Method for monitoring a machining region of a machine tool, monitoring system and machine tool

Abstract

The invention relates to a method (10) for monitoring a machining region (12) of a machine tool (14), in particular a laser cutting machine, having the following method steps: a) positioning (16) at least one optical distance sensor (18) above the machining region (12), wherein the distance sensor (18) is directed to the machining region (12); b) creating (28) a surface profile (24; 24a; 24b) of at least one portion of the machining region (12) by scanning the machining region (12) by means of a measuring beam (20) of the distance sensor (18); c) determining (28) at least one fault situation in the machining region (12) by evaluating the surface profile (24; 24a; 24b); d) outputting (42) a monitoring result depending on the determined fault situation. The invention also relates to a monitoring system (46) and a machine tool (14).

Description

[0001] Method for monitoring a machining area of ​​a machine tool, monitoring system and machine tool

[0002] The invention relates to a method for monitoring a machining area of ​​a machine tool. Furthermore, the invention relates to a monitoring system and a machine tool with a monitoring system.

[0003] Machine tools, especially laser cutting machines for manufacturing workpieces using a laser beam, place high demands on the machining area intended for manufacturing the workpieces. The machining area typically serves to position a workpiece blank to be machined in the machine tool and limits the spatial area in which a machining tool of the machine tool can be used.

[0004] Regular maintenance and servicing of the machining area is crucial for the production quality and the level of automation of the machine tool. To ensure the most effective maintenance and the associated short machine downtimes, continuous monitoring of the machining area is necessary.

[0005] In addition, monitoring methods are used to detect malfunctions during workpiece production and to minimize consequential damage. For example, incorrect positioning of a workpiece blank in the machining area can lead to damage due to misplaced machining by the machine tool. Furthermore, for example, particularly during sheet metal production, individual workpieces can be lifted, shifted, and / or tilted during production. Workpieces moved in this way can lead to collisions with moving parts of the machine tool, which can cause significant damage to the machine tool. Various monitoring methods and devices are known from the prior art.

[0006] CN 105382427 A discloses a laser cutting head that has one or more distance sensors to prevent collisions between a finished workpiece and the laser cutting head. The distance sensors determine the distance between the workpiece and a nozzle of the laser cutting head to prevent collisions.

[0007] DE 10 2015 015 651 B3 describes a monitoring device for a processing system for processing a workpiece using a high-energy processing beam. The monitoring device is designed to measure and assess a processing distance of the processing optics from an environment.

[0008] DE 10 2012 003 620 A1 describes a method and a device for the contactless geometric measurement of a measuring object, wherein a laser cross projected onto a measuring object to be measured is used for the graphic evaluation or triangulation of dimensions of the measuring object.

[0009] However, the aforementioned methods and devices from the state of the art only allow for inadequate monitoring of the processing area.

[0010] For example, the methods mentioned are not suitable for monitoring the condition of a support in the machining area. Heavily worn support webs, for example, can encourage workpieces to tilt, leading to collisions and machine downtimes. The condition of the machining area must therefore be assessed visually by the machine operator, which is often only inadequate because only sections of the machining area are visible. Furthermore, for example, the methods and devices mentioned are not suitable for detecting the position and orientation of the workpiece blank to be machined. The positioning of the blank must therefore be ensured in a predetermined position in the machining area, because incorrect positioning can lead to collisions, incorrect machining and ultimately to machine downtimes.This also increases the requirement for the positioning accuracy of an automation system and thus the manufacturing costs for the machine tool.

[0011] It is an object of the invention to provide comprehensive and cost-effective monitoring of the machining area of ​​a machine tool. It is a further object of the invention to provide a device for monitoring the machining area. It is also an object to provide a machine tool with a monitored machining area.

[0012] This object is achieved according to the invention by a method having the features of patent claim 1. The object is also achieved by a monitoring system having the features of patent claim 11. The object is further achieved by a machine tool having the features of patent claim 14. The subclaims represent preferred embodiments of the invention.

[0013] According to the invention, a method is provided. The method is designed for monitoring a machining area of ​​a machine tool. The method is typically computer-aided. In other words, the method is carried out using computers.

[0014] The method is particularly suitable for monitoring a processing area of ​​a flatbed machine tool, in particular a laser cutting machine. Such machine tools are typically designed for manufacturing sheet-metal workpieces. The method comprises at least the following steps:

[0015] In a first step a) of the method, at least one optical distance sensor is positioned above the machining area of ​​the machine tool. In other words, the distance sensor is positioned vertically above the machining area.

[0016] For example, the at least one distance sensor can be arranged in a position exposed to the processing area so as to be rotatable or pivotable at an edge of the processing area.

[0017] According to the invention, the distance sensor is directed towards the machining area of ​​the machine tool.

[0018] In a further method step b) of the method, a surface profile of at least a portion of the processing area is created. Alternatively, the surface profile can be created for the entire processing area.

[0019] In a preferred embodiment of the invention, the machining area is scanned depending on a malfunction to be detected. For example, it can be provided that a status of the machining area is determined by scanning the entire machining area, whereas the detection of possible collisions caused by tilted workpieces is performed by scanning a section of the machining area.

[0020] The processing area is scanned using a measuring beam from the distance sensor. In other words, the distance sensor is designed to optically determine a distance between the distance sensor and a point of incidence of the measuring beam. Scanning refers to the preceding and subsequent determination of a plurality of distances between the distance sensor and a plurality of points of incidence of the measuring beam in the processing area. Scanning can be performed by moving the measuring beam across the processing area. The measuring beam can be scanned, for example, by moving the distance sensor and / or by changing the orientation of the distance sensor.

[0021] Typically, a three-dimensional point cloud consisting of a plurality of measurement points is generated by scanning the processing area, with the measurement points representing a surface of the processing area. Preferably, the point cloud is subjected to computer-aided processing to create the surface image. Computer-aided processing can include the creation of a surface based on the measurement points of the point cloud. In particular, the point cloud can be converted into an area, volume, and / or line profile. This can simplify further processing or evaluation of the surface image.

[0022] A further method step c) of the method provides for determining at least one fault in the processing area by evaluating the surface profile.

[0023] Evaluating the surface image can be understood as the prior and subsequent determination of characteristic curves in the surface image. An evaluation can, for example, involve determining geometric dependencies, in particular parallel line curves, discontinuities, and / or gaps in the surface image.

[0024] The evaluation of the surface profile can further include, for example, determining deviations of the surface image profile from a reference value. In other words, the surface profile can be evaluated by comparing it with a predetermined, in particular absolute, reference value. Furthermore, the evaluation can include a comparison of the surface profile with a characteristic disturbance profile. Typically, a degree of similarity between the surface image profile and the characteristic disturbance profile is determined.

[0025] A malfunction is understood to mean a change in the machining area, both prior to and subsequent to the machining process, which can lead to an impairment of production by the machine tool. For example, a contaminated and / or worn workpiece support on the machine tool, which can lead to workpieces tipping, can be understood as a malfunction. Furthermore, for example, the tilting of one or more workpieces, which can lead to collisions with the machine tool, can be understood as a malfunction. Furthermore, for example, the inaccurate positioning of a workpiece blank in the machining area, which can lead to faulty workpiece production, can be understood as a malfunction.

[0026] Determination of faults can be achieved by assigning the evaluated characteristic curves of the surface profile to predetermined or stored faults. In particular, it can be provided that a fault is determined in conjunction with several characteristic curves evaluated from the surface image.

[0027] In a further method step d) of the method, a monitoring result is output depending on the detected malfunction. The monitoring result can be output acoustically, for example. Preferably, the monitoring result is output graphically, in particular by displaying it on a display of the machine tool.

[0028] The monitoring result typically includes the identified malfunction. The monitoring result preferably includes information on the severity of the malfunction and / or information on how to rectify the malfunction. In summary, a method is proposed in which the machining area of ​​a machine tool is monitored in a particularly simple and reliable manner by scanning the machining area using an optical distance sensor and evaluating the resulting surface image. This enables, on the one hand, the condition monitoring of the machining area between two production periods and, on the other hand, production monitoring during production by the machine tool.

[0029] In a preferred embodiment of the method, the surface profile is created by scanning the processing area with at least two, in particular at least three, distance sensors. With an increasing number of distance sensors, the scanning of the processing area can be faster and more seamless, thereby increasing the accuracy of the surface mapping.

[0030] Further preferred is an embodiment of the method in which at least one, in particular each, distance sensor for scanning the processing area is moved parallel to the processing area. In other words, the distance sensor is moved above the processing area. This eliminates the need to align the distance sensor, thereby increasing the accuracy of the scanning.

[0031] In a preferred embodiment of the method, the measuring beam from at least one distance sensor for scanning the machining area is directed obliquely onto the machining area. This allows scanning of sections of the machining area where vertical positioning of the distance sensor above the section is not possible. Furthermore, the arrangement of the distance sensor on a machining head of the machine tool is possible without a scanning shadow being created by the machining head. Preferably, the measuring beam has a predetermined measuring angle by which the measuring beam is deflected from a perpendicular to the distance sensor. Further preferably, the measuring angle of the distance sensor is adjustable. This allows the scanning of the machining area to be particularly advantageously adapted to various faults to be detected.

[0032] The distance sensor's measuring radius, resulting from the measuring angle, can be set between 5 centimeters and 100 centimeters, preferably between 10 and 50 centimeters. The inventor recognized that these measuring radii are particularly suitable for detecting typical machine tool malfunctions.

[0033] A preferred embodiment of the method is one in which the surface profile is created by circularly scanning the processing area with the measuring beam. In other words, the measuring beam is guided along a circular path over the processing area. Preferably, circular scanning is performed in conjunction with a measuring beam directed obliquely toward the processing area. In this case, the measuring beam can be configured to rotate around a perpendicular to the distance sensor, creating a measuring cone. This enables a flat and particularly fast scanning of the processing area.

[0034] In a preferred embodiment of the method, the monitoring result comprises a blank position and / or a blank orientation of a workpiece blank to be machined. In other words, a position of the workpiece blank in the machining area is determined and subsequently output.

[0035] To determine the position of the workpiece blank, the machining area can be scanned before machining by the machine tool. For this purpose, for example, a machining head with a distance sensor attached to it can be moved in a predetermined, suitable path above the machining area. This scanning allows the position and orientation of the workpiece blank relative to the distance sensor, or to the workpiece surface, to be determined.

[0036] Machining head. Following the determination of the position of the workpiece blank, the machining coordinate system of the machine tool can be adjusted in a particularly preferred manner. This allows incorrect positioning of the workpiece blank in the machining area to be corrected, particularly automatically.

[0037] Further preferred is an embodiment of the method in which the monitoring result comprises a workpiece position of at least one manufactured workpiece. In other words, the workpiece position in the processing area is determined and subsequently output. The determination of the workpiece position can be carried out analogously to the determination of the position of the workpiece blank. By determining the workpiece position, safe removal of the manufactured workpieces can be facilitated.

[0038] In a preferred embodiment of the method, the monitoring result indicates a degree of wear and / or a degree of contamination of the machining area. In other words, a condition of the machining area, in particular a support for a workpiece blank, is determined and subsequently output.

[0039] Wear of the machining area or the support, particularly the support webs, occurs due to a change in the geometry of the support, particularly the support webs. For example, laser processing can lead to the melting of teeth on the support webs. Wear and / or contamination of the support can be determined by evaluating the surface image. The condition of the machining area is preferably monitored between two production periods to avoid impairment by workpiece blanks or workpieces resting on it. The underlying problem is also solved by a monitoring system.

[0040] The monitoring system is designed and constructed to monitor the machining area of ​​the machine tool described above and below.

[0041] In particular, the monitoring system is set up and designed to carry out the method described above and below.

[0042] The monitoring system comprises at least one distance sensor, a computing unit, and an output unit. The at least one distance sensor, the computing unit, and the output unit are connected to each other for data exchange.

[0043] The at least one distance sensor is designed to scan a surface of the processing area using a measuring beam. The distance sensor can be designed, for example, as a laser scanner.

[0044] In a preferred embodiment, the monitoring system comprises at least two, in particular at least three, distance sensors. The distance sensors can be arranged evenly distributed across the processing area. This allows the scanning range of the distance sensors to be increased.

[0045] A preferred embodiment of the monitoring system provides that at least one, in particular each, distance sensor is designed as a LIDAR sensor. The inventor has recognized that LIDAR sensors are particularly suitable for scanning the processing area in terms of scanning speed and accuracy.

[0046] The underlying problem is further solved by a machine tool. The machine tool is preferably designed as a flatbed machine tool, in particular as a laser cutting machine.

[0047] The machine tool has a machining area for machining at least one workpiece blank. Furthermore, the machine tool has a monitoring system as described above and below.

[0048] The at least one distance sensor is arranged above the machining area on the machine tool, whereby scanning of the machining area by the distance sensor can be carried out particularly easily.

[0049] In a preferred embodiment of the machine tool, the monitoring system comprises several distance sensors, each of which is arranged above the machining area. This allows for particularly fast and precise scanning of the machining area.

[0050] Furthermore, an embodiment of the machine tool is preferred in which the machine tool has a machining head for machining the workpiece blank. Preferably, at least one, in particular each, distance sensor is arranged on the machining head of the machine tool. This allows the distance sensor to be carried along on the machining head particularly easily, thereby enabling a particularly cost-effective installation of the monitoring system on the machine tool. Furthermore, scanning of the machining area can take place in the immediate vicinity of the machining head, allowing dynamic changes in the machining area to be determined particularly quickly.

[0051] Preferably, the distance sensors are evenly distributed around the circumference of the machining head to enable continuous scanning of the machining area surrounding the machining head. Further advantages of the invention will become apparent from the description and the drawings. Likewise, the features mentioned above and those further described can each be used individually or in combination. The embodiments shown and described are not intended to be exhaustive, but rather are exemplary in nature for describing the invention.

[0052] Detailed description of the invention and drawing

[0053] Fig. 1 shows a method for monitoring a machining area of ​​a machine tool in a schematic representation.

[0054] Fig. 2 shows a first embodiment of a machine tool with a monitoring system arranged thereon in a schematic representation.

[0055] Fig. 3 shows a first cross section of a first surface profile in a schematic view.

[0056] Fig. 4 shows a second cross section of the first surface profile in a schematic view.

[0057] Fig. 5 shows a section of a machining area of ​​a machine tool in a schematic view.

[0058] Fig. 6 shows a first cross section of a second surface profile of the processing area from Fig. 5 in a schematic representation.

[0059] Fig. 7 shows a schematic representation of a second embodiment of a machine tool with a monitoring system arranged thereon. Fig. 8 shows a schematic representation of a third embodiment of a machine tool with a monitoring system arranged thereon.

[0060] Fig. 1 shows a method 10 for monitoring a machining area 12 (see Figures 2, 5, 7) of a machine tool 14 (see Figures 2, 7, 8).

[0061] The method 10 comprises at least the following method steps:

[0062] In a first method step 16 of the method 10, at least one optical distance sensor 18 (see Figures 2, 7, 8) is positioned above the machining area 12 of the machine tool 14. The optical distance sensor 18 is directed toward the machining area 12. In other words, the optical distance sensor 18 is aligned such that a measuring beam 20 (see Figures 2, 7, 8) of the optical distance sensor 18 is directed toward the machining area 12.

[0063] A further method step 22 of method 10 provides for the creation of a surface profile 24 (see Figures 3, 4, 6) of at least a portion of the processing area 12. The surface profile 24 is created by scanning the processing area 12. The scanning is performed using the measuring beam 20 of the distance sensor 18.

[0064] The distance sensor 18 is designed to measure the distance between the distance sensor 18 and an impact point 26 (see Figures 2, 7, 8) of the measuring beam 20 in the processing area 12. In other words, the distance sensor 18 is designed for point-based distance measurement. By moving the measuring beam 20 over the processing area 12, a distance measurement can be performed at a plurality of points in the processing area 12, whereby an imaging, in particular a planar imaging, of the processing area 12 can take place. Typically, the surface profile 24 is formed as a point cloud after scanning, with each point of the point cloud representing an impact point 26 of the surface of the processing area. The method 10 can provide for computer-aided processing of the point cloud. In particular, the point cloud can be converted into an area, volume, and / or line profile.

[0065] In a further method step 28 of method 10, at least one malfunction of the processing area 12 is determined. The malfunction is determined by evaluating the surface profile 24.

[0066] The evaluation of the surface profile 24 can be carried out, for example, by determining geometric dependencies, in particular parallel line courses, discontinuities 30 (see Figures 3, 4) and / or deviations from a reference variable 32a, 32b, 32c (see Figures 3, 4, 6) and / or comparing the surface profile 24 with a characteristic disturbance profile 34 (see Fig. 6).

[0067] A malfunction of the machining area can, for example, consist in a changed blank position and / or blank orientation of a workpiece blank 38 (see Figures 2, 7) provided for manufacturing workpieces 36 (see Figure 7) in the machining area 12.

[0068] Furthermore, a malfunction of the machining area 12 can, for example, consist of a tilted workpiece 36a (see Fig. 7), which can lead to a collision with moving parts of the machine tool 14 and / or to the difficult or even impossible removal of one of the workpieces 36.

[0069] Furthermore, for example, a malfunction in the machining area 12 may consist of wear and / or contamination of support webs 40 (see Fig. 5), which may lead to tilting of workpieces 36. In a further method step 42 of the method 10, the output of a monitoring result is provided depending on the detected malfunction. The monitoring result can be output acoustically, for example. Preferably, the monitoring result is output graphically, in particular by displaying it on a screen of the machine tool 14.

[0070] The monitoring result typically includes the identified fault. Preferably, the monitoring result includes information on the severity of the fault and / or information on how to resolve the fault.

[0071] In a particular embodiment of method 10, the fault is automatically rectified, for example, by machine tool 14. For example, it can be provided that a detected change in position or orientation of workpiece blank 38 is rectified by adjusting the production coordinate system of machine tool 14. This eliminates the need for intervention by an operator of machine tool 14, and the degree of automation of machine tool 14 can be increased.

[0072] Fig. 2 shows a machine tool 14 in a schematic representation from above.

[0073] The machine tool 14 has the machining area 12 with a workpiece blank 38 arranged therein. The machine tool 14 typically has a support 44 for supporting the workpiece blank 38, for example with a plurality of support webs 40 (see Fig. 5).

[0074] As shown, the machine tool 14 has a monitoring system 46. The monitoring system 46 comprises a distance sensor 18 as well as a computing unit (not shown in detail) and an output unit (not shown in detail). In a preferred embodiment, the computing unit is integrally formed on a controller (not shown) of the machine tool 14 and / or the output unit is formed on an output (not shown) of the machine tool 14.

[0075] The distance sensor 18 is arranged above the processing area 12. The measuring beam 20 of the distance sensor 20 is directed toward the processing area 12.

[0076] As shown, the distance sensor 18 can be arranged on a slide guide 48. As shown, the slide guide 48 can have a slide 50 that is movably arranged on a crossbeam 52 in the transverse direction 54 of the machining area 12. Alternatively or additionally, as shown, the slide guide 48 can be arranged on the machine tool 14 so that it can move in a longitudinal direction 56 of the machining area 12. In other words, the distance sensor 18 can be movable above the machining area 12, thus enabling scanning of the entire machining area 12.

[0077] In a preferred embodiment, the carriage 50 has a machining head 58 (see Figures 7, 8) of the machine tool 12. This allows the distance sensor 18 of the monitoring system 46 to be arranged on the machine tool 14 particularly quickly and easily.

[0078] As shown, it can be provided that the measuring beam 20 of the distance sensor 18 is moved along a measuring path 60 on the processing area 12 to scan the processing area 12. In other words, the measuring beam 20 forms a measuring cone 62 (see Fig. 7) by rotating around the distance sensor 18, which causes a circular scanning of the processing area 12.

[0079] The movement of the measuring beam 20 can be superimposed on a movement of the carriage guide 48, for example, a movement in the transverse direction 54 and / or the movement in the longitudinal direction 56. As shown, the processing area 12 is scanned by the measuring beam 20 of the distance sensor 18 along a first measuring path 60a and a second measuring path 60b. The second measuring path 60b is created by moving the distance sensor 18 in the longitudinal direction 56 above the processing area 12.

[0080] Typically, the machining area 12 is scanned along a plurality of measuring paths 60. This allows for particularly high accuracy in creating the surface profile 24.

[0081] As shown, the workpiece blank 38 has a changed blank position and a changed blank orientation compared to a provided blank position 64.

[0082] The determination of the changed blank position will be explained in more detail below using Figures 3 and 4.

[0083] Fig. 3 shows a cross section 66a through a surface profile 24a along the measuring path 60a from Fig. 2. As shown, a vertical axis 68 can show a distance 70, here a vertical distance 72 (see Fig. 7), between the processing area 12 (see Figs. 2, 5, 7, 8) and the distance sensor 18 (see Figs. 2, 7, 8) and a right axis 74 the position along the measuring path 60a.

[0084] As shown, the distance sensor 18 has a constant distance 70 along the measuring path 60a. In other words, no height differences are to be determined on the measuring path 60a. An evaluation may reveal, for example, that the processing area 12 along the measuring path 60a does not have a workpiece blank 38 (see Figures 2, 7) or that a workpiece blank 38 is present along the entire measuring path 60a. A possible comparison with the reference variable 32a, here a predetermined distance profile, may reveal, for example, that no workpiece blank 38 is positioned along the measuring path 60a in the processing area 12.

[0085] Fig. 4 shows a cross section 66b through the surface profile 24a along the measuring path 60b from Fig. 2. As shown, the vertical axis 68 can show the distance 70, here the vertical distance 72 (see Fig. 7), between the processing area 12 (see Figures 2, 5, 7, 8) and the distance sensor 18 (see Figures 2, 7, 8) and the right axis 74 the position along the measuring path 60b.

[0086] As shown, the distance sensor 18 has a varying distance 70 along the measuring path 60b. In other words, height differences along the measuring path 60b can be determined. Height differences can be determined, for example, by determining discontinuities 30 in the course of the cross-section 66b. An evaluation can reveal, for example, that the processing area 12 along the measuring path 60a has a workpiece blank 38 (see Figures 2, 7).

[0087] A possible comparison with the reference variable 32b, here a predetermined distance profile, can, for example, reveal that the workpiece blank 38 is displaced along the measuring path 60b in the machining area 12. For example, a profile distance 76 between the cross-section 66b and the reference variable 32b can be determined.

[0088] Furthermore, it can be provided that a displacement of the workpiece blank 38 is determined along a plurality of measuring paths 60 offset in the longitudinal direction 56 (see Fig. 2). In this way, in addition to the displacement of the workpiece blank 38, a rotation of the workpiece blank 38 relative to the predetermined blank position 64 (see Fig. 2) can also be determined.

[0089] Fig. 5 shows an exemplary section of a machining area 12 of a machine tool 14. The machining area 12 has a support 44 with a plurality of support webs 40. The support webs 40 are arranged parallel to one another and form the support 44, or a support plane 78. The support webs 40 can, as shown, have or form prongs 80, thereby enabling a particularly flat support 44. For reasons of clarity, only two prongs 80 are provided with a reference numeral.

[0090] During the machining of workpiece blanks 38 (see Figures 2, 7), wear and / or contamination of the support webs 40, in particular the teeth 80, can occur as a result of the tool action. As shown, wear can occur through material removal on the teeth 80, resulting in worn teeth 82. For reasons of clarity, only one worn tooth 82 is provided with a reference numeral. The worn teeth 82 have a lower tooth height, thereby reducing the support 44. As a result, tilting of the workpiece blank 38 and / or a finished workpiece 36 (see Figure 7) can occur, which often leads to undesirable machine downtimes.

[0091] Determining worn and / or contaminated prongs 82 by means of method 10 will be explained in more detail with reference to the following Figure 6.

[0092] Fig. 6 shows a cross section 66c through a surface profile 24b according to a cross-sectional plane 84 of the processing area 12 from Fig. 5. As shown, the vertical axis 68 can show the distance 70, here the vertical distance 72 (see Fig. 7), between the processing area 12 (see Figures 2, 5, 7, 8) and the distance sensor 18 (see Figures 2, 7, 8) and the right axis 74 the position along the cross-sectional plane 84.

[0093] As shown, the profile of cross-section 66c along cross-sectional plane 84 has a jaggedly changing distance 70. In other words, cross-section 66c has regularly changing height differences. A regularity of the height differences can be determined, for example, by determining the discontinuities 30 in the profile of cross-section 66c.

[0094] For example, an analysis may reveal that the course of cross-section 66c has one or more sections 86 with a larger minimum distance. Furthermore, the analysis may reveal that route sections 88 adjacent to a discontinuity 30 have a different gradient 90. For reasons of clarity, only three discontinuities 30, two sections 86, two route sections 88, and two gradients 90 are provided with a reference symbol.

[0095] An evaluation may further provide, for example, that the profile of cross-section 66c is compared with reference variable 32c, here a characteristic disturbance profile 34. Reference variable 32c can, for example, be compared graphically with the profile of cross-section 66c. If a predetermined degree of similarity between the profile of cross-section 66c and reference variable 32c is determined, a disturbance can be identified.

[0096] Fig. 7 shows a section of a machine tool 14 with a monitoring system 46 arranged thereon. The machine tool 14 is designed as a laser cutting machine as shown.

[0097] The machine tool 14 has the machining area 12 with a support 44 positioned therein. A workpiece blank 38 and workpieces 36 manufactured by the laser cutting machine are positioned on the support 44.

[0098] A machining head 58 of the machine tool 14 with a cutting nozzle 92 is positioned vertically above the machining area 12. The machining head 58 is designed to be movable at least parallel to the machining area 12, whereby workpieces 36 can be manufactured by moving the machining head 58 above the workpiece blank 38. As shown, two distance sensors 18 are attached to the machining head 58. The distance sensors 18 are positioned at a vertical distance 72 above the machining area 18 and aligned with the machining area 12. In other words, the measuring beam 20 of each distance sensor 18 is directed at the machining area 12.

[0099] As shown, the measuring beam 20 of the respective distance sensors 18 is deflected by a predetermined measuring angle 94 from a vertical 96. Typically, the measuring beam 20 rotates around the vertical 96, creating a measuring cone 62 with a projected circular measuring path 60 (see Figures 2, 8) on the processing area 12. This allows a planar scanning of the processing area 12 without changing the measuring angle 94, thereby increasing the scanning accuracy.

[0100] As shown, a finished workpiece 36a is tilted in the machining area 12. This can lead to collisions with moving parts of the machine tool 14, for example, the machining head 58, and / or to difficult removal of workpieces 36. By scanning the machining area 12 with the measuring beams 20 of the distance sensors 18, a tilted workpiece 36a can be detected and reported as a malfunction.

[0101] With the distance sensors 18 arranged on the machining head 58 as shown, effective monitoring of the machining area 12, particularly in the immediate vicinity of the machining head 58, can be carried out. This allows tilting of one or more workpieces 36a to be detected during the production of workpieces 36, and a possible collision to be prevented.

[0102] Fig. 8 shows a detail of another embodiment of a

[0103] Machine tool 14 with a monitoring system 46 arranged thereon in a view of a side of the machining head 58 facing the machining area 12 (see Figures 2, 5, 7).

[0104] As shown, three distance sensors 18, each with a measuring beam 20, can be arranged or attached to the machining head 58 of the machine tool 14. The distance sensors 18 are movable together with the machining head 58 above the machining area 12 (see Figures 2, 5, 7).

[0105] Typically, the distance sensors 18 are evenly distributed around the circumference of the machining head 58. This enables continuous monitoring.

[0106] Preferably, the distance sensors 18 each have a measuring angle 94 (see Fig. 7), which creates measuring radii 98 that lead to an overlap of the measuring cones 62. This allows for particularly seamless monitoring of the processing area 12.

[0107] In a special embodiment, the distance sensors 18 are adjustable with respect to the measuring radius 98 or the measuring angle 94. In other words, the respective measuring cone 62 can be adjusted. A large measuring radius 98 promotes the rapid mapping of the entire machining area 12. A small measuring radius 98 promotes a seamless mapping of the machining area 12, particularly in the case of a changing machining area 12, for example, during the production of workpieces 36 (see Fig. 7). Adjustable distance sensors 18 thus promote the particularly rapid implementation of the method 10 (see Fig. 1) before and during the production of workpieces 36. List of reference symbols

[0108] Process Machining area Machine tool Process step Distance sensor Measuring beam Process step Surface profile a Surface profile b Surface profile Impact point Process step Discontinuity a Reference size b Reference size c Reference size Disturbance profile Workpiece a Tilted workpiece Workpiece blank Support web Process step Support Monitoring system Slide guide Slide Cross-beam Transverse direction Longitudinal direction Machining head Measuring path a Measuring path b Measuring path Measuring cone Blank position a Cross section b Cross section c Cross section Vertical axis

[0109] Distance vertical distance right axis distance support plane prong worn prong cross-sectional plane section

[0110] Section Gradient Cutting nozzle Measuring angle Vertical Measuring radius

Claims

Patent claims 1. A method (10) for monitoring a processing area (12) of a machine tool (14), in particular a laser cutting machine, comprising the method steps: a) positioning (16) at least one optical distance sensor (18) above the processing area (12), wherein the distance sensor (18) is directed towards the processing area (12); b) creating (28) a surface profile (24; 24a; 24b) of at least a portion of the processing area (12) by scanning the processing area (12) using a measuring beam (20) of the distance sensor (18); c) determining (28) at least one malfunction of the processing area (12) by evaluating the surface profile (24; 24a; 24b); d) outputting (42) a monitoring result depending on the determined malfunction.

2. Method (10) according to claim 1, wherein the surface profile (24; 24a; 24b) is created by scanning the processing area (12) with at least two, in particular at least three, distance sensors (18).

3. Method (10) according to claim 1 or 2, wherein at least one, in particular each, distance sensor (18) for scanning the processing area (12) is moved parallel to the processing area (12).

4. Method (10) according to one of the preceding claims, wherein the measuring beam (20) from at least one distance sensor (18) for scanning the processing area (12) is directed obliquely onto the processing area (12).

5. Method (10) according to one of the preceding claims, wherein the surface profile (24; 24a; 24b) is created by circular scanning of the processing area (12) by the measuring beam (20).

6. Method (10) according to one of the preceding claims, wherein the surface profile (24; 24a; 24b) is evaluated by determining discontinuities (30) in the surface profile (24; 24a; 24b).

7. Method (10) according to one of the preceding claims, wherein the surface profile (24; 24a; 24b) is evaluated by comparison with at least one characteristic disturbance profile (34).

8. Method (10) according to one of the preceding claims, wherein the monitoring result comprises a blank position and / or a blank orientation of a workpiece blank (38) to be machined.

9. Method (10) according to one of the preceding claims, wherein the monitoring result comprises a workpiece position of at least one manufactured workpiece (36, 36a).

10. Method (10) according to one of the preceding claims, wherein the monitoring result comprises a degree of wear and / or a degree of contamination of the processing area (12).

11. Monitoring system (46) for monitoring a machining area (12) of a machine tool (14), in particular designed to carry out the method (10) according to one of the preceding claims, comprising at least one distance sensor (18), a computing unit and an output unit, wherein the at least one distance sensor (18) is designed to scan a surface of the machining area (12) by means of a measuring beam (20).

12. Monitoring system (46) according to claim 11, comprising at least two, in particular at least three, distance sensors (18).

13. Monitoring system (46) according to claim 11 or 12, wherein the at least one, in particular each, distance sensor (18) is designed as a LIDAR sensor.

14. Machine tool (14), in particular a laser cutting machine, with a processing area (12) for processing at least one workpiece blank (38) and a monitoring system (46) according to one of claims 11 to 13, wherein the distance sensor (18) is arranged above the processing area (12).

15. Machine tool (14) according to claim 14, in conjunction with a monitoring system (46) according to claim 13, wherein each distance sensor (18) is arranged above the machining area (12).

16. Machine tool (14) according to claim 14 or 15, comprising a machining head (58) for machining the workpiece blank (38), wherein at least one, in particular each, distance sensor (18) is arranged on the machining head (58).

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