Method for measuring the format of a plate-shaped workpiece

Abstract

A method for measuring the format of a plate-shaped workpiece (1), in which markings (2) are identified on a surface side of the workpiece, applied to the surface side of the plate-shaped workpiece (1) and / or introduced into the plate-shaped workpiece (1), wherein the relative positions of the markings (2) to each other are measured and / or the markings (2) are positioned in defined relative positions to each other, characterized in that at least two markings (2) are applied to the surface side of the plate-shaped workpiece (1) in the region of each narrow side (3) and / or introduced into the plate-shaped workpiece (1) in the region of each narrow side (3), wherein the markings (2) are positioned at defined distances (A) from the respective narrow side (3) of the plate-shaped workpiece (1) and / or distances (A) of the markings (2) from the respective narrow side (3) of the plate-shaped workpiece (1) are measured.wherein the position of a straight line (G) is determined from the positions of these markings (2), wherein for each of the narrow sides (3) of the workpiece (1) the position of a corresponding straight line (G) is determined on the basis of at least two markings (2) and the format of the workpiece (1) is determined from the positions of the straight lines (G), in particular from the positions of the points of intersection (S) of the straight lines (G), and the distances (A) of the markings (2) from the respective narrow sides (3).

Description

[0001] The invention relates to a method for measuring the format of a plate-shaped workpiece.

[0002] In the following, plate-shaped workpieces are understood to mean, in particular, workpieces whose dimensions in two mutually perpendicular main directions of extension are significantly larger than in a third thickness direction perpendicular to the main directions of extension.

[0003] In the following, the format of a plate-shaped workpiece is to be understood as meaning in particular its dimensions in its main directions of extension.

[0004] In the case of rectangular workpieces, the format refers specifically to the dimensions parallel to its narrow sides. However, the workpiece can also have other, particularly more complex, shapes. This particularly applies to workpieces with curved surfaces, as is often the case with tabletops, for example. In such cases, the format generally describes the dimensions of the workpiece parallel to its flat sides.

[0005] Mechanical measurement methods are generally available for measuring the format of such a plate-shaped workpiece. In this case, stops and / or probe elements are brought into contact with the workpiece, thus determining its dimensions in its main directions of extension. However, the disadvantage of such methods is that they require precise alignment of the workpiece to the stops or precise alignment of the probe elements to the workpiece.

[0006] This procedure is comparatively time-consuming, and the workpiece must usually be stationary for precise measurement. In modern production processes, this leads to delays that negatively impact the overall productivity of the process.

[0007] For this reason, methods have already been developed in the past that enable non-contact measurement of the workpiece's format. Such methods operate, for example, on the principle of an optical scanner, in which the workpiece is moved across an illuminated measuring field, and light-sensitive sensors measure the area shaded by the workpiece. Other methods utilize cameras and image recognition software. The workpiece is captured by a camera, and the area occupied by the workpiece is determined from the image generated by the camera. With appropriate calibration, this can be used to calculate the size of the actual workpiece.

[0008] From JP 2002 - 341 511 A a method according to the first alternative in the preamble of claim 1 is known.

[0009] The problem with such measurement methods is that inaccuracies occur in the area of ​​the workpiece's narrow sides, i.e., the sides of the workpiece that extend in the direction of its thickness, due to the workpiece's edges. Scattering effects play a role here, and rounded edges between the narrow sides and the flat sides of the workpiece, for example, can lead to the position of the narrow side not being accurately recorded.

[0010] The present invention is therefore based on the object of providing a method for measuring the format of a plate-shaped workpiece which allows both precise and rapid measurement of the format.

[0011] The object is achieved by a method having the features of independent claim 1. The features of the dependent claims relate to advantageous embodiments.

[0012] The method according to the invention provides for markings on the surface sides of the plate-shaped workpiece to be identified, applied to the surface side of the plate-shaped workpiece, and / or incorporated into the plate-shaped workpiece. In this sense, a single complex, connected marking can also be regarded as a combination of a plurality of individual markings. For example, a single complex pattern can be applied to the entire surface side of a workpiece, which makes it possible to identify a plurality of defined positions on the surface side. In this case, the individually defined positions are to be regarded as individual markings within the meaning of the present invention.

[0013] The markings can be optically recognizable markings applied to the surface of the workpiece. This can be done, for example, using printing processes, in particular using inkjet printing processes. Furthermore, it is also possible to incorporate markings into the plate-shaped workpiece. These can be electronic markings, such as RFID chips, for example. However, it is also possible, for example, to incorporate magnets into the plate-shaped workpiece and use them as markings in connection with the present invention.

[0014] According to the invention, the method is carried out in such a way that two markings are applied to and / or introduced into a surface side of the workpiece in the region of a first narrow side of the plate-shaped workpiece. The markings are preferably either applied to and / or introduced at a defined distance from the first narrow side, and / or the distances of the markings from the first narrow side of the plate-shaped workpiece are measured. In this way, markings are available whose distance from the first narrow side of the workpiece is known. Since the markings are located in spatial proximity to the first narrow side, only short distances need to be measured compared to the dimensions of the entire workpiece. In a next step, the position of a straight line connecting both markings is determined. It goes without saying that more than two markings can also be used for this purpose.It is also possible to apply a line to the workpiece, preferably parallel to the narrow side. This then represents an indefinite number of point-like markings within the meaning of the present invention.

[0015] According to the invention, the described determination of a straight line within the scope of the inventive format measurement is carried out for all four narrow sides of the workpiece. A quadrilateral can be constructed from the straight lines thus obtained. The corners of this quadrilateral are preferably located at the intersection points of the straight lines. The format of the workpiece can then be determined from the position and / or dimensions of this quadrilateral in conjunction with the distances of the markings from the respective narrow sides of the workpiece. This method is particularly advantageously suitable in conjunction with machining methods and / or machining devices in which a workpiece passes through a machining device several times and / or passes through a plurality of machining devices, with machining being carried out on a narrow side in each case. During this machining of the narrow side, the markings can then be applied and / or measured.The narrow side can advantageously be processed by applying an edge band, but other processes, preferably machining, can also be used. These can be used, for example, to provide the narrow side with a desired profile.

[0016] It is also possible to identify features of the surface side as markings. These features can preferably already be present on the surface side before application of the method according to the invention. These are in particular optical features of the surface side. This can be a graphic pattern of a coating on the surface side; alternatively and / or additionally, it is also possible, for example, to use a natural wood grain. Positions on the surface side that have characteristic features are then identified as markings so that they can be identified again by a position determination device. For example, a specific surface pattern can be stored in a control device equipped with a corresponding data memory in order to identify it as a marking.

[0017] According to the invention, the relative positions of the markings to one another are measured and / or the markings are applied and / or introduced at defined relative positions to one another. In this way, the known positions of the markings can be used to measure the workpiece with the aid of the positions of the markings. The detection of the markings can in particular be used to determine the format of the workpiece in conjunction with other known or measured relationships between the positions of the markings and certain points on the workpiece, in particular positions of the narrow sides of the workpiece. In other words, the - technically complex - direct measurement of the format of the workpiece is replaced by an indirect measurement of the format of the workpiece, in which dimensional information that is technically easier to obtain is geometrically orbe mathematically combined to obtain the format of the workpiece.

[0018] In this context, it is particularly advantageous if the markings are positioned in defined positions relative to the narrow sides of the plate-shaped workpiece. This means that, due to the known distance between the marking and the narrow side of the workpiece, the position of the narrow sides and thus the format of the workpiece can be determined by measuring the markings. Measuring the markings is technically much simpler than directly measuring the format of the workpiece itself, allowing for a faster and more accurate measurement of the workpiece format.

[0019] Alternatively or additionally, it is advantageously possible to measure the relative positions of the markings to the narrow sides of the plate-shaped workpiece. Especially in conjunction with known relative positions of the markings to each other, this allows for technically simple and precise determination of short distances between the markings and the narrow sides. These distances can be used to determine the format of the entire plate-shaped workpiece, which is much more difficult and imprecise to measure.

[0020] The panel-shaped workpieces are preferably workpieces made of wood or wood substitute materials, such as chipboard or wood fiberboard, laminates, HDF or MDF boards. The panel-shaped workpiece is preferably the result of dividing a large-format panel-shaped workpiece. In this case, it is advantageous if the markings are applied to the large-format panel-shaped workpiece before the large-format panel-shaped workpiece is divided. In practice, it often happens that panel-shaped workpieces of the type in question are produced in the desired formats by cutting them out of large-format panel-shaped workpieces. The large-format panel-shaped workpieces are preferably already provided with coatings on their surface sides and / or already have a suitable quality on these surfaces for their later use.If the markings are already applied to the large-format workpiece, it is possible to use the markings in the entire production process following the provision of the large-format plate-shaped workpieces.

[0021] A particular advantage in this context is when the markings are used to control the division of the large-format, panel-shaped workpiece. For example, the positions of the markings can be used to control a device for dividing the large-format workpiece, such as a saw and / or a milling tool. This can eliminate the need to precisely position the large-format workpiece for division. The positions of the markings can be used to determine the position of the large-format workpiece and thus the correct position for the desired cuts to be made when dividing the large-format panel-shaped workpiece.

[0022] In addition to their position, the markings can contain further information. This can be in the form of a barcode or a QR code, for example. It is also possible to apply entire text fields as markings. The markings can contain information about the quality and / or the dimensions. It is also possible to include information about processing steps to be carried out in the markings. For example, the markings can contain information about how, i.e. in particular according to which cutting plan, a large-format panel-shaped workpiece is to be divided. However, the markings can also contain information about the type and method of further processing of the narrow sides. This can particularly be information about any lamination that may be applied to the narrow sides, a so-called edge band.

[0023] However, it is also possible for the information to contain an individual identification of the workpiece. The individual identification can, for example, be a serial number - in plain text and / or coded. The individual identification preferably enables unambiguous identification of the workpiece in the further production process. Particularly in connection with batch-one production, the option of being able to identify individual workpieces in the production process at any time is advantageous. A higher-level control system can then ensure that the individual processing steps are carried out with the individual parameters desired for the respective workpiece. Individual workpieces that belong to a specific, preferably individually manufactured, product can also be put together automatically, in particular regardless of whether these workpieces are produced one after the other or.leave the production process together. Rather, the individual identification of the workpiece allows individual workpieces to be specifically directed to specific further processing and / or logistics processes.

[0024] The result of measuring the markings can advantageously be used for quality assurance purposes. This particularly means that the result of measuring the format of the plate-shaped workpiece is compared with a specified value. Tolerances that particularly depend on the respective quality requirements for the respective plate-shaped workpiece are preferably taken into account. In this way, an automated decision can be made as to whether or not a particular plate-shaped workpiece meets the format requirements. If the workpiece meets the requirements, it can preferably remain in the production process. Workpieces that do not meet the requirements are preferably automatically sorted out and / or sent for further processing.

[0025] Advantageously, it is also possible to apply a marking in the region of a first corner of the plate-shaped workpiece to the surface side of the plate-shaped workpiece and / or to the plate-shaped workpiece. The marking is preferably positioned at defined distances from the narrow sides of the plate-shaped workpiece adjacent to the first corner. Alternatively or additionally, it is also possible to measure the distances of the markings from the narrow sides of the plate-shaped workpiece adjacent to the first corner. In this way, the positions of the markings for two narrow sides of the plate-shaped workpiece can be determined by measuring and / or defining two distances that are comparatively short compared to the dimensions of the plate-shaped workpiece and can therefore be measured more easily and precisely.

[0026] This is particularly preferably performed for all four corners of a surface side of the plate-shaped workpiece. In this way, a quadrilateral with the markings as vertices can also be determined, the dimensions of which are representative of the dimensions of the plate-shaped workpiece's format. In particular, by using the measured and / or specified distances of the markings to the respective surface sides, a precise measurement of the format of the plate-shaped workpiece can be performed by simply and quickly recording the relative positions of the markings to one another.

[0027] Preferably, the positions of the markings are determined contactlessly. Contactless determination of the positions of the markings has the advantage that they can be determined quickly. Contactless methods generally have the advantage that precise alignment of the workpiece relative to the position-determining device used to determine the positions of the markings is not necessary. This represents an advantage over mechanical measures such as stops and / or sensing elements, particularly with regard to rapid detection of the positions during an ongoing production process.

[0028] Furthermore, the positions of the markings are preferably determined optically. Optical detection offers the advantage that it can be implemented comparatively quickly, reliably, and cost-effectively, particularly using modern digital camera systems, which preferably have a calibration suitable for measuring the positions of the markings.

[0029] It is advantageous if the positions of the markings are determined using a plurality of position-determining devices. This has the advantage that a single position-determining device only needs to capture a comparatively small area of ​​the plate-shaped workpiece. Particularly when the markings are concentrated on certain zones or areas of one surface side, such as the corner areas, the position-determining devices can thus specifically capture only those areas of the workpiece in which markings are actually located. In this way, for example, when using cameras as position-determining devices, a large portion of the image area that would have to be recorded with the cameras and evaluated for markings can be saved.This leads to savings both in terms of the camera systems, since a lower total number of pixels needs to be recorded, and in terms of the computing power required for the number of pixels to be evaluated.

[0030] Particularly preferably, the position-determining devices are movable relative to one another. This enables the areas having the markings to be specifically detected with the respective position-determining devices, even if different plate-shaped workpieces differ in terms of the positions of their markings and / or their dimensions. For example, if a workpiece to be measured with a small format is followed by a workpiece to be measured with a large format, the distances between the position-determining devices can be increased between the measurements of both workpieces. In this way, for example, markings that are located in the area of ​​the narrow sides and / or corners of both workpieces can be detected and their positions determined.

[0031] Advantageously, it is possible to evaluate the determination of the positions of the markings with regard to the angles of the workpiece corners. In this way, in addition to the pure dimensions in the main extension directions of the workpiece, the angles of the workpiece can also be measured. If the positions of the markings and their distances from the narrow sides are known, the positions of the narrow sides and thus their angles to each other can be calculated, for example, by constructing straight lines and / or quadrilaterals based on the positions of the markings.

[0032] Preferably, the markings are used to determine the thickness of a lamination applied to the narrow sides, in particular an edge band. This can be done, for example, for quality control purposes. However, it is also possible to use the data obtained in this way on the thickness of the lamination to control processing steps that follow the application of the lamination. This can particularly involve machining operations such as milling and / or drawing. Precise knowledge of the actual thickness of the lamination allows the post-processing to be controlled in such a way that the transition between the lamination and the flat side of the panel-shaped workpiece is as precise as possible.

[0033] Advantageously, it is possible to use the markings according to the invention in a downstream manufacturing process and / or logistics process. This can be advantageous, for example, when the panel-shaped workpieces are further processed into complex products in a downstream manufacturing process. For example, in the production of furniture, the assembly of the furniture from the panel-shaped workpieces can be controlled with the aid of the markings. This is particularly helpful in connection with markings that contain information about the respective workpiece. Alternatively and / or additionally, the markings can also be used in pure logistics processes. In this way, workpieces can be assigned to different commissions, for example.

[0034] It is particularly advantageous if the marking is an optical marking. Preferably, the optical marking is designed so that it is invisible to the human eye. Such a marking does not adversely affect the visual appearance of the workpiece during its intended use.

[0035] For this purpose, optical, particularly fluorescent, markings can preferably be used, which only become visible to the position-determining device under certain lighting conditions, for example, when exposed to UV light. Alternatively and / or additionally, the markings can also be designed such that the light they emit, reflect, and / or absorb lies within a spectrum invisible to the human eye. Such markings can then be detected, for example, by special cameras in the ultraviolet or infrared range, which is invisible to the human eye.

[0036] It is also possible to use markings that are designed such that they are no longer visible to the human eye after a defined period of time. This can be achieved, for example, with pigments that decompose after a certain time. Such a decomposition process can, for example, be the result of exposure to atmospheric oxygen or natural ultraviolet radiation. In this context, a defined period of time is understood to mean, in particular, a period of time that can be determined so precisely that it can be ensured that the markings remain visible to the position-determining device until the end of the method according to the invention and, at the same time, are no longer visible to the human eye when the workpiece is used for its intended purpose.It is understood that in practice this time period may be subject to certain fluctuations, for example due to different lighting conditions.

[0037] It can also be advantageous to use, for example, UV-sensitive pigments, which are preferably specifically irradiated with UV light within the scope of the process according to the invention. As soon as the markings are no longer needed, they can be specifically "erased." Also conceivable is the use of a chemical erasure process, with which visible markings are removed by treatment with a chemical substance and / or rendered invisible to the human eye.

[0038] The method according to the invention is suitable for implementation on so-called continuous feed machines as well as on so-called machining centers.

[0039] In this context, continuous-feed machines are processing systems in which the workpieces are conveyed, preferably continuously, through various processing stations during processing, with the individual processing stations performing sequential processing steps on the workpieces. Preferably, during a pass through a continuous-feed machine, one narrow side is machined first, with the other narrow sides being machined either in subsequent passes of the same continuous-feed machine or in additional continuous-feed machines. Continuous-feed machines are regularly combined with suitable conveyor systems to implement appropriate return lines and / or circuits for processing all narrow sides of the respective workpiece.

[0040] Through-feed machines are particularly suitable for machining workpieces with a rectangular cross-section. In the context of the present invention, the combination of through-feed machining with the method according to the invention is particularly advantageous for workpieces with a rectangular cross-section, since during through-feed machining, dimensions between the narrow sides and the markings can be determined, or these distances can be defined, in a simple and thus advantageous manner.

[0041] Machining centers, on the other hand, are understood to be machining facilities in which the workpiece remains, at least essentially, stationary while machining units are moved around the workpiece to perform the machining. Sequential machining steps are preferably performed without changing the position of the workpiece. While machining centers can also involve movement of the workpiece, for example, its rotation and / or a feed movement during machining, they do not involve the conveyance of workpieces from machining station to machining station that is characteristic of continuous-feed machines.

[0042] Machining centers are particularly suitable for workpieces with complex surface geometries. The strength of machining centers, namely the - at least largely - free positioning of the machining units, allows the production of virtually any workpiece shape. In combination with the method according to the invention, this is also particularly advantageous in view of the fact that distances between narrow sides and markings can be determined or specified even with complex surface geometries that vary from workpiece to workpiece. The machining centers allow marking devices and / or position detection devices - analogous to the machining units - to be positioned almost arbitrarily relative to the workpiece, and in particular to its narrow sides.

[0043] The invention is described below with reference to Fig. 1 to 14 are explained in more detail schematically. Fig. 1 shows exemplary positions of markings on a plate-shaped workpiece in a plan view. Fig. 2 to Fig. 5 show step by step the application of the markings according to an exemplary method. Fig. 6 and Fig. 7 show step by step the application of the markings according to another exemplary method. Fig. 8 shows a schematic representation of an exemplary device for carrying out a method according to the invention. Fig. 9 shows a schematic detailed representation of the device from Fig. 8 Fig. 10 shows a schematic representation of an exemplary position determination device. Fig. 11 shows a schematic representation of an arrangement with a plurality of position determining devices. Fig. 12 shows a schematic representation of the determination of the format from the positions of the markers. Fig. 13 and Fig. 14 show schematic representations of the determination of the format from the positions of the markings according to a method according to the invention.

[0044] The Fig. The workpiece 1 schematically illustrated in Figure 1 has markings 2 applied according to the invention. The markings 2 are advantageously positioned in the region of the narrow sides 3 and also advantageously in the region of the corners 4 of the exemplary plate-shaped workpiece 1.

[0045] The markings 2 can advantageously be applied during machining of the narrow sides 3 of the plate-shaped workpiece 1. This is shown, for example, in the Fig. 2 to 5. The schematic representations show how the individual markings 2 are applied step by step during machining of the narrow sides 3 of the workpiece 1. In the example shown, the machining of the narrow sides 3 and thus the application of the markings 2 according to the method shown preferably take place during machining using a through-feed machine. During machining, the workpiece 1 is conveyed through the working area of ​​a machining device (not shown in detail) by means of a conveyor device 5. The workpiece 1 is conveyed through the working area several times, with one of the narrow sides 3 being machined at a time.

[0046] During the Fig. 2, a first marking 2a is applied to a surface of the workpiece 1, preferably during the machining of the first narrow side 3a of the workpiece 1. The markings are advantageously located both in the area of ​​a first corner 4a and a first narrow side 3a and a second narrow side 3b of the workpiece. During the Fig. During the second pass of the workpiece 1 through the work area shown in Figure 3, the next marking 2c is applied to the workpiece 1. In the example shown, this is preferably located both in the area of ​​another corner 4c and in the area of ​​two further narrow sides 3c and 3d.

[0047] During the Fig. 4, the marking 2b is first applied to the workpiece 1. The marking 2b is advantageously located both in the area of ​​the corner 4b and in the areas of the narrow sides 3b and 3c. In the last, in Fig. In the pass shown in Figure 5, the marking 2d is applied. This is preferably located both in the area of ​​the corner 4d and in the areas of the narrow sides 3d and 3a.

[0048] In the Fig. 6 and Fig. 7 shows an alternative method for applying the markings 2. In contrast to the method shown in the Fig. The exemplary methods shown in Figures 2 to 5 are used in the alternative Fig. 6 and Fig. 7, two markings are applied during a single pass of the workpiece 1 through the work area. In a first pass, which is shown in Fig. 6, the markings 2a and 2d are applied to the workpiece 1. The application of both markings preferably takes place during the machining of the narrow side 3a. During a further pass, which is shown in Fig. As shown in Figure 7, the markings 2b and 2c are applied to the workpiece 1. The application of both markings preferably takes place during the machining of the narrow side 3c.

[0049] Even in the Fig. 6 and Fig. 7, the markings 2 are advantageously located in the areas of corners 4 and narrow sides 3. Analogous to the method shown in the Fig. In the example explained in Figures 2 to 5, each marking 2 is arranged in the area of ​​a corner 4 and two narrow sides 3.

[0050] An exemplary processing device 6 is shown in the Fig. 8 and Fig. 9. The workpieces are conveyed in the processing device 6, which is designed as a through-feed machine, by a conveyor device 5 in the through-feed direction X through the working area of ​​the processing device 6. The processing device 6 has a marking device 7 for applying the markings 2 to the workpiece 1. After a marking 2 has been applied to the workpiece 1, the workpiece 1 passes through a first position-determining device 8a. The position-determining device 8a is advantageously an optical position-determining device. The exemplary processing device 6 also has an illumination device 9a that interacts with the position-determining device 8a. The illumination device 9a can advantageously generate a specific light spectrum that makes the markings 2 visible to the position-determining device 8a.Advantageously, it may be a marking 2 which is not visible to the human eye - at least under natural lighting conditions.

[0051] The processing device 6 further comprises a first measuring device 10a. The measuring device 10a advantageously serves to measure the position of a narrow side 3, in the area of ​​which the marking 2 is applied. The measuring device 10a and the position determination device 8a now interact in such a way that the distance between the marking 2 and the narrow side 3 can be measured using both devices.

[0052] While passing through the work area of ​​the processing device 6, a narrow side 3 of the workpiece 1 is processed. In the example shown, the processing advantageously involves the application of an edge band 11. By applying the edge band 11 to the narrow side 3 of the plate-shaped workpiece 1, the distance between the narrow side 3 of the workpiece 1 and the marking 2 changes by the thickness of the edge band 11 in the applied state. The thickness of the edge band 11 in the applied state can differ from the thickness of the edge band 11 in the unprocessed state. This can be because a layer of glue between the edge band 11 and the workpiece 1 contributes to the thickness of the applied edge band 11. However, it is also possible that softened areas of the edge band are deformed during application, thereby reducing the thickness of the edge band 11.

[0053] The processing device 6 shown therefore advantageously has a further position-determining device 8b, which interacts with a further measuring device 10b. A further illumination device 9b, which interacts with the position-determining device 8b, is also provided. Through the interaction of the position-determining device 8b and the measuring device 10b, the new distance between the narrow side 3 and the marking 2 can be determined. This new distance is preferably used at a later time within the scope of an inventive measurement of the format of the plate-shaped workpiece 1. The advantage of the exemplary processing device 6 is that, based on the two distance measurements between the narrow side 3 and the marking 2, the thickness of the edge band 11 in the applied state can also be determined.The value of the thickness of the edge band 11 thus obtained can be used advantageously for quality assurance and / or for controlling a downstream processing step, for example a machining of the edge band 11.

[0054] In Fig. 10 shows an example of a position-determining device 8, which serves for the actual format measurement within the scope of the method according to the invention. In the example shown, this is preferably an optical position-determining device 8, such as a digital camera. In the example shown, the position-determining device 8 captures the entire surface of the workpiece 1 to which the markings 2 are applied. Using the position-determining device 8, the relative positions of the markings 2 to one another can now be determined.

[0055] In Fig. 11 shows an arrangement comprising a plurality of position-determining devices 8 by way of example. In the example shown, there are four position-determining devices 8. With such an arrangement, it is not necessary for the position-determining devices 8 to cover the entire surface of the workpiece 1 in order to determine the relative positions of the markings 2 to one another. Rather, it is sufficient if only small areas 12 of the surface of the workpiece 1 in which the markings 2 are actually located are covered. In the example shown, the position-determining devices 8 are advantageously movable relative to one another. This makes it possible to determine the positions of markings 2 whose relative positions to one another differ greatly between different workpieces 1, for example when the workpieces 1 have different formats.

[0056] In Fig. Figure 12 schematically illustrates the determination of the format of the plate-shaped workpiece 1 according to an exemplary method. The markings 2 are advantageously applied in the areas of the corners 4 of the workpiece 1. Thus, the respective markings 2 are located in the areas of two narrow sides 3 adjacent to the respective corner 4.

[0057] The markings 2 are advantageously applied at defined distances A from the narrow sides 3 in whose area they are located. Alternatively and / or additionally, it is also possible to measure the distances A between the respective markings 2 and narrow sides 3. The distances A are small compared to the format of the workpiece 1. They can thus be precisely determined or specified with comparatively little technical effort.

[0058] In a next step, the relative positions of the markings 2 to each other are determined. This can be done, for example, as in Fig. 12, by determining the distances B between the markings to the narrow sides of the workpiece 1 in parallel directions. By adding the respective distances A of the markings 2 to the narrow sides 3 and the corresponding distances B between the markings 2, the format of the workpiece 1 can be determined.

[0059] From the position data of the markings 2 in conjunction with their distances A from the narrow sides 3, further geometric data about the workpiece 1 to be measured can be obtained. This includes, in particular, the angles between the narrow sides 3 and the diagonal dimensions of the surface side of the workpiece 1.

[0060] In the Fig. 13 and Fig. Figure 14 shows a method according to the invention for determining the format of the plate-shaped workpiece from the positions of the markings 2. In the alternative method, only the distance to one narrow side is measured for each of the markings 2. This is shown in Fig. 13 is shown schematically. The advantage of this is that the measurement and / or application at a defined distance A of each marking 2 only needs to be carried out from one narrow side 3 of the workpiece 1.

[0061] In this case, in order to obtain the format of the workpiece 1 from the relative positions of the markings 2 to each other, for example, the Fig. 14 can be applied. Here, the markings 2, whose distance to the same narrow side 3 is known, are connected by a calculated straight line G. The straight lines G form a quadrilateral, the corners of which are known by the intersection points S of the straight line G. From the position data of this quadrilateral in conjunction with the measured distances A, the format of the workpiece 1 can now be calculated starting from the intersection points S. If the intersection points S are located near the corners 4 of the workpiece 1 and the markings 2 are located near the intersection points S of the straight line G, the distance A of a marking 2 adjacent to an intersection point S can be used with sufficient accuracy as a calculation value for the distance between the intersection point S and the corresponding narrow side 3. The format of the workpiece 1 can thus now be determined from the relative positions of the intersection points S to one another and the distances A analogous to that to the Fig. 12. In this case, too, it is possible to calculate further geometric data, such as angles between narrow sides 3 and / or diagonal dimensions of the surface side of the workpiece 1. List of reference symbols: 1 workpiece 2 markings 3 narrow sides 4 corners 5 Conveyor system 6 Processing device 7 Marking device 8 Position determination device 9 Lighting equipment 10 Measuring device 11 Edge band 12 areas a, b, c, d indices X Flow direction A distance B Distance G Straight S intersection point

Claims

[1] Method for measuring the format of a plate-shaped workpiece (1), in which markings (2) are identified on a surface side of the workpiece, applied to the surface side of the plate-shaped workpiece (1) and / or introduced into the plate-shaped workpiece (1), wherein relative positions of the markings (2) to one another are measured and / or the markings (2) are positioned in defined relative positions to one another, characterized bythat at least two markings (2) are applied to the surface side of the plate-shaped workpiece (1) in the area of each narrow side (3) and / or are introduced into the plate-shaped workpiece (1) in the area of each narrow side (3), wherein the markings (2) are positioned at defined distances (A) from the respective narrow side (3) of the plate-shaped workpiece (1) and / or distances (A) of the markings (2) from the respective narrow side (3) of the plate-shaped workpiece (1) are measured, wherein the position of a straight line (G) is determined from the positions of these markings (2), wherein for each of the narrow sides (3) of the workpiece (1) the position of a corresponding straight line (G) is determined on the basis of at least two markings (2) and from the positions of the straight lines (G), in particular from the positions of the intersection points (S) of the straight lines (G),and the distances (A) of the markings (2) from the respective narrow sides (3) the format of the workpiece (1) is determined., [2] Method according to claim 1, characterized by that the markings (2) are positioned in defined positions relative to the narrow sides (3) of the plate-shaped workpiece (1) and / or the relative positions of the markings (2) to the narrow sides (3) of the plate-shaped workpiece (1) are measured. [3] Method according to claim 1 or 2, characterized bythat the plate-shaped workpiece (1) is the result of a division of a large-format plate-shaped workpiece, wherein the markings (2) are applied to the large-format plate-shaped workpiece and / or introduced into the large-format plate-shaped workpiece before the division of the large-format plate-shaped workpiece, wherein positions of the markings (2) and / or information contained in the markings (2) are preferably used to control the division of the large-format plate-shaped workpiece. [4] Method according to one of the preceding claims, characterized by that at least one of the markings (2) contains information about the workpiece (1), in particular about the nature of the workpiece (1), the dimensions of the workpiece (1), processing steps to be carried out on the workpiece (1) and / or the individual identification of the workpiece (1). [5] Method according to one of the preceding claims, characterized by that the result of the determination of the positions of the markings (2) is used for a quality assurance measure, in particular depending on the result of the determination of the positions of the markings (2) a reworking and / or separation of the affected workpiece (1) takes place. [6] Method according to one of claims 1 to 5, characterized bythat a marking (2) is applied to the surface side of the plate-shaped workpiece (1) in the region of a first corner (4) and / or is introduced into the plate-shaped workpiece (1) in the region of a first corner (4), wherein the marking (2) is positioned at defined distances (A) from the narrow sides (3) of the plate-shaped workpiece (1) adjacent to the first corner (4) and / or the distances of the marking (2) from the narrow sides (3) of the plate-shaped workpiece (1) adjacent to the first corner (4) are measured, in particular wherein the position of a corresponding marking (2) is determined for each of the corners (4) of the workpiece (1), wherein the format of the workpiece (1) is determined from the positions of the markings (2), preferably by means of the distance (A) of the markings (2) from the respective narrow sides (3). [7] Method according to one of the preceding claims, characterized bythat the positions of the markings (2) are determined without contact, in particular optically. [8] Method according to one of the preceding claims, characterized by that the determination of the position of the markings (2) is carried out with a plurality of position determination devices (8), in particular cameras, wherein the position determination devices (8) are preferably moved relative to one another, in particular in order to determine the positions of the markings (2) on workpieces (1) of different sizes. [9] Method according to one of the preceding claims, characterized by that results of the determination of the positions of the markings (2) are evaluated with regard to the angles of the corners (4) of the plate-shaped workpiece (1). [10] Method according to one of the preceding claims, characterized bythat the position of a marking (2), preferably a plurality of markings (2), is used to determine the thickness of a lamination applied to a narrow side, in particular an edge band (11). [11] Method according to one of the preceding claims, characterized by that a marking (2) is used to track the workpiece (1) in a downstream manufacturing process and / or logistics process. [12] Method according to one of the preceding claims, characterized by that the marking (2) is an optical marking (2) which is not visible to the human eye and / or which is no longer visible to the human eye after a defined period of time and / or which is only optically detectable under certain lighting conditions.

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