into the spindle of the machine tool / machining center.

[0026] The runout monitoring tool module, which establishes the connection between the spindle and the rotating tool, can be manufactured as a single unit, for example, by a tool manufacturer. This eliminates detachable interfaces (and thus potential sources of contamination or deposits that prevent precise flatness), such as the tool interface and the tool holder interface according to the first aspect. This allows various tools to be provided with further improved runout monitoring functionality, which is particularly in demand in high-precision applications.

[0027] When features of a "module" or a "monitoring module" are described below, these features may, in particular, refer to the runout monitoring module according to the first aspect, the runout monitoring tool holder module according to the second aspect, and the runout monitoring tool module according to the third aspect. This applies in particular when describing components such as the computing unit, the sensor unit, and the communication unit, which are included in the modules according to the first to third aspects.

[0028] The computing unit of the monitoring module can be contained in a data processing unit. This data processing unit can additionally include a (temporary) memory. Thus, the variables detected by the sensor unit can be processed and temporarily stored in the data processing unit, or transmitted as data to the machine tool or a concentricity monitoring signal interface. The data processing unit, the sensor unit, and the communication unit (also known as the data transmission unit) can be contained in an electronics unit.

[0029] To signal whether a radial runout error is present in the rotating tool, digital IO signals (OK: OK, or NOK: not OK) can be transmitted to the machine tool as 1-bit signals. The transmission, like the rest of the communication between the monitoring module and the machine tool, can be wireless.

[0030] The sensor unit can comprise an acceleration sensor. The acceleration sensor can be a piezoelectric acceleration sensor or based on a spring-mass system. Alternatively, strain gauges or acceleration sensors that operate with magnetic induction can be used.

[0031] The acceleration sensor of the sensor unit can be a two-axis acceleration sensor, which is designed, for example, to measure accelerations in x and y directions that are orthogonal to one another. Alternatively, the acceleration sensor can be two, in particular identical, single-axis acceleration sensors, which are arranged, for example, one above the other or next to one another and offset by 90° with respect to their sensitive axes (the axes of inertia in which accelerations are measured), so that accelerations in x and y directions that are orthogonal to one another can be measured. Alternatively, a three-axis acceleration sensor can also be used to additionally record process variables such as vibrations in a z direction that is orthogonal to the x and y directions.

[0032] The rotational axis of the monitoring module can run at least approximately centrally through a body of the sensor unit, but does not have to run through the acceleration sensor itself (although this is of course also possible). In other words, the sensor unit can be arranged within the monitoring module such that at least one axis of inertia of the sensor unit is oriented at least approximately coaxially to the rotational axis of the monitoring module, in particular within a tolerance distance. This axis of inertia can be the z-axis of the acceleration sensor—even in the case of a two-axis acceleration sensor configured to measure accelerations in the x- and y-directions.In other words, this axis of inertia does not have to coincide with a sensitive axis of the sensor unit (this also applies if the sensor unit comprises two single-axis acceleration sensors), which is the case with a three-axis acceleration sensor.

[0033] If a two- or three-axis acceleration sensor is used, it can comprise two or three measuring chips (for two or three different measuring directions) that are spatially spaced from each other. To obtain acceleration values ​​close to zero with perfect concentricity, the sensor unit can be arranged in the monitoring module such that the orientation of an x-measuring chip (which measures acceleration in the x-direction) of the two- or three-axis acceleration sensor coincides with the yz-plane of the monitoring module, and a y-measuring chip (which measures acceleration in the y-direction) of the two- or three-axis acceleration sensor coincides with the xz-plane of the monitoring module.In these variants, the inertia axis of the sensor unit, which is oriented at least approximately coaxially to the rotation axis of the monitoring module, particularly within the tolerance distance, is not a sensitive axis of one of the measuring chips themselves, but the z-axis of inertia of the body of the sensor unit.

[0034] In this case, made possible by the spatially separated arrangement of the x- and y-measuring chips, a round recess, for example, can extend through the body of the sensor unit along the z-axis of inertia of the body of the sensor unit and between the individual measuring chips.

[0035] The tolerance distance can in particular be a radial (normal) distance from the rotational axis of the monitoring module to the inertia axis of the sensor unit, which can be in a range of up to ± 10 µm.

[0036] The fact that the inertia axis of the sensor unit is oriented at least approximately coaxially to the rotation axis of the monitoring module means that a maximum angular error (angular offset) of up to ± 3 ° can exist between the inertia axis and the rotation axis.

[0037] The sensor unit can generally be arranged in the monitoring module in such a way that, in the event of a given radial runout error, the sensor unit's position or orientation changes to a position known, in particular through prior calibration, at a known speed. This suggests a faulty planar contact of the monitoring module with the tool holder (spindle) of the machine tool.

[0038] In particular, the sensor unit can be mounted in the monitoring module in such a way that the acceleration sensor is positioned as ideally as possible along the rotation axis. This makes it possible to record the quantities representative of the acceleration in the xy-plane perpendicular to the rotation axis (which runs in the z-direction), since a tilt and / or lateral offset of the rotation axis of the monitoring module, caused, for example, by a jammed chip or a defective spindle, is detected as a change in the acceleration in the (radial) xy-plane. This change can preferably refer to reference acceleration values ​​determined during a calibration process and thus to a "learned" reference system.

[0039] The positioning of the sensor unit can therefore be selected such that the acceleration sensor provides the greatest possible deflection with the smallest possible tilt / eccentricity, so that the acceleration sensor reliably detects the runout error that increases with increasing tilt (of the monitoring module relative to the spindle or to a rotational axis of the spindle of the machine tool).

[0040] An acceleration sensor positioned precisely on the rotational axis of the monitoring module measures zero centrifugal acceleration even at comparatively high speeds (radial distance of the acceleration sensor from the rotational axis of the monitoring module r = 0). However, an offset from the center, for example due to a clamping error (r ≠ 0), causes the acceleration sensor to experience centrifugal acceleration during rotation. To monitor tool runout, this centrifugal acceleration in the xy plane (rotational plane) can be recorded as the representative acceleration variables.The selected position of the acceleration sensor in the monitoring module, which aligns it as centrally as possible to the tool holder of the machine tool when the monitoring module is inserted into the machine tool, can in particular ensure that a maximum change in the centrifugal forces acting on the acceleration sensor is achieved in the event of even the smallest concentricity errors.

[0041] For centrifugal acceleration a applies: a = ω 2< * r, where ω = 2 * π * n and consequently a = 4 * π 2< * n 2< * r, with n = rotational speed of the monitoring module (and consequently of the sensor unit) in 1 / sec, ω = angular velocity and r = radial distance of the acceleration sensor from the rotation axis of the monitoring module.

[0042] The speed is squared in this calculation of centrifugal acceleration. Therefore, it can be important for the measurement (the determination of centrifugal acceleration) that the speed at which the measurement takes place is known precisely. This (test) speed can, for example, have a substantially constant value throughout the entire measurement or, alternatively, lie within a tolerance range of up to ±10% of a specified speed value.

[0043] The acquisition of the quantities representative of the acceleration by means of the sensor unit can be carried out within a specific evaluation time (also referred to as the acquisition period). The evaluation time can be a time window of several seconds, e.g., 0.1 seconds to 5 seconds. In particular, however, it can alternatively also be a specific number of revolutions (of the monitoring module and thus also of the tool in the machine tool) over which the quantities representative of the acceleration are acquired. The evaluation time can be, for example, 4 or 8 or 16 or 32 or 64 revolutions; however, the present disclosure is not limited thereto. This "evaluation time" also applies to all other quantities to be acquired by the monitoring module, unless otherwise stated at the relevant points.

[0044] Since the direction of the center offset (eccentricity) is unknown prior to detection, acceleration values ​​in the x- and y-direction (in the rotation plane) can be detected, particularly using the two-axis acceleration sensor or the three-axis acceleration sensor, and calculated to form a (total) acceleration vector. Thus, the total acceleration value can be determined from the acceleration-representative variables detected by the sensor unit. a_ges = √( a _x ^ 2 + a _ y ^2 ). If this total acceleration value exceeds the threshold value specified for the speed during acquisition, an error (NOK) can be reported to the machine tool. Alternatively or additionally, the center offset can be calculated and transmitted to the machine tool as a value.

[0045] The calculation of the total acceleration, as well as other calculations described in this disclosure that are based on variables detected by the sensor unit, can each be performed based on acceleration values ​​output by the acceleration sensor. Alternatively, such calculations can be performed using (digital) converter values ​​(raw data) generated by a converter associated with the acceleration sensor.

[0046] The data processing unit (processing unit) of the monitoring module can be connected to the sensor unit via a digital or analog communication interface. A digital SPI or I 2< C interface between the sensor unit and the data processing unit is possible, for example. It is also conceivable to provide analog acceleration values ​​at the sensor unit's output and then record these analog acceleration values ​​in the data processing unit using an analog-to-digital converter (ADC).

[0047] A fourth aspect relates to a machine tool or machining center. The machine tool / machining center comprises a spindle that rotates about a rotational axis during operation of the machine tool / machining center, which spindle is configured to receive and operatively interact with a tool holder interface of a runout monitoring module according to the first aspect, a tool holder of a runout monitoring tool holder module according to the second aspect, and / or a tool holder of a runout monitoring tool module according to the third aspect. A communication unit of the machine tool / machining center is configured to receive signals from the communication unit of the runout monitoring module according to the first aspect.the communication unit of the concentricity monitoring tool holder module according to the second aspect and / or the communication unit of the concentricity monitoring tool module according to the third aspect. A controller of the machine tool / machining center is connected to the communication unit of the machine tool / machining center and configured to receive acceleration-representative variables detected by the sensor unit of the concentricity monitoring module according to the first aspect, the sensor unit of the concentricity monitoring tool holder module according to the second aspect, and / or the sensor unit of the concentricity monitoring tool module according to the third aspect, and to determine a total acceleration based on the detected acceleration-representative variables.to compare the total acceleration with a threshold value dependent on a rotational speed of the spindle during the detection of the variables representative of the acceleration and to determine that a runout error of the runout monitoring module according to the first aspect, the runout monitoring tool holder module according to the second aspect and / or the runout monitoring tool module according to the third aspect exists if the total acceleration is greater than the threshold value.

[0048] The spindle of the machine tool / machining center can in particular be designed to interact operatively with tool holders such as steep tapers or hollow shank tapers.

[0049] The acceleration-representative variables received from the monitoring module can be transmitted as process data to the machine tool controller via the communication unit, which can also function as a data transmission unit and can be part of a machine tool-side interface. Alternatively, the acceleration-representative variables can be transmitted to the machine tool controller via a separate data transmission unit, which can be configured, in particular, for wireless data and signal transmission from / to the monitoring module and, in particular, for wired data and signal transmission from / to the machine tool. Radio-based transmission technologies or transmission via infrared signals are preferred for wireless transmission.

[0050] The controller can further be configured to cause the spindle to rotate at a specific speed when recording the variables representative of the acceleration and / or to transmit this speed to the monitoring module. If there is no runout error, a center axis of the monitoring module can run essentially coaxially with the axis of rotation of the spindle to be rotated. The machine tool / machining center can additionally be configured to cause the monitoring module to be (automatically) inserted into the spindle of the machine tool. The machine tool / machining center can additionally be configured, e.g., via the communication unit, to signal to the monitoring module that the recording of the variables representative of the acceleration should start. This start command for recording can, e.g.,are only transmitted to the monitoring module after the machine tool has signaled to the monitoring module that it is ready to collect data (here the quantities representative of the acceleration).

[0051] If the control system of the machine tool / machining center determines that no concentricity error is present in the monitoring module, the machine tool / machining center can also be configured to enable machining of a workpiece to be machined by the machine tool, particularly immediately after determining that no concentricity error is present. Machining can then begin immediately without the need for further tool changes.

[0052] If the control system of the machine tool / machining center determines that a runout error exists, the machine tool / machining center can also be configured to inhibit any pending workpiece machining, stop the spindle, and place the entire machine tool into a safe state, and / or issue a visual and / or audible error signal, e.g., via a display and / or loudspeaker on the machine tool / machining center. Before one or more of these measures are taken, the machine tool / machining center can be configured to remove and re-insert the monitoring module and / or the tool into the spindle. In the meantime, the spindle (taper interface) can be blown down with a stream of compressed air for cleaning.The corresponding measures are then only taken if the runout error persists after the monitoring module has been replaced.

[0053] A fifth aspect relates to a concentricity monitoring signal interface. The concentricity monitoring signal interface comprises a communication unit configured to receive signals from a communication unit of a concentricity monitoring module according to the first aspect, a communication unit of a concentricity monitoring tool holder module according to the second aspect, and / or a communication unit of a concentricity monitoring tool module according to the third aspect, and to send signals to a communication unit of a machine tool / machining center according to the fourth aspect. The concentricity monitoring signal interface further comprises a computing unit connected to the communication unit of the concentricity monitoring signal interface and configured to receive signals from the sensor unit of the concentricity monitoring module according to the first aspect,to receive values ​​representative of the acceleration detected by the sensor unit of the concentricity monitoring tool holder module according to the second aspect and / or the sensor unit of the concentricity monitoring tool module according to the third aspect, to determine a total acceleration based on the detected values ​​representative of the acceleration, to compare the total acceleration with a threshold value dependent on a rotational speed of the spindle, a rotational speed of the concentricity monitoring module, a rotational speed of the concentricity monitoring tool holder module, or a rotational speed of the concentricity monitoring tool module during the detection of the values ​​representative of the acceleration, and to determine that a concentricity error of the concentricity monitoring module according to the first aspect, the concentricity monitoring tool holder module according to the second aspect, and / or the concentricity monitoring tool module according to the third aspect exists,If the total acceleration is greater than the threshold value, the communication unit of the runout monitoring signal interface is configured to signal to the machine tool / machining center whether or not a runout error is present in the tool being rotated during operation, the runout monitoring module, the runout monitoring tool holder module, and / or the runout monitoring tool module.

[0054] The runout monitoring signal interface, with its components, a computing unit (data processing unit) and a communication unit, can communicate with the monitoring module via the communication unit or via a separate data transmission unit. This data transmission unit can be used, in particular, for wireless data and signal transmission between the monitoring module and the runout monitoring signal interface, as well as, in particular, for wired data and signal transmission between the runout monitoring signal interface and the machine tool. Radio-based transmission technologies or transmission via infrared signals are preferred for wireless transmission.

[0055] Using the runout monitoring signal interface, the same calculations can be performed as with the monitoring module, provided the monitoring module transmits the corresponding measured variables (here, the variables representative of acceleration) to the runout monitoring signal interface. After these calculations have been performed, in addition to signaling whether a runout error is present (OK or NOK signal), calculated results such as the total acceleration and / or the measured variables underlying the calculation can be transmitted to the machine tool controller. If larger amounts of data are to be transmitted, this can be done in the form of data words between the runout monitoring signal interface and the machine tool, whereby a digital bus system can be used for transmission. Fieldbus systems such as Profibus, Profinet, Ethercat, or Ethernet are preferably used for this purpose.

[0056] The runout monitoring signal interface can also be configured to activate the monitoring module, i.e., to place it into a monitoring mode (measurement mode) before the monitoring module determines the variables representative of the acceleration. Furthermore, the runout monitoring signal interface can also be configured to determine the rotational speed when recording the measured variables and transmit it to the monitoring module and / or to the machine tool / machining center. Alternatively or additionally, the rotational speed can be specified by the machine tool's control system during recording, or it can be determined by the monitoring module and transmitted to the runout monitoring signal interface.

[0057] The concentricity monitoring signal interface can be configured to wait for a signal from the monitoring module, particularly upon activation of the monitoring module, indicating that the monitoring module is ready for data acquisition. After data acquisition is complete, the concentricity monitoring signal interface can be configured to deactivate the monitoring module again, i.e., to place it into a state in which concentricity monitoring is not possible. This allows energy to be saved between individual concentricity measurements. Both the activation and deactivation of the monitoring module can be performed alternatively by the monitoring module itself or by the machine tool / machining center.The concentricity monitoring signal interface can be configured to transmit the result of whether a concentricity error exists to the control system of the machine tool by means of a test signal (OK or NIO), so that the control system of the machine tool can, if necessary, take the measures described above (blocking processing, displaying errors, etc.).

[0058] A sixth aspect relates to a runout monitoring method for a tool to be rotated during operation in a machine tool or in a machining center. The runout monitoring method comprises the following steps: (i) automatically inserting a monitoring module to be rotated during operation, or the monitoring module to be rotated during operation and the tool to be rotated, into a spindle of the machine tool / machining center, wherein the monitoring module to be rotated comprises a sensor unit associated with the monitoring module to be rotated such that a rotational axis of the monitoring module to be rotated passes through the sensor unit; (ii) rotating the spindle of the machine tool / machining center at a predetermined speed;(iii) receiving and / or detecting acceleration-representative variables in a plane oriented substantially normal to the rotational axis of the monitoring module to be rotated, while the monitoring module to be rotated rotates at the predetermined rotational speed; (iv) determining a total acceleration based on the detected acceleration-representative variables; (v) comparing the total acceleration with a threshold value dependent on a rotational speed of the monitoring module to be rotated during the detection of the acceleration-representative variables; and (vi) determining that a runout error of the monitoring module to be rotated and / or the tool to be rotated exists if the total acceleration is greater than the threshold value.

[0059] The "rotating monitoring module" refers in particular to the runout monitoring tool module according to the third aspect, which already has an integrated tool. In contrast, the "monitoring module to be rotated during operation and the tool to be rotated" refers in particular to the runout monitoring module according to the first aspect and the runout monitoring tool holder module according to the second aspect, into which a tool to be rotated during operation is inserted before workpiece machining.

[0060] The runout monitoring process or individual steps thereof can be executed or at least initiated by various components such as the monitoring module (which is always responsible for detecting the acceleration-representative variables using the sensor unit), the machine tool / machining center, and / or the runout monitoring signal interface. Thus, in one variant, all steps of the runout monitoring process are performed by the machine tool. Step (iii) then includes, in particular, receiving the acceleration-representative variables from the monitoring module and / or the runout monitoring signal interface.

[0061] In certain variants, only steps (i) and (ii) of the runout monitoring method can be carried out by the machine tool. Steps (iii) to (vi) can then be carried out by the monitoring module or by the runout monitoring signal interface, whereby in the latter case, step (iii) then comprises, in particular, receiving the variables representative of the acceleration by the runout monitoring signal interface. Further steps can then follow, such as signaling whether a runout error is present to the runout monitoring signal interface (if steps (iii) to (vi) are carried out by the monitoring module) or to the machine tool (if steps (iii) to (vi) are carried out by the runout monitoring signal interface).

[0062] If steps (iii) to (vi) are performed by the monitoring module, the recorded acceleration-representative variables can be temporarily stored in the module's data processing unit or in another module memory prior to further processing. The total acceleration can then be determined, preferably taking into account initial acceleration-representative variables determined in a calibration run. This total acceleration is then compared with the threshold value to determine whether a predefined tolerance threshold is exceeded or at least reached.

[0063] If steps (iii) to (vi) are performed by the machine tool or the runout monitoring signal interface, the acceleration-representative variables can be continuously transmitted to the machine tool / the runout monitoring signal interface, particularly during the measurement process (the acquisition of the acceleration-representative variables). In this case, the variables representative of the initial acceleration can also be transmitted to the machine tool / the runout monitoring signal interface, if available. Evaluation, filtering, offsetting with the initial values, calculating the total acceleration, and comparing the total acceleration with the threshold value can then be performed by the computing unit of the runout monitoring signal interface / the machine tool controller.

[0064] Since the threshold value indicates the permissible range of eccentricity of the tool to be rotated during operation, this value can in all the cases described above be known to the computing unit of the monitoring module, the machine tool controller and / or the computing unit of the runout monitoring signal interface or made known (by one of the other components). The threshold value can be present as an analog value or as a digital value, e.g. in micrometers (µm). The threshold value can be adjustable. This can be done, for example, using suitable means directly on the monitoring module. For example, the threshold value can be entered on the monitoring module using a magnetic pen and SET / MODE. Alternatively, the threshold value can be entered into the control system of the machine tool / machining center and then, if necessary, transmitted to the monitoring module via the runout monitoring signal interface.This procedure is particularly intended when steps (iii) to (vi) of the runout monitoring procedure are carried out by the monitoring module.

[0065] However, if the evaluation of the variables representative of the acceleration takes place in the machine tool / in the runout monitoring signal interface, the threshold value can preferably be entered directly on the machine tool and - if evaluated in the runout monitoring signal interface - transmitted to it and stored in a memory.

[0066] The runout monitoring method may include a further optional step of activating the monitoring module, so that the monitoring module is placed in a monitoring mode (measurement mode) before the monitoring module determines the values ​​representative of the acceleration. This further step thus precedes at least step (iii). The activation step may be followed by a step in which the rotational speed is reached when the values ​​representative of the acceleration (i.e., the test rotational speed) are detected.

[0067] The runout monitoring method may include a further optional step in which, if necessary, the monitoring module is activated and a signal from the monitoring module is waited for, indicating that the monitoring module is ready for data acquisition. Furthermore, in a further optional step of the runout monitoring method, the monitoring module can be deactivated again, i.e., placed in a state in which no runout monitoring takes place. This optional step is performed at the earliest when the acquisition of the variables according to step (iii) has been completed.

[0068] In a further optional process step of the concentricity monitoring process, the rotational speed can be determined during the acquisition of the measured variables, for example, by the monitoring module and transmitted to the concentricity monitoring signal interface and / or to the machine tool / machining center. This step can be omitted, in particular, if process steps (iii) to (vi) are performed by the monitoring module. Alternatively or additionally, the rotational speed can be specified by the machine tool's control system during acquisition.

[0069] The runout monitoring method can be carried out for a single predetermined speed when recording the variables representative of the acceleration. Alternatively or additionally, it is possible for method steps (iii) to (vi) to be repeated for different speeds. In particular, between one and five repetitions are possible at different speeds, but the present disclosure is not limited to the specific number of repetitions. If this is the case, the different speeds are each set in step (ii). The optional signaling to the machine tool / the runout monitoring signal interface as to whether a runout error is present can then be carried out, for example, once for all (test) speeds together or for each test speed individually, whereby the corresponding test speed can be transmitted additionally in each case.

[0070] In particular, if the method steps (iii) to (vi) are carried out repeatedly, it is conceivable that the test speed is determined by the monitoring module or at least on the basis of measured variables recorded by the monitoring module (such as other variables representative of an acceleration).

[0071] What all of the aspects described above have in common is that the variables representative of the acceleration (i.e., the radial accelerations in an xy plane of the monitoring module and the sensor unit assigned to the monitoring module) can be filtered, e.g., using a low-pass or band-pass filter, before the total acceleration is determined. Furthermore, all of the aforementioned computing units and controllers can be assigned suitable memories in which received signals and signals to be transmitted, which are described in the context of this disclosure and which are related in some way to the concentricity monitoring, can be (temporarily) stored.

[0072] A seventh aspect relates to a computer program product comprising instructions that cause the machine tool / machining center of the fourth aspect to carry out method steps (i) to (vi) according to the sixth aspect and / or that the runout monitoring module of the first aspect, the runout monitoring tool holder module of the second aspect, or the runout monitoring tool module of the third aspect to carry out method steps (iii) to (vi) according to the sixth aspect and / or that the runout monitoring signal interface of the fifth aspect to carry out method steps (iii) to (vi) according to the sixth aspect.

[0073] The computer program product may comprise further instructions which cause optional steps described with regard to the runout monitoring method to be executed by the corresponding components (monitoring module, machine tool and / or runout monitoring signal interface).

[0074] In principle, it is important for the accuracy of determining the runout error that the monitoring module / machine tool / runout monitoring interface knows exactly the test speed when recording the (initial) variables representative of the acceleration in order to be able to make an exact statement as to whether the runout of the tool to be rotated during operation is still below the specified threshold value.

[0075] The machine tool controller can communicate the exact test speed to the computer unit of the runout monitoring signal interface / monitoring module. This test speed is then assumed to be given, and further verification in the form of speed calibration is not necessary.

[0076] In certain variants, the monitoring module can further comprise a further sensor unit that is radially spaced from the rotational axis and configured to detect, essentially simultaneously with the detection of the acceleration-representative variables, further variables representative of an acceleration in a plane oriented essentially perpendicular to the rotational axis. The computing unit is further configured to receive the further variables representative of the acceleration detected by the further sensor unit and to determine the rotational speed of the concentricity monitoring module / the concentricity monitoring tool holder module / the concentricity monitoring tool module from the further variables representative of the acceleration while detecting the acceleration-representative variables.Alternatively, in some variants, the communication unit can be configured to transmit the further variables representative of the acceleration to the machine tool / machining center according to the fourth aspect and / or to the runout monitoring signal interface according to the fifth aspect.

[0077] The additional (second) sensor unit can be configured similarly or identically to the (first) sensor unit with regard to its sensitivity and possible detection directions. Thus, the additional sensor unit can also be a dual-axis acceleration sensor configured and arranged in the monitoring module in such a way that it can detect additional variables representative of the acceleration in an xy plane and normal to the rotational axis of the monitoring module. Alternatively, it is particularly possible for the additional (second) sensor unit to comprise a single-axis acceleration sensor whose sensitive axis is arranged in the radial direction, i.e., such that this single-axis acceleration sensor can detect the additional variables representative of the acceleration in the xy plane and normal to the rotational axis of the monitoring module.If the uniaxial acceleration sensor is used in the additional sensor unit, the "additional variables representative of acceleration" generally comprise only a single "variable representative of acceleration." For this reason, the terms "variable representative of acceleration" and "variable representative of acceleration" are used synonymously in this disclosure, unless otherwise stated elsewhere or a contrary technical meaning is obvious.

[0078] In one variant, the additional sensor unit can also comprise two opposing acceleration sensors, spaced radially from the axis of rotation and arranged in a plane oriented perpendicular to the axis of rotation. In this case, the acceleration sensors each have measuring axes that are aligned or in a plane containing the axis of rotation and orthogonal to the plane. Preferably, the acceleration sensors provide measured values ​​from which respective mean values ​​of the additional variables representative of the acceleration are calculated. While the speed determined with only one sensor as described above can be influenced by a possibly existing concentricity error, this influence can be minimized or even eliminated by the arrangement of the two opposing sensors. In the case of a concentricity error, for example,The radial distance to the rotational axis of the first acceleration sensor decreases, while the radial distance of the second acceleration sensor decreases accordingly. The mean value of the accelerations measured with both opposing acceleration sensors is therefore independent of any possible runout error. The rotational speed can also be calculated in the computing unit.

[0079] If the other variables representative of the acceleration are transmitted to the machine tool / the runout monitoring signal interface, the speed can be determined based on these variables by the control unit of the machine tool / by the computing unit of the runout monitoring signal interface.

[0080] The additional sensor unit can, for example, be arranged adjacent to and / or adjacent to an inner peripheral surface of the monitoring module. This peripheral surface can be a substantially cylindrical peripheral surface. The additional sensor unit can thus be placed, in particular, outside the central position (off-center), such that it is radially spaced from the sensor unit and such that the rotational axis of the monitoring module does not pass through the additional sensor unit.

[0081] An off-center acceleration sensor arranged in this way (as the additional sensor unit) provides the additional acceleration-representative variables (as acceleration values ​​or as transducer values). The rotational speed is then calculated from these variables, which represent the centrifugal acceleration of the additional sensor unit.

[0082] In some variants, the computing unit of the monitoring module can be configured to determine the rotational speed of the monitoring module during the detection of the quantities representative of the acceleration based on a signal frequency prevailing during the detection of the quantities representative of the acceleration, if the axis of rotation of the monitoring module is oriented substantially horizontally during the detection of the quantities representative of the acceleration.

[0083] This can be particularly advantageous in applications where the monitoring module must be oriented exclusively horizontally, or at least exclusively for concentricity testing purposes, as this eliminates the need for an additional sensor unit in the monitoring module to determine the speed. This can lead to significant cost savings. When the monitoring module is oriented horizontally when recording the variables representative of the acceleration, a sinusoidal signal caused by the acceleration due to gravity is superimposed on these variables. This sinusoidal signal can be evaluated separately in the monitoring module's computing unit and provides an amplitude that corresponds at least approximately to the acceleration due to gravity (1 g). The frequency of the sinusoidal signal corresponds to the speed at the time of recording, i.e. the test speed. This type of speed determination can be particularly efficient because it does not require calibration.

[0084] In some variants, the monitoring module may further comprise a photosensitive unit having a photosensitive surface located on the outer circumference of the monitoring module, wherein the photosensitive unit is configured to detect brightness differences during the detection of the quantities representative of the acceleration, wherein the computing unit is configured to determine the rotational speed of the monitoring module during the detection of the quantities representative of the acceleration based on a frequency of the brightness differences.

[0085] This can therefore be an optical test speed detection system, whereby the photosensitive unit can have a photodetector, e.g. a photodiode, which can be integrated into the monitoring module in such a way that the photosensitive surface is directed radially outwards. During speed detection, a light signal can be detected which is generated by the prevailing lighting conditions during rotation of the monitoring module. The sequence of light-dark differences creates a light pattern which is converted into a voltage by the photosensitive unit. This light pattern and therefore also the voltage pattern is repeated with each revolution. This makes it possible to determine the fundamental frequency of the light pattern by applying appropriate signal analysis. This fundamental frequency of the light pattern corresponds to the test speed.

[0086] In certain modifications, it is conceivable that an IR photodiode is used in the photosensitive unit. If this is the case, it is not the ambient light that is detected, but rather light beams with frequencies in the infrared range, which are emitted, for example, by IR LEDs assigned to the machine tool and, in particular, are arranged on or in the machine tool in such a way that, if the monitoring module is located in the machine tool spindle, they can illuminate its photosensitive surface. This allows for reliable determination of the test speed, particularly in poor (dark) lighting conditions. This type of optical test speed detection can also be particularly efficient because it does not require calibration.

[0087] In some variants of the monitoring module, at least the sensor unit and preferably additionally the further sensor unit can be arranged on a sensor board, wherein the sensor board is connected to a board holder, and wherein a position of the board holder can be adjusted normal to the rotation axis via adjustment means of the monitoring module.

[0088] In one variant, the sensor board is fixed to the board holder. Furthermore, in one variant, the board holder is suspended (mounted) in a floating manner, and in another variant, it is positioned precisely in the (rotational) center of the monitoring module via the adjustment means. For this purpose, threaded pins radially attached to the board holder of the monitoring module are used for lateral fine adjustment of the board holder and thus of the sensor unit. In one variant, this fine adjustment is performed in particular by the manufacturer, but the present disclosure is not limited to this.

[0089] Additional threaded pins, which differ from the threaded pins for fine adjustment of the circuit board holder and can be used, in particular, for user-side fine balancing of the monitoring module, can have different weights and / or be designed to accommodate additional mass. These threaded pins can be used to fine balance the monitoring module via threaded holes on the circumference of the monitoring module, particularly after a tool change.

[0090] In certain variants, the monitoring module may further comprise a power supply unit configured to be switched from an energy-saving or standby mode into a monitoring mode, preferably in response to a wake-up signal, and / or to switch the sensor unit, the further sensor unit, the computing unit, and / or the communication unit from an energy-saving or standby mode into a monitoring mode, preferably in response to a wake-up signal.

[0091] For example, the activation of the roundness monitoring module described above can be an activation by means of the wake-up signal.

[0092] In energy-saving mode, the computing unit (data processing unit), the sensor unit, and the communication unit (also known as the data transmission unit) of the monitoring module's electronic unit can be on standby and consume comparatively little energy. In monitoring mode (also known as measurement mode), the electronic unit can be in standard operation, in which all measurements described in this disclosure can be performed. The electronic unit can consume a lot of energy in measurement mode compared to energy-saving mode.

[0093] In some variants, the energy supply unit can comprise an energy storage device for storing electrical energy. In some variants, the energy supply unit can further comprise a generator unit for generating electrical energy. The energy supply unit can therefore be responsible for the generation and / or storage and preferably also for the conditioning of the supply voltage for all components of the electronics unit. The energy supply unit can supply the components of the electronics unit with energy that is stored in at least one battery or in at least one accumulator. In this case, the generator unit can be omitted and the battery / accumulator can have a comparatively high capacity and / or energy density. Alternatively or additionally, the monitoring module can generate its own power via the generator unit, for which purpose, for example,the energy of the rotating spindle of the machine tool or a pressurised medium can be used. These different forms of energy can be converted into electrical energy by using the generator unit. In these cases (particularly compared to energy supply from an accumulator) comparatively small energy storage devices with lower capacity and / or energy density such as one or more small batteries and / or one or more small capacitors can be used for energy storage. The generator unit can have, for example, a first part which comprises three induction coils arranged offset by 120° to one another. A second part of the generator unit, which is rotatable relative to the first part of the generator unit, can have, for example, one or more permanent magnets. Alternatively, the first part can have the permanent magnets and the second part can have the coils.When the first part rotates relative to the second part, alternating voltages are generated which are shifted by 120° with respect to their phase position. However, the present disclosure is not limited to this specific embodiment of the generator unit. Variants with six induction coils are also conceivable, of which, for example, two induction coils are connected in series, or variants with nine induction coils, of which, for example, three induction coils are connected in series. In these cases, more permanent magnets are also present in the second part of the generator unit, so the number of permanent magnets increases in particular with an increasing number of induction coils. The energy supply unit can also comprise a rectifier which converts the alternating voltages generated in the generator unit into a direct voltage and smooths this voltage.

[0094] In certain variants of the monitoring module, the wake-up signal can be a signal or be triggered by a signal that is generated by the further sensor unit as soon as the further variables representative of the acceleration exceed a wake-up threshold, or is received via the communication unit from the machine tool / machining center according to the fourth aspect and / or from the concentricity monitoring signal interface according to the fifth aspect, or is generated when an amount of energy generated by the energy supply unit exceeds a predetermined level.

[0095] In one variant, the additional sensor unit can be configured to generate a wake-up signal when a preset wake-up threshold is reached or exceeded. This wake-up signal allows the power supply unit, the processing unit, and the communication unit of the monitoring module to switch from energy-saving mode to monitoring mode. To ensure the most reliable activation of the monitoring module and its components and to prevent incorrect activation, the following sequence (activation sequence) is conceivable.

[0096] First, the monitoring module (see, for example, step (i) according to the sixth aspect) is inserted into the spindle of the machine tool. The monitoring module is then rotated in the spindle (see step (ii) according to the sixth aspect), whereby the additional sensor unit experiences centrifugal acceleration and generates the wake-up signal. The wake-up signal from the additional sensor unit activates the electronics unit of the monitoring module. The electronics unit can check, as described above, whether a speed is actually applied to the monitoring module. If the monitoring module is actually rotating, the electronics unit remains in monitoring mode. In one variant, the monitoring module (within the spindle or on its own, i.e. removed from the spindle) is not rotated. The electronics unit can then check whether a speed is nevertheless applied to the monitoring module.If the monitoring module is actually not rotating, the electronics unit switches back to energy-saving mode. This ensures that the monitoring module remains in monitoring mode for as long as necessary, but as short as possible. This ultimately saves energy for powering the components of the electronics unit or the entire monitoring module.

[0097] When the wake-up signal is received from the machine tool / the runout monitoring signal interface, the machine tool controller / the computing unit of the runout monitoring signal interface sends the activation signal (the wake-up signal) to the monitoring module via its corresponding communication unit, which then switches to monitoring mode. If the wake-up signal is generated when the amount of energy generated by the power supply unit exceeds a predetermined level, the monitoring module is initially inserted into the machine tool spindle according to step (i) in accordance with the sixth aspect. As soon as the monitoring module is rotated according to step (ii) in accordance with the sixth aspect, the generator unit begins to generate energy. When a certain level is reached, the electronics unit is automatically supplied with energy and switched to monitoring mode.In addition to all activation variants, i.e., placing the monitoring module in monitoring mode, shock events such as a fall to the floor or a collision with an object in the machine room can be logged. The results of this logging can be stored in the module and / or transmitted to the machine tool and / or to the runout monitoring signal interface. The activation sequence described above can be performed or not, regardless of the variant used to activate the monitoring module.In some variants, the generator unit comprises a stator that is directly or indirectly coupled to the tool holder of the monitoring module, or can be directly or indirectly coupled to the tool holder according to the first aspect, and wherein the generator unit further comprises a rotor that is assigned to the monitoring module such that it interacts with the stator such that the generator unit generates electrical energy when the monitoring module rotates about the axis of rotation. The rotational acceleration can be a positive or a negative rotational acceleration, which occurs when the spindle speed is increased or when the spindle speed is decreased, respectively. Alternatively, the stator can be directly or indirectly coupled to the monitoring module. The stator can be the first part of the generator unit described above.In this case, the rotor can be the second part of the generator unit described above. Alternatively, the stator can be the second part of the generator unit described above. In this case, the rotor can be the first part of the generator unit described above. The rotor can be a flywheel with permanent magnets. The stator can then be provided with one or more induction coils. The induction coils can be coils with a manganese-zinc-ferrite core, for example, which are interconnected via a circuit board. In addition, the coils can be arranged in corresponding recesses in a coil cage and / or glued to it. In this way, high stability can still be guaranteed at high machining speeds.If the spindle of the machine tool is accelerated around the axis of rotation (or later braked again), a speed difference arises between the stator and rotor (i.e. the flywheel) due to the inertia of the flywheel. This induces a voltage in the induction coils, which is then fed directly to the consumer (i.e. the components of the electronic module itself, particularly if this is currently in monitoring mode) or stored in the energy storage device of the monitoring module. In this way, when the speed of the spindle changes, a voltage is generated until the flywheel has reached the (new) spindle speed, i.e. when there is no longer any negative or positive acceleration. The mechanical energy (rotational energy) theoretically available when the speed of the spindle changes is calculated as follows: . E_rot = 1 / 2 * I * ( ω_ 2 - ω_ 1 )^2 This results in the moment of inertia Iof a hollow cylinder rotating around the axis of symmetry to: I = m (( r_ 1^2 + r _2^2) / 2). Since the mass and the radii of the flywheel are known, for a given angular frequency ( ω = 2 πf ) the rotational energy can be calculated, whereby in this consideration both friction and eddy current losses as well as losses on the electrical side (in the induction coils, in the rectifier, in electrical resistors, etc.) are not taken into account.

[0098] The time required for a runout monitoring cycle, i.e. the activation of the electronic unit, the recording of the variables representative of the acceleration, the other variables representative of the acceleration and, if applicable, the speed(s), the determination of the total acceleration, the determination of whether a runout error is present and the signalling of whether a runout error is present, can in particular be between one and two seconds. In order to cover the energy requirement for this period, the amount of energy that can be generated by the generator unit when accelerating the spindle and thus the tool to be rotated to a typical machining speed for a workpiece is sufficient. Should the amount of energy still be insufficient in certain cases, e.g. because the machining speed is very low, additional energy can be generated by repeatedly changing the speed. In this way, the spindle can, for example, be switched off for a relatively short period of time (e.g.2 to 3 seconds) to 1000 revolutions / min and then decelerated to a machining speed of 500 revolutions / min, wherein energy can be generated during acceleration as well as during deceleration. In some variants, the monitoring module can further comprise a fluid channel which extends in a fluid-tight manner between two outer sides of the monitoring module which are spaced apart in the axial direction of the axis of rotation. In some variants, the generator unit can have a turbine unit with a turbine wheel which is arranged within the fluid channel, and a generator integrated in the turbine unit which is designed to generate electrical energy when fluid flows through the turbine wheel. In this way, the aforementioned energy conversion of a pressurised medium, e.g. a coolant and / or lubricant used in the machine tool, can be achieved.The medium available in the spindle can be fed into the interior of the monitoring module to the turbine via the fluid channel and / or a coolant pipe.

[0099] The flow of the medium through the turbine wheel causes it to rotate, so that a voltage is induced by the integrated generator, which in turn is fed to the monitoring module itself or its components as a consumer or stored in the energy storage device of the monitoring module. The turbine wheel can in particular be the second part of the generator unit (generator) described above. The permanent magnets can in particular be attached to a lower surface of the turbine wheel or incorporated into it there. The stator with the induction coils can then be permanently arranged on a circuit board below the turbine wheel in the monitoring module. In order to monitor the functioning of this form of energy generation, the monitoring module can, for example,An error will be output to the machine tool / runout monitoring signal interface if the monitoring module detects that no energy is being harvested even if the machine tool spindle is accelerated positively or negatively.

[0100] Since the sensor unit can be located exactly in the (rotational) center (in the rotational axis) of the monitoring module, it may be necessary to route the medium, which is usually channeled centrally through a coolant channel, past the sensor board. For this purpose, a distributor can be provided in the monitoring module, which directs the flow of the medium past the sensor board and the sensor unit and can simultaneously supply the rotating tool with the medium.

[0101] By generating its own power (own energy generation), it is possible to provide a continuous power supply for the monitoring module. This can be particularly desirable if, during a machining process of a workpiece, data is to be continuously recorded by the sensor unit or the additional sensor unit and transmitted to an external evaluation unit, such as the runout monitoring signal interface or the machine tool. In some variants of the monitoring module, the sensor unit is configured to record initial quantities representative of an acceleration in the plane oriented essentially normal to the axis of rotation at an essentially constant speed or at several different essentially constant speeds, at a time separate from normal operation, in which the monitoring module rotates, in particular together with the spindle, wherein the computing unit is configured toto store the initial acceleration-representative variables together with the corresponding rotational speed(s) in a memory of the monitoring module, and / or wherein the communication unit is configured to transmit the initial acceleration-representative variables, preferably together with the corresponding rotational speed(s), to the machine tool / machining center according to the fourth aspect and / or to the concentricity monitoring signal interface according to the fifth aspect. The acquisition of the initial acceleration-representative variables can be carried out separately from normal operation (in which the machine tool can machine a workpiece), in particular in a calibration operation (calibration run). This calibration run can take place in particular under conditions in which the machine tool, the spindle, the tool changer, the working area of ​​the machine tool,The concentricity monitoring signal interface and the monitoring module (in particular, the most accurate centric alignment of the sensor unit) are in a state where they operate flawlessly. In particular, during calibration, the tool holder is designed to be as flat as possible in the spindle, with no chips or other contamination in the area of ​​the spindle and the tool holder. This can be monitored by the manufacturer and / or the user if necessary.

[0102] The calibration run, which can be performed by the manufacturer, can be particularly important because it can be extremely complex from an assembly point of view (primarily due to manufacturing and assembly tolerances) to position the sensor unit precisely in the center (i.e., in the rotational axis of the monitoring module). Even clamping the monitoring module precisely in the center of the spindle (so that the rotational axes of the monitoring module and spindle are exactly coaxial) cannot always be expected, as certain tolerances also exist. This can lead to an "off-center" of the sensor unit, in which, in particular, an axis of inertia (e.g.,The z-axis (which does not have to be a sensitive axis) of the sensor unit (or alternatively, an inertia axis of the acceleration sensor of the sensor unit) is radially spaced from the rotational axis of the monitoring module, particularly within the tolerance distance described above, and the angular error described above between the rotational axis of the monitoring module and the inertia axis of the sensor unit is maintained. This eccentricity can result in offset values ​​that can distort the actual values ​​representative of the acceleration.

[0103] For this reason, the aforementioned offset values ​​can be determined during the calibration run as initial values ​​representative of the acceleration and taken into account when calculating the overall acceleration. The calibration run thus refers to a "learning process" for determining the initial values ​​representative of the acceleration of the corresponding monitoring module. The calibration run can be performed in a calibration mode in which the initial values ​​representative of the acceleration are determined for one test speed or for several test speeds. The test speed(s) themselves can be specified and / or determined as described above. If the test speed is determined using the additional sensor unit, it is particularly possible for this speed determination to also be calibrated by the manufacturer or via the calibration process at a known speed.

[0104] A function of the initial acceleration variables, dependent on the test speed, can then be calculated. This speed-dependent function can be stored in the monitoring module's memory and / or transferred to the runout monitoring signal interface / machine tool. The calculations required for calibration can then be performed by the machine tool / the runout monitoring signal interface.

[0105] The acquisition of the initial variables representative of the acceleration can - similar to the acquisition of the variables representative of the acceleration - take place over a specific evaluation time, which can be characterized in particular by a specific number of revolutions (e.g. between 4 and 100 revolutions) of the spindle. Over the evaluation time, the speed (or speeds) can be essentially constant or fluctuate within a range of no more than 10% of the speed(s) in order to determine the most accurate initial acceleration variables possible. It can be provided that the acquisition of the initial variables representative of the acceleration only starts when the speed(s) has / have been reached, i.e. outside the run-up phase of the spindle to the corresponding speed(s). This also applies to the determination of the variables representative of the acceleration.If the initial acceleration-representative variables and the acceleration-representative variables at essentially the same rotational speeds are known, the total acceleration, in the sense of a resulting total acceleration, can be determined as a function of these variables. As with the method according to the sixth aspect, the calibration run can be performed at least partially by different components described above, such as the monitoring module, the concentricity monitoring signal interface, the machine tool, and / or through the interaction of these components.

[0106] If the calibration run is performed entirely by the monitoring module itself, the monitoring module can signal the machine tool / the runout monitoring signal interface that it is ready for the calibration run. The initial values ​​representative of the acceleration can then be recorded, filtered, and saved. This can be done particularly well when the speed remains stable throughout the recording period. If the calibration run is performed for multiple speeds, the respective speed can also be determined during the recording. The speed can then be changed if necessary, and the filtering and determination of the values ​​representative of the initial acceleration can be performed again for the changed speed.This results in the speed-dependent function mentioned above or – in the case of a calibration run with a single speed – a pair of test speed and initial acceleration values ​​that can be stored in the monitoring module. Once this process is complete, the monitoring module can signal the machine tool / the runout monitoring signal interface that the calibration run is complete. Alternatively or additionally, the monitoring module can transmit a signal (OK or NOK) to the machine tool / the runout monitoring signal interface that the calibration process was completed successfully or that an error occurred.

[0107] Alternatively, the filtering and storage of the initial acceleration-representative variables can also take place in the machine tool / in the runout monitoring interface. Here, too, the tool module can transmit its readiness for the calibration run to the machine tool / runout monitoring signal interface, if necessary upon request. The initial acceleration-representative variables can then be recorded at a speed that remains stable over the recording period. The recorded values ​​can, for example, be continuously transmitted to the machine tool / runout monitoring signal interface until the recording period is reached. If the calibration run is to be performed for multiple speeds, the speed can then be changed.The initial acceleration values ​​representative of the acceleration can then be recorded and transmitted at the newly set speed until the recording duration is reached again. Once the initial acceleration values ​​for all test speeds have been recorded and transmitted, the calibration run can be terminated, e.g., by a signal from the machine tool / the runout monitoring signal interface. The initial acceleration values ​​can then be filtered in the machine tool / the runout monitoring signal interface and stored together with the speed(s) during the calibration run, particularly as a speed-dependent function of the initial acceleration values.

[0108] In some variants of the monitoring module, the computing unit can further be configured to process the acceleration-representative variables detected by the sensor unit and / or the initial acceleration-representative variables and / or the further acceleration-representative variables detected by the further sensor unit and / or the rotational speed of the monitoring module during the detection of the acceleration-representative variables, each for a specific time window of preferably between 50 ms and 200 ms, in the form of a data packet, wherein the processing is carried out by operations such as signal filtering, averaging and / or determining a frequency spectrum per time window, and to transmit the data packet after processing to the machine tool / machining center according to the fourth aspect and / or to the runout monitoring signal interface according to the fifth aspect.

[0109] This can be a variant of continuous process data transmission, in which all variables recorded by the sensor units and / or other units (e.g., the photosensitive unit) of the monitoring module are continuously transmitted to the machine tool / the runout monitoring signal interface. This is particularly important for the monitoring and control of complex manufacturing processes into which the monitoring module / the machine tool / the runout monitoring signal interface can be integrated. A high bandwidth may be necessary for this continuous transmission, particularly when high temporal resolution is required (e.g., if a vibration measurement is to be performed based on the variables recorded by the sensor units), or when a large number of recorded variables are to be transmitted by the monitoring module simultaneously.Wireless data transmission between the monitoring module and the machine tool / concentricity monitoring signal interface can represent a bottleneck and thus limit data transmission. In these cases, it is possible for a partial evaluation of the variables recorded by the sensor units to take place in the monitoring module, allowing secure and complete radio-based data transmission. With this variant, it is particularly conceivable for the monitoring module to continuously monitor the concentricity of the tool rotating during operation, preferably throughout the entire machining cycle of a workpiece (or at least the part of the machining cycle that is executed using the corresponding monitoring module).For this purpose, the machine tool / the runout monitoring signal interface can, if necessary upon request, wait for a signal from the monitoring module indicating its readiness to acquire data. The monitoring module can then continuously acquire, in particular, the variables representative of acceleration and the other variables representative of acceleration as process parameters and transmit the data package containing these and, if applicable, other process parameters such as coolant flow and / or pressure or detected vibrations to the machine tool / the runout monitoring signal interface within or at the end of the time window. The acquired process parameters and / or the data package can be temporarily stored in the memory of the monitoring module.

[0110] As part of the preparation of the process parameters as a data packet, which is not mandatory but is particularly useful for complex process parameters such as vibrations, the RMS value of the recorded variables can be determined over the time window, for example. Furthermore, the data packet can include the peak value occurring within the time window and the frequency spectrum of the recorded variables determined via an FFT for each time window. Thus, a data packet containing a summary of the process variables determined in the respective time window can be transmitted to the machine tool / the runout monitoring signal interface per time unit.

[0111] In these cases, the evaluation of the data packets with speed determination, filtering of the process parameters or the recorded acceleration variables, determining acceleration values, determining the total acceleration, and / or comparing them with the threshold value can be performed in the machine tool / in the runout monitoring signal interface. If the evaluation takes place in the runout monitoring signal interface, the runout monitoring signal interface of the machine tool can then signal whether or not a runout error in the monitoring module is present.

[0112] In some variants of the monitoring module, the communication unit is further configured to transmit the acceleration-representative variables detected by the sensor unit and / or the initial acceleration-representative variables and / or the further acceleration-representative variables detected by the further sensor unit and / or the rotational speed of the monitoring module during the detection of the acceleration-representative variables and / or the data packet to the machine tool / machining center according to the fourth aspect and / or to the concentricity monitoring signal interface according to the fifth aspect when a buffer of the monitoring module is at least approximately full.

[0113] This variant can, for example, be combined with the variant (in this respect, the explanations described for this variant apply accordingly), according to which the recorded process variables are transmitted to the machine tool / the runout monitoring signal interface for each time window. It is conceivable that the recorded process variables are initially buffered in the monitoring module and that the transmission of the process variables begins as soon as the memory of the monitoring module is full or 90%, 80% or 70% full. This transmission can then be maintained until the intended recording duration is reached, or until the memory of the monitoring module is almost empty again (e.g. only 30%, 20% or 10% full) or completely empty.

[0114] In some variants of the monitoring module, the computing unit may be configured to determine the total acceleration based on a subtraction of the quantities representative of the initial acceleration from the corresponding quantities representative of the acceleration.

[0115] This determination of the total acceleration can, of course, also be carried out by the machine tool / the runout monitoring signal interface if not all steps according to the sixth aspect are carried out by the monitoring module.

[0116] The total acceleration value can therefore be a resulting value of the acceleration representative variables (ax, ay) determined by the sensor unit, taking into account the initial acceleration representative variables (also called initial values ​​ax_initial, ay_initial). If these variables are known at essentially corresponding speeds, the total acceleration (in the sense of a resulting total acceleration) can be calculated as a_ges = a_resultierend = √(( a_x - a_ ( x, initial ) )^2 + ( a_y - a_ ( y, initial ) ) ^2 ). Whenever reference is made to the resulting total acceleration in this disclosure, this means that the initial values ​​ax_initial, ay_initial are taken into account, while the expression ages is used for a total acceleration both taking the initial values ​​into account and without taking the initial values ​​into account.

[0117] The threshold value with which this total acceleration is compared to determine whether or not a runout error of the monitoring module is present can, in particular, be a threshold value that relates to the deviation of the variables representative of the acceleration from the initial values. This threshold value can thus characterize the still permissible range of eccentricity (i.e., the deviation from ideal concentricity, but at which no runout error within the meaning of this disclosure yet exists) of the tool to be rotated. Accordingly, in particular, a runout error of the monitoring module can be present (the machine tool / the runout monitoring interface is signaled as NOK) if the total acceleration exceeds the threshold value. The (speed-dependent) threshold value can be specified, for example, as a digital value or as an analog value and, for example, as a µm value.

[0118] In some variants of the monitoring module, the computing unit can be configured to determine the magnitude of the runout error and / or the direction of the runout error when a runout error is present. The communication unit can then be configured to transmit the magnitude and / or the direction of the runout error to the machine tool / machining center according to the fourth aspect or to the runout monitoring signal interface according to the fifth aspect. Additionally or alternatively, the communication unit can be configured to signal the presence of the runout error to the machine tool / machining center according to the fourth aspect and / or to the runout monitoring signal interface according to the fifth aspect when a runout error is present, while the monitoring module is rotating, in particular together with the spindle.

[0119] In this way, it is particularly possible to quickly and efficiently signal to the machine tool / the concentricity monitoring signal interface - preferably before a workpiece is machined by the machine tool - that a concentricity error of the monitoring module is present, so that the machine tool can quickly take appropriate countermeasures. The amount of the concentricity error and the direction of the concentricity error can be transmitted, for example, as digital values ​​(e.g.: 30 µm at 110°). The amount r of the concentricity error is calculated taking into account are resultant and the speed n during detection to r = a_resultierend / (4 * π ^2 * n 2< ). When determining the direction of the runout, the angle αThe maximum radial runout is determined by the monitoring module's computing unit. The calculation distinguishes between the quadrants in which the direction vector lies. The determination of the direction angle α The calculation of the largest runout deviation using a tangent function taking into account ay, ay_initial, ax and ax_initial can essentially be carried out according to the following table. ax - ax_initial ay - ay_initial Quadrant Berechnung > 0 > 0 QI α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) = 0 > 0 - α = 90° < 0 > 0 QII α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) + 180° < 0 < 0 QIII α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) + 180° = 0 < 0 - α = 270° > 0 < 0 QIV α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) + 360°

[0120] In some variants, the monitoring module is configured to detect the additional variables representative of the acceleration, determine the total acceleration, determine whether a radial runout error exists, and signal whether a radial runout error exists within a period of time in which the monitoring module, in particular together with the spindle, is moved by a machine tool / machining center from a spindle start position to a machining position of a workpiece, and wherein this period of time is in particular less than 5 seconds and preferably less than 3 seconds. The period of time can be, for example, between one second and two seconds.In contrast to many other tactile runout monitoring methods (or those with a laser measuring system), it is possible to perform the entire runout check, including the transmission of the results, essentially parallel to machining time, i.e., while the rotating tool is approaching the machining point. In some variants, the monitoring module can further comprise at least one antenna unit with at least one antenna and at least one antenna cover. The antenna is arranged within the monitoring module, and the antenna cover covers the antenna outwardly from the perspective of the rotation axis. The antenna cover extends in the axial direction of the rotation axis over a greater length than the antenna.

[0121] The antenna can be used, in particular, for wireless data transmission and communication with the machine tool / the runout monitoring signal interface. One additional antenna or two (or possibly three or more) additional antennas can be provided in the antenna unit. Alternatively, two, three, or more antenna units, each with an antenna and an antenna cover, can be provided. In some variants, the antenna cover can be omitted. This allows for a better circular radiation pattern and improves data transmission quality, particularly with a rapidly rotating monitoring module.

[0122] What all of the aspects described above have in common is that vibrations that occur, particularly while a workpiece is being machined by the machine tool with the monitoring module, can be recorded. For this purpose, the variables representative of acceleration recorded by the sensor unit and / or the additional variables representative of acceleration recorded by the additional sensor unit can be analyzed. In particular, the oscillation width (peak-to-peak value), the effective value (RMS value), and RMS values ​​of harmonic vibration components of the recorded variables can be analyzed. Preferably, the frequency spectrum of the recorded variables can also be analyzed, e.g., using FFT.

[0123] If the sensor unit / additional sensor unit comprises a three-axis acceleration sensor, the acceleration values ​​in all three axes (X, Y, and Z) can be considered; the same applies to a two-axis acceleration sensor, where the acceleration values ​​in both axes (X and Y) can be considered. Alternatively, it is also conceivable to analyze the vibrations based on accelerations occurring along a single one of the three or two axes. In these cases, the axis direction along which the greatest acceleration occurs can be considered in particular.

[0124] The vibration analysis can take place in the monitoring module. The monitoring module then sends an error signal to the machine tool / the runout monitoring signal interface if the vibrations reach or exceed a defined tolerance threshold. Alternatively, only the raw data underlying the vibration analysis, i.e., the quantities representative of acceleration and / or other quantities representative of acceleration, are transmitted to the machine tool / the runout monitoring signal interface, where they are evaluated and compared with the defined tolerance threshold. If the tolerance threshold is exceeded, the machine tool can change machining parameters and / or stop machining and place the machine tool into a safe state.By measuring and analyzing vibrations and other process parameters during workpiece machining, it is possible, in particular, to monitor the entire machining process, the condition of the tool (wear, tool breakage) and the spindle bearing condition in addition to concentricity monitoring in order to be able to react quickly if problems arise.

[0125] In some variants, the computing unit of the monitoring module is configured to monitor at least one additional process parameter when the monitoring module rotates, in particular, together with the tool to be rotated and / or with the tool holder and / or with the spindle, wherein the at least one process parameter includes vibration, temperature, coolant pressure, coolant flow, cutting force, and / or torque. If one of the parameters exceeds or falls below a certain threshold value, the monitoring module can signal a corresponding error to the concentricity monitoring signal interface / the machine tool.

[0126] Each of the monitoring modules can also incorporate additional sensors. These include, for example, a temperature sensor for monitoring the tool temperature, particularly during machining of a workpiece by the machine tool with the monitoring module installed. Furthermore, strain gauge sensors and / or piezo sensors can be provided on / in the monitoring module to determine variables occurring during workpiece machining, such as forces (e.g., cutting forces) and torques. Furthermore, a flow sensor can be assigned to the monitoring module. This makes it possible, for example, to continuously check whether sufficient fluid is flowing through the turbine wheel to generate energy using the turbine unit.

[0127] The flow sensor can comprise a flow sensor unit arranged within the monitoring module. Alternatively, it is possible to determine the media flow via the rotational speed of the turbine wheel. Additionally and / or alternatively, a pressure sensor can be provided in the monitoring module to measure the pressure of the media in the fluid channel / coolant pipe. A drop in pressure can indicate a lack of media flow and, consequently, a problem with the energy generation by the turbine unit. The runout monitoring signal interface and the machine tool can then be configured to receive the error signaled by the monitoring module (in the case of the machine tool, possibly via the runout monitoring signal interface) and initiate appropriate countermeasures.

[0128] To further save energy, in another variant, the monitoring module can be kept completely in "deep sleep" until it wakes up. In this case, operational readiness can be established via a predefined speed (sequence) for a predefined period of time (each), or via manual activation using an input device. This is in contrast to established radio transmission systems, in which terminal devices wake up from deep sleep at regular intervals and query whether communication is required, or transmit their status at regular intervals. In the variants presented here, the monitoring module can only send an event signal for specific events. The receiving unit confirms receipt of the signal with a confirmation signal, as explained, for example, in EP 2 208 017 A2. The confirmation signal can also contain instructions.These instructions may include a change of operating mode in the radio transmission so that the monitoring unit no longer sends any further event signals but switches to bidirectional data transmission.

[0129] In one variant, operating mode selection can be made via a speed profile. Communication between the monitoring module and a receiver base station can be established in one variant, for example, as explained in EP 2 208 017 A2. In one variant, the monitoring module is notified to the base station through a learning or pairing process. In one variant, the monitoring module executes the learning process by having the spindle of the machine tool execute a predefined speed pattern or a predefined first speed profile. The monitoring module is configured to recognize the profile using its own sensors (e.g., acceleration sensors) or by evaluating the generator voltage and then switches to the "Execute learning or pairing process" operating mode. Using additional predefined speed profiles, additional functions can be executed by the monitoring module, e.g.a "Perform calibration process" function. Here, the monitoring module automatically records the calibration values. After successful calibration, a confirmation signal is sent. In one variant, the speed profile parameters are (i) the speed, (ii) the duration of a predefined speed (sequence), (iii) the gradient of the change from one speed level to the next, and / or (iv) the duration of the change from one speed level to the next of the machine tool spindle. The individual parameters of these profiles can be detected, particularly by evaluating the generator voltage. An example of such a speed profile is: 200 rpm for 1 second, followed by 400 rpm for 0.5 seconds, followed by 200 rpm for 1 second.Another example of such a speed profile is: 200 rpm for 1 second, followed by 0.5 seconds for the transition to 500 rpm (rate of change: Δrpm / Δt = 300 / 0.5 = 600), followed by 500 rpm for 0.5 seconds, followed by 0.5 seconds for the transition to 300 rpm (rate of change: Δrpm / Δt = 200 / 0.5 = 400), followed by 300 rpm for 1 second. It should be understood that the sequence can have several different speed steps, each of which can be longer or shorter. This also applies to the duration of the speed changes.

[0130] In addition to the functions "perform a learning or pairing process", "perform a calibration process", the functions "generate a wake-up signal", "enter monitoring or measuring mode", "enter deep sleep or standby mode" and other functions must also be transmitted from the machine tool control system to the runout monitoring system using such predefined speeds or speed sequences of the machine tool spindle.

[0131] In one variant, the runout monitoring module, the runout monitoring tool holder module or the runout monitoring tool module are configured to only begin recording the variables representative of the acceleration, recording the further variables representative of the acceleration, determining the total acceleration, determining whether a runout error is present or signaling whether a runout error is present when a defined speed is reached, wherein during the evaluation time the spindle speed is essentially constant or varies within a range of at most 10% of the speed.

[0132] The machine tool (or its control system), the runout monitoring signal interface, and the monitoring module (i.e., both the runout monitoring module according to the first aspect and the runout monitoring tool holder module according to the second aspect and the runout monitoring tool module according to the third aspect) can be comprised by a runout monitoring system. Such a runout monitoring system can comprise all of the features described above with regard to the individual components. The runout monitoring signal interface can serve, in particular, as a communication interface (machine interface) between the monitoring module and the machine tool.It can be provided that at least some of the evaluations of variables recorded by the monitoring module take place in the machine interface (circularity monitoring signal interface), or that only data to be transmitted from the monitoring module to the machine tool is forwarded from the machine interface in order to carry out the corresponding evaluations in the machine tool itself. The communication and data transmission between the monitoring module and the machine interface can take place wirelessly, preferably using radio-based transmission or IR transmission. The communication and data transmission between the machine interface and the machine tool can take place via wires, and for evaluations in the machine interface, for example, using I / O status signals. Alternatively, data words can be used (for a larger amount of data to be transmitted, e.g.In continuous process data monitoring, data is transmitted between the machine interface and the machine tool via a digital bus system (e.g., fieldbus systems such as Profibus, Profinet, Ethercat, or Ethemet). The applicant reserves the right to assert an independent claim for such a concentricity monitoring system.

[0133] The aspects described above provide modular solutions for improving the concentricity monitoring of a rotating tool during operation. This eliminates additional installation costs if a measuring system, particularly one with a radio-based communication interface, is already installed on the machine tool. This allows for easy retrofitting, which (in addition to the general design of the monitoring module) leads to significant cost savings compared to conventional spindle-integrated systems. The complex design of sensors integrated into a spindle and the deep integration into the machine tool make these spindle-integrated systems expensive, and retrofitting involves significant intervention in the machine tool structure.

[0134] The modularity also leads to increased flexibility, as the monitoring modules are not machine-specific but can be used in a wide variety of machine tools. This allows task-specific tools with runout monitoring to be assembled with minimal effort as needed. Even when converting an entire production line, the monitoring modules can be flexibly combined with other cutting tools.

[0135] Compared to a tactile runout check or a runout measurement with a laser measuring system, the runout monitoring according to the aspects described above can be carried out more quickly and, in particular, at least almost parallel to the machining time during the approach of the tool to the machining point, since the runout monitoring modules provide the necessary measurement results in a very short time.

[0136] It will be apparent to those skilled in the art that the aspects and features described above (except those relating to the structural components, which were described solely with reference to the monitoring module) may be arbitrarily combined in a monitoring module, in a runout monitoring signal interface, in a machine tool, in a runout monitoring system and / or in a runout monitoring method for a tool to be rotated in operation in a machine tool / machining center.

[0137] Short description of the Fig.

[0138] Further objectives, features, advantages, possible applications, and possible modifications will become apparent from the following description of non-limiting embodiments and variants with reference to the accompanying drawings. All described and / or illustrated features, individually or in any combination, illustrate the subject matter disclosed herein. The dimensions and proportions of the components shown schematically in the figures are not to scale. Identical or equivalent components are provided with the same reference numerals. Wherever reference is made to value ranges in this disclosure, the upper and lower range limits are included in the ranges. It is noted that all calculations in this disclosure, as well as the representations of values ​​in the figures, are based on digital output values ​​(as raw data) from, for example, acceleration sensors.Alternatively, all calculations can be based on analog output values ​​from the corresponding acceleration sensors. If, within the scope of the following description, (sub)process steps are described with reference to a specific figure and the same (sub)process steps exist in another figure, the description with reference to the specific figure is equally valid there, unless otherwise stated. When terms such as "essentially" or "approximately" are used in connection with the structural unit of a device (monitoring module, etc.), the terms "essentially" or "approximately" refer to technical features that are produced within the technical tolerance limits of the respective manufacturing processes. Fig. 1 shows a runout monitoring module according to certain embodiments. Fig. 2 shows a runout monitoring tool holder module according to certain embodiments. Fig. 3 shows a runout monitoring tool module according to certain embodiments. Fig. 4 shows a machine tool / machining center in interaction with a monitoring module according to certain embodiments. Fig. 5 shows a runout monitoring signal interface in cooperation with a machine tool / machining center and with a monitoring module according to certain embodiments. Fig. 6 shows a flowchart of a runout monitoring method according to certain embodiments. Fig. 7 shows an arrangement of a sensor board, a board holder, adjustment means for the board holder, an antenna with antenna cover and a photosensitive unit within the monitoring module according to certain embodiments. Fig. 8 shows quantities representative of acceleration detected by the sensor unit of the monitoring module at different speeds according to certain embodiments. Fig. 9A shows schematically how an amount and an angle of a runout error of a monitoring module are determined according to certain embodiments. Fig. 9B shows a total acceleration versus speed for different positions of a sensor unit according to certain embodiments. Fig. 10 shows acceleration representative quantities, initial acceleration representative quantities, a total acceleration and a threshold value above the speed according to certain embodiments. Fig. 11 shows a sine signal superimposed on a value detected by the sensor unit when the monitoring module is aligned horizontally and at different speeds. Fig. 12 shows a sine signal superimposed on a value detected by the sensor unit when the monitoring module is aligned horizontally and at different speeds. Fig. 13A shows the arrangement and design of a fluid channel and other optional components of a monitoring module according to certain embodiments. Fig. 13B schematically shows a sensor board and a sensor unit with fluid channel according to certain embodiments. Fig. 14 shows a turbine unit for self-generating energy in a monitoring module according to certain embodiments. Fig. 15 shows a flywheel for self-generating energy in a monitoring module according to certain embodiments. Fig. 16 shows the sequence of a calibration process with evaluation in the monitoring module according to certain embodiments. Fig. 17 shows the sequence of a calibration process with evaluation in the concentricity monitoring signal interface / in the machine tool according to certain embodiments. Fig. 18 shows a test sequence for the concentricity monitoring of a tool to be rotated during operation with evaluation in the monitoring module at a single test speed according to certain embodiments. Fig. 19 shows a test sequence for the concentricity monitoring of a tool to be rotated during operation with evaluation in the monitoring module at several test speeds according to certain embodiments. Fig. 20 shows a sequence for the concentricity monitoring of a tool to be rotated during operation with evaluation in the concentricity monitoring signal interface / of the machine tool at several test speeds according to certain embodiments. Fig. 21 shows a sequence of continuous process data transmission to the runout monitoring signal interface / the machine tool according to certain embodiments. Fig. 22 shows a sequence on the machine tool during communication with the monitoring module / the runout monitoring signal interface via IO signals according to certain embodiments. Detailed description of the characters

[0139] The Fig. 1 shows a concentricity monitoring module 10 (hereinafter also referred to as monitoring module 10) with which the concentricity of a tool WZG that is to be rotated during operation is monitored. The concentricity monitoring module 10 comprises a substantially rotationally symmetrical hollow body in which all the supply, measuring, computing, and communication units necessary for concentricity monitoring are housed.

[0140] The tool WZG is a tool that rotates during operation (for machining a workpiece), which is designed here as a milling cutter. In addition, Fig. 1 a tool holder WZGA and a spindle S of a machine tool are shown, which interact with the runout monitoring module 10 for the runout monitoring. The tool holder WZGA is shown here outside the spindle S, but it can also already be integrated into the spindle S if the runout monitoring module 10 is inserted into the spindle S of the machine tool to monitor the runout of the tool WZG. When the monitoring module 10 rotates together with the spindle S and the tool WZG to machine a workpiece, the runout of the monitoring module 10 and thus indirectly the runout of the tool WZG (or the runout of the combination of monitoring module 10, tool holder WZGA and tool WZG) is monitored. If a runout error is present, this indicates e.g.faulty planar or conical contact caused by chips adhering to the spindle S, in particular of the tool holder WZGA and thus of the concentricity monitoring module 10 in the spindle S.

[0141] As shown in a sectional view through the concentricity monitoring module 10 according to Fig. 1 As can be seen, the runout monitoring module 10 has a substantially cylindrical body, which can be rotationally symmetrical with respect to its rotational axis 20. The runout monitoring module 10 comprises a tool interface 12, which is designed to receive the tool WZG. In the present example, the tool interface 12 comprises a receptacle that mates with a corresponding counterpart of the tool WZG (in the Fig. 1 indicated as a double arrow between the interface 12 and the tool WZG).

[0142] Similarly, the concentricity monitoring module 10 has a tool holder interface 14 which fits with a corresponding holder of the tool holder WZGA (in the Fig. 1 indicated as a double arrow between the interface 14 and the tool holder WZGA). The concentricity monitoring module 10 can therefore be coupled to the tool holder WZGA and the tool WZG via the interfaces 12, 14 - either by the manufacturer or by an operator. If the concentricity monitoring module 10, the tool holder WZGA and the tool WZG are then inserted together in the assembled state into the spindle S of the machine tool (in the Fig. 1 (indicated as a double arrow between the spindle S and the tool holder WZGA), the tool holder WZGA, the runout monitoring module 10, and the tool WZG rotate together around the rotational axis 20 of the runout monitoring module 10 to machine a workpiece. The speed is determined by the rotating spindle S.

[0143] Within the monitoring module 10, an electronic unit is arranged, which comprises a first sensor unit 16, a second optional sensor unit B, a computing unit 22, a communication unit 24 and a power supply unit V. As in Fig. 1 As indicated by the arrows from the energy supply unit V to the corresponding components, the energy supply unit V supplies the first sensor unit 16, the second sensor unit B, the computing unit 22 and the communication unit 24 with the necessary electrical energy to carry out the measuring, computing and communication operations described in this disclosure, which are necessary for the concentricity monitoring of the tool WZG.

[0144] Communication within the concentricity monitoring module 10 between the computing unit 22 and the first sensor unit 16, the second sensor unit B and the communication unit 24 takes place via Fig. 1 Communication lines shown as dashed arrows, which are implemented here as an SPI bus as an example.

[0145] To monitor the concentricity of the concentricity monitoring module 10 and thus of the tool WZG, centrifugal accelerations in a rotational plane E are observed by means of the first sensor unit 16 during a rotation of the concentricity monitoring module 10 about the rotational axis 20 - either before, after and / or during the machining of a workpiece. For this purpose, the first sensor unit 16 comprises a two-axis acceleration sensor which is arranged in the concentricity monitoring module 10 in such a way that it detects accelerations in an xy-plane (rotational plane E) which is oriented essentially normal to the rotational axis 20. This rotational plane E is in the Fig. 1 as running through the concentricity monitoring module 10.

[0146] In order to realize such a type of acceleration detection, the first sensor unit 16 is arranged in the rotation center of the runout monitoring module 10 such that the rotation axis of the runout monitoring module 10 passes through the sensor unit 16. As shown in Fig. 1 As shown, the axis of rotation 20 and an axis of inertia 18 of the acceleration sensor of the first sensor unit 16 ideally run essentially coaxially. Due to this arrangement of the axis of inertia of the sensor unit 16 in the z-direction, the other axes of inertia of the sensor unit 16 in the x- and y-direction run essentially orthogonal to the axis of rotation 20, so that the accelerations in the plane E can be measured. In the present example, the sensor unit 16 has only two sensitive axes of inertia, namely in the x- and y-directions. The third axis of inertia, namely the one in the z-direction, is not sensitive in the present example (no accelerations are recorded along this axis) and therefore serves in particular for the exact alignment of the sensor unit 16 with the axis of rotation 20. In other examples, however, the sensor unit 16 can be designed so that an acceleration measurement can also be carried out in the z-direction.

[0147] The following applies to the centrifugal acceleration a: a = ω 2< * r, where ω = 2 * π * n and consequently a = 4 * π 2< * n 2< * r, with n = rotational speed of the runout monitoring module 10 (and consequently of the sensor unit 16) in 1 / sec, ω = angular velocity and r = radial distance of the sensor unit 16 from the rotational axis 20 of the monitoring module 10. Accordingly, the centrifugal acceleration acting on the sensor unit 16 increases with increasing rotational speed of the spindle S, whereby the rotational speed is taken into account quadratically.

[0148] However, if the inertial axis of the sensor unit 16 coincides exactly with the rotation axis 20 of the monitoring module 10 and, in addition, the rotation axis 20 is coaxial with a rotation axis D (see also Fig. 4 ) of the spindle S, the centrifugal acceleration is zero even at relatively high spindle S speeds, since the radial distance is zero (r = 0). This is therefore the case with optimal alignment of the sensor unit 16, when there is no concentricity error.

[0149] However, if, for example, there is a clamping error of the tool holder WZGA in the spindle S, because a chip gets caught when the tool holder WZGA is inserted into the spindle S, this results in an offset of the monitoring module 10 and thus of the sensor unit 16 with respect to the axis of rotation D of the spindle S. The radial distance is then no longer zero (r ≠ 0), so that a centrifugal acceleration acts on the sensor unit 16 during rotation. The sensor unit 16 then records variables ax, ay representative of the acceleration in the x-direction and the acceleration in the y-direction during rotation and transmits these to the computing unit 22, in particular in the form of digital sensor values ​​which characterize the acceleration in the respective direction or can be converted into the acceleration in the respective direction in the computing unit 22.Based on the quantities ax, ay representative of the acceleration in the x and y directions, the computing unit 22 then calculates a total acceleration value . a_ges = √ (a_x^ 2 + a_y^ 2 ) and compared with a threshold value. If the total acceleration is greater than the threshold value, a runout error of the monitoring module 10 exists.

[0150] The optional additional sensor unit B is embodied, for example, as a single-axis acceleration sensor whose sensitive axis is arranged orthogonally to the rotation axis (20) in the radial direction and which is configured to detect at least one additional variable representative of an acceleration (hereinafter also referred to as an additional acceleration variable). However, the present disclosure is not limited thereto. Thus, the optional sensor unit B can alternatively be embodied in the same way as the first sensor unit B, i.e., as a two-axis acceleration sensor configured to detect additional variables representative of an acceleration (hereinafter also referred to as additional acceleration variables) in two directions orthogonal to one another.Since the further sensor unit B can be designed as a single-axis or a dual-axis acceleration sensor that measures either one or two further variables representative of the acceleration, the terms "further variable representative of the acceleration" and "further variables representative of the acceleration" are also used synonymously in this disclosure, unless otherwise stated at the relevant point or a contrary technical meaning is obvious.

[0151] The further sensor unit B is spaced radially from the rotational axis (20) and arranged in the concentricity monitoring module 10 in such a way that it also detects this further acceleration variable(s) in the plane E oriented perpendicular to the rotational axis 20 of the monitoring module, i.e. as centrifugal accelerations. From these further acceleration variables, in particular the speed can be determined during the detection of the variables ax, ay representative of the acceleration, for example, based on the formula a = 4 * π 2< * n2< * r by reconfiguring to n and, given a known angular velocity, the rotational speed n is calculated. The off-center position of the additional sensor unit B causes a significant signal change (of the value(s) representative of the acceleration) with changing rotational speed. A radial runout error of the monitoring module 10, 26, 28 causes only a very small radius change in relation to the radius position (radial distance from the rotational axis 20) of the additional sensor unit B, whereby the influence of the radial runout error on the accuracy of the rotational speed determination is negligible.

[0152] The Fig. 2 shows a concentricity monitoring tool holder module 26 (hereinafter also referred to as monitoring module 26), with which the concentricity of a tool WZG to be rotated during operation is monitored. The concentricity monitoring tool holder module 26 comprises a substantially rotationally symmetrical hollow body, preferably designed as a hollow cylinder, in which all supply, measuring, computing, and communication units necessary for concentricity monitoring are accommodated.

[0153] The tool WZG is a tool that rotates during operation (for machining a workpiece), which is designed here as a milling cutter. In addition, Fig. 2 a spindle S of a machine tool (see also Fig. 4 ), which interacts with the concentricity monitoring tool holder module 26 for concentricity monitoring. When the concentricity monitoring tool holder module 26 rotates together with the spindle S and the tool WZG to machine a workpiece, the concentricity of the tool WZG is monitored. If a concentricity error of the tool WZG is present, this indicates a faulty flat contact of the concentricity monitoring tool holder module 26 in the spindle S, caused, for example, by chips adhering to the spindle S.

[0154] The concentricity monitoring tool holder module 26 further comprises a tool holder WZGA, via which the concentricity monitoring tool holder module 26 is inserted into the spindle S of the machine tool. The tool holder WZGA is designed here, for example, as a hollow shank taper (HSK) and is firmly coupled to the concentricity monitoring tool holder module 26.

[0155] Otherwise, the concentricity monitoring tool holder module 26 comprises the same components: first sensor unit 16 (with non-sensitive inertia axis 18 in the z-direction), optional second sensor unit B, computing unit 22 and communication unit 24. These components have the same functionality in the concentricity monitoring tool holder module 26 as in the concentricity monitoring module 10 and are arranged identically and operatively connected to each other (for communication and power supply), so that in this regard, reference is made to the explanations for Fig. 1 including the explanations regarding the consideration of centrifugal accelerations in plane E.

[0156] The Fig. 3 shows a concentricity monitoring tool module 28 (hereinafter also referred to as monitoring module 28), with which the concentricity of a tool WZG to be rotated during operation is monitored. The concentricity monitoring tool module 28 comprises a substantially rotationally symmetrical hollow body, preferably designed as a hollow cylinder, in which all supply, measuring, computing, and communication units necessary for concentricity monitoring are accommodated.

[0157] The tool WZG is a tool that rotates during operation (for machining a workpiece), which is designed here as a milling cutter. In addition, Fig. 3 a spindle S of a machine tool (see also Fig. 4 ), which interacts with the concentricity monitoring tool module 28 for concentricity monitoring. When the concentricity monitoring tool module 28 rotates together with the spindle S to machine a workpiece, the concentricity of the tool WZG is monitored. If a concentricity error of the tool WZG is present, this indicates a faulty flat contact of the concentricity monitoring tool module 28 in the spindle S, caused, for example, by chips adhering to the spindle S.

[0158] The concentricity monitoring tool module 28 includes, similar to the Fig. 2 The concentricity monitoring tool module 26 shown additionally has a tool holder WZGA, via which the concentricity monitoring tool module 28 is inserted into the spindle S of the machine tool. The tool holder WZGA is designed here, for example, as a hollow shank taper (HSK) and is firmly coupled to the concentricity monitoring tool module 28.

[0159] In contrast to the Fig. 1 and 2 The concentricity monitoring tool module 28 comprises the tool WZG as shown in the monitoring modules 10 and 26. The tool WZG and the concentricity monitoring tool module 28 are firmly coupled to one another and are inserted into the spindle S as a complete unit together with the tool holder WZGA. Otherwise, the concentricity monitoring tool module 28 comprises the same components: first sensor unit 16 (with non-sensitive inertia axis 18 in the z-direction), optional second sensor unit B, computing unit 22 and communication unit 24. These components have the same functionality in the concentricity monitoring tool module 28 as in the concentricity monitoring module 10 and are arranged identically and operatively connected to one another (for communication and power supply), so that in this regard, reference is made to the explanations for Fig. 1 including the explanations regarding the consideration of centrifugal accelerations in plane E.

[0160] With reference to the Fig. 4 A machine tool WZM is described, which is designed as a multi-axis machining center BA. The machine tool WZM, in conjunction with one of the monitoring modules 10, 26, or 28, monitors the concentricity of a tool WZG that is to be rotated during operation. The example in the Fig. 4 is illustrated using the runout monitoring tool module 28. However, it should be noted that the runout monitoring tool module 28 here only represents one of the monitoring modules 10, 26, 28, and that the machine tool WZM can interact in the same way with the runout monitoring module 10 and the runout monitoring tool holder module 26 during operation.

[0161] The machine tool WZM of Fig. 4 comprises a main spindle S, which can be moved in three orthogonal directions X, Y, Z within a working area of ​​the machine tool WZM and can be rotated about the Z-axis. Such a rotation about a rotation axis D (which is in the plane of the drawing of the Fig. 4 in the z-direction) of the spindle S of the machine tool WZM usually occurs when a workpiece is machined by the machine tool WZM.

[0162] In addition, the machine tool comprises a controller 32, a communication unit 30, and a tool changer (not shown in the figure) configured to accommodate at least the monitoring modules 10, 26, and 28. In this way, a monitoring module 10, 26, 28 (the monitoring modules 10 and 26 are then, in particular, already coupled to a tool WZG) can be inserted into the spindle S at any time before or after machining a workpiece, initiated by the controller 32 of the machine tool WZM, in order to check the concentricity of the tool WZG, in particular during a subsequent machining step.

[0163] For this purpose, the controller 32 of the machine tool WZM is further configured to set a speed of the spindle S. In addition, the controller 32 is configured to control communication with the monitoring module 28 via the communication unit 30. For this purpose, the communication unit 30 of the machine tool WZM communicates via wire with a data transmission unit 34. The data transmission unit 34 is coupled to the communication unit 24 of the monitoring module 28 via a radio connection and is configured and intended to receive signals and data such as the variables ax, ay and other variables described in the context of this disclosure from the communication unit 24 of the monitoring module 28 and to transmit them to the machine tool WZM, more precisely to its communication unit 30.

[0164] In an alternative variant, which is Fig. 4 is not shown, the function of the data transmission unit 34 is included in the communication unit 30 of the machine tool WZM. The data transmission unit 34 is then omitted as a physical unit. In these cases, data and signal transmission between the machine tool WZM and the monitoring module 28 takes place directly and preferably via radio or infrared signals.

[0165] For the purpose of concentricity monitoring, the sensor unit 16 of the monitoring module 28 detects the quantities ax, ay representative of the acceleration, as described with reference to Fig. 1 The quantities ax, ay are then transmitted via the communication unit 24 (according to Fig. 4 The measured values ​​are transmitted (via the data transmission unit 34 and the communication unit 30 of the machine tool WZM) to the computing unit 32 of the machine tool WZM. The computing unit 32 determines the total acceleration ages from the variables ax, ay and then compares it with the threshold value. If the total acceleration ages exceeds the threshold value, the machine tool WZM determines that a runout error of the monitoring module 28 exists.

[0166] The Fig. 5 shows a concentricity monitoring signal interface SGS with a communication unit 36 ​​and a computing unit 38. The concentricity monitoring signal interface SGS is designed to communicate with the machine tool WZM (e.g. the machine tool from Fig. 4 ) and to cooperate operatively with one of the monitoring modules 10, 26, 28 in order to monitor the concentricity of a tool WZG that is to be rotated during operation. The example in the Fig. 5 is illustrated using the runout monitoring tool module 28. However, it should be noted that the runout monitoring tool module 28 is only representative of one of the monitoring modules and that the runout monitoring signal interface SGS can interact in the same way with the runout monitoring module 10 and the runout monitoring tool holder module 26 during operation.

[0167] The computing unit 38 of the roundness monitoring signal interface SGS is configured to control communication with the monitoring module 28 via the communication unit 36. For this purpose, the communication unit 36 ​​of the roundness monitoring signal interface SGS communicates via wired communication with a data transmission unit 34. The data transmission unit 34 is coupled to the communication unit 24 of the monitoring module 28 via a radio connection and is configured and intended to receive signals and data such as the variables ax, ay and other variables described in the context of this disclosure from the communication unit 24 of the monitoring module 28 and to transmit them to the roundness monitoring signal interface SGS, more precisely to its communication unit 36.

[0168] In an alternative variant, which is Fig. 5 is not shown, the function of the data transmission unit 34 is included in the communication unit 36 ​​of the roundness monitoring signal interface SGS. The data transmission unit 34 is then omitted as a physical unit. In these cases, data and signal transmission between the roundness monitoring signal interface and the monitoring module 28 takes place directly and preferably via radio or infrared signals.

[0169] In addition, the computing unit 38 of the concentricity monitoring signal interface SGS is configured to control communication with the machine tool WZM via a wired communication interface of the communication unit 36. This "communication connection", which is exemplified here as a fieldbus system, is in the Fig. 5 by the double arrow with a solid line between the communication unit 36 ​​of the concentricity monitoring signal interface SGS and the communication unit 30 of the machine tool WZM.

[0170] The runout monitoring signal interface SGS is configured to receive the acceleration-representative variables ax, ay, recorded by the monitoring module 28 in plane E, via the communication unit 36. The computing unit 38 of the runout monitoring signal interface SGS is further configured and intended to determine the total acceleration ages from the variables ax, ay received from the monitoring module 28. The total acceleration ages is then compared with the threshold value. If the total acceleration ages is above the threshold value, the runout monitoring signal interface SGS determines that a runout error of the monitoring module 28 exists.

[0171] The computing unit 38 of the concentricity monitoring signal interface SGS is also configured and intended to signal to the machine tool WZM whether or not a concentricity error is present. This occurs via the wired communication connection between the communication unit 36 ​​of the concentricity monitoring signal interface SGS and the communication unit 30 of the machine tool WZM, via which the concentricity monitoring signal interface SGS informs the machine tool WZM by means of a test signal (OK / NIO) whether a concentricity error is present (NIO) or whether there is no concentricity error (OK).

[0172] With reference to the Fig. 6 A concentricity monitoring procedure for a tool rotating in a machine tool (WZM) is now described. All process steps can be carried out by the Fig. 4 The described machine tool WZM can be executed. Alternatively, it is possible for some of the method steps to be executed by the monitoring module 10, 26, 28 and / or some of the method steps to be executed by the runout monitoring signal interface SGS. In particular, determining the total acceleration ages, comparing the total acceleration with the threshold value, and determining whether a runout error is present (these three steps are also referred to as "evaluation" below) can be executed by the monitoring modules 10, 26, 28, the runout monitoring signal interface SGS, and the machine tool WZM.

[0173] As in the Fig. 6 As shown, the runout monitoring method has a first step (i) in which an automatic insertion of a monitoring module 10, 26, 28 to be rotated during operation or of the monitoring module 10, 26 to be rotated during operation and the tool WZG to be rotated into a spindle S of the machine tool WZM takes place. In particular, the tool changer of the machine tool WZG is approached with the spindle S in order to insert one of the monitoring modules 10, 26, 28 contained therein into the spindle S. If this is the monitoring module 10 or the monitoring module 26, these are usually already coupled to the tool WZG and the tool holder WZGA (monitoring module 10) or to the tool WZG (monitoring module 26).

[0174] In a second step (ii), the spindle S of the machine tool WZM is rotated at a specified speed. This speed (also known as the test speed) is set by the machine tool (or a user of the machine tool) and transmitted by the machine tool – if necessary via the runout monitoring signal interface SGS – to the monitoring module 10, 26, 28 or directly to the runout monitoring signal interface SGS if the evaluation takes place in the monitoring module 10, 26, 28 or in the runout monitoring signal interface SGS.

[0175] In a third step (iii), the quantities ax, ay representative of an acceleration are detected or received in a plane E oriented substantially perpendicular to the rotational axis 20 of the monitoring module 10, 26, 28 to be rotated, while the monitoring module 10, 26, 28 to be rotated rotates at the predetermined speed. This detection is carried out in particular with one of the monitoring modules 10, 26, 28, as described with reference to Fig. 1 The corresponding explanations for the Fig. 1 are therefore also valid here. If the machine tool WZM or the concentricity monitoring signal interface SGS executes the concentricity monitoring process, in the third step, the acceleration variables ax, ay are transmitted from the monitoring module 10, 26, 28 as raw data to the machine tool / the concentricity monitoring signal interface SGS and received there.

[0176] Then, in steps (iv) to (vi), the above-mentioned evaluation is carried out, wherein in a fourth step (iv) the total acceleration ages is determined based on the detected variables ax, ay representative of the acceleration, in a fifth step (v) the total acceleration ages is compared with a threshold value dependent on a speed of the monitoring module 10, 26, 28 to be rotated during the detection of the variables ax, ay representative of the acceleration, and in a sixth step (vi) it is determined that a runout error of the monitoring module 10, 26, 28 to be rotated and / or of the tool WZG to be rotated is present if the total acceleration ages is greater than the threshold value.

[0177] In particular, if the evaluation (steps (iv) to (vi)) takes place in the monitoring module 10, 26, 28 or in the concentricity monitoring signal interface SGS, an optional step (vii) can follow, in which the monitoring module 10, 26, 28 or the concentricity monitoring signal interface SGS of the machine tool WZM via the described communication units 24 and / or 36 (see also Fig. 5 ) signals whether or not there is a runout error of the monitoring module 10, 26, 28 and thus of the tool WZG.

[0178] The present disclosure also relates to a computer program product (not shown in the figures) with instructions which cause, in particular, the Fig. 6 described method steps (i) to (vi) and optionally method step (vii) as well as further method steps described below are carried out. According to one example, the computer program product comprises instructions which cause the machine tool (as described with reference to Fig. 4 described) executes method steps (i) to (vi) of the runout monitoring method. According to a further example, the computer program product comprises instructions that cause the monitoring module 10, 26, 28 to execute method steps (iii) to (vi) of the runout monitoring method. According to yet another example, the computer program product comprises instructions that cause the runout monitoring signal interface (SGS) to execute method steps (iii) to (vi) of the runout monitoring method. These different variants can also be combined in a single computer program product.

[0179] The following are based on the Fig. 7 bis 22 Further optional features and configurations of the monitoring module 10, 26, 28 and further (sub-)process aspects of the runout monitoring process when recording and / or evaluating the variables ax, ay representative of the acceleration as well as further process variables relevant for the runout monitoring are described. The features described with reference to further optional steps of the runout monitoring process are also transferable to the monitoring module 10, 26, 28 and vice versa. Whenever within the scope of the description of the Fig. 7 bis 22 When reference is made to the first sensor unit 16 (with inertia axis 18 in the z-direction), the second sensor unit B, the energy supply unit V, the computing unit 22 or the communication unit 24, these descriptions refer to the corresponding components of each monitoring module 10, 26 and 28.

[0180] The Fig. 7 shows a section through a monitoring module 10, 26, 28, a tool holder WZGA and a spindle S of a machine tool WZM (see also Fig. 4 ) in a clamping situation, i.e. shortly before the spindle S loads the monitoring module 10, 26, 28 from the tool changer into the spindle. The sectional view shows the first sensor unit 16 and the further optional sensor unit B, which are arranged on a sensor board 40. The sensor board 40 is connected here, for example, via vertical struts to a board holder 42. The board holder 42 is mounted in a floating manner in the monitoring module 10, 26, 28, which is why no exact type of suspension is specified in the Fig. 7 is shown. In the Fig. 7 In addition, two threaded pins 44 are shown, which serve as adjustment means for the floating board holder 42 and which press directly onto the board holder 42. In addition, the Fig. 7 that the monitoring module 10, 26, 28 comprises two optional antenna covers 46 and two optional antennas 48 (for better clarity, the reference symbols 46, 48 are in the Fig. 7 mentioned only once). Finally, the monitoring module 10, 26, 28 comprises a photosensitive unit PE with a photosensitive surface 50 located on the outer circumference of the monitoring module 10, 26, 28 and directed radially outwards.

[0181] The antennas 48 and the antenna covers 46 together form an antenna unit. The antenna covers 46 are arranged here, for example, directly on the outer circumference of the monitoring module 10, 26, 28 and can, for example, comprise a body manufactured separately from the remaining body of the monitoring module 10, 26, 28 and / or form a subsection of the monitoring module 10, 26, 28 made of a different material. The antennas 48 are arranged within the monitoring module 10, 26, 28 between the antenna covers 46 and the rotation axis 20, wherein the Fig. 7 The horizontal position of the antennas 48 shown is merely an example; they can also be arranged further towards the axis of rotation 20. The antenna cover 46 extends in the axial direction of the axis of rotation 20, here by way of example by four times the length of the antennas 48. In other variants, the antenna cover 46 can extend in the axial direction of the axis of rotation 20 by two to ten times, with all integer intermediate values ​​being included as further possible range limits. The antenna covers 46 thus cover the antennas 48 on the outside in order to protect them from damage, dirt and cooling lubricant. The antenna covers 46 can comprise at least predominantly or completely non-conductive materials in order not to impair the propagation of the radio waves. The antenna covers can comprise, for example, plastics, glass, ceramics and / or potting compounds.

[0182] The threaded pins 44 position the floating circuit board holder 42 and thus the sensor unit 16, or as in this example, its z-axis of inertia 18, directly in the center of rotation of the monitoring module 10, 26, 28. The threaded pins 44 thus serve to balance the sensor unit 16. The sensor unit 16, or its z-axis of inertia, is aligned at least nearly coaxially with the axis of rotation 20 of the monitoring module 10, 26, 28. This centering is preferably performed during the manufacture of the monitoring module 10, 26, 28.

[0183] Further threaded pins 45 are in the Fig. 7 Not shown radial threaded holes on the circumference of the body of the monitoring module 10, 26, 28 can be introduced into the latter and thus enable a fine adjustment of the sensor unit 16, which can also be carried out by the user. The radial threaded holes are designed to accommodate a plurality of threaded pins 45 of different weights (the different weights of the threaded pins 45 are shown in the Fig. 7 indicated by their different sizes) and all of these threaded pins can accommodate additional masses. This allows for each monitoring module 10, 26, 28, e.g. depending on the optional components used and the resulting weight ratios in the monitoring module(s) 10, 26, 28 or even after a tool change WZG (this applies in particular to the monitoring modules 10 and 26 according to the Fig. 1 and 2 ) the fine balancing must be carried out.

[0184] The Fig. 7 also shows that the additional sensor unit B, which is also arranged on the sensor board 40, is radially spaced from the sensor unit 16. The distance between the additional sensor unit B and the sensor unit 16 normal to the axis of rotation 20 is approximately 75% of the radius of the monitoring module 10, 26, 28. However, the present disclosure is not limited thereto. The distance can also be between 3% and 90% (where all integer intermediate values ​​are included as further possible range limits). It is only essential that the additional sensor unit B is not aligned coaxially with the axis of rotation 20, since reliable speed determination is not possible at this position.

[0185] With reference to the Fig. 8 The measurement principle used for concentricity monitoring is discussed in more detail using real measurement data. For illustration, two diagrams show the (absolute) digital output values ​​of sensor unit 16 in the x-direction (ax, upper diagram) and in the y-direction (ay, lower diagram) versus the number of measured values, each at different speeds.

[0186] The monitoring module 10, 26, 28 is used for measurement according to Fig. 8 arranged vertically in a spindle S, so that the rotational axis 20 of the monitoring module 10, 26, 28 follows the vertical and the quantities representative of the acceleration (the output values ​​of the sensor) are recorded by the sensor unit 16 in the plane E oriented perpendicular to the vertical, i.e. in a horizontal rotation plane of the monitoring module 10, 26, 28. The test speeds are approximately 500 rpm, 1000 rpm, 1500 rpm and 2000 rpm and the corresponding sections of the diagrams of the Fig. 8 , which show the output values ​​of sensor unit 16 at these test speeds, are separated by dashed vertical lines. The measuring range of sensor unit 16 is, for example, ± 2 g, the resolution (sensitivity) of sensor unit 16 is, for example, 1024 digital values ​​(corresponding to 10 bits) per g, and the sampling rate is - also for example - 0.5 kHz.

[0187] The diagrams of the Fig. 8 differ in particular in that the upper diagram shows the output values ​​of the sensor unit 16 in the x-direction (ax) and the lower diagram shows the output values ​​of the sensor unit 16 in the y-direction (ay). In addition, three different curves are shown for each axis. The solid curves represent the output values ​​of the sensor unit 16 when the z-axis of inertia 18 of the sensor unit 16 is aligned as coaxially as possible to the axis of rotation 20 of the monitoring module 10, 26, 28. The dashed curves represent the output values ​​of the sensor unit 16 when its z-axis of inertia 18 is arranged at a radial distance of around 10 µm from the axis of rotation 20 due to tilting / eccentricity of the monitoring module 10, 26, 28.Finally, the dot-dash curves represent the output values ​​of the sensor unit 16 when its z-axis of inertia 18 is arranged at a radial distance of approximately 30 µm from the axis of rotation 20 due to tilting / eccentricity of the monitoring module 10, 26, 28.

[0188] As can be seen from the diagram above, Fig. 8 As can be seen, the sensor unit 16 is actually arranged in the x-direction at least approximately coaxially to the rotational axis 20 of the monitoring module 10, 26, 28, which is complex due to tolerances in the manufacture of the sensor unit 16, but also due to assembly and manufacturing tolerances of the monitoring module 10, 26, 28. As a result, even with an increase in the speed, there is no increased acceleration in the x-direction. The acceleration value ax therefore remains constant up to a speed of approximately 2000 rpm; no increased acceleration ax is measurable. In contrast, the dashed curve and the dash-dotted curve in the upper diagram of the Fig. 8 how the acceleration value ax behaves when the sensor unit is spaced apart in the x-direction by 10 µm or 30 µm from the rotational axis 20. At a speed of 500 rpm, slight changes in the acceleration values ​​ax occur at 10 µm and at 30 µm. After that, the acceleration value ax increases more strongly with each increase in speed, particularly with a center offset of the sensor unit 16 in the x-direction of 30 µm (dash-dotted curve), so that at a speed of about 2000 rpm, an ax value of over 2200 is already established, which corresponds to an additional acceleration of over 1 g (here in the example about 1.3 m / s 2< ). As can be seen in the lower diagram of the Fig. 8 As shown, the acceleration curves in the y-direction at a center offset of 10 µm (dashed curve) as well as at a center offset in the y-direction of 30 µm (dash-dotted curve) behave almost identically to the measurement of the corresponding center offset in the x-direction, which is why we refer to the description of the upper diagram of the Fig. 8 The solid curve in the lower diagram in Fig. 8 represents the acceleration values ​​in the y-direction recorded by the sensor unit 16. While these ay values ​​are still almost constant near zero at a relatively low speed of approximately 500 rpm (the sensor value of 2050 corresponds approximately to 0 g), they increase with increasing speed at approximately 2000 rpm to almost 2100, which corresponds to approximately 0.5 m / s 2<. Although this is a comparatively low acceleration value, it indicates that the sensor unit 16 was not aligned exactly coaxially with the rotational axis 20 during the measurement.

[0189] Since correct concentricity is extremely important in high-precision applications in the field of workpiece machining, such an "unbalance" of the sensor unit 16, which results from a slight radial and / or angular offset (still within the corresponding tolerance limits) of the sensor unit 16 to the rotational axis 20, can be compensated for, for example, by performing a calibration run. In this calibration run, initial values ​​ax, ay representative of the acceleration (hereinafter also referred to as initial (acceleration) values) are measured by the sensor unit 16 installed in the monitoring module 10, 26, 28. This recording of the values ​​ax_initial, ay_initial representative of the initial acceleration is basically carried out in the same way as the recording of the values ​​ax, ay representative of the acceleration (see also the description of Fig. 1 ). The initial variables ax_initial, ay_initial are stored after acquisition, here as an example, together with the test speed during acquisition, in a memory of the monitoring module 10, 26, 28. Alternatively, the initial variables ax_initial, ay_initial can be transmitted via the communication unit 24 of the monitoring module 10, 26, 28 to the concentricity monitoring signal interface and / or to the machine tool WZM and stored there in local memories.

[0190] The calibration run, which can be performed for one or more test speeds, is carried out at a time separate from normal operation in which a workpiece is being machined in the machine tool WZM, when the spindle S has run up, i.e., when a substantially constant test speed prevails or deviates by a maximum of 10% from the specified test speed. If multiple calibration runs are performed for different speeds, this results in a speed-dependent function of the initial variables ax_initial, ay_initial, which is stored in the memory of the monitoring module 10, 26, 28 and / or the concentricity monitoring signal interface SGS and / or the machine tool WZM.

[0191] In addition, the calibration run is carried out here as an example under ideal conditions monitored by the manufacturer, whereby the spindle S and the monitoring module 10, 26, 28 are clean and there are no chips in the effective range of these components, so that the monitoring module 10, 26, 28 lies ideally flat against the spindle S.

[0192] The determined initial values ​​ax_initial and ay_initial are then taken into account in the form of offset values ​​when determining the total acceleration ages. The total acceleration value ages is calculated as a resultant total acceleration as follows. a _ ges = a _ resultierend = √ a _ x − a _ x _ initial ∧ 2 + a _ y − a _ y _ initial ∧ 2

[0193] The Fig. 9A shows how the determined total acceleration a resultierend consists of the acceleration components ax, ax_initial, ay and ay_initial and consequently, as can be seen from the determined total acceleration a resultierend , i.e. taking into account the initial acceleration values ​​ax_initial and ay_initial, an amount r and an angle of a runout error can be determined. Fig. 9A a unit circle divided into four quadrants is shown, through whose center the axis of rotation 20 runs in the direction of view from the spindle S to the tool WZG.

[0194] While the amount r (in µm) of the runout error, taking into account the speed n prevailing during the acquisition of the acceleration variables, is r = a_resultierend / (4 * π^ 2 * n 2< ), the magnitude of the angle of the runout error depends on the quadrant in which the direction vector of the total acceleration is located. The calculation of the direction angle α The runout is calculated using a tangent function according to the following table. ax - ax_initial ay - ay_initial Quadrant Berechnung > 0 > 0 QI α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) = 0 > 0 - α = 90° < 0 > 0 QII α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) + 180° < 0 < 0 QIII α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) + 180° = 0 < 0 - α = 270° > 0 < 0 QIV α = arctan (( a_y - a_ ( y_initial )) / ( a_x - a_ ( x_initial ) )) + 360°

[0195] In the Fig. 9B The total acceleration ages is shown as the output value of a calibrated sensor unit 16 over different speeds and at different positions of the z-axis of inertia 18 of the sensor unit 16 relative to the rotational axis of the monitoring module 10, 26, 28. The measuring range of the sensor unit 16 is again, for example, ± 2 g, the resolution (sensitivity) of the sensor unit 16 is again, for example, 1024 digital values ​​(corresponding to 10 bits) per g, and the sampling rate is - again, for example - 0.5 kHz. All calculations that the Fig. 9B are based on the values ​​ax, ay, ax_initial and ay_initial averaged over eight revolutions of the monitoring module 10, 26, 28 / of the spindle S.

[0196] The solid curve (first from the bottom) of the Fig. 9B shows the total acceleration ages when the sensor unit 16 assumes a position "off-center 10 µm". The dashed curve (second from bottom) of the Fig. 9B shows the total acceleration ages when the sensor unit 16 assumes a position "off-center 30 µm". The dotted line (third from the bottom) of the Fig. 9B shows the total acceleration ages when the sensor unit 16 takes a position "center 10 µm". The dash-dotted curve with double points (first from the top) of the Fig. 9B shows the total acceleration ages when the sensor unit 16 assumes a position "center 10 µm." The calculation results of the total acceleration are summarized in the following table. Drehzahl Mitte 10 µm Außermitte 10 µm Mitte 30 µm Außermitte 30 µm 500 / min 3 1 11 3 1000 / min 14 3 50 6 1500 / min 33 4 114 15 2000 / min 60 8 206 26

[0197] As can be seen from the table together with the Fig. 9B As can be seen, the total acceleration in particular increases at the "middle 30 µm" position in the range of a speed of 1500 rpm to a value of 114 and at 2000 rpm to 206, which corresponds to approximately 0.2 g.

[0198] The Fig. 9B It also shows that, regardless of the exact positioning or center offset of the sensor unit 16, the total acceleration ages increases with increasing speed. Therefore, the threshold value with which the total acceleration ages is compared to check whether a runout error of the monitoring module 10, 26, 28 is present is not a static threshold value, but a "dynamic" threshold value that increases with increasing speed.

[0199] This is in the Fig. 10 in which the acceleration values ​​ax, ay, ax_initial, ay_initial and ages (correspondingly resulting) as well as a threshold value SW are plotted against the speed of the monitoring module 10, 26, 28. Fig. 10 It is again evident that all of these variables increase with each increase in speed. The initial variables ax_initial, ay_initial, which are representative of the acceleration, each have a lower acceleration value than the corresponding variables ax, ay, which are representative of the acceleration in the sensitivity direction. This is due, for example, to the fact that when measuring the variables ax, ay in a monitoring mode of the monitoring module 10, 26, 28, a certain (greater) eccentricity / tilting of the sensor unit 16 was present compared to the calibration run. However, the calculated total acceleration ages (correspondingly resulting) is below the threshold value SW at all speeds, i.e., within a tolerable range. This means that there is no runout error in this evaluation, but rather the runout of the monitoring module 10, 26, 28 is OK (IO).If such an evaluation is performed in the monitoring module 10, 26, 28, the result can be transmitted as a test signal IO to the machine tool WZM and / or to the concentricity monitoring signal interface SGS. Alternatively, it is possible to transmit the raw data of the measured variables ax, ay, ax_initial, ay_initial to the machine tool WZM and / or to the concentricity monitoring signal interface SGS and perform the evaluation there.

[0200] Since the rotational speed is quadratically included in the determination of the variables ax, ay, ax_initial, and ay_initial, it is important that the component performing the evaluation knows the exact rotational speed(s) at which these variables were determined. Several options are available for this within the scope of the present disclosure.

[0201] A first possibility is to determine the speed based on additional acceleration variables (or a single additional acceleration variable) that are determined by the additional sensor unit B during the acquisition of the acceleration-representative variables ax, ay (and during the calibration run during the acquisition of the initial variables ax_inital, ay_initial). The acquisition principle for the speed via the additional sensor unit B is described with reference to Fig. 1 described, the statements there also apply here.

[0202] A second possibility, where the additional optional sensor unit B for speed detection can be dispensed with, is with reference to the Fig. 11 and 12 The sensor unit 16 has a measuring range of ± 2 g and a resolution of 1024 digital values ​​per g. The sampling rate is 1 kHz. Fig. 11 and 12In the measurements shown, the monitoring module 10, 26, 28 is oriented horizontally. As a result, a sinusoidal signal is superimposed on the actual value to be measured (e.g., ax, ay, ax_initial, ay_initial) due to the acceleration of gravity acting on the monitoring module 10, 26, 28 during the measurement.

[0203] The Fig. 11 shows such a signal superposition, where output values ​​(ax) of the sensor unit 16 in the x-direction are shown at different speeds. Similarly, the Fig. 12 Such a signal superposition, where output values ​​(ay) of the sensor unit 16 in the y-direction are shown at different speeds. The sinusoidal oscillations superimposed on the measured values ​​correspond in amplitude approximately to the acceleration due to gravity. This applies in particular at a speed of approximately 1000 rpm, since here (cf. the Fig. 11 and 12) has an amplitude of about 1000, which corresponds approximately to the acceleration due to gravity of about 1 g. In the Fig. 11 It is also shown that the mean value of the sine signal increases with increasing speed. Thus, at approximately 1000 rpm, the mean value is at a digital sensor value of 2075, while at approximately 1500 rpm, the mean value increases to a digital sensor value of 2115, and at approximately 2000 rpm, to a digital sensor value of approximately 2155.

[0204] As can also be seen from the Fig. 11 and 12As can be seen, the frequency of the sinusoidal signal changes with increasing speed. The frequency therefore correlates with the speed; in particular, the frequency corresponds to the speed. Thus, the frequency of the sinusoidal oscillation superimposed on the actual measured variables when the monitoring module 10, 26, 28 is horizontally aligned can be used to determine the speed of the module when the actual measured variables are being recorded.

[0205] Another possibility of determining the speed during the acquisition of the acceleration variables ax, ay, ax_initial, ay_initial uses the Fig. 7 described photosensitive unit PE with the photosensitive surface 50. This involves optical speed detection using a natural light pattern that arises during detection. This light pattern is created by the rotation of the monitoring module 10, 26, 28 and is converted by the computing unit 22 of the monitoring module 10, 26, 28 into a voltage pattern that repeats with each revolution. The fundamental frequency of the voltage pattern or the underlying light pattern is then determined. This fundamental frequency corresponds to the speed of the monitoring module 10, 26, 28 when the acceleration variables ax, ay, ax_initial, ay_initial are detected by the sensor unit 16. If there is insufficient ambient light in the application situation of the monitoring module 10, 26, 28, the photosensitive unit PE is an IR photodiode. In this case, it is not the ambient light that is detected, but infrared radiation, from which the speed can be determined.This infrared radiation is emitted by an infrared transmitter and receiver module on the machine tool (WZM). The transmitter includes an IR LED.

[0206] Finally, it is also possible for the machine tool WZM to signal the exact test speed (as specified by the controller 32 for the spindle S) to the monitoring module 10, 26, 28 and / or the concentricity monitoring signal interface SGS via its communication unit 30. This is particularly useful if the evaluation of the concentricity monitoring is carried out in the monitoring module 10, 26, 28 or in the concentricity monitoring signal interface SGS.

[0207] The Fig. 13A shows a sectional view of an example of a monitoring module 10, 26, 28, which has an optional fluid channel FK. The fluid channel is also in the middle of the additional Fig. 13A The components shown, spindle S and tool holder WZGA, are indicated. The tool WZG, in particular of the monitoring module 28, can also have such a fluid channel. Tools WZG that can be coupled to the monitoring modules 10, 26 can also have a fluid channel. Through these fluid channels, the cooling and / or lubricating agents required during machining of a workpiece are guided through the spindle S, the monitoring module 10, 26, 28 and the tool WZG to the machining point, for example, to avoid damage to the tool WZG and the workpiece and to achieve better machining results.

[0208] If the sensor unit 16 is aligned at least approximately coaxially to the rotational axis 20 of the monitoring module 10, 26, 28 as in the present example, the cooling lubricant flow in the example is Fig. 13A not exactly centrally located in the monitoring module 10, 26, 28. As in Fig. 13A As shown, the fluid channel FK, which initially originates centrally from a surface of the monitoring module 10, 26, 28 facing the spindle S, is divided into two subsections of the fluid channel FK by a coolant distributor shortly before the sensor unit 16. As a result, when a workpiece is machined by the machine tool WZM with monitoring module 10, 26, 28, the coolant is directed into the two subsections of the fluid channel FK and thus guided around the sensor unit 16 or past the sensor unit 16. The fluid channel FK and its subsections are designed in such a way that the coolant flow from the machine tool WZM to the tool WZG is not impaired.

[0209] In an alternative variant, which is Fig. 13B As shown, the cooling lubricant flow is guided centrally in the monitoring module 10, 26, 28, although the sensor unit 16 (whose housing in Fig. 13B for clarity is only indicated) is aligned at least approximately coaxially with the rotational axis 20 of the monitoring module 10, 26, 28. For this purpose, both the sensor board 40 and the sensor unit 16 each comprise a central recess (shown here as round by way of example). As can be seen from Fig. 13B As can be seen, these central recesses overlap, and the axis of rotation 20 of the monitoring module 10, 26, 28 runs through the centers of the recesses. During operation of the monitoring module 10, 26, 28, the recesses serve as a fluid channel FK, which thus runs centrally through the monitoring module 10, 26, 28. In this variant, two single-axis acceleration sensors Sensor X and Sensor Y, arranged offset by 90° to one another, are used within the sensor unit 16. In this case, the sensor unit 16 can comprise a central recess which is aligned approximately coaxially to the axis of rotation 20 and comprises two acceleration sensors SX, SY. The first acceleration sensor SX is arranged on the yz plane and has a sensitive axis oriented orthogonally to the yz plane. The second acceleration sensor SY is arranged on the xz plane and has a sensitive axis oriented orthogonally to the xz plane.This also makes it possible to perform runout monitoring when the X and Y sensors are spatially separated by a small distance due to the centrally running fluid channel. Due to the spatial arrangement of the X sensor in the YZ plane, no centrifugal acceleration acts on the sensor during rotation if there is no tilt. If tilted in the X direction, an acceleration acts in the tangential direction, depending on the speed and runout error in the X direction. The same applies analogously in the Y direction. As explained above, both accelerations are recorded proportionally by both sensors according to magnitude and direction (vectorial). By evaluating the tangential acceleration, rotation has no influence on the acceleration value.

[0210] The monitoring module 10, 26, 28 must be supplied with electrical energy during operation. For this purpose, the voltage specified in Fig. 1 described energy supply unit V is provided in the monitoring module 10, 26, 28. This energy supply unit V comprises an energy storage device, which in the simplest case consists of a replaceable or rechargeable battery or an accumulator. With reference to the Fig. 14 and 15Options for generating internal energy in the monitoring module 10, 26, 28 are now described. In these cases, the energy storage unit of the energy supply unit V can also include batteries with comparatively lower capacity or capacitors in which the generated energy is temporarily stored. This requires a generator unit to convert, for example, rotational energy into electrical energy. This electrical energy is then fed to the energy storage unit via a rectifier circuit. The energy drawn from the energy storage unit can be brought to the nominal voltage required for operation of the monitoring module 10, 26, 28 by an optional voltage regulator.

[0211] The Fig. 14 shows the arrangement of a turbine unit TE in the fluid channel of a monitoring module 10, 26, 28 (shown in sectional view). The turbine unit serves as a generator unit for generating its own electricity. The coolant (lubricant) flow through a turbine wheel 52 is used. This coolant (lubricant) flow causes the turbine wheel 52 to rotate, which has permanent magnets 54 (in the Fig. 14 two permanent magnets are shown as an example). The turbine wheel 52 then rotates relative to a plate 49, on which induction coils 56 (e.g. three coils arranged at a 120° offset from each other, of which Fig. 14 (For the sake of clarity, only two coils 56 are referenced) are arranged and coupled to one another. The turbine wheel 52 and the circuit board 49 are arranged and aligned with one another in such a way that the relative rotational movement between the turbine wheel 52 and the induction coils 56 induces a voltage in the induction coils 56, which is then stored in the energy storage device of the energy supply unit V.

[0212] The Fig. 15 shows the arrangement of a flywheel drive in a monitoring module 10, 26, 28 (shown in a sectional view). The flywheel drive serves as a generator unit for self-generated power. A circuit board 51 serves as the stator, which is why it is directly coupled to the monitoring module 10, 26, 28. According to other examples, an indirect coupling of the circuit board 51 to the monitoring module 10, 26, 28 can alternatively be provided.

[0213] On board 51 according to Fig. 15 A coil cage 60 with induction coils 62 is arranged. To ensure stability at high machining speeds, the coils 62 are firmly glued to the coil cage 60 in corresponding recesses (this also applies to the coil cage 60 with reference to Fig. 14 described coils 56). The coils 62 here have, for example, a manganese-zinc ferrite core and are coupled to one another via the circuit board 51.

[0214] A flywheel 64, which has several ball bearings 66 (in the Fig. 15 For the sake of clarity, only a reference symbol 66 is given) is rotatably arranged inside the monitoring module, has permanent magnets 68 (here, too, the Fig. 15 For the sake of clarity, only a reference symbol 68 is given). When the spindle S and thus the monitoring module 10, 26, 28 is accelerated (positively or negatively), a speed difference arises between the flywheel 62 and the circuit board 51 due to the inertia of the flywheel 64. The flywheel 64 and the circuit board 51 are arranged and aligned with one another in such a way that, as a result of this speed difference, when the monitoring module 10, 26, 28 accelerates, a voltage is induced in the induction coils 68 between the flywheel 64 and the induction coils 68, which voltage is then stored in the energy storage device of the energy supply unit V.

[0215] With reference to the Fig. 16 bis 22 Process sequences and subprocess sequences that can be executed by the monitoring module 10, 26, 28, by the concentricity monitoring signal interface SGS and / or by the machine tool WZM are now described. In particular, process steps that are not described in the previous figure description represent optional process steps for the concentricity monitoring and / or for the calibration run. These optional process steps are particularly related to the Fig. 6 described method steps as well as with further method steps described within the scope of this disclosure (in particular those relating to the calibration run).

[0216] In the Fig. 16 The calibration procedure for one or more test speeds and for an evaluation of the concentricity in the concentricity monitoring module 10, 26, 28 is shown. According to the Fig. 16 After the start of the calibration process in the monitoring module 10, 26, 28 of the machine tool WZM and / or the runout monitoring signal interface SGS, it is signaled that the monitoring module 10, 26, 28 is ready to record the initial variables ax_initial, ay_initial. The monitoring module 10, 26, 28 is then in calibration mode. When the spindle S is rotating, the machine tool WZM, for example, monitors whether a predetermined test speed is stable during the recording. The recording lasts for a predetermined number of revolutions of the spindle S, which here should be eight revolutions, for example. However, the present disclosure is not limited to this exact number of revolutions for the recording period (also evaluation time).

[0217] If the monitored test speed deviates significantly, e.g., by more than 10%, from the specified test speed, no acceleration variables are recorded by the sensor unit 16. At a stable speed, however, the acceleration values ​​ax_initial, ay_initial for the first (or only) test speed are recorded. In a subsequent step, the initial variables ax_initial, ay_initial recorded by the sensor unit 16 are filtered. In addition, the exact test speed is determined during recording using one of the variants described above. For this purpose, for example, further acceleration variables in the x- and / or y-direction can be determined by the additional sensor unit B, which can then be filtered in the same way. Then, according to the example in Fig. 16 Average values ​​of the quantities ax_initial, ay_initial are determined over the number of revolutions (i.e. the acquisition time).

[0218] The test speed can then be changed (e.g. increased). The optionality of this step is indicated by the dashed border of the "Change speed" step in the Fig. 16 The acquisition of the initial values ​​ax_initial, ay_initial is then, as can be seen from Fig. 16 visible, is carried out again for the increased test speed. Once the initial acceleration variables ax_initial, ay_initial have been recorded for all test speeds, the initial variables ax_initial, ay_initial (in particular their mean values) are assigned to the exact test speed prevailing during the recording, so that a test speed-dependent function of the initial variables ax_initial, ay_initial is determined. This function is then stored in the memory of the monitoring module 10, 26, 28 and is thus available for calculating the total acceleration ages when the concentricity of a tool WZG is monitored by the monitoring module 10, 26, 28. To exit the calibration mode, the monitoring module 10, 26, 28 signals to the machine tool WZM and / or the concentricity monitoring signal interface SGS that the calibration run is ended ("finished").

[0219] In the Fig. 17 is a partial sequence of a calibration run for one or more test speeds and for an evaluation of the initial variables ax_initial, ay_initial recorded in the calibration run in the machine tool WZG (cf. Fig. 4 ) or in the roundness monitoring signal interface SGS (see Fig. 5 ). Some steps correspond to those of the Fig. 16 , so that instead of a redundant description, the respective steps of the Fig. 16 which is referred to in the context of the Fig. 17 apply equally.

[0220] According to Fig. 17 In particular, the machine tool WZM or the concentricity monitoring signal interface SGS can initiate, i.e., start, the calibration run using one of the monitoring modules 10, 26, 28. After the "Ready" message from the monitoring module 10, 26, 28, the initial variables ax_initial, ay_initial recorded at a stable speed are transmitted to the machine tool WZM / to the concentricity monitoring signal interface SGS. This continues until the recording duration is reached. Then, the transmission of the initial variables ax_initial, ay_initial is stopped and – in the variant of the calibration run for multiple test speeds – the speed is changed. The initial variables ax_initial, ay_initial are recorded and transmitted again at a stable speed until the recording duration is reached again.If this process has been carried out for all test speeds (this is the case when the machine tool WZM / the concentricity monitoring signal interface SGS has received initial acceleration values ​​ax_initial, ay_initial for all specified test speeds), the machine tool WZM / the concentricity monitoring signal interface SGS ends the calibration process.

[0221] The Fig. 18 shows the sequence of a concentricity test of a tool WZG performed in the monitoring module 10, 26, 28 at a single test speed. The monitoring module 10, 26, 28 rotates together with the spindle S of the machine tool WZM and with the tool WZG, e.g., for machining a workpiece.

[0222] First, the monitoring module 10, 26, 28 is activated. This occurs via a wake-up signal, which causes the monitoring module 10, 26, 28 to switch from an energy-saving mode (standby mode) to a monitoring mode (also known as measuring mode). In the present example, the wake-up signal is transmitted from the machine tool WZM or from the runout monitoring signal interface SGS to the monitoring module 10, 26, 28. However, the present disclosure is not limited thereto. In other variants, the wake-up signal is generated by the additional sensor unit B when the additional variables representative of the acceleration in the x- and / or y-direction exceed a wake-up threshold. The wake-up signal can also be generated when an amount of energy generated by the energy supply unit V exceeds a predetermined level.In this case, the monitoring module 10, 26, 28 will only be switched to monitoring mode when self-generated power is possible in the monitoring module 10, 26, 28. In addition to activation, the monitoring module 10, 26, 28 logs potential shock events such as falls to the floor or collisions and stores them in the memory of the monitoring module 10, 26, 28.

[0223] The monitoring module 10, 26, 28 checks in monitoring mode whether a speed is actually present at the monitoring module 10, 26, 28. If no speed is present, the monitoring module 10, 26, 28 switches back to energy saving mode. However, if a speed is actually present at the monitoring module 10, 26, 28, it remains in monitoring mode and signals its readiness for data acquisition to the machine tool WZM / the concentricity monitoring signal interface SGS (see also the description of Fig. 16 ). When the spindle S rotates, the machine tool WZM, for example, monitors whether a specified test speed is stable during the recording. The recording lasts for a specified number of X revolutions of the spindle S (see Fig. 18 ), which here, by way of example, is eight revolutions. However, the present disclosure is not limited to this exact number of revolutions for the detection period.

[0224] If the monitored test speed deviates significantly, e.g., by more than 10%, from the specified test speed, no acceleration variables are detected by the sensor unit 16. At a stable speed, however, the variables ax, ay representative of the acceleration are detected at the test speed. Then, the acceleration variables ax, ay detected by the sensor unit 16 are filtered. In addition, before, after, or during the detection and filtering (this also applies to all other embodiments of this disclosure with corresponding steps), the initial variables ax_initial, ay_initial representative of the acceleration are detected, e.g., by reading in the values ​​determined in the calibration run according to Fig. 16 The total acceleration ages is determined and compared with the threshold value SW (see also Fig. 10 ). If the total acceleration is below the threshold value SW, the machine tool WZM / the concentricity monitoring signal interface SGS is signaled that there is no concentricity error (OK). If, on the other hand, the total acceleration ages is equal to or greater than the threshold value SW, the machine tool WZM / the concentricity monitoring signal interface SGS is signaled that there is a concentricity error (NIO). The monitoring mode is then deactivated, so that the monitoring module 10, 26, 28 switches back to energy-saving mode. Deactivation occurs here, for example, in response to a corresponding signal from the machine tool WZM / the concentricity monitoring signal interface SGS. Alternatively, this deactivation can generally (i.e., according to all examples described herein) also occur automatically by the monitoring module 10, 26, 28, e.g.if no acceleration values ​​are detected at all over a certain period of time, which indicates that the monitoring module 10, 26, 28 is not currently in use.

[0225] The Fig. 19 shows the sequence of a concentricity test of a tool WZG performed in the monitoring module 10, 26, 28 at several test speeds. The monitoring module 10, 26, 28 rotates together with the spindle S of the machine tool WZM and with the tool WZG, e.g., for machining a workpiece.

[0226] The process of Fig. 19 differs from that in Fig. 18 merely by recording the acceleration variables ax, ay, their filters, recording the initial variables ax_initial, ay_initial, determining the total acceleration ages and comparing them with the threshold value SW for several test speeds. Therefore, some steps correspond to those of Fig. 18 , so that instead of a redundant description, the respective steps of the Fig. 18 which is referred to in the context of the Fig. 19 apply equally.

[0227] In contrast to Fig. 18 is in accordance with the Fig. 19 For each acquisition run (acquisition of acceleration variables, etc.), the exact test speed n is determined using one of the variants described above while the acceleration variables ax, ay are being acquired. Between the individual acquisition runs, the test speed is changed (e.g. increased). After the test speed has been increased, the acceleration variables ax, ay are acquired for the increased test speed, the exact test speed is recorded, the acceleration variables ax, ay are filtered, the initial acceleration variables ax_initial, ay_initial are determined, the total acceleration ages is determined, and this is compared with the threshold value SW emeut until the acceleration variables ax, ay have been acquired for all test speeds.

[0228] The test speed can be increased either before the machine tool (WZM) or the concentricity monitoring signal interface (SGS) is signaled as to whether or not a concentricity error is present. In other words, the machine tool (WZM) or the concentricity monitoring signal interface (SGS) can be signaled, for example, in a single data packet as to whether a concentricity error was present at one of the test speeds (NOK) or whether no concentricity error was present (OK). Alternatively, these results can be transmitted individually for each test speed to the machine tool (WZM) or the concentricity monitoring signal interface (SGS).

[0229] The Fig. 20 shows the sequence of a machining operation in the machine tool WZG (cf. Fig. 4 ) or in the roundness monitoring signal interface SGS (see Fig. 5 ) of a tool (WZG) at a single test speed and at various test speeds. One of the monitoring modules 10, 26, 28 rotates together with the spindle S of the machine tool (WZM) and with the tool (WZG), e.g., for machining a workpiece.

[0230] After the runout check has been started by the machine tool WZM / the runout monitoring signal interface SGS, the system waits for the monitoring module 10, 26, 28 to signal that it is ready to perform acceleration measurements. Then (this is shown in the Fig. 20 not shown) the recording of the acceleration representative quantities ax, ay instead (as e.g. with reference to Fig. 19 These acceleration values ​​ax, ay are measured by the machine tool WZM / the runout monitoring signal interface SGS either continuously (as described in the Fig. 20 ) or when the recording in the monitoring module 10, 26, 28 is completed, and saved in the memory of the machine tool WZM / the runout monitoring signal interface SGS. As soon as all recorded acceleration variables ax, ay and, if applicable, associated test speeds have been received, the evaluation begins in the machine tool WZM / the runout monitoring signal interface SGS. The test speed(s) are determined during the recording and the variables ax, ay representative of the acceleration are filtered. In addition, the initial variables ax_initial, ay_initial representative of the acceleration (in the case of several test speeds as a test speed-dependent function) are determined, for example by reading them from the memory of the machine tool WZM / the runout monitoring signal interface SGS. The total acceleration ages is determined for each test speed and compared with a threshold value SW that is dependent on the test speed.If this evaluation takes place in the concentricity monitoring signal interface (SGS), it can then signal to the machine tool (WZM) whether a concentricity error of the tool (WZG) is present (NOK) or not (OK). This optional signal, which is available in the . Fig. 20 However, the step indicated by a dashed frame is omitted if the evaluation was performed in the machine tool (WZM). After this, the machine tool (WZM) / the concentricity monitoring signal interface (SGS) knows the concentricity properties of the tool (WZG) at the corresponding test speeds, and the concentricity test in the machine tool (WZM) / the concentricity monitoring signal interface (SGS) is completed.

[0231] In the Fig. 21 is a partial process of a machining operation in a machine tool (cf. Fig. 4 ) or in the roundness monitoring signal interface SGS (see Fig. 5 ) is shown. One of the monitoring modules 10, 26, 28 rotates together with the spindle S of the machine tool WZM and with the tool WZG, e.g. for machining a workpiece. For detailed explanations of the steps of activating and deactivating the monitoring module 10, 26, 28, transmitting the status "Ready" to the machine tool / to the runout monitoring signal interface (in the Fig. 21 abbreviated to WZM / SGS) as well as the verification of the stability of the speed during the recording period, for example, refer to the corresponding descriptions for Fig. 18 which are equally valid here.

[0232] During the process in Fig. 21 This is a variant in which measured values ​​are continuously transmitted to the machine tool WZM / the concentricity monitoring signal interface SGS. The transmitted measured values ​​can then, for example, be Fig. 20 be evaluated (in Fig. 21 not shown).

[0233] While monitoring whether the speed is stable, the sensor unit 16 of one of the monitoring modules 10, 26, 28 records values ​​ax, ay representative of acceleration and continuously transmits them to the machine tool WZM / the concentricity monitoring signal interface SGS. This can be done according to the Fig. 21 directly after the acquisition of individual acceleration values ​​ax, ay. Optionally (indicated by the dashed frame of the step of Fig. 21 , in which it is checked whether the module memory is full), the acceleration variables ax, ay can also be stored in the memory of the monitoring module 10, 26, 28 until this memory is at least almost full, or until a defined amount of data is reached. Alternatively, it is possible that data packets defined over a period of time, which contain several acceleration variables ax, ay, are temporarily stored in the module memory and, after this period of time, are transmitted to the machine tool WZM / the concentricity monitoring signal interface SGS. Once the recording duration has been reached, the transmission of the recorded acceleration variables ax, ay is terminated. Since in this variant the acceleration variables ax, ay are continuously monitored, the recording duration can, for example,an entire machining cycle of a workpiece or at least part thereof, in particular if this (partial) machining cycle is carried out using the same monitoring module 10, 26, 28 and with the same tool WZG. Alternatively, the recording duration can be adapted to the duration of one or more machining steps to be carried out by the tool WZG (drilling, milling, etc.). The module memory can be dimensioned such that it can store all values ​​recorded during the recording duration, particularly in cases where the recording duration is known. Fig. 21 a high energy expenditure is necessary, the monitoring module 10, 26, 28 can be equipped in particular with a generator unit for generating its own energy as described with reference to the Fig. 14 or 15 described.

[0234] The Fig. 22 shows a partial sequence of a concentricity test (evaluation) of a tool WZG from the perspective of the machine tool WZM, performed in one of the monitoring modules 10, 26, 28 or in the concentricity monitoring signal interface SGS. One of the monitoring modules 10, 26, 28 rotates together with the spindle S of the machine tool WZM and with the tool WZG, e.g., for machining a workpiece.

[0235] First, the machine tool WZM causes the monitoring module 10, 26, 28 to be inserted into the spindle S of the machine tool WZM and that the spindle S is rotated at the required detection speed (see also the description of steps (i) and (ii) of the Fig. 6 ). Then wait until the monitoring module 10, 26, 28 signals its readiness for data acquisition. For detailed information on this step, please refer to the corresponding descriptions for Fig. 18 which are equally valid here. When the monitoring module 10, 26, 28 is ready, the values ​​ax, ay representative of the acceleration are recorded by the monitoring module 10, 26, 28. The evaluation can be carried out as per the Fig. 18 and 19 in the monitoring module 10, 26, 28 or as per Fig. 20 in the SGS round-trip monitoring signal interface (in Fig. 22 not shown).

[0236] The machine tool WZM waits until information about a runout error of the tool WZG is available. This information is transmitted from the evaluating unit, i.e. the monitoring module 10, 26, 28 or the runout monitoring signal interface SGS, to the machine tool WZM. If a runout error of the tool WZG is present (NOK), the machine tool WZM initiates the replacement of the monitoring module 10, 26, 28 from the spindle S and cleaning it by blowing it off with a stream of compressed air (these steps are described in the Fig. 22 omitted). The machine tool WZM then causes the monitoring module 10, 26, 28 to be replaced in the spindle again and then waits again until information about a runout error (a runout test is carried out again according to one of the described variants) of the tool is available (this step is also included in the Fig. 22omitted). If a runout error still exists, the machine tool WZM first blocks workpiece machining so that, for example, no further non-dimensionally accurate workpieces (scrap) are produced. In addition, the rotation of the spindle S is stopped in order to bring the machine tool WZM and the monitoring module 10, 26, 28 with the mounted tool WZG into a safe state. In addition, an error is indicated, for example, on a display of the machine tool WZM, and / or an acoustic error signal is emitted. These three steps can essentially take place simultaneously. If there is no runout error (NIO), the machine tool WZM enables workpiece machining.

[0237] Subsequently, one of the (partial) methods for calibration and / or for concentricity checking etc. described in the context of this disclosure can of course be carried out again using the monitoring module 10, 26, 28 with mounted tool WZG, the machine tool WZM and / or the concentricity monitoring signal interface, if appropriate effected by the described computer program product.

[0238] It is understood that the exemplary embodiments and variants explained above are not exhaustive and do not limit the subject matter disclosed herein. In particular, it will be apparent to those skilled in the art that they may combine the features of the various embodiments and variants with one another and / or omit various features of the embodiments and variants.

Claims

1. Concentricity monitoring module (10) for a tool (WZG) to be rotated during operation, comprising: - a tool interface (12) designed to receive the tool (WZG) to be rotated; - a tool mounting interface (14) designed to be inserted into a tool holder (WZGA), in particular of a machine tool (WZM) or a machining center (BA); - a sensor unit (16) which is assigned to the concentricity monitoring module (10) in such a way that a rotational axis (20) of the concentricity monitoring module (10) passes through the sensor unit (16), wherein the sensor unit (16) is designed to detect quantities (ax, ay) representative of acceleration in a plane (E) oriented essentially normal to the axis of rotation (20) of the concentricity monitoring module (10) when the concentricity monitoring module (10) rotates, in particular together with the rotatable tool (WZG) and / or with the tool holder (WZGA); - a computing unit (22) which is designed to: - receive the acceleration-representative variables (ax, ay) detected by the sensor unit (16); - determine a total acceleration (ages) based on the detected acceleration-representative variables (ax, ay); - compare the total acceleration (ages) with a threshold value dependent on a rotational speed of the concentricity monitoring module (10) during detection of the quantities (ax, ay) representative of acceleration (SW) dependent on a rotational speed of the concentricity monitoring module (10) during the detection of the quantities (ax, ay) representative of acceleration; and - determining that a rotary speed error of the rotary tool (WZG), the concentricity monitoring module (10) and / or the tool holder (WZGA) is present if the total acceleration (ages) is greater than the threshold value (SW); and - a communication unit (24) which is connected communicatively to the computing unit (22) and is designed to signal to the machine tool (WZM) / the machining center (BA) whether or not there is a concentricity error of the rotating tool (WZG), the concentricity monitoring module (10) and / or the tool holder (WZGA).

2. Concentricity monitoring tool holder module (26) for a tool (WZG) to be rotated during operation, comprising: - a tool interface (12) designed to hold the tool (WZG) to be rotated; - a tool holder (WZGA) designed to be inserted into a spindle (S) of a machine tool (WZM) or a machining center (BA); - a sensor unit (16) which is assigned to the tool holder module (26) for monitoring concentricity in such a way that a rotational axis (20) of the rotary concentricity monitoring tool holder module (26) passes through the sensor unit (16), wherein the sensor unit (16) is designed to detect quantities representative of acceleration (ax, ay) in a plane (E) oriented substantially normal to the axis of rotation (20) of the concentricity monitoring tool holder module (26) when the concentricity monitoring tool holder module (26), in particular together with the tool (WZG) to be rotated and / or with the spindle (S), rotates; - a computing unit (22) which is designed to - receive the quantities (ax, ay) representative of acceleration detected by the sensor unit (16); - determine a total acceleration (ages) based on the detected quantities (ax, ay) representative of acceleration; - comparing the total acceleration (ages) with a threshold value (SW) dependent on a rotational speed of the rotary monitoring tool holder module (26) during detection of the quantities (ax, ay) representative of the acceleration; and - determining that a concentricity error of the rotating tool (WZG) and / or the tool holder (WZGA) is present if the total acceleration (ages) is greater than the threshold value (SW); and - a communication unit (24) which is connected in a communicative manner to the computing unit (22) and is designed to signal to the machine tool (WZM) / machining center (BA) whether or not there is a concentricity error of the rotating tool (WZG) and / or the tool holder (WZGA).

3. Tool concentricity monitoring module (28), comprising: - a tool (WZG) to be rotated during operation; - a tool holder (WZGA) designed to be inserted into a spindle (S) of a machine tool (WZM) or a machining center (BA); - a sensor unit (16) which is assigned to the concentricity monitoring tool module (28) in such a way that a rotational axis (20) of the concentricity monitoring tool module (28) passes through the sensor unit (16), wherein the sensor unit (16) is designed to detect quantities representative of acceleration (ax, ay) representative of acceleration in a plane (E) oriented essentially normal to the axis of rotation (20) of the concentricity monitoring tool module (28) when the concentricity monitoring tool module (28), in particular together with the spindle (S); - a computing unit (22) designed to - receive the quantities (ax, ay) representative of acceleration detected by the sensor unit (16); - determining a total acceleration (ages) based on the detected quantities (ax, ay) representative of the acceleration; - comparing the total acceleration (ages) with a threshold value (SW) dependent on a rotational speed of the concentricity monitoring tool module (28) during detection of the quantities (ax, ay) representative of the acceleration; and - determining that a concentricity error of the concentricity monitoring tool module (28) is present if the total acceleration (ages) is greater than the threshold value (SW); and - a communication unit (24) which is connected in a communicative manner to the computing unit (22) and is designed to signal to the machine tool (WZM) / machining center (BA) whether or not a concentricity error of the concentricity monitoring tool module (28) is present or not.

4. Machine tool (WZM) or machining center (BA), comprising: - a spindle (S) rotatable about an axis of rotation (D) during operation of the machine tool (WZM) / machining center (BA), which is designed to hold a tool holder interface (14) of a concentricity monitoring module (10) according to claim 1, a tool holder (WZGA) of a concentricity monitoring tool holder module (26) according to claim 2 and / or a tool holder (WZGA) of a concentricity monitoring tool module (28) according to claim 3 and to interact operatively therewith; - a communication unit (30) for receiving signals from the communication unit (24) of the concentricity monitoring module (10) according to claim 1, the communication unit (24) of the concentricity monitoring tool holder module (26) according to claim 2 and / or the communication unit (24) of the concentricity monitoring tool module (28) according to claim 3; and - a control (32) which is connected to the communication unit (30) of the machine tool (WZM) / machining center (BA) and is designed to: - receive signals from the sensor unit (16) of the concentricity monitoring module (10) according to claim 1, the sensor unit (16) of the concentricity monitoring tool holder module (26) according to claim 2 and / or the sensor unit (16) of the concentricity monitoring tool module (28) according to claim 3; - determining a total acceleration (ages) based on the detected quantities (ax, ay) representative of the acceleration; - comparing the total acceleration (ages) with a threshold value (SW) dependent on a rotational speed of the spindle (S) during detection of the quantities (ax, ay) representative of the acceleration; and - determining that a concentricity error of the concentricity monitoring module (10) according to claim 1, of the concentricity monitoring tool holder monitoring module (26) according to claim 2 and / or the concentricity monitoring tool module (28) according to claim 3 is present if the total acceleration (ages) is greater than the threshold value (SW).

5. Rotary monitoring signal interface (SGS), comprising: - a communication unit (36) for receiving signals from a communication unit (24) of a concentricity monitoring module (10) according to claim 1, a communication unit (24) of a rotary monitoring tool holder module (26) according to claim 2 and / or a communication unit (24) of a rotary monitoring tool module (28) according to claim 3, and for sending signals to a communication unit (30) of a machine tool (WZM) / machining center (BA) according to claim 4; and - a computing unit (38) connected to the communication unit (36) of the concentricity monitoring signal interface (SGS) and designed to: - receive signals from the sensor unit (16) of the concentricity monitoring module (10) according to claim 1, the sensor unit (16) of the concentricity monitoring tool holder module (26) according to claim 2 and / or the sensor unit (16) of the concentricity monitoring tool module (28) according to claim 3; - determining a total acceleration (ages) based on the detected quantities (ax, ay) representative of the acceleration; - comparing the total acceleration (ages) with a dependent threshold value (SW) determined from a rotational speed of the spindle (S), a rotational speed of the concentricity monitoring module (10), a rotational speed of the concentricity monitoring tool holder module (26) or a rotational speed of the concentricity monitoring tool module (28) during the detection of the quantities (ax, ay) representative of the acceleration; and - determining that a concentricity error of the concentricity monitoring module (10) according to claim 1, of the concentricity monitoring tool holder module (26) according to claim 2 and / or of the concentricity monitoring tool module (28) according to claim 3 is present if the total acceleration (ages) is greater than the threshold value (SW), wherein the communication unit (36) of the concentricity monitoring signal interface (SGS) is configured to signal to the machine tool (WZM) / the machining center (BA) whether or not there is a concentricity error of the tool (WZG) to be rotated during operation, the concentricity monitoring module (10), the concentricity monitoring tool holder module (26) and / or the concentricity monitoring tool module (28).

6. Concentricity monitoring method for a tool (WZG) to be rotated during operation in a machine tool (WZM) or in a machining center (BA), comprising the steps: (i) automatically inserting a monitoring module (10; 26; 28) to be rotated during operation or the monitoring module (10; 26) and the tool (WZG) to be rotated into a spindle (S) of the machine tool (WZM) / machining center (BA), wherein the monitoring module (10; 26; 28) comprises a sensor unit (16) which is assigned to the monitoring module (10; 26; 28) to be rotated in such a way that a rotational axis (20) of the monitoring module (10; 26; 28) to be rotated passes through the sensor unit (16); (ii) rotating the spindle (S) of the machine tool (WZM) / machining center (BA) at a predetermined speed; (iii) Receiving and / or detecting quantities (ax, ay) representative of acceleration in a plane (E) oriented essentially normal to the axis of rotation (20) of the monitoring module (10; 26; 28) to be rotated, while the monitoring module (10; 26; 28) to be rotated rotates at the predetermined rotational speed; (iv) determining a total acceleration (ages) based on the detected quantities (ax, ay) representative of the acceleration; (v) comparing the total acceleration (ages) with a threshold value dependent on a rotational speed of the monitoring module (10; 26; 28) to be rotated during the detection of the quantities (ax, ay) representative of the acceleration (ax, ay) during the detection of the quantities representative of the acceleration; and (vi) determining that a rotational error of the monitoring module (10; 26; 28) to be rotated and / or of the tool (WZG) to be rotated is present if the total acceleration (ages) is greater than the threshold value (SW).

7. Computer program product comprising instructions that cause: - the machine tool (WZM) / machining center (BA) of claim 4 to perform the process steps (i) to (vi) according to claim 6; and / or - the concentricity monitoring module (10) of claim 1, the concentricity monitoring tool holder module (26) of claim 2 or the concentricity monitoring tool module (28) of claim 3 performs the process steps (iii) to (vi) according to claim 6; and / or - that the concentricity monitoring signal interface (SGS) of claim 5 performs the process steps (iii) to (vi) according to claim 6.

8. A concentricity monitoring module (10) according to claim 1, or a concentricity monitoring tool holder module (26) according to claim 2, or a concentricity monitoring tool module (28) according to claim 3, further comprising a further sensor unit (B) which is radially spaced from the axis of rotation (20) and is designed to detect, essentially simultaneously with the detection of the quantities (ax, ay) representative of acceleration, further quantities representative of acceleration in a plane (E) oriented essentially normal to the axis of rotation (20); and wherein the computing unit (22) is further designed to: receive the further quantities representative of acceleration detected by the further sensor unit (B); and to determine the rotational speed of the concentricity monitoring module (10) / rotation monitoring tool holder module / rotation monitoring tool module during the detection of the quantities representative of acceleration (ax, ay) from the further quantities representative of acceleration; and / or wherein the further sensor unit (B) comprises two opposing acceleration sensors (B1, B2) spaced radially from the axis of rotation, which are arranged in a plane (E) oriented normally to the axis of rotation, wherein the acceleration sensors B1, B2 have measuring axes which lie in a line or in a plane orthogonal to the plane (E) containing the axis of rotation (20) containing the axis of rotation (20) and orthogonal to the plane (E), wherein the acceleration sensors (B1, B2) preferably supply measured values from which respective mean values of the further quantities representative of the acceleration are formed; or wherein the communication unit (24) is designed to transmit the other variables representative of acceleration to the machine tool (WZM) / machining center (BA) according to claim 4 and / or to the concentricity monitoring signal interface (SGS) according to claim 59. Concentricity monitoring module (10) according to claim 1 or 8, or concentricity monitoring tool holder module (26) according to claim 2 or 8, or concentricity monitoring tool module (28) according to claim 3 or 8, wherein the computing unit (22) is designed to determine the rotational speed of the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28) during the detection of the quantities representative of the acceleration based on a signal frequency prevailing during the detection of the quantities (ax, ay) representative of the acceleration, when the rotational axis (20) of the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28) is oriented substantially horizontally when detecting the quantities (ax, ay) representative of acceleration.

10. Concentricity monitoring module (10) according to one of claims 1, 8 or 9, or rotary concentricity monitoring tool holder module (26) according to one of claims 2, 8 or 9, or a concentricity monitoring tool module (28) according to one of claims 3, 8 or 9, further comprising a photosensitive unit (PE) with a photosensitive surface (50) located on the outer circumference of the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28), wherein the photosensitive unit (PE) is designed to detect brightness differences during the detection of the quantities (ax, ay) representative of the acceleration, wherein the computing unit (22) is designed to detect the rotational speed of the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28) shortly before, after and / or during the detection of the quantities (ax, ay) representative of the acceleration based on a frequency of the differences in brightness.

11. Concentricity monitoring module (10) according to one of claims 1 or 8 to 10, or rotary concentricity monitoring tool holder module (26) according to one of claims 2 or 8 to 10, or rotary concentricity monitoring tool module (28) according to one of claims 3 or 8 to 10, wherein at least the sensor unit (16) and preferably additionally the further sensor unit (B) is arranged on a sensor board (40), wherein the sensor board (40) is connected to a board holder (42), and wherein a position of the board holder (42) is adjustable via adjustment means (44) of the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28) normal to the axis of rotation (20); and / or further comprising an energy supply unit (V) which is designed to be switched, preferably in response to a wake-up signal, from an energy-saving or standby mode into a monitoring mode and / or to switch the sensor unit (16), the further sensor unit (B), the computing unit (22) and / or the communication unit (24) preferably in response to a wake-up signal from an energy-saving or standby mode into a monitoring mode; and / or wherein the wake-up signal is a signal or is triggered by a signal which: - is generated by the further sensor unit (B) as soon as the further quantities representative of the acceleration exceed a wake-up threshold; or - is received via the communication unit (24) from the machine tool (WZM) / machining center (BA) according to claim 4 and / or from the concentricity monitoring signal interface (SGS) according to claim 5; or - is generated when an amount of energy generated by the power supply unit (V) exceeds a predetermined level.

12. Concentricity monitoring module according to claim 11, or concentricity monitoring tool holder module according to claim 11, or concentricity monitoring tool module according to claim 11, wherein the power supply unit (V) comprises an energy storage device for storing and / or a generator unit for generating electrical energy; and / or wherein the generator unit comprises a stator (60) which is coupled directly or indirectly to the tool holder (WZGA) of the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28), or is directly or indirectly couplable to the tool holder (WZGA) according to claim 1, and wherein the generator unit further comprises a rotor (64) which is assigned to the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / rotational monitoring tool module (28) such that it interacts with the stator (60) in such a way that the generator unit generates electrical energy around the axis of rotation (20) when the rotational monitoring module (10) / rotational monitoring tool holder module (26) / rotational monitoring tool module (28) about the axis of rotation (20) generates electrical energy; and / or wherein the sensor unit (16) is designed to be separated in time from normal operation, in which the rotational monitoring module (10) / the concentricity monitoring tool holder module (26) / concentricity monitoring tool module (28) rotates, in particular together with the spindle (S), initial values (ax_initial, ay_initial) representative of acceleration (ax_initial, ay_initial) in the plane (E) oriented essentially normal to the axis of rotation (20) at an essentially constant speed or at several different essentially constant speeds, and wherein the computing unit (22) is designed to store the initial quantities (ax_initial, ay_initial) representative of acceleration (ax_initial, ay_initial) together with the corresponding rotational speed(s) in a memory of the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28) and / or the concentricity monitoring tool module (28), and / or wherein the communication unit (24) is designed to store the initial quantities (ax_initial, ay_initial) representative of the acceleration (ax_initial, ay_initial) preferably together with the corresponding speed(s) to the machine tool (WZM) / machining center (BA) according to claim 4 and / or to the concentricity monitoring signal interface (SGS) according to claim 5.

13. Concentricity monitoring module (10) according to one of claims 1 or 8 to 12, or concentricity monitoring tool holder module (26) according to one of claims 2 or 8 to 12, or concentricity monitoring tool module (28) according to one of claims 3 or 8 to 12, wherein the computing unit (22) is further configured to: - monitor at least one further process parameter when the concentricity monitoring module (10), in particular together with the tool (WZG) to be rotated and / or with the tool holder (WZGA), rotates, or when the concentricity monitoring tool holder module (26), in particular together with the tool (WZG) to be rotated and / or with the spindle (S), rotates, or when the concentricity monitoring tool module (28), in particular together with the spindle S, rotates, wherein the at least one process parameter comprises a vibration, a temperature, a coolant pressure, a coolant flow, a cutting force and / or a torque, and / or the quantities (ax, ay) representative of the acceleration detected by the sensor unit (16) and / or the initial quantities (ax, ay) representative of the acceleration detected by the further sensor unit (B) and / or the quantities representative of the acceleration detected by the further sensor unit (B) and / or the rotational speed of the concentricity tool monitoring module (28) are compared with each other. (ax_initial, ay_initial) and / or the further quantities representative of acceleration detected by the further sensor unit (B) and / or the rotational speed of the concentricity monitoring module (10) / the concentricity monitoring tool holder module (26) / the concentricity monitoring tool module (28) during the detection of the quantities representative of acceleration (ax, ay) for a specific time window of preferably between 50 ms and 200 ms in the form of a data packet, wherein the processing is carried out by operations such as signal filtering, averaging and / or determining a frequency spectrum per time window; and transmitting the data packet after processing to the machine tool (WZM) / machining center (BA) according to claim 4 and / or to the concentricity monitoring signal interface (SGS) according to claim 5.

14. Concentricity monitoring module (10) according to claim 13, or concentricity monitoring tool holder module (26) according to claim 13, or concentricity monitoring tool module (28) according to claim 13, wherein the computing unit (22) is designed to determine the total acceleration (ages) based on a subtraction of the quantities representative of the initial acceleration (ax_initial, ay_initial) from the corresponding quantities representative of the acceleration (ax, ay); and / or then, if a concentricity error is present, to determine the amount of the concentricity error and / or the direction of the concentricity error; and wherein the communication unit (24) is designed to transfer the amount and / or the direction of the round-trip error to the machine tool (WZM) / machining center (BA) according to claim 4 or to the round-trip monitoring signal interface (SGS) according to claim 5; and / or wherein the communication unit (24) is designed to signal the presence of the concentricity error to the machine tool (WZM) / machining center (BA) according to claim 4 and / or to the concentricity monitoring signal interface (SGS) according to claim 5, while the rotary position monitoring module (10) / the rotary position monitoring tool holder module (26) / the concentricity monitoring tool module (28), in particular together with the spindle (S), rotates; and / or wherein the module is designed to use predefined speed profiles to recognize functions that are to be performed by the module or triggered in other modules or assemblies, wherein the predefined speed profiles comprise at least (i) a speed, (ii) a duration of a predefined speed(-sequence), (iii) a gradient of a change from one speed stage to the next speed stage, and / or (iv) a duration of a change from one speed stage to the next speed stage of the spindle of the machine tool, in particular by evaluating the generator voltage, and wherein, in particular, the functions "execute teach-in or pairing process," "execute calibration process," "generate wake-up signal," "entering monitoring or measurement mode," and / or "entering deep sleep or standby mode" can be included, and wherein the detection of the quantities representative of acceleration (ax, ay), the detection of the further quantities representative of acceleration, the determination of the total acceleration (ages), determining whether a running error is present, and signaling whether a running error is present only begins when a defined speed is reached, characterized in that during the evaluation time, the spindle speed is essentially constant or varies within a range of at most 10% of the speed.