METHOD FOR LOADING A BOARD STORAGE DEVICE OF A FLATBED TOOL MACHINE AND FLATBED TOOL MACHINE

Description

[0001] The present invention relates to a method for loading a sheet storage device of a flatbed machine tool with a sheet of material. The invention further relates to a flatbed machine tool.

[0002] Flatbed machine tools, such as laser cutting machines, are used to process sheet materials like raw metal sheets. For this purpose, the sheet to be processed is typically placed on a pallet and then loaded into the machining area of ​​the flatbed machine. Loading is usually done manually for small sheets, i.e., without tools, or with a lifting device for larger sheets. In both cases, stops can be provided on the pallet to ensure that the pallet is loaded in a fixed position.

[0003] An example of a lifting device for plate-shaped metallic workpieces is known from DE 10 2017 223 574 A1, in particular for use with a flatbed machine tool.

[0004] The operator must obtain the information relevant for loading, such as the material sheet type (specified, for example, by the sheet dimensions and material type) and sheet orientation, from the order and production documents. The processing procedure is geared towards correctly loading the sheet with the workpieces to be cut. This requires, in particular, the correct alignment of the material sheet with the stops, at least within specified tolerances.

[0005] Alternatively, it is known from JP 2013-039591 A to use a camera in a cutting region to detect a material to be cut using base points, wherein the base points are provided in the cutting region and can thus be detected in a captured image by the camera.

[0006] From WO 2017 / 190258 A1, a feeding of a sheet metal panel to a stamping press is known, wherein the orientation of the sheet metal panel in the feeding direction is set by means of stops and the orientation in the second direction orthogonal to the feeding direction is carried out in such a way that the position of the sheet metal panel in the second direction is determined by a sensor and a control device and the deviation of the sheet metal panel from the predetermined orientation position in the second direction is determined by the control device and the deviation is compensated with a gripping arrangement.

[0007] From EP 1 222 975 A2 a positioning system for sheet metal in press brakes is known, wherein sensors detect the current position of the sheet metal, and the position is corrected until the current position corresponds to the pre-programmed desired position.

[0008] From EP 0 546 364 A1 a device for setting up planar elements with reference to a die is known.

[0009] A device for image-based assembly is known from US patent 6,167,607 B1.

[0010] From WO 2007 / 134631 A1 a method for optimizing an arrangement of support point tips is known.

[0011] One aspect of this revelation is the task of simplifying the loading process of flatbed machine tools and enabling flexible integration of the loading process into the manufacturing process. Another task is to optimize the use of a lifting device during the loading process in order to support a flatbed machine tool operator in loading and also in singulating machined parts.

[0012] At least one of these problems is solved by a method for loading a panel storage device according to claim 1 and by a flatbed machine tool according to claim 11. Further developments are specified in the dependent claims. The invention is defined by the claims.

[0013] One aspect of the disclosure relates to a method for loading a sheet support device of a flatbed machine tool with a sheet of material, wherein the sheet of material is to be fed to the machining process by the flatbed machine tool starting from a target position assigned to the machining process in a machine coordinate system, and the flatbed machine tool comprises a camera system with at least one camera. The camera system is configured to generate images of the sheet support device that are spatially calibrated to the machine coordinate system of the flatbed machine tool. The method may comprise the following steps: Generating an image of the material panel in the area of ​​the panel storage device, evaluating the image to determine the actual panel position in the machine coordinate system, recording any deviation of the determined actual panel position from the target position, and using the recorded deviation to align and position the material panel.

[0014] In another aspect, a flatbed machine tool, optionally a laser cutting flatbed machine, includes: A sheet storage device, optionally configured as a pallet changer with a pallet or as a machine table, for providing a storage surface for the material sheet; a camera system with at least one camera configured to generate an image of the sheet storage device, spatially calibrated with respect to the machine coordinate system of the flatbed machine tool, wherein the image optionally shows a pallet with the material sheet resting on it or vertically spaced; a processing unit, optionally configured as a laser cutting unit; and a control unit for carrying out a process as described above and generally herein. Furthermore, the flatbed machine tool may optionally have a lifting device. The at least one camera may be mounted on the processing unit. The camera system may also be configured for two-dimensional and / or three-dimensional image acquisition.

[0015] In some advanced training courses, the actual position of the board can be determined within a support plane of the board support device. The actual and target positions can each be defined by a distance within the support plane between a reference point on the material board and a reference point on the support plane, as well as by the orientation of the material board within the support plane.

[0016] In some training courses, the procedure includes the step: placing the material board on the board storage device, so that the actual board position for a placed material board is determined.

[0017] In some advanced training courses, a lifting device is also used to place the material board on the board storage device, and the procedure further includes the steps: picking up the material board with the lifting device and transporting the material board with the lifting device over the board storage device, so that the actual board position is determined for a material board held above the board storage device.

[0018] The actual position of the sheet in the support plane of the sheet support device can be determined assuming a simple downward movement of the sheet onto the support device. Additionally or alternatively, a transformation equation of the sheet's spatial position into the machine coordinate system can be derived using at least one marker or key feature provided on the lifting device to determine the actual position of the sheet in the support plane. Additionally or alternatively, the lifting device can include a weighing unit for determining the mass of the picked-up sheet. The weighing unit can optionally be a scale or a computational unit that derives the mass from the initial image of the sheet and predefined parameters. The method can further comprise the following steps: Determining the mass of the recorded material sheet, comparing the determined mass with a predetermined mass of the material sheet intended for processing, and outputting an error signal if the comparison reveals a difference between the determined mass and the predetermined mass.

[0019] In some embodiments, the method may further include the following steps: deriving geometric dimensions of the material sheet from the image capture using the spatial calibration of the camera and determining the actual sheet position based on the geometric dimensions of the material sheet.

[0020] In some embodiments of the method, the detected deviation can be used to control the lifting device so that the material sheet is placed at the target position, optionally with automated placement. Additionally or alternatively, the detected deviation can be used to display information about the deviation, and optionally the target position and / or the actual sheet position, to an operator of the flatbed machine tool. This can be done, for example, on a monitor of the flatbed machine tool or displayed in an augmented reality display unit. Optionally, further process information can be displayed. Additionally or alternatively, the detected deviation can be used to adjust the machining process and optionally the target position based on the actual sheet position and optionally on an arrangement of support ribs of the sheet placement device, which is detected, in particular, by the camera.

[0021] According to the invention, the target position can be: Depending on a detected arrangement of support bars of the sheet support device, which is optionally detected with the camera system, at the time the material sheet is placed, and depending on a nesting of workpieces to be produced from the material sheet and optionally depending on at least one of the parameters avoidance of tilting workpieces, support of the workpieces during the cutting process and avoidance of slag splashes on workpieces and welding of workpieces.

[0022] Alternatively, the target position can be manually specified by an operator of the flatbed machine tool.

[0023] The concepts described herein relate in particular to the processing of sheet metal (sheet metal panels, plate-shaped metallic workpieces) with a (laser cutting) flatbed machine tool.

[0024] Advantages of the invention include precise and largely error-free loading of a sheet storage device of a flatbed machine tool with one or more sheet metal sheets, as well as easier transport and simplified positioning of heavy individual parts.

[0025] Furthermore, the invention can increase process reliability by, for example, taking into account a support ridge situation during processing. Exemplary procedures for generating laser cutting plans that take this into account are disclosed in the unpublished German patent application DE 10 2018 126 077.6, filed on October 19, 2018, by the applicant.

[0026] Furthermore, a beneficial increase in productivity can result from shorter material changeover times.

[0027] This document reveals concepts that allow for at least partial improvements to aspects of the prior art. In particular, further features and their advantages become apparent from the following description of embodiments with reference to the figures. The figures show: Fig. 1 a schematic spatial representation of a flatbed machine tool with a pallet ready for insertion into the flatbed machine and loaded with a sheet of material, Fig. 2 a schematic spatial representation of a flatbed machine tool with a lifting device for loading a pallet, Fig. 3 a flowchart to illustrate a method for loading a sheet storage device, and Figs. 4A and 4B schematic representations of exemplary images that can be displayed to an operator to support the loading process and machining planning.

[0028] The aspects described herein are partly based on the finding that the loading process, whether performed manually or with the aid of a lifting device, can be supported by an optical measuring system with regard to the position of a sheet metal panel on a panel support device. It was thus recognized that optically detecting the sheet metal panel to be processed can make it possible, for example, to correctly position a sheet metal panel on the panel support device with regard to the processing to be carried out, independent of stops. The positioning can optionally be adjusted to the processing process.

[0029] Furthermore, an evaluation of the position of the optically detected sheet metal panel can be incorporated into the processing of the material panel itself, for example in the case of the creation of a machining plan, the checking of the material and geometry of the deposited / to-be-deposited material sheet and thus the checking with regard to a correct selection of the material sheet or the checking of the position of a deposited or to-be-deposited material sheet with regard to the configuration of the sheet storage device, e.g. with regard to the relative position of the support points to the cutting line.

[0030] According to the invention, when manually loading a sheet metal working machine (for example, a flatbed machine), the position of a sheet metal panel (for example, a material panel) can be detected by an optical measuring system, and the detected current position can be displayed to the operator of the sheet metal working machine. According to the invention, the operator can be assisted in placing a material panel in an optimal or intended storage position (target position) for processing, if the storage position is specified, for example, by the control system of the flatbed machine. The target position need not be an absolute position but can have tolerances. For example, tolerances of up to + / - 50 mm can be permitted if, for example, the machining plan has taken this into account. The control system of the flatbed machine, in particular the laser control, can display the actual position (if, for example, it is not specified).(within the tolerance range) and adapt the machine machining program (e.g., the cutting plan) to the actual position using transformation. Similarly, the use of a lifting device can be optimized to provide optimal support to the operator when loading a tray storage device of a flatbed machine tool and, optionally, also during the subsequent singulation of machined parts.

[0031] The Figuren 1 and 2 Figure 1 shows exemplary configurations of flatbed machine tools in which the concepts disclosed herein can be implemented. Fig. 1 This refers to manual loading and further clarifies the aspect of information presentation. In contrast, this shows Fig. 2 Loading supported by a lifting device.

[0032] In Fig. 1 The flatbed machine tool 1 includes a machining unit 3, for example a cutting unit, which represents a machine area in which material processing takes place, for example a cutting operation can be carried out.

[0033] The flatbed machine tool 1 further comprises an upstream pallet changer 5, which allows the operation of the flatbed machine tool 1 with one or more pallets 7. A material sheet 9 (in particular made of sheet metal) is placed on the pallet 7 for a processing operation, for example, a cutting operation. The pallet changer 5 with the pallet 7 is an example of a sheet storage device, which in this case is assigned to the flatbed machine tool 1. In general, the sheet storage device can be part of a device for separating sheet-like workpieces, in particular metal sheets, such as a laser flatbed machine tool. The processing operation takes place in the processing unit 3 as soon as the pallet 7 with the material sheet 9 is moved into the processing unit 3. The sequence of the processing operation is controlled and monitored, for example, by a control unit 11.

[0034] The pallet 7 comprises, for example, a rectangular pallet frame 13 with short and long side sections, as well as an arrangement of support ribs 13A. The support ribs 13A are attached to the pallet frame 13 at the long side sections and run parallel to the short side sections of the pallet 7. The material sheet 9 to be cut was placed on a support surface defined by the support ribs 13.

[0035] Fig. 1 Figure 15 schematically shows a camera 15 as an example of a camera system for capturing two-dimensional or three-dimensional images. For multi-dimensional images, several cameras can also be used. The camera 15 is shown, by way of example, centrally mounted on the processing unit 3 with respect to the pallet changer 5 at a distance from the support plane and aligned with the pallet 7 for receiving it. Herein, a camera is generally defined as an image recording device that preferably operates in the visible wavelength range. However, image recording can also be based on other wavelength ranges (e.g., the infrared range) or on other radiation sources (ultrasound). For the concepts disclosed herein, for example, a camera system for image acquisition can be used as described in DE 10 2016 120 131 A1 for supporting the sorting of workpieces or in the unpublished German patent application DE 102018 133 524.5, with filing date 21 December 2018, is described by the applicant with regard to the processing of residual grids.

[0036] Camera 15 transmits image data to the control unit 11 of the flatbed machine tool 1, where an image processing algorithm can be executed. Specifically, it is proposed here to use the image processing algorithm to obtain information about the position and orientation of the material sheet 9 and to utilize this information in the machining process and / or its preparation. For example, the image processing algorithm can determine the current position of the material sheet 9 on the pallet 7 from an image of the pallet 7 (with the material sheet 9 resting on it). The position and orientation of the material sheet 9 can be determined relative to a reference point of the datum system of the flatbed machine tool 1.For example, the image processing algorithm can derive an orientation (rotation) of a rectangular material panel 9 in the support plane and / or a translation of a reference point of the material panel 9 with respect to a reference point 0, which is assigned to a corner point of the rectangularly shaped palette 7.

[0037] For example, camera 15 is calibrated to a machine coordinate system of the processing unit 3. Accordingly, a transformation from image coordinates to machine coordinates (e.g., as a transformation equation) can be stored in the control unit, so that image captures, and in particular the position of the material sheet 9 captured therein, can be related to the machine coordinate system. In other words, calibrating camera 15 makes it possible to calculate a translation and / or a rotation of the material sheet 9 to a reference point, or to a target position, which is given in relation to the reference point (and usually with a tolerance range).

[0038] For a machining operation, the pallet 7 can be moved into the machining unit 3 along a pallet insertion direction 17. The pallet changer shown allows the laser flatbed machine 1 to be operated with a pallet from one side. Alternatively, a pallet changer can be provided on opposite sides of the machining unit 3, so that the flatbed machine 1 can be operated from two sides and two camera systems are required accordingly.

[0039] Fig. 1 Figure 19 shows exemplary contours of parts to be cut from material sheet 9, as defined in a machining plan, here a cutting plan, with regard to a target position.

[0040] As in connection with Fig. 3 As explained, according to the concepts disclosed herein, the camera 15 serves to generate images of the material panel 9 in the area of ​​the panel storage device (in Fig. 1 filed and in Fig. 2 (shortly before unloading). The images are then analyzed to support the loading process. For example, the results of the analysis can be displayed by the control unit 11 on a monitor 21, which is connected to the control unit 11 for data exchange. The monitor 21 is positioned, for example, in a clearly visible location near the processing unit 3 for an operator who is in the area of ​​the pallet changer 5. Fig. 1 Figure 22 shows an image of the deposited material panel 9, as it is displayed on the monitor 21.

[0041] Alternatively or additionally, the results of the image processing algorithm can be displayed as information in the field of vision of (3D) data glasses 23, which are connected to the control unit 11 for data exchange. If the wearer of the data glasses 23 (not shown) looks at the pallet 7, additional information regarding the positioning of the material panel 9 can be displayed.

[0042] Examples show in Fig. 1 The data glasses 23 and the monitor 21 display a displacement arrow 25 that starts at the seen or recorded material panel 9 and indicates the direction in which the material panel 9 must be moved to reach its target position. As already mentioned, the data glasses 23 and the monitor 21 can display additional information about the current processing operation to the operator. Examples include... Fig. 1 Contours 19' of workpieces to be cut are shown on the data glasses 23 and order data 27 for a workpiece to be cut, such as information on the material sheet (lateral dimensions and thickness as well as sheet material type), are indicated on the monitor 21.

[0043] The in Fig. 2 The flatbed machine tool 1 shown comprises a lifting device 31 for transporting and depositing, in particular, large material sheets, whereby the lifting device can also be provided independently of the flatbed machine tool 1. Regarding the design of the sheet storage device, the camera system, etc., reference is made to... Fig. 1 The control unit 11, for example, is connected to the processing unit 3, the lifting device 31, the monitor 21 and the camera 15 for data exchange.

[0044] In Fig. 2 The lifting device 31 is schematically depicted as a crane with a boom 33. A holding device 37 is suspended from the boom 33, for example, by a chain 35 or a rigid mounting system. The holding device 37 allows the material panel 9 to be fixed, for example, by means of suction cups 39. For example, the lifting device 31 picks up the topmost material panel from a pallet of raw panels (not shown) and pivots it over the pallet 7 to place it there.

[0045] Fig. 2 The image shows the state shortly before placement, in which the material panel 9 hovers approximately above its target position on the pallet 7. In this (initial) actual panel position, a (first) image is captured using the camera system 15. The detection of the position and orientation of the material panel 9 in space can be supported, for example, by markers 41 provided on the holding device 37.

[0046] The results of the image processing algorithm can be displayed to an operator, for example on monitor 21 (in Fig. 2 (For example, an arrow 43 is indicated to clarify a required rotation) or displayed in the field of vision of data glasses. Furthermore, the information can be used to control the lifting device 31 in such a way that the material panel 9 is moved precisely over the target position and can be placed accordingly on the pallet 7. This can be done semi- or fully automatically.

[0047] The lifting device 31 can also include a weighing unit for determining the weight of the attached material panel 9. The determined weight allows verification of whether the correct material panel has been picked up. The weighing unit can be based, for example, on a scale 45 and / or on an evaluation of the captured images. In the latter case, the control unit 11 can deduce the weight of the material panel 9 from its dimensions, together with material information (material type).

[0048] Fig. 3 A flowchart illustrates various aspects that can be incorporated, individually or in groups, into a process for loading a sheet storage device of a flatbed machine tool with one or more material sheets. The concepts proposed here are particularly advantageous for multi-sheet loading, for example, when the storage positions (target positions) of all material sheets cannot be predetermined by stops.

[0049] The starting point is the provision of an optical measuring system (camera system) consisting of 2D and / or 3D cameras. The measuring system generates an initial image of the material sheet 9 (step 101), from which an initial (current) actual sheet position can be derived. The initial image can be generated after the material sheet has been placed on a support surface (step 101A). Alternatively, the initial image of the material sheet 9 can be captured while the material sheet 9 is positioned above the support surface on the lifting device (step 101B). The support surface is also referred to as the work surface, such as that provided by the sheet storage device (e.g., a machine table or a pallet).

[0050] The first image capture is then evaluated (step 103).

[0051] If the material sheet 9 is placed on the machine table or the pallet, the sheet position can be determined via the geometric dimensions of the material sheet 9 (step 103A).

[0052] If the material sheet 9 is to be placed on the machine table or pallet using a lifting device, the optical measuring system can detect the position and orientation of the material sheet 9, which is attached to the lifting device, relative to the target position shortly before placement (step 103B). Provided that a purely vertical placement movement is performed, the actual position of the lifted material sheet can be derived, while it is still in place, by projecting its position in space onto the support plane. When determining the position in space, markers or key feature points on the lifting device, in combination with the optical detection of the sheet orientation, can facilitate the determination of a transformation equation into the machine coordinate system or pallet coordinate system. In general, according to the invention, tolerances can be taken into account in specifying target positions and / or in detecting actual positions.Tolerances of up to + / - 50 mm are common in positioning.

[0053] The evaluation allows a deviation of the determined actual position of the board from the target position to be detected, for example with an image processing algorithm (step 105), and this to be used for the alignment and positioning of the material board (step 107).

[0054] For example, the operator can be shown the current position, a correction value, and / or the (optimal) target position (step 107A). This information can also be displayed using augmented reality (AR), for example, by overlaying the current position, the correction value, and / or the target position onto the live image in the smart glasses (step 107B). Alternatively, the information can be displayed on a monitor, which can also be connected to the lifting device (step 107C). ​​Additionally, information about the current loading process, such as raw panel information, multi-panel configuration, and storage position, as well as information about the subsequent loading process, can be displayed (step 107D).

[0055] To determine the deviation, the target position must be provided (step 109). Generally, the target position can be specified manually (step 109A) or calculated during loading on laser flatbed machines depending on the support configuration (step 109B). Furthermore, the target position can be determined based on part nesting on the material sheet, particularly depending on parameters such as preventing parts from tilting, providing optimal support for the parts during the cutting process, avoiding slag spatter, and preventing parts from welding to the substrate (step 109C).

[0056] Furthermore, the nesting of the parts to be produced can be subsequently adjusted, and in particular optimized, depending on the loading position and the support rib configuration (step 111). This can be done depending on parameters such as preventing parts from tilting, providing optimal support for the parts, e.g., during the cutting process, preventing slag spatter, and preventing parts from welding to the base.

[0057] When using a lifting device with weight determination capability, the mass of the material sheet can be recorded (step 113). The mass of the material sheet to be loaded can be measured, for example, using a scale on the lifting device or calculated from the material's specific density and geometric dimensions. If the calculated and actual weight of the material sheet deviate from each other or from a target weight, an error can be identified (e.g., incorrect raw material, multiple sheets stuck together, etc.). The weight determination capability can thus help avoid loading errors.

[0058] The lifting device can be designed in accordance with the aforementioned DE 10 2017 223 574 A1. Furthermore, for separating parts from a residual grid after the processing operation, the lifting device can be equipped with passive suction cups (modular) to assist the operator in lifting heavy parts (e.g., < 20 kg).

[0059] In addition to or as an alternative to the steps described above, the material panel can be placed fully or semi-automatically based on the evaluation of the initial image capture (step 103) and the detection of the deviation (step 105). For this purpose, the operator can, for example, select an "automatic mode" for placing / setting down the material panel after manually controlled gripping (step 115). The (semi-)automatic mode can also include control of the crane (lifting device) via radio and / or by the optical measuring system (the control unit). Additionally, safety monitoring with a room scanner can be implemented.

[0060] The Figuren 4A und 4B show schematic representations of the contact area, as they can be displayed, for example, on monitor 21 or shown in the data glasses 23.

[0061] The presentation of Fig. 4A includes simplified image recordings of 22 from a palette, such as those found in Fig. 1 The image shows a rectangular frame 13, which delimits the pallet 7, as well as the support ribs 13A evenly spaced within the frame 13. The image 22 further shows a surface 51 (hatched) of a material sheet and its outer contour 53 (dashed) in a rectangular shape, which corresponds to the actual position 55 of the material sheet. Contours 19 of workpieces to be cut are also shown, as they are to be cut from the material sheet using a cutting plan aligned to a fixed target position 57 (dashed-dotted). The actual sheet position 55 and the target position 57 are each defined, for example, by a distance in the support plane between a reference point of the material sheet 9 (e.g., a center point or centroid) and a reference point 0 of the support plane (the pallet), and by an orientation of the material sheet 9 in the support plane.

[0062] It can be seen that the current actual position, as captured by image 22, would not guarantee the overlap of contour 19A with the material panel positioned in this way. The image processing algorithm recognizes this and initiates the display of displacement arrows 59.

[0063] Based on this display, the operator can manually correct the position and orientation of the material panel or have a corresponding automated correction performed. The expert will recognize that the procedure for increasing accuracy can be carried out iteratively, particularly with subsequent (second, third, etc.) image acquisitions.

[0064] For completeness, a reference point 0 of a pallet coordinate system is shown on image 22, which establishes the relationship of the pallet to the machine coordinate system.

[0065] Fig. 4BThis illustrates that the generated image can also be used to suggest adjustments to the machining plan. For example, when checking the nesting of the workpieces, it can be seen that when the target position 22 is reached, a swap of workpiece positions suggested by an exchange arrow 61 would lead to higher machining quality.

[0066] It is explicitly stated that all range specifications or specifications of groups of units disclose any possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a limit of a range specification.

Claims

1. A method for loading a material panel (9) onto a panel depositing device of a flatbed machine tool (1), wherein - the material panel (9) of the machining with the flatbed machine tool (1) is to be fed in starting from a target position (57) assigned to the machining in a machine coordinate system, and - the flatbed machine tool (1) includes a camera system with at least one camera (15) designed to produce image recordings (22) of the panel depositing device, the recordings being spatially calibrated to the machine coordinate system of the flatbed machine tool (1), comprising the steps: producing (step 101) an image recording (22) of the material panel (9) in the region of the panel depositing device, evaluating (step 103) the image recording (22) to determine an actual panel position (55) in the machine coordinate system, detecting (step 105) a deviation of the determined actual panel position (55) from the target position (57) and using (step 107) the detected deviation to align and position the material panel (9), characterized in that the target position (57) - is calculated depending on a detected arrangement of supporting bars (13A), which are detected with the camera system, of the panel depositing device at the time the material panel (9) is deposited, and - is ascertained depending on a nesting of workpieces to be produced from the material panel (9).

2. The method according to any one of the preceding claims, wherein the actual panel position (55) is determined in a support plane of the panel depositing device and wherein the actual panel position (55) and the target position (57) are each given by a separation in the support plane between a reference point of the material panel (9) and a reference point (0) of the support plane and by an alignment of the material panel (9) in the support plane.

3. The method according to claim 1 or 2, further comprising: depositing the material panel (9) on the panel depositing device so that the actual panel position (55) is determined for a deposited material panel (9).

4. The method according to claim 1 or 2, wherein a lifting device (31) is further provided for depositing the material panel (9) on the panel depositing device, further comprising: receiving the material panel (9) with the lifting device (31) and transporting the material panel (9) with the lifting device (31) above the panel depositing device so that the actual panel position (55) is determined for a material panel (9) held above the panel depositing device.

5. The method according to claim 4, wherein, assuming a purely lowering movement of the material panel (9) onto the panel depositing device, the actual panel position is determined in the support plane of the panel depositing device and / or wherein in order to determine the actual panel position (55) in the support plane, a transformation equation of a spatially determined position of the material panel (9) into the machine coordinate system is obtained with the aid of at least one marker (41) or at least one key feature which is provided on the lifting device (61), and / or wherein the lifting device (31) includes a weighing unit for determining the mass of the received material panel (9), wherein the weighing unit is optionally a balance (45) or a computing unit which derives the mass from the first image recording (22) of the material panel (9), as well as predefined material panel (9) parameters, and the method further has the steps of: - determining the mass of the received material panel (9), - comparing the determined mass with a predefined mass of the material panel (9) provided for the machining, and - outputting an error signal in the case that the comparison yields a difference between the determined mass and the predefined mass.

6. The method according to any one of the preceding claims, further comprising deriving geometrical dimensions of the material panel (9) from the image recording (22) by using the spatial calibration of the camera (15) and determining the actual panel position (55) on the basis of the geometrical dimensions of the material panel (9).

7. The method according to any one of claims 4 or 5, wherein the detected deviation is used to activate the lifting device (31) in such a way that the material panel is deposited at the target position, wherein optionally an automated depositing takes place.

8. The method according to any one of the preceding claims, wherein the detected deviation is used to display to an operator of the flatbed machine tool (1) information concerning the deviation, and optionally the target position (57) and / or the actual panel position (55), optionally on a monitor (21) of the flatbed machine tool (1) or superimposed in an augmented reality display unit (23), wherein further process information can be optionally displayed.

9. The method according to any one of the preceding claims, wherein the detected deviation is used to adapt the machining process, and optionally the target position (57), depending on the actual panel position (55) and on an arrangement, detected with the camera (15), of supporting bars (13A) of the panel depositing device.

10. The method according to any one of the preceding claims, wherein the arrangement of supporting bars (13A) of the panel depositing device is detected with the camera system.

11. A flatbed machine tool (1), wherein the flatbed machine tool (1) comprises: a panel depositing device for providing a deposition surface for storing the material panel (9), a camera system with at least one camera (15) designed for producing an image recording (22) of the panel depositing device, the camera being spatially calibrated with respect to the machine coordinate system of the flatbed machine tool (1), a machining unit (3), a lifting device (31) and a control unit (11), wherein the control unit (11) is configured to carry out a method according to any one of the preceding claims.

12. The flatbed machine tool (1) according to claim 11, wherein the at least one camera (15) is attached to the machining unit (3), and / or the camera system is designed for two-dimensional and / or three-dimensional image detection.

13. The flatbed machine tool (1) according to claim 11 or 12, wherein the flatbed machine tool (1) is designed as a laser cutting flatbed machine tool for cutting out workpieces from a material panel (9) with a laser beam, and the machining unit (3) is designed as a laser cutting unit.

14. The flatbed machine tool (1) according to any one of claims 11 to 13, wherein the panel depositing device is designed as a pallet changer (5) with a pallet (7) or as a machine table, and the image recording (22) optionally shows a pallet (7) with the material panel (9) lying thereon or vertically separated therefrom.