Device and method for avoiding downtimes in a machine tool

Abstract

The invention relates to a device (1) for avoiding downtimes in 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 programme for producing at least one workpiece part; wherein the device (1) is configured to identify an error of the machine tool (2) by means of the error sensor (4); wherein the device (1) is configured to identify a risk 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) if a risk to the machine tool (2) has been identified; wherein, if an error of the machine tool (2) has been identified and a risk to the machine tool (2) has been eliminated, the computing unit (5) is configured to evaluate the error and, depending on the evaluation of the error, to control the machine tool (2) in a deviation from the production programme and to continue production of the at least one workpiece part.

Description

[0001] Device and method for avoiding downtimes of a machine tool

[0002] The invention relates to a device for avoiding downtimes of a machine tool.

[0003] The invention further relates to a method for avoiding downtimes of a machine tool.

[0004] From DE 10 2015 003 435 A1 a laser processing device is known, wherein a processing nozzle is retracted in the event of a power failure.

[0005] The invention is based on the object of providing a device and a method as mentioned above which avoids fault-related downtime in a machine tool.

[0006] The object is achieved by a device for avoiding downtimes of a machine tool, comprising the machine tool, a safety sensor system, at least one error sensor and a computing unit, wherein the computing unit is connected to the machine tool, the safety sensor system and the error sensor, wherein the computing unit is configured to control the machine tool according to a production program for producing at least one workpiece part, wherein the device is configured to detect an error in the machine tool by means of the error sensor, wherein the device is configured to detect a danger to the machine tool by means of the safety sensor system, wherein the computing unit is configured to stop the machine tool when a danger to the machine tool has been detected, wherein the computing unit is configured toIf a machine tool error has been detected and a danger to the machine tool has been ruled out, the error is evaluated and, depending on the error evaluation, the machine tool is controlled differently from the production program and the production of at least one workpiece part is continued. The device distinguishes between error sensors and safety sensors. Safety sensors can be designed to detect the intrusion of persons or objects into the working area of ​​the machine tool. This can be done, for example, using light barriers,Radar and / or ultrasonic sensors are used. The intrusion of persons or objects into a machine tool's working area poses a hazard and leads to the immediate stop of the machine tool. An error sensor can be designed to detect abnormal and / or unexpected behavior of the machine tool. Such an error often does not pose a direct hazard. The invention makes it possible to avoid a machine tool stoppage in the event of an error that does not pose a hazard. By controlling the machine tool in a manner that deviates from the production program, production of at least one workpiece part can continue despite the error.

[0007] In other words, if an error occurs, the processing unit adapts the production program to the changed conditions and continues production of at least one workpiece as far as possible. Production is only stopped if a hazard is detected by the safety sensors.

[0008] A machine tool can in particular be a laser cutting machine, a punching machine or a laser cutting-punching combination machine.

[0009] In an advantageous embodiment, the machine tool comprises a laser cutting head, wherein the error 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, for example, be configured to cut a plurality of workpiece parts out of a sheet metal using the laser cutting head. In this case, it can happen that an 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, in addition to the error sensor, an imaging system, 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 using the imaging system.The imaging system provides the processing unit with additional information for evaluating the error. This makes it easier for the processing unit to adjust the machine tool's control. This is particularly advantageous in combination with the collision sensor. The imaging system can determine the location and type of object with which the laser cutting head collided. This allows the processing unit to adjust the machine tool's control accordingly. The imaging system can include a camera, a radar sensor, and / or a lidar sensor.

[0010] In an advantageous embodiment, the computing unit is configured to evaluate the error as either automatically correctable or manually correctable. By distinguishing between manually correctable and automatically correctable, the computing unit is able to implement the best strategy for correcting the error.

[0011] In an advantageous embodiment, the processing unit is configured to control the machine tool to correct an automatically correctable error. Automatic error correction eliminates the need for manual error correction at a later time. After the error has been corrected, the processing unit can continue executing the production program without any adjustments.

[0012] 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 rectifiable error. The signal output can alert the operator to the need for manual error correction. The operator can thus rectify the error promptly, and a downtime of the machine tool that would otherwise occur later is avoided. The computing unit controls the machine tool with an adapted production program as long as the error persists and production is possible. After manual error correction, the execution of the production program can be continued by the computing unit without adjustment.

[0013] In an advantageous embodiment, the computing unit is configured to detect the rectification of the error, in particular by means of the error sensor, and to return the machine tool to normal mode after the error has been rectified and to continue the production program. After the error has been rectified, no adjusted control of the machine tool is necessary, and the production program can be executed unchanged by the computing unit.

[0014] In one embodiment, the machine tool comprises a cooling system, wherein the error sensor is configured to detect inadequate cooling, wherein the computing unit is configured to control the machine tool, in particular with reduced power, so that the machine tool produces the at least one workpiece part despite inadequate cooling. Inadequate cooling can arise, for example, from a defect in the cooling system or from incorrect operation. Thanks to the adapted control, production of the at least one workpiece part is still possible. This is particularly advantageous for a laser cutting machine. Lasers for laser cutting machines often have an output of several kilowatts and therefore require sufficient cooling. Reducing the laser power increases the processing time, but the cooling requirement decreases, so that production is possible.

[0015] In one embodiment, the machine tool comprises a peripheral component, in particular a pallet changer, a nozzle changer, a loading unit or an unloading unit, wherein the error sensor is configured to detect an error in the peripheral component, wherein the computing unit is configured to control the machine tool such that the machine tool produces the at least one workpiece part without using the faulty peripheral component. An error 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 an error in a 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 necessary. In the event of an error in a nozzle changer, e.g.On a laser cutting machine, production can continue with the existing nozzle. This may result in reduced quality of the produced workpiece, but it avoids downtime.

[0016] The invention also relates to a method for avoiding downtimes of a machine tool, wherein a computing unit controls the machine tool according to a production program, wherein the computing unit stops the machine tool when a safety sensor detects a danger, wherein the computing unit detects an error by means of an error sensor, wherein the computing unit evaluates the error and, depending on the evaluation, controls the machine tool deviating from the production program and thus the production of the at least one workpiece part is continued by means of the machine tool when an error sensor detects an error and the safety sensor excludes a danger.

[0017] In a preferred embodiment, the error is assessed as either automatically correctable or manually correctable. By distinguishing between manually correctable and automatically correctable, the computing unit is able to implement the best strategy for correcting the error.

[0018] In a preferred embodiment, the error is automatically corrected if the error has been assessed as being automatically correctable. Due to the automatic correction of the error, it is not necessary to carry out manual error correction at a later time. After the error has been corrected, the processing unit can continue to execute the production program without adjustment. In a preferred embodiment, a signal is output to an operator by means of a signal output unit if the error has been assessed as being manually correctable.

[0019] The following description of preferred embodiments, taken in conjunction with the drawings, serves to further explain the invention. They show:

[0020] Fig. 1 shows a device with a laser cutting machine.

[0021] Identical or functionally equivalent elements are designated by the same reference numerals in all embodiments.

[0022] Fig. 1 shows a device 1 with a machine tool 2, in this case a laser cutting machine. Part of the machine tool 2 is delimited by a safety sensor system 3, in this case a light barrier system. Using the safety sensor system 3, the device is able to detect a hazard to the machine tool 2. In this example, the light barrier system 3 can be used to detect when an object enters a safety zone of the machine tool 2. The entry of an object into the safety zone is assessed as a hazard and leads to an immediate shutdown of the machine tool 2.

[0023] The machine tool 2 comprises a laser source 21. The laser source 21 generates a laser with which workpiece parts can be cut from a sheet metal in a work area 31 of the machine tool 2. The machine tool 2 comprises several peripheral components 12. In this example, the peripheral components 12 are a cooling system 11 for cooling the laser source 21 and a pallet changer 13.

[0024] The device 1 also comprises a computing unit 5 and a signal output unit 9. The computing unit 5 is configured to control 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 work area 31 and 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 sheet within the work area 3 such that contours of the workpiece part are cut into the sheet by means of the laser, thus cutting the workpiece part out of the sheet. After cutting, the workpiece part is transported out of the work area 31 by means of the pallet changer 13, and a new sheet is transported into the work area 31. The device 1 also comprises an imaging system 8, here a camera. The camera 8 is configured so that its field of view is directed into the work area.The computing unit 5 can output information to an operator via the signal output unit 9, here a screen.

[0025] The device 1 comprises several 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. Using the error sensors 4, the device can detect errors in the cooling system 11, on the laser cutting head 6, or on the pallet changer 13. The computing unit 5 is configured to evaluate the error when an error has been detected and a danger to the machine tool 2 has been ruled out. Depending on the error evaluation, it can control the machine tool 2 deviating from the production program and continue production of at least one workpiece part.

[0026] If the error sensor 4 on the cooling system 11 detects inadequate cooling, the processing unit 5 can evaluate the laser power that can still be reliably cooled and whether this power is sufficient for the production of at least one workpiece part. The processing unit then controls the machine tool, deviating from the production program, so that the at least one workpiece part is produced with a reduced laser power and the cooling power is sufficient.

[0027] If the error sensor 4 on the pallet changer 13 detects an error, the computing unit 5 can evaluate whether the function of the pallet changer 13 is necessary for the production of at least one workpiece part. The computing unit 5 then controls the machine tool 2 deviating from the production program in such a way that the control of the pallet changer is skipped and the control of the functions necessary for the production of at least one workpiece part is executed. The control of the machine tool 2 deviating from the production program is immediately stopped if a hazard is detected by the safety sensor system 3. If an error is detected by an error sensor 4 and a hazard is detected by the safety sensor system 3, this leads to an immediate stop of the machine.

[0028] Figure 2 shows a laser cutting head 6. The laser cutting head 6 has an error 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 automatically return to its original position.

[0029] Figure 3 shows that the lower housing part 23 can be deflected relative to the upper housing part 22 when the laser cutting head 6 collides with an object, for example, a cut-out workpiece part. This deflection can be detected by the error sensor 4. The laser cutting head 6 includes a reset assembly comprising springs and dampers. The reset assembly aligns the lower housing part 23 with the upper housing part 22 after a collision.

[0030] Further details on the laser cutting head 6 are known from DE102021126756A1, the disclosure content of which is hereby incorporated in its entirety.

[0031] If the error sensor 4 on the laser cutting head 6 detects a collision, the computing unit 5 can evaluate whether a deflection of the lower housing part 23 caused by the collision can be reversed by a travel movement and use of the reset arrangement. The computing unit 5 then controls the machine tool 2 in a manner deviating from the production program so that the laser cutting head is moved away from the object with which it collided and the deflection is reversed. The production program then continues to produce at least one workpiece part. When evaluating the error on the laser cutting head 6, the computing unit 5 can use images from the camera 8. In the images, the computing unit can determine whether the influence of the collision was so small that the deflection can be reversed by the reset arrangement. In this case, the computing unit 5 evaluates the error as automatically remediable.If the impact of the collision was so strong that the deflection cannot be reversed by the reset arrangement, the computing unit 5 evaluates the error as manually correctable and outputs information to an operator via the signal output unit 9.

[0032] Using the error sensor 4, the processing unit 5 detects whether the error has been corrected. Once the error has been corrected, production of at least one workpiece continues according to the production plan. The processing unit 5 can also use data from the camera 8 to detect whether the error has been corrected.

[0033] List of reference symbols

[0034] device

[0035] Machine tool Safety sensor Error sensor Computing unit Laser cutting head Object Imaging system Signal output unit

[0036] Cooling system Peripheral component Pallet changer Laser source

[0037] Upper housing part Lower housing part Working area

Claims

Patent claims 1. 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.

2. Device (1) according to claim 1, wherein the machine tool (2) comprises a laser cutting head (6), wherein the error 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).

3. 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 process an error detected by the error sensor (2) by means of the imaging system (8) to evaluate.

4. Device (1) according to one of the preceding claims, wherein the computing unit (5) is configured to evaluate the error as being automatically rectifiable or manually rectifiable.

5. Device (1) according to claim 4, wherein the computing unit (5) is configured to control the machine tool (2) to correct an automatically correctable error.

6. Device (1) according to claim 4 or 5, wherein the device (1) has a signal output unit (9), wherein the computing unit (5) is connected to the signal output unit (9), wherein the computing 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 rectifiable error.

7. Device (1) according to one of the preceding claims, wherein the computing unit (5) is configured to detect a rectification of the error, in particular by means of the error sensor (4), and to put the machine tool (2) into a normal mode after the error has been rectified and to continue the production program.

8. Device (1) according to one of the preceding claims, wherein the machine tool (2) comprises a cooling system (11), wherein the error sensor (4) is configured to detect inadequate cooling, wherein the computing unit (5) is configured to control the machine tool (2) in such a way, in particular with reduced power, that the machine tool (2) produces the at least one workpiece part despite inadequate cooling.

9. 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 error sensor (4) is designed to detect an error in the peripheral component (12), wherein the The computing unit (5) is configured to control the machine tool (2) in such a way that the machine tool (2) produces the at least one workpiece part without using the faulty peripheral component (12).

10. Experienced for avoiding downtimes of a machine tool (2), wherein a computing unit (5) controls the machine tool (2) according to a production program, wherein the computing unit (5) stops the machine tool (2) when a safety sensor (3) detects a danger, wherein the computing unit (5) detects an error by means of an error sensor (4), wherein the computing unit (5) evaluates the error and, depending on the evaluation, controls the machine tool (2) deviating from the production program and thus the production of the at least one workpiece part is continued by means of the machine tool when the error sensor (4) detects an error and a safety sensor (3) excludes a danger.

11. Method according to claim 10, characterized in that the error is assessed as being automatically correctable or manually correctable.

12. The method according to claim 11, characterized in that the error is corrected automatically if the error has been assessed as being automatically correctable.

13. The 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 error has been assessed as being manually rectifiable.

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