Device and method for avoiding downtimes of a machine tool

Abstract

Device (1) for avoiding downtimes of a machine tool (2), comprising the machine tool (2), a safety sensor system (3), at least one error sensor (4) and a computing unit (5), wherein the computing unit (5) is connected to the machine tool (2), the safety sensor system (3) and the error sensor (4), wherein the computing unit (5) is configured to control the machine tool (2) according to a production program for producing at least one workpiece part, wherein the device (1) is configured to detect an error in the machine tool (2) by means of the error sensor (4), wherein the device (1) is configured to detect a danger to the machine tool (2) by means of the safety sensor system (3), wherein the computing unit (5) is configured to stop the machine tool (2) when a danger to the machine tool (2) has been detected, wherein the computing unit (5) is configured toif a fault of the machine tool (2) has been detected and a danger to the machine tool (2) has been excluded, to evaluate the fault and, depending on the evaluation of the fault, to control the machine tool (2) deviating from the production program and to continue the production of at least one workpiece part.

Description

The invention relates to a device for avoiding downtime of a machine tool.The invention further relates to a method for avoiding downtime of a machine tool.DE 10 2015 003 435 A1 discloses a laser processing device, wherein a processing nozzle is retracted in the event of a power failure.The object of the invention is to provide a device mentioned at the beginning and a method mentioned at the beginning which avoids fault-related standstill in a machine tool.The object is achieved by a device for avoiding downtime of a machine tool, comprising the machine tool, a safety sensor system, at least one fault sensor and a computing unit, wherein the computing unit is connected to the machine tool, the safety sensor system and the fault sensor, wherein the computing unit is configured to actuate the machine tool according to a production program for producing at least one workpiece part, wherein the device is configured to detect a fault of the machine tool by means of the fault sensor, wherein the device is configured to detect a risk for the machine tool by means of the safety sensor system, wherein the computing unit is configured to stop the machine tool if a risk for the machine tool has been detected, wherein the computing unit is configured to detect a fault of the machine tool and a risk for the machine tool has been excluded, evaluating the fault and, depending on the evaluation of the fault, controlling the machine tool differently from the production program and continuing the production of the at least one workpiece part.In the device, a distinction is made between the fault sensor and the safety sensor system. A safety sensor system can be designed to detect persons or objects entering a working area of the machine tool. This can be done, for example, by means of light barriers, radar and / or ultrasonic sensors. Entry of persons or objects into a working area of the machine tool represents a risk and leads to an immediate stop of the machine tool. A fault sensor may be configured to detect abnormal and / or unexpected behavior of the machine tool. Such a fault frequently represents no direct risk. The invention makes it possible to avoid a standstill of the machine tool in the event of a fault which does not represent a risk. By controlling the machine tool deviating from the production program, the production of the at least one workpiece part can be continued despite the fault.In other words, in the event of a fault, the computing unit adjusts the production program to the changed boundary conditions and continues the production of the at least one workpiece as much as possible. Production is stopped only in the event of a risk detected by the safety sensor system.A machine tool can be, in particular, a laser cutting machine, a punching machine or a laser cutting-punching combination machine.In an advantageous embodiment, the machine tool comprises a laser cutting head, wherein the fault sensor is a collision sensor, wherein the collision sensor is configured to detect a collision of the laser cutting head with an object. The machine tool can be configured, for example, to cut a plurality of workpiece parts from a sheet metal by means of the laser cutting head. In this case, it can occur that already cut-out workpiece part tilts on the sheet metal support and the laser cutting head collides with the tilted workpiece part. The collision can be detected by means of the collision sensor.In an advantageous embodiment, the device comprises an imaging system in addition to the error sensor, wherein the computing unit is connected to the imaging system, wherein the computing unit is configured to evaluate an error detected by means of the error sensor by means of the imaging system. By means of the imaging system, additional information for evaluating the fault is available to the computing unit. The computing unit is thus better able to adapt the control of the machine tool. This is particularly advantageous in combination with the collision sensor. The imaging system can be used to determine the location and type of object with which the laser cutting head collides. As a result, the computing unit is able to adapt the control of the machine tool accordingly. The imaging system may include a camera, a radar sensor, and / or a lidar sensor.In an advantageous embodiment, the computing unit is configured to evaluate the error as automatically elevatable or manually elevatable. By distinguishing it from manually recoverable and automatically recoverable, the computing unit is able to execute the best strategy for recovering from the fault.In an advantageous embodiment, the computing unit is configured to actuate the machine tool to eliminate an automatically recoverable fault. Due to the automatic correction of the error, it is not necessary to carry out a manual error correction at a later point in time. After the error correction, the execution of the production program can be continued by the computing unit without adaptation.In an advantageous embodiment, the device has a signal output unit, wherein the computing unit is connected to the signal output unit, wherein the computing unit is configured to output a signal to an operator by means of the signal output unit in the event of a manually recoverable fault. By outputting the signal, the operator can be alerted to a necessary manual error correction. The operator can thus carry out the error correction promptly and a shutdown time of the machine tool that otherwise occurs later is avoided. The arithmetic unit controls the machine tool as long as the fault exists and production is possible with an adapted production program. After the manual error correction, the execution of the production program can be continued by the arithmetic unit without adaptation.In an advantageous embodiment, the computing unit is configured to detect a correction of the fault, in particular by means of the fault sensor, and to put the machine tool into a normal mode after the fault has been corrected and to continue the production program. After the fault has been eliminated, no adapted control of the machine tool is necessary and the production program can be executed unchanged by the computing unit.In one configuration, the machine tool comprises a cooling system, wherein the fault sensor is configured to detect inadequate cooling, wherein the computing unit is configured to actuate the machine tool, in particular with reduced power, such that the machine tool produces the at least one workpiece part despite inadequate cooling. Defective cooling can arise, for example, as a result of a defect in the cooling system or else as a result of erroneous operation. The adapted control nevertheless allows production of the at least one workpiece part. This is particularly advantageous in a laser cutting machine. Lasers for laser cutting machines frequently have a power of several kilowatts and require sufficient cooling for this purpose. By lowering the laser power, the processing time increases, but the cooling requirement decreases, so that production is possible.In one configuration, the machine tool comprises a peripheral component, in particular a pallet changer, a nozzle changer, a loading unit or an unloading unit, wherein the fault sensor is configured to detect a fault of the peripheral component, wherein the computing unit is configured to actuate the machine tool such that the machine tool produces the at least one workpiece part without using the faulty peripheral component. A fault does not directly lead to a standstill of the machine tool, but production is continued as far as possible without using the faulty peripheral component. For example, in the event of a fault on pallet changer, a loading unit or an unloading unit, work can be carried out with the materials located in the machine tool as long as the faulty peripheral unit is not absolutely required. In the event of a defect in a nozzle changer, for example in a laser cutting machine, production can be continued with the nozzle present. This may result in a reduced quality of the produced workpiece, but avoids downtime.The invention also relates to a method for avoiding downtime of a machine tool, wherein a computing unit actuates the machine tool according to a production program, wherein the computing unit stops the machine tool when a safety sensor system detects a risk, wherein the computing unit detects a fault by means of a fault sensor, wherein the computing unit evaluates the fault and actuates the machine tool in a manner deviating from the production program as a function of the evaluation, and thus production of the at least one workpiece part by means of the machine tool is continued when a fault sensor detects a fault and the safety sensor system excludes a risk.In a preferred embodiment, the error is evaluated as automatically elevatable or manually elevatable. By distinguishing it from manually recoverable and automatically recoverable, the computing unit is able to execute the best strategy for recovering from the fault.In a preferred embodiment, the fault is corrected automatically if the fault has been evaluated as automatically recoverable. Due to the automatic correction of the error, it is not necessary to carry out a manual error correction at a later point in time. After the error correction, the execution of the production program can be continued by the computing unit without adaptationIn a preferred embodiment, a signal is output to an operator by means of a signal output unit if the error has been evaluated as being manually liftable.The following description of preferred embodiments serves to explain the invention in more detail in conjunction with the drawings. The following are shown: FIG. 1 shows an apparatus with a laser cutting machine.Identical or functionally equivalent elements are denoted by the same reference symbols in all exemplary embodiments.FIG. 1 shows a device 1 with a machine tool 2, here a laser cutting machine. A part of the machine tool 2 is delimited by a safety sensor system 3, here a light barrier system. By means of the safety sensor system 3, the device is able to detect a risk for the machine tool 2. In this example, it is possible to determine by means of the light barrier system 3 when an object penetrates into a safety area of the machine tool 2. The penetration of an object into the safety area is evaluated as a risk and leads to an immediate standstill of the machine tool 2.The machine tool 2 comprises a laser source 21, and the laser source 21 generates a laser with which workpiece parts can be cut from a sheet metal in a working region 31 of the machine tool 2. The machine tool 2 includes a plurality of peripheral components 12, and in this example, the peripheral components 12 are a cooling system 11 for cooling the laser source 21, and a pallet changer 13.The apparatus 1 also includes a computing unit 5 and a signal output unit 9. the computing unit 5 is configured to drive the machine tool 2 according to a production program for producing at least one workpiece part. For production, the laser is guided from the laser source 21 into the working region 31 and is guided there into a laser cutting head 6, which is described in more detail in connection with FIG. 2. The laser cutting head 6 is moved over a metal sheet within the working region 3 in such a way that contours of the workpiece part are cut into the metal sheet by means of the laser and the workpiece part is thus cut from the metal sheet. After cutting, the workpiece part is conveyed out of the work area 31 by means of the pallet changer 13 and a new sheet is conveyed into the work area 31. The device 1 also comprises an imaging system 8, here a camera. The camera 8 is configured such that its field of view is directed into the working area. Via the signal output unit 9, here a screen, the computing unit 5 can output information to an operator.The device 1 comprises a plurality of error sensors 4. In this example, error sensors 4 are located on the cooling system 11, on the laser cutting head 6 and on the pallet changer 13. The arithmetic unit 5 is configured to, when a fault has been detected and a risk for the machine tool 2 has been ruled out, evaluate the fault and, depending on the evaluation of the fault, actuate the machine tool 2 differently from the production program and continue the production of the at least one workpiece part.If the fault sensor 4 on the cooling system 11 detects inadequate cooling, the arithmetic unit 5 can assess which power of the laser can still be reliably cooled and whether this power is sufficient for the production of the at least one workpiece part. The arithmetic unit then controls the machine tool, deviating from the production program, in such a way that the at least one workpiece part is produced with a reduced laser power and the cooling power is sufficient.If the fault sensor 4 detects a fault on the pallet changer 13, the computing unit 5 can assess whether the function of the pallet changer 13 is necessary for the production of the at least one workpiece part. The arithmetic unit 5 then controls the machine tool 2 in such a way, deviating from the production program, that the actuation of the pallet changer is skipped and the actuation of the functions necessary for the production of the at least one workpiece part is carried out.The actuation of the machine tool 2 deviating from the production program is stopped immediately if a risk is detected by means of the safety sensor system 3. If a fault is detected by means of a fault sensor 4 and a risk is detected by means of the safety sensor system 3, this leads to an immediate standstill of the machine.In FIG. 2, a laser cutting head 6 is shown. The laser cutting head 6 has a fault sensor with which a collision of the laser cutting head 6 with an object can be detected. The laser cutting head 6 has an upper housing part 22 and a lower housing part 23. The laser cutting head 6 has an overload clutch 24 between the upper housing part and the lower housing part 23, which is always guided, even in the deflected state, and can thus independently find its original position.FIG. 3 shows that the lower housing part 23 can be deflected with respect to the upper housing part 23 when the laser cutting scope 6 collides with an object, for example a cut workpiece part. This deflection can be detected by the error sensor 4. The laser cutting head 6 comprises a reset arrangement which comprises springs and dampers. With the reset arrangement, after a collision, the lower housing part 23 is aligned with the upper housing part 22.Further details of the laser cutting head 6 are known from DE102021126756A1, the disclosure content of which is hereby incorporated in its entirety.If the fault sensor 4 on the laser cutting head 6 detects a collision, the computing unit 5 can assess whether a deflection of the lower housing part 23 that occurred due to the collision can be reversed by a travel movement and use of the reset arrangement. The arithmetic unit 5 then controls the machine tool 2 in such a way, deviating from the production program, that the laser cutting head is removed from the object with which it has collided and the deflection is reversed. Thereafter, the production program is continued for producing the at least one workpiece part. In evaluating the defect on the laser cutting head 6, the calculation unit 5 can use images of the camera 8. In the images, the computing unit can identify whether the influence of the collision was so slight that the deflection can be reversed by the restoring arrangement. In this case, the arithmetic unit 5 evaluates the error as being able to be automatically eliminated. If the influence of the collision was so strong that the deflection cannot be reversed by the reset arrangement, the arithmetic unit 5 evaluates the error as being able to be cancelled manually and outputs information to an operator via the signal output unit 9.By means of the fault sensor 4, the arithmetic unit 5 recognizes whether the fault has been corrected. When the fault is corrected, production of the at least one workpiece is continued according to the production plan. In order to identify whether the fault has been corrected, data from the camera 8 can also be used by the computing unit 5.List of reference characters1 Device 2 Machine tool 3 Safety sensor system 4 Fault sensor 5 Computing unit 6 Laser cutting head 7 Object 8 Imaging system 9 Signal output unit 11 Cooling system 12 Peripheral component 13 Pallet changer 21 Laser source 22 Upper housing part 23 Lower housing part 31 Working regionReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2015 003 435 A1

[0003] DE 102021126756A1

[0032]

Claims

Device (1) for avoiding standstill times of a machine tool (2), comprising the machine tool (2), a safety sensor system (3), at least one fault sensor (4) and a computing unit (5), wherein the computing unit (5) is connected to the machine tool (2), the safety sensor system (3) and the fault sensor (4), wherein the computing unit (5) is configured to actuate the machine tool (2) according to a production program for producing at least one workpiece part, wherein the device (1) is configured to detect a fault of the machine tool (2) by means of the fault sensor (4), wherein the device (1) is configured to detect a risk for the machine tool (2) by means of the safety sensor system (3), wherein the computing unit (5) is configured to stop the machine tool (2) if a risk for the machine tool (2) has been detected, wherein the computing unit (5) is configured to, when a fault of the machine tool (2) has been detected and a risk for the machine tool (2) has been ruled out, evaluate the fault and, depending on the evaluation of the fault, actuate the machine tool (2) differently from the production program and continue the production of the at least one workpiece part.The device (1) according to claim 1, wherein the machine tool (2) comprises a laser cutting head (6), wherein the fault sensor (4) is a collision sensor, wherein the collision sensor is configured to detect a collision of the laser cutting head (6) with an object (7).Device (1) according to one of the preceding claims, wherein the device (1) comprises an imaging system (8) in addition to the error sensor (2), wherein the computing unit (5) is connected to the imaging system (8), wherein the computing unit (5) is configured to evaluate an error detected by means of the error sensor (2) by means of the imaging system (8).Device (1) according to one of the preceding claims, wherein the computing unit (5) is configured to evaluate the error as automatically recoverable or manually recoverable.Device (1) according to Claim 4, wherein the arithmetic unit (5) is configured to actuate the machine tool (2) in order to eliminate an automatically recoverable fault.Device (1) according to Claim 4 or 5, wherein the device (1) has a signal output unit (9), wherein the arithmetic unit (5) is connected to the signal output unit (9), wherein the arithmetic unit (5) is configured to output a signal to an operator by means of the signal output unit (9) in the event of a manually recoverable fault.Device (1) according to one of the preceding claims, wherein the arithmetic unit (5) is configured to detect a correction of the fault, in particular by means of the fault sensor (4), and to put the machine tool (2) into a normal mode after the correction of the fault and to continue the production program.Device (1) according to one of the preceding claims, wherein the machine tool (2) comprises a cooling system (11), wherein the fault sensor (4) is configured to detect inadequate cooling, wherein the computing unit (5) is configured to actuate the machine tool (2), in particular with reduced power, such that the machine tool (2) produces the at least one workpiece part despite inadequate cooling.Device (1) according to one of the preceding claims, wherein the machine tool (2) comprises a peripheral component (12), in particular a pallet changer, a nozzle changer, a loading unit or an unloading unit, wherein the fault sensor (4) is configured to detect a fault of the peripheral component (12), wherein the computing unit (5) is configured to actuate the machine tool (2) such that the machine tool (2) produces the at least one workpiece part without using the faulty peripheral component (12).Method for avoiding standstill times of a machine tool (2), wherein a computing unit (5) actuates the machine tool (2) according to a production program, wherein the computing unit (5) stops the machine tool (2) when a safety sensor system (3) detects a risk, wherein the computing unit (5) detects a fault by means of a fault sensor (4), wherein the computing unit (5) evaluates the fault and actuates the machine tool (2) in a manner deviating from the production program depending on the evaluation, and thus the production of the at least one workpiece part by means of the machine tool is continued when the fault sensor (4) detects a fault and a safety sensor system (3) excludes a risk.Method according to claim 10, characterised in that the error is assessed as automatically elevatable or manually elevatable.Method according to Claim 11, characterized in that the fault is corrected automatically if the fault has been evaluated as automatically recoverable.Method according to Claim 11, characterized in that a signal is output to an operator by means of a signal output unit (9) if the fault has been assessed as being able to be corrected manually.

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