Machining tool comprising a valve arrangement

Abstract

The invention relates to a machining tool, in particular a milling head (1), comprising: a tool main body (1.1) having a mounting structure (1.1.1) for attaching the machining tool to a rotating tool holder of a machine tool; a plurality of cutting-element mounting structures (1.1.2) for a plurality of cutting elements; and a fluid arrangement having a plurality of coolant / lubricant outlets (1.2) and a coolant / lubricant connection (1.3) for connection to a coolant / lubricant supply; and a valve arrangement. The coolant / lubricant outlets (1.2) are fastened to the tool main body (1.1) and / or are at least partially integrated into the tool main body (1.1), wherein the valve arrangement is disposed within the tool main body (1.1), and the coolant / lubricant outlets (1.2) are fluidically connected to the coolant / lubricant connection (1.3) by the valve arrangement.

Description

[0001] Machining tool with valve arrangement

[0002] TECHNICAL AREA

[0003] The present invention relates to a cutting tool, in particular a cutter head, and the use of a valve arrangement for supplying coolant to a number of cutting elements of a cutting tool.

[0004] BACKGROUND, GENERAL DESCRIPTION OF THE REVELATION

[0005] In machining processes such as drilling, milling, or turning, the use and supply of coolant is often essential, both with regard to tool wear and tool life, as well as surface finish and the overall properties of the machined workpiece. Machine tools are typically equipped with a coolant supply system for this purpose.

[0006] In principle, it is desirable to keep the supply or flow of coolant as low as possible without negatively impacting the quality of the machined product and / or tool life. This is particularly relevant in milling, as this process often involves a high coolant flow rate. This is desirable both with regard to coolant consumption and the dimensioning of the coolant supply system, and specifically the coolant pump(s). The current state of the art in this regard is generally unsatisfactory.

[0007] With a continuous and essentially uncontrolled supply of coolant, the coolant flow can also strike and cool the cutting elements or the cutting edges of the tool even without cutting action, particularly after the workpiece exits at the end of a cutting action. This causes the cutting element, which is hot from the cutting action, to experience a thermal shock, increasing wear and reducing the tool life.

[0008] It is generally known from the prior art to measure the cutting force in a machining process. Furthermore, measuring the cutting edge temperature is known. It is also known to supply the coolant in a pulsating manner to influence the chip length during turning. When sawing with a circular saw blade, it is known to supply coolant only to the teeth in engagement. Furthermore, the integration of actuators into a cutting tool for active vibration reduction is known.

[0009] A general objective of the present disclosure is to improve the state of the art with regard to the supply of coolant in machining, particularly in milling with a cutter head as the cutting tool. Preferably, one or more of the aforementioned problems are solved wholly or at least partially. According to one aspect, the objective is achieved by a cutting tool. The cutting tool can, in particular, be a cutter head, also referred to as a milling head. A cutting tool according to the disclosure comprises a tool body with a mounting structure for attaching the cutting tool to a rotating tool holder of a machine tool. The cutting tool further comprises a number of cutting element mounting structures for a number of cutting elements. Depending on the embodiment, the cutting elements can be an integral part of the cutter head.

[0010] A machining tool as disclosed further comprises a fluidic arrangement. The fluidic arrangement includes a number of coolant outlets, a coolant connection for connection to a coolant supply, and a valve arrangement. The coolant outlets are attached to the tool body and / or at least partially integrated into the tool body. The coolant outlets serve to supply coolant to the cutting elements. In some embodiments, the valve arrangement is electrically actuated or comprises a number of electrically actuated valves. In another embodiment, the valve arrangement alternatively or additionally comprises one or more purely mechanically actuated valves.

[0011] The valve assembly is integrated into or arranged within the tool body. Furthermore, the coolant outlets are fluidically connected to the coolant connection via the valve assembly. Unless otherwise stated, the term "number" in this document refers to any number, including one. Typically, the number of cutting element mounting structures and coolant outlets is greater than one.

[0012] The fact that the valve assembly and the coolant outlets are directly integrated into and / or attached to the tool body means that they are components of the cutter head and rotate as part of it during operation. Such an arrangement allows for a particularly small or minimal fluidic volume in the lines and connections between the valve assembly and the coolant outlets. The same applies to the elasticities typically present in the fluidic system downstream of the valve assembly. The fluidic volume between the valves or valve assembly and the coolant outlet(s), as well as the fluidic elasticities, is fundamentally disadvantageous for precise control of the coolant metering, especially in terms of timing.

[0013] Preferably, the fluidic lines or connections between the coolant connection, valve arrangement, and coolant outlets are also integrated into or arranged within the tool body. Preferably, the fluidic connections are rigid.

[0014] The mounting structure for attaching the tool to a rotating tool holder of a machine tool can, in principle, be implemented in a known manner, in particular as a tool shank, which, for example, can be designed as a hollow taper shank. The coolant connection is provided through the tool interface; in the case of a hollow taper shank, this connection is made via the standardized transfer tube. In further embodiments, the coolant connection can be integrated into the mounting structure and, moreover, be concentric with the axis of rotation. The rotating tool holder can, in particular, be part of the main spindle of a machine tool, especially a milling machine, or be mounted on the main spindle of a machine tool.

[0015] The cutting element mounting structures can each be designed to secure a cutting element, particularly in the form of an indexable insert of a generally known type, by clamping and / or screwing. The cutting elements are typically made of carbide or a ceramic material. The cutting elements can be attached directly to the tool body or secured via corresponding cutting element holders mounted on the tool body. The cutting element holders, for example in the form of cassettes, can optionally be movably, and in particular adjustable, attached to the tool body relative to it. With multiple cutting element mounting structures, these are typically arranged, in particular evenly, around the circumference of the tool body. In one embodiment, the cutting tool comprises a number of cutting elements.

[0016] The coolant outlets can, in particular, each be a nozzle or be formed by the outlet opening of a nozzle. In one embodiment, the valve arrangement is electrically driven. Furthermore, the cutting tool can include an electronic control unit and / or sensors, as described below. To supply power to electrically operated components, the cutting tool can include an electrical power supply, for example, in the form of a replaceable or rechargeable battery. The cutting tool can also have a power supply interface. The power supply interface can be designed for electrical connection with a corresponding power supply interface of the machine tool and can be implemented, for example, via contact-based connections, electrical contacts, or inductive coupling.The power supply interface can be located on the mounting structure or be fully or partially integrated into it. On the machine tool side, the corresponding power supply interface can be located on the tool holder or be fully or partially integrated into it.

[0017] In one embodiment, the cutting tool is designed to control, and in particular to control separately, the supply of coolant to each cutting element via the valve unit, depending on its respective cutting engagement. As explained in more detail below, the coolant supply can be controlled, in particular, by supplying each cutting element with coolant during its cutting engagement and by supplying no coolant or only a negligible, in particular negligible, amount of coolant outside of its cutting engagement. The cutting engagement refers to the state of a cutting element or its cutting edge(s) in which the cutting element is engaged with the workpiece and is machining. The duration of the cutting engagement corresponds to the time between the workpiece entry and exit of a cutting element or its cutting edge(s).The supply of cooling lubricant can be controlled, or coordinated, particularly depending on the start and / or end of the cutting operation.

[0018] In such a design, cooling lubricant is supplied to a cutting element essentially only when and when this is actually necessary due to the cutting action. Furthermore, in particular by coordinating one end of the cooling lubricant supply with the end of the cutting action, the thermal shock to the respective cutting element can be reduced and ideally completely or largely eliminated.

[0019] In one embodiment, each cutting element mounting structure is uniquely assigned at least one coolant outlet. In such an embodiment, the number of coolant outlets is at least equal to the number of cutting element mounting structures. This arrangement has the advantage that the assigned coolant outlet is located directly next to the respective cutting element mounting structure or the respective cutting element, thus supplying each cutting element individually with coolant during operation. In this way, the overall coolant consumption can be optimized and a uniform supply to all cutting elements can be ensured. In another embodiment, each cutting element mounting structure is assigned exactly one coolant outlet, and the number of cutting element mounting structures is identical to the number of coolant outlets.In other words, the assignment is one-to-one or pairwise. In an alternative embodiment, each cutting element mounting structure is assigned a number of two or more coolant / lubricant outlets.

[0020] In one embodiment, each coolant outlet is uniquely assigned to a valve of the valve arrangement, wherein each coolant outlet and assigned valve are fluidically connected. In particular, the valve outlet and the coolant outlet can each be directly fluidically connected.

[0021] In one embodiment, each coolant outlet and / or cutting element mounting structure is assigned exactly one valve, and the number of cutting element mounting structures and / or coolant outlets is identical to the number of valves. In other words, the assignment is one-to-one. In an alternative embodiment, each valve is assigned to a group of two or more coolant outlets and / or cutting element mounting structures. In such an embodiment, each valve is assigned to the valve arrangement of a group of two or more coolant outlets and / or cutting element mounting structures. The coolant outlets and / or cutting element mounting structures of a group can be arranged directly one behind the other, particularly with respect to the circumference of the cutting tool or its rotation during operation.The valves of the valve arrangement can be controlled together or separately. In one embodiment, the valve arrangement comprises at least one switching valve and / or control valve. A switching valve has the alternative states "open" or "closed," between which it can switch binary by means of its control signal. A control valve, for example a proportional valve, has a variable valve opening via a corresponding control signal and thus allows, in particular, continuous flow control of the coolant flow. In an embodiment with multiple valves, all valves of the valve arrangement are identical. A valve inlet of each valve can be directly fluidically connected to the coolant connection. A valve outlet of each valve can be directly fluidically connected to the associated coolant outlet(s).

[0022] The term "valves," which is generally used in the plural below, refers equally to a single valve within a corresponding valve arrangement. The same applies to other related terms such as cutting element mounting structure(s), coolant outlet(s), and cutting element(s).

[0023] The valves can be designed, in particular, as high-speed miniature valves. The response or switching speed is preferably in the range of approximately 10 milliseconds. Preferably, the response time is short compared to the rotational time of the cutting tool per revolution. In particular, the response time can be short compared to the duration of the cutting engagement of a single cutting element or its cutting edge(s) per rotation. The response time must, in particular, be less than 50% of the engagement period of a cutting edge. The valves can be designed, in particular, as diaphragm valves or poppet valves with a control element movable relative to a valve seat. The control element can, in particular, be designed as a plunger, which may optionally have elasticity or an elastic coating, such as a rubber coating.The valves can be driven, in particular, by piezoelectric and / or electromagnetic means. Especially for piezoelectrically driven poppet valves, a motion-enhancing coupling mechanism, such as a toggle lever mechanism, can be provided between the piezo actuator and the control element coupled to it.

[0024] In one embodiment, the valves are pilot-operated. In this configuration, a minimal amount of coolant is lost during the switching process (control flow). This amount is kept as small as possible and discharged away from the cutting edges at the tool shank, so that it does not have a cooling effect on the cutting elements. Such pilot operation is advantageous with regard to smaller valve size and reduced electrical energy consumption. The control flow is required to move the main valve. This amount of coolant can also be added to the main flow.

[0025] In one embodiment, the valves are functionally independent and each includes its own valve inlet, valve outlet, and valve actuator. They can therefore be controlled separately. To smooth the supply flow and protect the machine tool's pump and hose systems, a pressure accumulator is integrated into the tool. In one embodiment, this accumulator consists of an air-filled rubber bladder.

[0026] In a further embodiment, several, in particular all, valves in the valve arrangement are jointly configured as a distribution valve. The distribution valve has a valve inlet and a number of valve outlets, each valve outlet being fluidically connected to a coolant outlet or a group of coolant outlets as previously described. The distribution valve also includes a valve actuator. The distribution valve is designed to sequentially connect its valve inlet to the valve outlets, or to sequentially open the valve outlets. Depending on the configuration, a single valve outlet or a number of two or more, in particular sequentially successive, valve outlets can be open. The number of open valve outlets at any given time is typically constant.The valve outlets are assigned to the cutting elements or cutting element mounting structures according to the sequence in which the individual cutting element or its cutting edge(s) enter and exit the cutting engagement with each revolution of the cutting tool. In an example with three cutting element mounting structures numbered "1", "2", and "3" consecutively in the circumferential direction for three cutting elements, the distribution valve can have a corresponding number of three valve outlets "1a", "2a", and "3a". If, during operation, two adjacent cutting elements are in cutting engagement, a sequence for the open valve outlets 1a and 2a can be used. 3a+1 a ->1 a+2a, etc.

[0027] This applies accordingly to a different, especially larger, number.

[0028] The valve actuator of a distribution valve as described can in particular be a rotary actuator. This can be designed, for example, as a synchronous motor or preferably as a brushless (electronically commutated) DC motor or stepper motor.

[0029] As an alternative to a distribution valve as described, the valve arrangement can also have a number of individual valves as described, which are controlled sequentially and thus together form a distribution valve.

[0030] In one embodiment, the cutting tool comprises a control unit operationally coupled to the valve unit. The control unit is designed to control the valve unit or its valves. The control unit can, in particular, be an electronic control unit. The control unit is arranged in the tool body. As an electronic control unit, the control unit can, in particular, comprise one or more microcontrollers and / or microprocessors with corresponding program code and / or other components of a generally known type, such as ASICs. In particular, in an embodiment in which the cutting tool comprises a sensor unit as described below, the control unit can simultaneously be designed for signal processing and evaluation, or comprise a signal processing unit. In one embodiment, the cutting tool comprises a sensor unit.The sensor unit is at least partially integrated into the tool body. The sensor unit is operationally coupled to the control unit for transmitting a sensor signal. The sensor unit is designed to detect at least one measured variable that characterizes the state of the cutting tool relative to a workpiece. The control unit is designed to control the valve unit based on the sensor signal.

[0031] The control unit generally comprises one or more sensors, as described below. A sensor can provide a quantitative analog or digital output signal representing a measured quantity, or it can provide a binary signal that changes abruptly depending on the measured quantity when a threshold value is exceeded or fallen below. This can be the case, for example, with proximity sensors, as described below.

[0032] The control unit is specifically designed as an electronic control unit for real-time data processing. The control unit is preferably designed to evaluate the sensor signal without significant delay and to control the valve unit accordingly.

[0033] The condition of the cutting tool in relation to the workpiece can be characterized, in particular, by the presence or absence of a cutting engagement. In one embodiment, the sensor unit is designed to detect whether machining is taking place, or whether a cutting engagement is present for at least one cutting element.

[0034] In one embodiment, the sensor unit is designed to detect a cutting engagement for each cutting element separately. In particular, the sensor unit can be designed to detect for each cutting element whether a cutting engagement is taking place. Additionally or alternatively, the sensor unit can be designed to detect the imminent entry and / or exit of a workpiece for each cutting element. Additionally or alternatively, the sensor unit can be designed to detect a completed workpiece entry and / or exit for each cutting element.

[0035] In principle, the sensor unit can comprise a single sensor. However, in one embodiment, the sensor unit comprises a number of sensors. In this case, the sensor signal can comprise a number of components, each component being the individual sensor signal of a single sensor, or the sensor signal can be a vector whose components are formed by the individual sensor signals of the individual sensors. The number of vector components typically corresponds to the number of individual sensors. A sensor can also generate multiple individual sensor signals. This can be the case, in particular, for sensors that measure a vector quantity or a quantity in multiple spatial directions, such as multi-axis force, acceleration, vibration, or deformation sensors.In one embodiment, the sensor unit comprises at least one local sensor, wherein each local sensor is assigned to a specific cutting element mounting structure or a specific cutting element. In another embodiment, at least one local sensor is assigned to each cutting element mounting structure or each cutting element. In further embodiments, a sensor is provided not on every cutting element, but, for example, only on one, and the cutting engagement is individually detected for each revolution only for this cutting element, while the cutting engagement for the remaining cutting elements is determined computationally based on the tool movement.

[0036] A local sensor is typically located directly on or in the immediate vicinity of the respective cutting element mounting structure, or is wholly or partially integrated into it. Depending on the design, a local sensor can also be wholly or partially integrated into a cutting element.

[0037] A measured value detected by such a local sensor, or the individual sensor signal it provides, relates to the cutting action of a cutting element attached to the respective cutting element mounting structure. The individual sensor signal is characteristic of the state of the respective cutting element in relation to the workpiece, particularly with regard to the cutting action.

[0038] In one embodiment where at least one local sensor is uniquely assigned to each cutting element mounting structure, the number of local sensors corresponds at least to the number of cutting element mounting structures. With a number of sensors corresponding to the number of cutting element mounting structures, a one-to-one assignment or a pairwise assignment is particularly possible. In another embodiment, a group of more than one local sensor is uniquely assigned to each cutting element mounting structure. The sensors assigned to one and the same cutting element mounting structure can, in particular, be designed to detect different measured variables. Due to the unique assignment between sensors and cutting elements, the state of each cutting element on the workpiece can be detected separately and evaluated by the electronic control unit.In another embodiment, not all, but only one cutting element mounting structure or a number of cutting element mounting structures, which is less than the total number of cutting element mounting structures, are uniquely assigned one or more local sensors.

[0039] In one embodiment, the sensor unit comprises at least one global sensor. Unlike a local sensor, a global sensor is not assigned to a specific cutting element mounting structure or a specific cutting element.

[0040] A global sensor can provide information, via its measured variable(s), that characterizes the overall state of the cutting tool in relation to the workpiece. Specifically, global sensors can detect whether machining is taking place, or whether at least one cutting element is engaged. As described below, a global sensor can also be designed, like a local sensor or an array of local sensors, to provide specific information regarding a particular cutting element, and especially regarding each cutting element, with respect to the cutting engagement.

[0041] In one embodiment, the sensor unit comprises at least one acoustic sensor and / or one vibration sensor and / or at least one force sensor for force measurement on the mounting structure as a global sensor.

[0042] An acoustic sensor can be designed, in particular, as a microphone. Each impact of a cutting element or edge onto the workpiece generates a percussive noise. The control unit can be designed to detect this percussive noise and thus the initial contact of a cutting element or edge with the workpiece. The percussive noise is characterized, in particular, by a sudden increase in the signal level. The workpiece contact of the cutting tool is characterized by a substantially abrupt drop in the signal level. The control unit can further be designed to filter the signal provided by the acoustic sensor using a high-pass, low-pass, or band-pass filter. In particular, band-pass filtering can be provided for a frequency range characteristic of machining processes. This range is typically between 50 kHz and 200 kHz.

[0043] A force sensor for measuring force on the mounting structure can, for example, comprise at least one strain gauge and / or piezoelectric sensors as transducers. The force detected by the force sensor acts between the mounting structure and the tool holder. It results from the cutting force of the cutting elements in cutting engagement. In particular, the magnitude of the force can be used to determine whether cutting engagement is taking place or whether machining is occurring. In one embodiment, the cutting tool comprises a number of force sensors distributed circumferentially around the mounting structure, each providing an individual sensor signal. The control unit can be designed to jointly evaluate the individual sensor signals provided by the individual force sensors and determine which cutting element(s) are in cutting engagement.For this purpose, the control unit can be designed to evaluate the individual sensor signals according to magnitude and phase, particularly using a fast Fourier transform (FFT). Phase can also be determined based on a single signal. For example, if the force on a cutting edge is measured, the phase of the impacts changes by 90° when milling is first performed along the X-axis and then switched to the Y-axis at a corner of the component. The valves must trigger accordingly with a delay or advance.

[0044] An acceleration or vibration sensor, acting as a global sensor, can be arranged, in particular, inside the tool body. An acceleration or vibration sensor can, in particular, be a multi-axis sensor, especially a two-axis or three-axis sensor, wherein two axes are in a plane perpendicular to the axis of rotation. The control unit can be designed to determine, from directional information provided by the acceleration or vibration sensor, which cutting element(s) are engaged.

[0045] In one embodiment, the sensor unit comprises at least one temperature sensor and / or at least one force sensor and / or at least one optical sensor, in particular an optical proximity sensor, and / or at least one electrical contact and / or proximity sensor as a local sensor.

[0046] In one embodiment, the sensor unit comprises at least one associated local sensor for each cutting element mounting structure or cutting element. In another embodiment, the sensor unit comprises at least one identical sensor for each cutting element mounting structure or cutting element. In yet another embodiment, the sensor unit comprises a group of local sensors for each cutting element mounting structure or cutting element. The local sensors associated with one and the same cutting element mounting structure or cutting element are preferably different. The sensor groups are preferably identical to each other.

[0047] Force sensors can be implemented, for example, as piezoelectric, capacitive, or tensile strip force sensors and can be fully or partially integrated into the respective cutting element mounting structure and / or operationally coupled to it. A force sensor, as a local sensor, detects the cutting force acting on the respective cutting element during cutting. A temperature sensor, also as a local sensor, detects the temperature of the respective cutting element. A temperature sensor can, for example, be an electrical temperature sensor integrated into the respective cutting element mounting structure and / or thermally coupled to it. In another embodiment, the temperature sensor comprises a sensor circuit that interacts with a thermoelectric coating of the cutting elements via an electrical interface.In a further embodiment, the temperature sensor comprises a radiation-based temperature sensor, in particular an infrared temperature sensor. A temperature sensor, acting as a local sensor, detects the cutting element temperature of the respective cutting element. The control circuit can be designed to detect a cutting action based on the cutting element temperature. In particular, the cutting element temperature rises during an ongoing cutting action.

[0048] An optical proximity sensor can be designed, in particular, as an infrared reflective optical barrier. In this context, it is advantageous that typical cooling lubricants are essentially optically transparent in the near-infrared range. An optical proximity sensor is designed to detect the approach of the respective cutting element to the workpiece and / or the departure of the respective cutting element from the workpiece. Similarly, an electrical proximity sensor can be provided for this purpose. This can be designed, in particular, as an inductive or capacitive sensor. An electrical contact sensor can be designed to detect an electrically conductive connection between the respective cutting element and the workpiece, which is usually metallic or electrically conductive.For this purpose, an electrical contact sensor can include an electrical impedance or resistance measuring circuit designed to detect an electrical impedance or resistance between the respective cutting element and the workpiece. In such an embodiment, the cutting element mounting structures are advantageously insulating with respect to the respective cutting element.

[0049] Proximity sensors are particularly advantageous because they allow the impending entry of a cutting element into the workpiece, and thus the start of a cutting action, to be detected prematurely, even before, for example, an electrical contact is closed across the workpiece or a measurable cutting force is present. This allows the valve assembly or the individual valve for supplying coolant to be activated before the start of the cutting action, or with a pre-action. The pre-action is preferably determined by, and can correspond to, the response time of the valve assembly or the individual valve. In this way, contact between the cutting element and the coolant can begin as soon as the workpiece engagement starts.

[0050] The global and local sensors described above are electrical sensors that transmit electrical signals to the control system. In a further embodiment, the cutting tool comprises one or more thermomechanical elements that combine a temperature sensor and a valve actuator. A thermomechanical element generates movement depending on a temperature or a temperature change. In this case, the control of the valve unit or its valves is wholly or partially mechanical. The control unit can be designed wholly or partially as a mechanical control unit and may include linear and / or nonlinear transmission elements between the thermoelectric element and the valve assembly or the respective valve.Thermomechanical elements can be, in particular, expansion material factorizers, especially those based on thermosetting wax, and / or bimetallic elements. A thermomechanical element is thermally coupled to the respective cutting element or the cutting element mounting structure.

[0051] In one embodiment, the control unit is designed to take a valve response time into account when controlling the valve unit. The valve response time is a time delay with which the valve arrangement, or its valves, react to a control signal. It can be identical in both directions, i.e., when opening and closing, or increasing or decreasing the valve opening, but it can also be different. At the start of a cutting operation, the valve response time can be taken into account, as described above, by initiating the control signal for the supply of coolant with a corresponding lead time and before the start of the cutting operation. This ensures that coolant is present from the start of machining, but not, or not significantly, earlier.At the end of the cutting operation, the valve response time can also be taken into account by a lead time, whereby a control signal to stop the supply of coolant is triggered before the end of the cutting operation or before the workpiece exits the respective cutting element. By stopping the supply of coolant at the end of the cutting operation, the undesirable thermal shock after the workpiece exits can be reduced and ideally avoided.

[0052] In one embodiment, the control unit comprises or implements a mathematical model, in particular a first-order mathematical model, for calculating the cutting element temperature of one or more cutting elements from the cutting force and the duration of the cutting engagement. This has proven advantageous because a cutting edge that is only engaged briefly for the same chip thickness has a lower cooling requirement than a cutting edge that is engaged for a longer period, even though the forces acting on it are the same.

[0053] In one embodiment, the control unit is designed to filter or post-process the sensor signal, or some or all of the individual sensor signals, over time, for example by low-pass filtering, such as moving average calculation, and / or the elimination of outliers. This results in a post-processed sensor signal. The post-processing is preferably carried out over several tool revolutions. In this way, smoothing and damping and / or elimination of artifacts such as outliers can be achieved. The control unit can be designed to control the valve unit depending on the post-processed, and in particular filtered, sensor signal. In another embodiment, the control unit can be designed to predict the time of workpiece entry and / or exit for each cutting element from the sensor signal.Knowing the tool movement, this predictive calculation can be performed, in particular, by evaluating the post-processed, especially filtered, sensor signal. In such a design, future cutting engagements are determined by evaluating previous cutting engagements in earlier revolutions, which are detected by the sensor unit or its sensors. This is possible because the situation regarding the cutting engagement, or the times of workpiece entry and exit, typically changes only slightly between individual revolutions of the cutting tool.

[0054] In one embodiment, the control unit is designed for data exchange with an external sensor unit and / or an external data processing system. An external sensor unit can, for example, comprise an external force sensor. "External" means that the respective unit is not part of the cutting tool, but is, for example, part of a machine tool or mounted on one. The output signals of external sensor units can be processed by the control unit in the same way as those of a previously described integrated sensor unit and can be a functional component of a sensor unit.

[0055] An external data processing system can be, for example, a machine tool control system, particularly a CNC control system, and / or another data acquisition system for monitoring and / or storage, such as for quality assurance and wear detection. Furthermore, the machine control system can transmit operating parameters and / or commands to the control unit of the cutting tool. For instance, the control unit can have an operating mode and an alternative standby mode with low or negligible energy consumption. Commands transmitted by the machine control system allow switching between these modes. Parameters can include, for example, required coolant dosages, as well as intended and / or maximum cutting forces and / or temperatures of the cutting element.

[0056] In one embodiment, the control unit and / or an external data processing system is designed to monitor one or more measured variables or variables derived therefrom for compliance with limit values ​​and, in the event of limit value being exceeded, to imitate a corresponding reaction, for example, triggering an alarm and / or a controlled termination of the workpiece processing.

[0057] In one embodiment, an external data processing system can be, in particular, the control unit for the coolant supply system of the machine tool. Specifically, the control unit can be designed to transmit the required pressure and / or flow rate of coolant to the control unit of the coolant supply system. For data exchange, the cutting tool and the external data processing system or the machine tool can have corresponding communication interfaces, which can be unidirectional or bidirectional. The communication interfaces can be wireless and, for example, be radio interfaces based on the Bluetooth standard or WLAN interfaces. Furthermore, the communication interfaces can be designed as wireless inductive and / or capacitive interfaces.The corresponding interfaces can be arranged, in particular, in or on the mounting structure of the cutting tool and the tool holder of the machine tool. In one embodiment, the communication interfaces comprise electrical contacts, which are preferably arranged on the mounting structure of the cutting tool and the tool holder of the machine tool.

[0058] In another aspect, the problem is solved by using a valve arrangement to control the supply of coolant to a number of cutting elements of a cutting tool. The valve arrangement is located in a base body of the cutting tool. The cutting tool is attached to a rotating tool holder of a machine tool. The cutting tool can, in particular, be a cutting tool according to the present disclosure as described above and below. Specific embodiments of the use result directly from corresponding embodiments of the cutting tool. BRIEF DESCRIPTION OF FIGURES

[0059] Fig. 1 shows a cutter head according to the revelation in a highly schematic overview representation.

[0060] EXAMPLES OF EXECUTION

[0061] Figure 1 shows a cutter head 1 as an example of a machining tool according to the disclosure in a schematic functional representation. The cutter head 1 comprises a tool body 1.1, typically made of steel. A mounting structure 1.1.1 serves to mount the cutter head 1 to the tool holder of a machine tool (not shown), such as a milling machine. The mounting structure 1.1.1 can, for example, be designed as a hollow shank cone. A number of cutting element mounting structures 1.1.2 are arranged on the tool body as described in the general description. The cutting element mounting structures 1.1.2 are typically arranged evenly distributed around the circumference of the tool body 1.1. Figure 1 shows, by way of example, two cutting element mounting structures 1.1.1 for two cutting elements 2.

[0062] According to the disclosure, the cutter head 1 has a fluidic arrangement with a number of coolant outlets 1.2 in the form of nozzles. For example, one coolant outlet 1.2 is provided for each cutting element mounting structure 1.1.1. The respective coolant outlet 1.2 for each cutting element mounting structure 1.1.2 and the cutting element 2 mounted thereon is arranged such that it supplies coolant to the respective assigned cutting element 2 and only to that cutting element. The supply of coolant is therefore individually controlled during operation.

[0063] The fluidic arrangement further comprises a coolant connection 1.3 arranged on and / or integrated into the mounting structure 1.1.1 for supplying coolant from a (not shown) coolant supply system of the machine tool.

[0064] The fluidic arrangement further comprises a valve arrangement located in the base body 1.1. In the illustrated embodiment, the valve arrangement comprises two valves 1.4, which are implemented, for example, as piezoelectric or electromagnetic high-speed switching valves. Other valves as described in the general description are possible. Each valve 1.4 is uniquely assigned to a cutting element mounting structure 1.1.2 or a cutting element 2 and the respective coolant outlet 1.2. Coolant can be supplied in a controlled manner to the respective coolant outlet 1.2 and thus to the respective cutting element 2 via a valve 1.4. The coolant outlets 1.2 are fluidically connected to the coolant connection 1.3 via the corresponding valve 1.4 and fluidic lines (not referenced) located in the tool base body 1.1.The arrangement within the cutter head 1 results in low fluidic volumes and elasticities of the fluidic arrangement. The cutter head 1 also includes a control unit 1.5, which is implemented electronically and typically comprises one or more microprocessors and / or microcontrollers, as well as optionally other electronic components and / or functional units. The control unit 1.5 further includes a signal processing unit and a control circuit for controlling the valves 1.4.

[0065] The cutter head 1 further comprises a sensor unit 1.8 arranged in the tool body 1.1. The sensor unit comprises a number of electrical sensors, each of which is connected to the control unit 1.5 or its signal processing unit. By way of example, the sensor unit 1.8 comprises a temperature sensor 1.8.1, a vibration sensor 1.8.2 and an acoustic sensor or microphone 1.8.3.

[0066] The temperature sensor 1.8.1 is thermally coupled to a cutting element mounting structure 1.1.1 and the corresponding cutting element 2, thus measuring its temperature. The temperature sensor 2 is a local sensor in this context.

[0067] The preferably multi-axis, in particular two-axis, vibration sensor 1.8.2 and the acoustic sensor 1.8.3 are also arranged within the tool base body 1.1 and are global sensors. Additional or alternative sensors as described in the general description are possible.

[0068] The control unit 1.5 is designed, in particular through appropriate programming using program code, to evaluate a sensor signal formed by the individual sensor signals of sensors 1.8.1, 1.8.2, and 1.8.3, and to determine in real time the status of each cutting element 2 with respect to a workpiece, and to control the valves 1.4 accordingly. Specifically, the control unit 1.5 is designed to determine for each cutting element 2 whether it is in a cutting engagement and / or to detect the times of workpiece entry and / or exit for each cutting element 2. In this embodiment, the control unit 1.5 is designed to control or open the respective associated valve 1.4. Control the supply of coolant to each cutting element 2 in such a way that coolant is supplied to the cutting element 2 at least substantially during its cutting action and no or only a negligible amount of coolant is supplied outside of its cutting action.

[0069] In the illustrated embodiment, the cutter head 1 further comprises an electrical power supply 1.6 mounted in the tool body 1.1, which is implemented here by way of example as a rechargeable battery. Alternatively or additionally, an inductive or contact-based supply interface to the machine tool can be provided for the power supply and, if necessary, for charging the battery.

[0070] In the illustrated embodiment, the cutter head 1 further comprises an optional communication interface 1.7 arranged in the tool body 1.1 for data communication with an external data processing system as described in the general description. The communication interface 1.7 can, in particular, be a radio interface, an inductive interface, or a contact-based interface. The electrical power supply 1.6 and / or a power supply interface, as well as the communication interface 1.7, can be part of the control unit 1.5 or operationally coupled to it.

[0071] LIST OF REFERENCE MARKS

[0072] 1 cutter head

[0073] 1.1 Tool body

[0074] 1.1.1 Mounting structure 1.1.2 Cutting element mounting structure

[0075] 1.2 Coolant leakage

[0076] 1.3 Coolant connection

[0077] 1.4 Valve

[0078] 1.5 Control unit 1.6 Electrical power supply

[0079] 1.7 Communication interface

[0080] 1.8 Sensor unit

[0081] 1.8.1 Temperature sensor

[0082] 1.8.2 Vibration sensor

[0083] 1.8.3 acoustic sensor / microphone

[0084] 2 cutting element

Claims

PATENT CLAIMS 1. Cutting tool, in particular cutter head (1), the cutting tool comprising: - a tool body (1.1 ) with a mounting structure (1.1.1 ) for attaching the cutting tool to a rotating tool holder of a machine tool and a number of cutting element mounting structures (1 .1 .2 ) for a number of cutting elements, - a fluidic arrangement comprising a number of coolant outlets (1.2), a coolant connection (1.3) for connection to a coolant supply and a valve arrangement, wherein the coolant outlets (1.2) are attached to the tool body (1.1) and / or are at least partially integrated into the tool body (1.1), wherein the valve arrangement is located in the tool body (1.1) and the coolant outlets (1.2) are fluidically connected to the coolant connection (1.3) through the valve arrangement.

2. Cutting tool according to claim 1, wherein the cutting tool is designed to control the supply of coolant to each cutting element (2) via the valve unit depending on its respective cutting engagement.

3. Cutting tool according to one of the preceding claims, wherein each cutting element fastening structure (1.1.2) is uniquely assigned at least one coolant lubricant outlet (1.2).

4. Cutting tool according to one of the preceding claims, wherein each coolant outlet (1.2) is uniquely assigned a valve (1.4) of the valve arrangement, wherein each coolant outlet (1.2) and the assigned valve (1.4) are fluidically connected.

5. Cutting tool according to one of the preceding claims, wherein the valve arrangement comprises at least one switching valve and / or control valve.

6. Cutting tool according to one of the preceding claims, wherein the cutting tool comprises a control unit (1.5) coupled to the valve unit, in particular an electronic control unit, wherein the control unit (1 ,5) is preferably arranged in the tool body (1.1 ).

7. Cutting tool according to claim 6, wherein the cutting tool comprises a sensor unit (1.8), wherein the sensor unit (1.8) is at least partially arranged in the tool body (1.1), wherein the sensor unit (1.8) is operationally coupled to the control unit (1.5) for transmitting a sensor signal, wherein the sensor unit (1.8) is designed to detect at least one measured quantity that characterizes a state of the cutting tool with respect to a workpiece, wherein the control unit (1 .5) is designed to control the valve unit depending on the sensor signal.

8. Cutting tool according to claim 7, wherein the sensor unit (1.8) is designed to detect a cutting engagement separately for each cutting element.

9. Cutting tool according to one of claims 7 to 8, wherein the sensor unit (1.8) comprises at least one local sensor, wherein each local sensor is assigned to a specific cutting element mounting structure or a specific cutting element.

10. Machining tool according to claim 9, wherein at least one local sensor is assigned to each cutting element mounting structure or to each cutting element.

11. Cutting tool according to claim 9 or claim 10, wherein the sensor unit (1 .8) comprises at least one temperature sensor (1 .8.1 .) and / or at least one force sensor and / or at least one optical sensor, in particular an optical proximity sensor, and / or at least one electrical contact and / or proximity sensor as a local sensor.

12. Cutting tool according to claims 7 to 11, wherein the sensor unit (1.8) comprises at least one global sensor, wherein each global sensor is not associated with any specific cutting element fastening structure.

13. Machining tool according to claim 12, wherein the sensor unit (1.8) comprises at least one acoustic sensor (1.8.3) and / or at least one force sensor for force measurement on the mounting structure as a global sensor.

14. Cutting tool according to any one of claims 6 to 13, wherein the control unit is designed for data exchange with an external sensor unit and / or an external data processing system.

15. Use of a valve arrangement which is arranged in a tool body (1.1 ) of a cutting tool, in particular a cutter head (X), for controlling the supply of coolant to a number of cutting elements, wherein the cutting tool is attached to a rotating tool holder of a machine tool.

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