Method and universally applicable device for producing a predetermined breaking line and machining installation with such a device

Abstract

The invention relates to a device (0) and a procedure for creating a predetermined refraction line (2) on a vehicle interior trim piece (1) by means of a scanning laser beam (S). In this context, the actual position of the vehicle interior trim piece (2), held in a working plane (A) relative to a laser scanning device (6), is determined by means of a camera (8), and the actual position of the predetermined refraction line is obtained. A target position recorded for a scanning figure corresponding to the predetermined refraction line is corrected according to the actual position, so that when the scanning figure is scanned, the predetermined refraction line (2) is created at a predetermined position on the vehicle interior trim piece (1). A position shift of the scanning figure is made possible by the use of a sensor matrix (3) containing an upstream diffuser (12) which can detect the transmitted portions of the laser beam (S) along the scanning figure, regardless of the position of the laser beam.

Description

[0001] The invention relates to a method and a device for producing a predetermined breaking line in a vehicle interior trim part, preferably an airbag cover, which is suitable for universal use in a production line, according to the preamble of claims 1 and 4 (see, for example, DE 10 2016 121644 A1). This invention also relates to a processing system with such a device, see claim 6.

[0002] Universal application of the device means that it is suitable for use in combination with various feed devices, including multiple feed devices with varying feed accuracy, and for producing predetermined breaking lines of different contours. The device comprises a sensor matrix and a laser scanning unit. During processing of the vehicle interior trim panel, a laser beam scanning across the panel removes material along a predetermined breaking line until the individual sensors of the sensor matrix detect a portion of the laser beam transmitting through the panel.

[0003] The invention also relates to a processing plant with a device according to the invention and two feeding devices.

[0004] It should be noted that, for the purposes of this description, a predetermined breaking line is defined as a line along which the predetermined breaking line is created, regardless of the processing state.

[0005] The creation of predetermined breaking lines using lasers in vehicle components, such as airbag openings in the dashboard, door panels, or steering wheel hub, or as break points on components protruding into the passenger compartment, like cup holders, has been known for a long time. Due to the high demands placed on both the reliable breaking action when needed and the aesthetic appearance of the components, where a vehicle occupant should not perceive the predetermined breaking points with the naked eye, material removal along a predetermined breaking line that defines the breaking points is sensor-monitored or sensor-controlled.

[0006] It is also known in other applications, e.g. in the packaging industry, to introduce predetermined breaking lines using lasers as separating aids in containers etc.

[0007] To create a predetermined breaking point by laser material removal, slits or holes, or so-called microperforations, which only penetrate the vehicle's interior trim panel with a very small opening, are made along a predefined line in the relevant vehicle interior trim panel. Sensor monitoring and control allow for the creation of either a reproducible remaining wall thickness or small holes with a reproducible diameter along the line forming the predetermined breaking point. This is achieved by using the detection of radiation energy transmitted through the remaining wall or the hole, and the exceeding of a predefined threshold value, as the control parameter.For this purpose, at least one sensor is positioned on the side of the vehicle interior trim panel opposite the laser (visible side). During processing, this sensor detects a transmitting portion of the processing laser radiation when the interior trim panel within the predetermined breaking line at the respective processing point has only a certain remaining wall thickness or already a micro-hole. The necessary relative movement for generating the predetermined breaking lines can, in principle, be generated by the laser beam as a tool or by the interior trim panel itself, with the tool remaining stationary. However, moving the laser beam has proven to be simpler to implement. Compared to robot-controlled guidance of a laser source above and along the predetermined breaking line, two- or three-dimensional scanning of a laser beam along the predetermined breaking line is technically simpler to implement and also allows for significantly faster processing.

[0008] DE 10 2018 129 329 A1 discloses a method for laser processing of a painted workpiece using a laser processing device, as well as the laser processing device itself. The workpiece is positioned in a working area of ​​the laser processing device, and a sensor element of the laser processing device detects its position and / or orientation. Subsequently, values ​​for operating parameters of the laser processing device can be generated, whereby the operating parameters can be generated depending on the detected position and / or orientation. A laser beam is generated by the laser processing device according to the generated values, and the workpiece is exposed to the laser beam. The laser beam is moved in such a way that material from a paint layer is removed along a working path.

[0009] DE 10 2005 026 906 A1 discloses an interior trim part for vehicles and a method for manufacturing such an interior trim part. A device for carrying out the method comprises a laser with focusing optics and a scanner mirror system. A focus of a laser beam generated by the laser lies at a depth within the interior trim part, and material is removed at this focus.

[0010] From DE 10 2017 112 072 A1, a device and a method for partially removing a coating applied to a vehicle wheel are known. In the method, an area on the vehicle wheel is exposed to a processing beam generated by a radiation source and exiting a processing head until at least part of the coating in the area of ​​the surface is thermally destroyed.

[0011] From DE 10 2005 054 607 A1 a method for determining a residual layer thickness during the formation of blind holes or cut edges in components is known, in which blind holes or cut edges are formed by means of laser radiation starting from one side of a component and the temperature on the opposite surface of the component is determined without contact by means of electromagnetic radiation emitted from this surface and thus the residual layer thickness in the respective processing area of ​​the laser radiation is determined.

[0012] A method disclosed in patent EP 1 118 421 B1 describes the production of a predetermined breaking line consisting of perforations using pulsed or continuous laser radiation. The laser beam is directed onto the back of a vehicle interior trim panel by means of a processing optic. Opposite the front of the vehicle interior trim panel, a sensor is located in the laser's beam path, i.e., on the optical axis of the processing optic. During a relative movement between the vehicle interior trim panel and the processing optic along the predetermined breaking line to be created, the laser emits a limited sequence of individual pulses, which partially overlap on the vehicle interior trim panel, or a continuous laser beam of limited duration. This creates a slot in the vehicle interior trim panel with a continuously decreasing residual wall thickness.The laser radiation is interrupted as soon as the sensor on the front detects a breakthrough of the laser beam. If the required relative movement is to be performed by the laser, highly precise tracking of the sensor must be achieved so that the sensor axis and the optical axis of the processing optics always coincide.

[0013] According to EP 0 827 802 B1, a defined material removal down to a remaining residual wall thickness (material thickness) is ensured by detecting the transmitted radiation at the processing point from the outside using a sensor. For this purpose, the sensor must be positioned on the optical axis of the laser beam directed at the vehicle interior trim panel. No details are provided here regarding how the relative movement between the laser beam and the vehicle interior trim panel necessary to generate the predetermined breaking line is achieved.

[0014] EP 3 321 024 A1 discloses a method and a device for producing a weakening line in a planar workpiece along a predetermined contour by material removal using a laser. In this method, a workpiece is positioned in a working area between an array of sensors and a laser scanner. The laser scanner scans a pulsed laser beam across the back side of the planar workpiece along a weakening line, removing material in the form of holes down to a predetermined residual wall thickness at a multitude of ablation points along the weakening line. During material removal, individual sensors detect measurement signals generated by a portion of the laser beam transmitted at the ablation points. Subsequently, a comparison signal is generated, which is compared with a reference signal to which the predetermined residual wall thickness is assigned.The laser generator that produces the laser pulses is controlled such that laser pulses only strike the ablation points until the predetermined residual wall thickness is reached. The transmitted laser radiation power of a laser pulse is detected when it exceeds a lower limit of the sensor's sensitivity range, and the attenuation line can be positioned arbitrarily within the sensor array's field of view. The disclosed method does not include cameras or image processing methods for optically monitoring the positioning of the workpieces to be processed or for any necessary adjustment of the target processing data to the actual situation. Furthermore, no comparative measurements are generated from the simultaneously acquired data.

[0015] Devices with a sensor arrangement that replicates the contour of the predetermined breaking line are also known from the prior art. The linear sensor arrangement and the workpiece to be processed remain stationary, and a laser beam is guided along the predetermined breaking line. To achieve a uniform, reproducible residual wall thickness on several identical vehicle interior trim panels, each panel must be positioned in the same relative orientation to the sensor arrangement.

[0016] From DE 10 2012 109 245 B3, a method and a device for processing non-rotationally symmetrical workpieces using laser radiation are known. The device can have several feed devices, processing devices, or clamping devices that can be operated in parallel to each other, thereby allowing several workpieces or changing workpieces to be fed to a processing device.

[0017] DE 10 2019 133 745 A1 discloses a manufacturing system for the laser-processing production of a workpiece and a method for producing a laser-processed workpiece. One embodiment of the device includes a positioning device, which can, for example, be configured as a multi-axis robot and is set up to position a batch of multiple workpieces, in particular a batch of multiple workpieces arranged on a workpiece carrier, relative to a laser processing device. An existing transfer system can include a robot system with at least one multi-axis robot.

[0018] According to EP 0711 627 B1, one embodiment of the device disclosed herein includes an ultrasonic sensor that covers the working area of ​​the laser beam and therefore does not need to be moved around, but can remain stationary. During the creation of a predetermined breaking line using a laser, the vehicle interior trim part to be processed is placed on the ultrasonic sensor, and the laser beam is guided along the desired breaking line, with the material being removed in the form of a continuous groove or a series of perforated holes (blind holes). The movement of the laser beam is achieved, for example, via a system of position-controlled, movable mirrors (which would be provided by a scanner), or the laser generator is attached to a robotic arm manipulator.

[0019] The ultrasonic sensor detects signals corresponding to the thickness of the material remaining as a residual wall after the laser beam has been used to score the surface. This signal is then sent back to the central computer to adjust the position of the laser generator and / or its output power, thereby controlling the thickness of the residual wall. An advantage over a solution according to EP 0 711 627 B1 is that this solution allows for movement of the laser beam alone, which, if necessary, enables a higher positioning speed between the laser beam and the respective processing point on the score line. However, the unrestricted practical functioning of an extended ultrasonic sensor in a device according to EP 0 711 627 B1 appears doubtful. At a minimum, this would require that the sensor surface be in air-free contact with the surface of the vehicle interior trim panel.This proves particularly difficult if the surface of the vehicle interior trim part is a three-dimensionally extended freeform surface or if its surface has a structured height profile.

[0020] German patent application DE 10 2007 024 510 B3 discloses a device with a sensor arranged on the outside of the vehicle interior trim panel to be processed, the sensor's measuring range encompassing the entire predetermined breaking line. The sensor is a matrix camera whose pixels can be read individually. An associated control and processing unit is connected to the sensor and a laser generator, which generates the processing laser radiation. The control and processing unit is designed to store the positional data of the matrix camera's pixels, assigned to the individual processing locations, so that during processing only the pixels assigned to the relevant processing location are read out.

[0021] Accordingly, the vehicle interior trim part must be positioned with precise alignment to the sensor so that the individual processing locations along the predetermined breaking line assume a predetermined relative position to the respective assigned pixels.

[0022] This only reveals that the matrix camera is designed as a CMOS camera.

[0023] It is advantageous to arrange several matrix cameras instead of just one, each of whose measuring ranges capture sub-areas of the predetermined breaking line.

[0024] According to the method described in the aforementioned DE 10 2007 024 510 B3, a predetermined breaking line is produced in a vehicle interior trim panel. A laser beam is directed onto the inner surface of a vehicle interior trim panel held stationary in a holding device, guided along the predetermined breaking line, and material is removed in the form of holes with a residual wall thickness at a multitude of processing locations along the predetermined breaking line. Predetermined pixels of a stationary sensor, which detects the complete course of the predetermined breaking line on the outer surface of the vehicle interior trim panel, acquire measurement values ​​equivalent to the residual wall thickness. Depending on these measurement values, a laser generator emitting the laser beam is controlled by comparison with at least one reference measurement value.Essential to the method disclosed in the aforementioned DE 10 2007 024 510 B3 is that only predetermined pixels of a matrix camera are read out to determine the measured values. These predetermined pixels are the pixels that are stored as receiving pixels assigned to the individual processing locations.

[0025] A disadvantage of the aforementioned method is that the vehicle interior trim part to be processed must be positioned exactly in relation to the sensor, which means an increased time expenditure when feeding the vehicle interior trim part into a device for producing a predetermined breaking line.

[0026] The object of the invention is to develop a method by which the ratio between the working time of the laser generator and the auxiliary times necessary to carry out the method is improved in favor of the working time of the laser generator.

[0027] It is also the object of the invention to find a suitable device for this purpose and a processing plant with such a device that further improves productivity improved by the device.

[0028] The problem for a method is solved by a method for producing a predetermined breaking line in a vehicle interior trim part according to claim 1, in which the vehicle interior trim part is picked up and arranged in a working plane between a sensor matrix and a processing head defined for this purpose, containing a laser scanning device, the laser scanning device scans a laser beam on an inner side of the vehicle interior trim part, describing a scan pattern, along the predetermined breaking line, whereby material removal in the form of holes is effected up to a predetermined residual wall thickness at a plurality of processing locations along the predetermined breaking line, and measured values ​​are acquired by individual sensors of the sensor matrix during the material removal, caused by a portion of the laser beam transmitting at the processing locations, and a comparative measured value is formed from simultaneously acquired measured values.which is compared with a reference measurement value to which the predetermined remaining wall thickness is assigned, and a laser generator emitting the laser beam is controlled depending on the comparison result. It is essential to the invention that the measured values ​​of all individual sensors that lie above a predetermined threshold value are recorded, whereby the predetermined breaking line can be positioned arbitrarily within a field of view of the sensor matrix; that an actual position of the vehicle interior trim part relative to the laser scanning device is optically recorded and an actual position of the predetermined breaking line relative to the laser scanning device is derived from this; and that a predetermined position of a scan figure stored for a predetermined position of the predetermined breaking line is corrected to an actual position of the scan figure for scanning the predetermined breaking line, whereby the predetermined breaking line is created at a predetermined position on the vehicle interior trim part when the scan figure is scanned.

[0029] Advantageously, the procedure is carried out by using two delivery devices to arrange the vehicle interior trim parts one after the other in the working plane and to determine an actual position of the scan figure individually for each actual position of the respective vehicle interior trim part.

[0030] Preferably, the first of the three vehicle interior trim parts is held in the first of the two delivery devices and processed, while the second delivery device transports the finished, second vehicle interior trim part to an output location, and subsequently the unprocessed, third vehicle interior trim part is picked up at an input location and transported for processing.

[0031] The problem is solved by a device for producing a predetermined breaking line in a vehicle interior trim part according to claim 4, which includes a sensor matrix, a processing head arranged for this purpose, comprising a laser scanning device connected to a laser generator, an intermediate working plane in which the vehicle interior trim part to be processed is arranged, and a control and processing unit. The field of view of the sensor matrix is ​​larger than the maximum extent of a predetermined breaking line. A camera directed towards the working plane is provided, which is designed to detect the actual position of the vehicle interior trim part arranged in the working plane relative to the laser scanning device and to derive the actual position of the predetermined breaking line from this. The control and processing unit is designed to align the scan pattern with the predetermined breaking line.It is essential to the invention that a diffuser is placed upstream of the sensor matrix.

[0032] It is advantageous if the individual sensors of the sensor matrix each have a sensitivity that is coordinated with each other so that the sensor matrix has a homogeneous sensitivity.

[0033] For a processing system, the problem is solved by a processing system with a device according to the invention for producing a predetermined breaking line in a vehicle interior trim part according to claim 6 by including at least two delivery devices with which a vehicle interior trim part is alternately transported and positioned in the working plane of the device for producing a predetermined breaking line. Advantageously, the at least two delivery devices include multi-axis robots which hold the vehicle interior trim parts suspended in the working plane.

[0034] It is essential to the invention that, for the exact production of a predetermined breaking line in a predetermined position on the vehicle interior trim part, the vehicle interior trim part to be processed only needs to be roughly held in a working plane, thereby reducing the delivery time of the vehicle interior trim part.

[0035] Because all individual sensors in the sensor matrix that generate a measurement signal above a threshold are read out, precise positioning of the vehicle interior trim panel relative to the sensor matrix is ​​not required. Instead, a scan pattern describing the predetermined breaking line is aligned with the vehicle interior trim panel.

[0036] The invention is explained in more detail below using exemplary embodiments and the accompanying drawings. These drawings show: Fig. 1 a schematic representation of a device for producing a predetermined breaking line in a vehicle interior trim part and Fig. 2 a machining system with a device according to Fig. 1 and two delivery facilities.

[0037] In Fig. 1 Figure 1 is a schematic representation of a device according to the invention for producing a predetermined breaking line 0 in a vehicle interior trim part 1. It comprises a sensor matrix 3, a processing head 4 arranged for this purpose, and an intermediate working plane A in which the vehicle interior trim part 1 to be processed is arranged, as well as a control and processing unit 5. The working plane A is adapted to the surface contour of the vehicle interior trim part 1 and need not be a geometric plane. The processing head 5 contains a laser generator 7 or is connected to a laser generator 7, a laser scanning device 6, and a camera 8 fixedly arranged with the laser scanning device 6. The laser generator 7, the laser scanning device 6, and the camera 8 are connected to the control and processing unit 5 via signal transmission.

[0038] Advantageously, a camera's field of view lying in the working plane A covers at least one field of view of the sensor matrix lying in the same working plane A. Advantageously, the two fields of view in the working plane A are of equal size and completely overlap each other. A scan area of ​​the laser scanning device, determined by the maximum deflection of a laser beam S emitted by the laser generator 7 in the x and y directions of a scanner coordinate system, is matched to the size of the sensor matrix's field of view so that it can be scanned as completely as possible. The camera 8 and the laser device 6 are rigidly connected, meaning that a camera coordinate system has a fixed, known relative position to the scanner coordinate system of the laser scanning device. This allows the image coordinates of each pixel in an image generated by the camera 8 to be assigned to the scan coordinates of a scanner position of the laser scanning device 6.

[0039] For the complete creation of a predetermined breaking line 2 with a device according to the invention, the field of view of the sensor matrix must be larger than the maximum extent of a possible predetermined breaking line 2.

[0040] A significant advantage of a device according to the invention is that a vehicle interior trim part 1 to be processed, which is held in the working plane A, only needs to be roughly positioned. Rough positioning here means that the predetermined breaking line 2 to be produced only needs to lie within the field of view of the camera and within the scan field of the laser scanning device. This opens up the possibility of processing the vehicle interior trim part 1, e.g., with a multi-axis robot 9, see Fig.2 ,The vehicle interior trim part 1 can be held in the working plane A instead of being placed in a part-specific holding device, which achieves higher positioning accuracy. Furthermore, the vehicle interior trim part 1 can be picked up less precisely, e.g., with suction cups 10, which is particularly advantageous for holding larger vehicle interior trim parts 1 compared to a gripper 11. The camera 8 optically captures the vehicle interior trim part 1, which is only roughly positioned in the working plane A, in order to determine the actual position of the vehicle interior trim part 1 from the acquired image data using the processing and control unit 5 and to derive the actual position of the predetermined breaking line.The target position of a scan pattern (predefined processing coordinates), stored for a target position of the predetermined breaking line, is corrected to an actual position (corrected processing coordinates), and the laser scanning device 6 is controlled in the actual position of the vehicle interior trim part 1 to execute the scan pattern along the predetermined position of the predetermined breaking line. For this purpose, the relative position of the vehicle interior trim part 1 in the camera coordinate system, and thus relative to the scanner coordinate system, is determined from the image data. To this end, defined features on the vehicle interior trim part 1, to which the predetermined breaking line 2 has a known fixed positional relationship, are identified in the image data.

[0041] Advantageously, not only one scan figure but several scan figures can be stored in the computing and control unit 5, each relating to a target position or to different target positions of a predetermined breaking line to be produced.

[0042] The device can therefore be used for various vehicle interior trim parts that differ in the position and contour of the predetermined breaking line.

[0043] The device enables the precise application of the predetermined breaking line 2 to the vehicle interior trim panel 1 at the specified position, even though the vehicle interior trim panel 1 was only roughly positioned in the working plane A. This is made possible by using the sensor matrix 3 in conjunction with image data-based control of the laser scanning device 6. The sensor matrix 3 has a homogeneous sensitivity, which is preferably adjusted by electronically coordinating the sensitivities of the individual sensors within the sensor matrix 3. This ensures that, regardless of the number and position of the individual sensors providing a measurement, a consistent reference value is established for the same remaining wall thickness.

[0044] A diffuser 12 is arranged upstream of the sensor matrix 3. The portion of the laser beam transmitted at the individual processing locations during the production of the predetermined breaking line 2 (here, secondary radiation caused by the laser beam at the processing location is also understood to be) is scattered by the diffuser 12 and is therefore distributed among a larger number of individual sensors than if no diffuser were arranged upstream.

[0045] A device 0 according to the invention is particularly suitable for installation in a production line, since it is compatible with the device for various delivery devices 13 due to its low requirements for the positioning accuracy of the vehicle interior trim part to be processed.

[0046] Together with at least one delivery device 13, preferably with two, it forms a processing plant, see Fig. 2, in which a vehicle interior trim part 1 is alternately removed from a stack by the delivery devices 13 and transported into the working plane A of the device for producing a predetermined breaking line 2.

[0047] Particularly high flexibility of movement is achieved when the delivery devices 13 include a multi-axis robot 9, which holds the vehicle interior trim parts 1 suspended in the working plane A.

[0048] In a method according to the invention for producing a predetermined breaking line in a vehicle interior trim part 1, the vehicle interior trim part 1 is received and arranged in a working plane A between a sensor matrix 3 and a processing head 4, containing a laser scanning device 6, which is defined for this purpose.

[0049] The laser scanning device 6 directs a laser beam S onto an inner surface of the vehicle interior trim panel and scans it, describing a scan pattern, along the predetermined breaking line 2. Material is removed in the form of holes, down to a predetermined residual wall thickness, at a multitude of processing locations along the predetermined breaking line 2. As material removal increases, the residual wall thickness at each processing location decreases progressively until individual sensors in the sensor matrix detect transmitting components of the laser beam during material removal and record measured values.

[0050] A comparative measurement is generated from simultaneously recorded measurements by individual sensors of the sensor matrix and compared with a reference measurement to which the specified remaining wall thickness is assigned.

[0051] In this process, an identical comparison value is generated from each of the individual sensors, regardless of location, when the same residual wall thickness is reached at the respective processing location.

[0052] Depending on a comparison result between the comparison value and the reference value, a laser generator 7 emitting the laser beam S is controlled. Control can mean that the laser generator is switched off or that the laser parameters, e.g. pulse length or pulse amplitude, are changed.

[0053] The system records the measured values ​​of all individual sensors that exceed a predefined threshold, allowing the break line to be positioned arbitrarily within the sensor matrix's field of view. However, knowing the approximate position of the vehicle's interior trim panel also allows for an estimation of the area within the sensor matrix where individual sensors will deliver a measurement signal, thus eliminating the need to read out all individual sensors.

[0054] Whereas, in the case of an exact positioning of the vehicle interior trim part to a laser scanning device, as is usual in the prior art, the predetermined breaking line is arranged in a predetermined position, so that a scan figure stored for this purpose describes the predetermined breaking line, here, according to the invention, the predetermined position of the scan figure stored for the predetermined position of the predetermined breaking line is corrected to an actual position for the scan figure assigned to the concrete actual position.

[0055] For this purpose, the actual position of the vehicle interior trim part is optically recorded with a camera in relation to the laser scanning device, and the actual position of the predetermined breaking line is derived in relation to the laser scanning device.

[0056] A target position of the scan figure, stored for the target position of the predetermined breaking line, is corrected to an actual position of the scan figure, thus bringing the scan figure into alignment with the predetermined breaking line.

[0057] The method is advantageously carried out by arranging the vehicle interior trim parts one after the other in the working plane using two delivery devices. Preferably, the first of the three vehicle interior trim parts is held in the first of the two delivery devices and processed, while the second delivery device transports the finished, second vehicle interior trim part to an output location, and subsequently the unprocessed, third vehicle interior trim part is picked up at an input location and transported for processing.

[0058] Ideally, the sensor matrix should have a homogeneous sensitivity across its entire area. This can be optimized by scattering the transmitting component of the laser beam, allowing more individual sensors to detect transmitting components and record measurements, thus mitigating any potential fluctuations. Reference symbol list

[0059] 0 Device (for creating a predetermined breaking line) 1 Vehicle interior trim part 2 Predetermined breaking line 3 Sensor matrix 4 Machining head 5 Control and computing unit 6 Laser scanning device 7 Laser generator 8 Camera 9 Multi-axis robot 10 Suction cup 11 Gripper 12 Diffuser 13 Feeding device AWorking plane SLaser beam

Claims

1. A method for producing a predetermined breaking line (2) in a vehicle interior trim part (1), wherein the vehicle interior trim part (1) is picked up and arranged in a working plane (A) between a sensor matrix (3) and a machining head (4) arranged in a defined manner with respect thereto and containing a laser scanning device (6), the laser scanning device (6) scans a laser beam (S) on an inner side of the vehicle interior trim part (1), describing a scan figure, along the predetermined breaking line (2), wherein material removal in the form of holes is effected in each case down to a predetermined residual wall thickness at a plurality of machining locations along the predetermined breaking line (2) and measured values are acquired by individual sensors of the sensor matrix (3) during the material removal caused by a portion of the laser beam (S) transmitted at the machining locations, a respective comparative measured value is formed from measured values acquired simultaneously and is compared with a reference measured value to which the predetermined residual wall thickness is assigned, and a laser generator (7) emitting the laser beam (S) is controlled as a function of a comparison result, characterized in that the measured values of all individual sensors that lie above a predefined threshold value are acquired, which means that the predetermined breaking line (2) can be positioned as desired within a field of view of the sensor matrix, an actual position of the vehicle interior trim part (1) relative to the laser scanning device (6) is optically detected by means of a camera (8) directed towards the working plane (A) and an actual position of the predetermined breaking line relative to the laser scanning device (6) is derived therefrom, a desired position of a scan figure stored for a desired position of the predetermined breaking line for scanning the predetermined breaking line (2) is corrected to an actual position of the scan figure, whereby the predetermined breaking line (2) is produced at a predetermined position on the vehicle interior trim part (1) during scanning of the scan figure, and the transmitted part of the laser beam (S) is scattered so that measured values are acquired by more individual sensors.

2. The method for producing a predetermined breaking line (2) in a vehicle interior trim part (1) according to claim 1, characterized in that two feeding means (13) alternately pick up a vehicle interior trim part (1) and arrange it sequentially in the working plane (A), and that an actual position of the scan figure is determined individually for a respective actual position of the respective vehicle interior trim part (1).

3. The method for producing a predetermined breaking line (2) in a vehicle interior trim part (1) according to claim 2, characterized in that a first of three vehicle interior trim parts (1) is machined while being held in the first of the two feeding means (13), while the second of the two feeding means (13) transports a finished second vehicle interior trim part (1) to an output location and then picks up an unmachined third vehicle interior trim part (1) at an input location and transports it for machining.

4. A device (0) for producing a predetermined breaking line (2) in a vehicle interior trim part (1), said device (0) including a sensor matrix (3) which comprises individual sensors, a machining head (4) arranged in a defined manner with respect to the sensor matrix (3), said machining head (4) containing a laser scanning device (6) connected to a laser generator (7), and an intermediate working plane (A), in which the vehicle interior trim part (1) to be machined is arranged, as well as a control and computing unit (5), wherein a field of view of the sensor matrix (3) is larger than a maximum extension of a predetermined breaking line (2), characterized in that a camera (8) directed towards the working plane (A) is present, which is configured to detect the actual position of the vehicle interior trim part (1) arranged in the working plane (A) in relation to the laser scanning device (6) in order to derive therefrom an actual position of the predetermined breaking line (2), the control and computing unit (5) is configured to bring a scan figure into alignment with the predetermined breaking line (2), and a diffuser (12) is arranged upstream of the sensor matrix (3).

5. The device (0) for producing a predetermined breaking line (2) in a vehicle interior trim part (1) according to claim 4, characterized in that individual sensors of the sensor matrix (3) each have a sensitivity that is matched to each other so that the sensor matrix (3) has a homogeneous sensitivity.

6. A machining installation comprising a device for producing a predetermined breaking line in a vehicle interior trim part according to any one of claims 4 to 5, characterized in that it contains at least two feeding means by which a vehicle interior trim part (1) is alternately transported and positioned in the working plane (A) of the device for producing a predetermined breaking line (2).

7. The machining installation according to claim 6, characterized in that the at least two feeding means (13) include multi-axis robots (9), which hold the vehicle interior trim parts (1) suspended in the working plane (A) in each case.