Apparatus for working a surface of a workpiece

Abstract

The invention relates to a laser apparatus (2) which comprises at least one laser processing head (7), which is designed to direct a plurality of laser beams (4) in the direction of the support surface (6), and / or comprises a plurality of laser processing heads (7a, 7b), which are each designed to direct at least one laser beam (4a, 4b) in the direction of the support surface (6), wherein a first movement device (8) for moving the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b) along a first movement axis (X), a second movement device (9) for moving the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b) along a second movement axis (Y), and a third movement device (10) for moving the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b) along a third movement axis (Z) are provided, and wherein the laser apparatus (2) comprises a control unit (11), which is designed to control the first movement device (8), the second movement device (9) and the third movement device (10) and to actuate the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b) such that at least one process parameter of the at least two laser beams (4, 4a, 4b) can be changed individually and / or the at least two laser beams (4, 4a, 4b) can be individually switched on and off.

Description

[0001] Device for machining the surface of a workpiece

[0002] The invention relates to a device for machining the surface of a workpiece, a use of the device, and a system comprising several devices.

[0003] Devices of this type are used to process the surface of workpieces in such a way as to create a desired surface structure. The workpieces used in the present application are primarily products of the wood and furniture industry that comprise a wood-based material or a plastic, for example, engineered panels for the manufacture of furniture, in particular cabinets, doors, worktops, tables, but also flooring, in particular laminate flooring, etc. The workpieces may also be laminated with foils or otherwise coated, e.g., lacquered. To achieve a specific design, the surface may, for example, have a certain basic structure. The basic structure may, for example, be modeled on a natural surface, such as a wood surface, a stone surface, a concrete surface, etc.

[0004] Furthermore, press tools for the production of the aforementioned products are also used as workpieces within the scope of this application. Such press tools include, for example, press plates, press strips, or embossing rollers. The desired surface structure can be created on a pressing surface of the respective press tool and transferred to the product by pressing.

[0005] For the aforementioned products, it may be desirable to create an additional surface texture on the essentially smooth surface or, if applicable, the existing base structure. For example, it may be desirable to change the gloss level to create a more matte or glossy appearance in specific areas compared to the existing surface. It may also be desirable to create a specific roughness, for example, to selectively influence the product's feel. Color effects can also be achieved by creating a targeted surface texture that is suitable for refracting or diffracting incident light.

[0006] Until now, surface textures have typically been created through etching, pressing a sheet of metal onto the surface, or engraving, which is relatively complex. The corresponding devices (etching device, pressing device, engraving device) are also relatively intricate and offer limited flexibility, as usually only one specific surface texture can be produced. Furthermore, the achievable size of the surface texture is limited.

[0007] The object of the present invention was to overcome the disadvantages of the prior art and to provide a device that is simple in design, easy to handle and enables rapid, precise and flexible machining of a surface of a workpiece, in particular a product or press tool.

[0008] This problem is solved by a device according to claim 1. The laser device according to the invention has a simple design and enables very rapid, precise, and flexible processing of the workpiece. Because at least one laser processing head is provided that can generate a plurality of laser beams whose process parameters can be individually, i.e., independently of one another, set, it is possible, for example, to process non-periodic structures in parallel. By means of several laser processing heads, each of which can generate one or more laser beams whose process parameters can be individually, i.e., independently of one another, set, it is possible, for example, to create different surface structures in spaced-apart processing areas of the workpiece surface, e.g., different roughness or gloss levels.The laser device according to the invention thus enables high productivity and flexibility of the processing process. The individual laser beams can be switched on / off individually and their position relative to the support surface can be manipulated individually. Hereinafter, the device is designed and referred to as a laser device.

[0009] Optionally, the laser device includes a support table that provides the support surface.

[0010] Preferably, the laser device includes a support table with an air cushion system. This simplifies the positioning of the workpiece on the support table.

[0011] Optionally, the laser device includes a device that actively pulls in the workpiece, for example using pull eyes, motorized rollers, an airflow, or similar.

[0012] Alternatively, the support surface can also be ensured by other devices. For example, the support surface can also be oriented at an angle or vertically by providing the workpiece in an at least partially upright position.

[0013] Alternatively, the support surface can be provided in a manner other than by a support table, for example by a foundation or a floor structure.

[0014] In some embodiments, each laser beam directed at the workpiece is assigned a scan field. The scan field can be variably positioned within a processing area of ​​the workpiece reachable by the respective laser beam using the first, second, and third motion devices. The control unit is configured to control at least the first, second, and third motion devices in such a way that the entire processing area of ​​the workpiece is completely covered by the scan fields of the laser beams, at least after repeated passes of the laser beams and different positioning using the first, second, and third motion devices. As previously explained, several laser beams are used to process the workpiece. Each laser beam processes the workpiece according to one of its assigned scan fields.In this context, components are used to apply a laser beam to the workpiece, such as optical components or scanners, as explained in detail later. These components are typically part of a laser processing head.

[0015] The components, or the laser processing head as a whole, can be variably positioned using the motion devices. Due to spatial limitations, such as the relative arrangement of the components used to apply the laser beams, a specific (potential) processing area of ​​the workpiece is reachable by each laser beam. Within this reachable processing area, the laser beam can generally be directed at the workpiece. However, the scan field typically only represents a portion of this reachable processing area. Since the workpiece is "passed over" multiple times by the laser beams, the scan field can be shifted for repeated passes, for example, using the motion devices. Thus, after repeated repositioning of the scan fields, the entire processing area of ​​the workpiece can be covered by the scan fields.

[0016] Preferably, the control unit is configured to ensure alignment of the scan fields of the different laser beams based on individual processing programs. These individual processing programs include at least control signals for the first, second, and third motion devices and calibration parameters, by means of which alignment of the scan fields relative to each other is ensured.

[0017] The control unit's objective is to fulfill a specific machining requirement for the workpiece, such as creating particular structures. Misalignments of laser device components, such as the motion components, or other external effects like thermal drift, control nonlinearities, or individual friction effects can cause the actual position of a scan field to deviate from its intended target position. The machining programs include calibration parameters to compensate for such relative alignment errors between scan fields. Furthermore, the programs contain the control signals issued by the control unit to actuate the various components, such as the motion components, ensuring that a scan field is positioned according to its target position.Since different processing programs are provided for each scan field, and therefore, if necessary, individual calibration parameters, a specific alignment of the scan fields relative to each other can be ensured by the different processing programs.

[0018] The arrangement of the scan fields, which represent a partial division of the workpiece's total machining area, is also referred to as "stitching." Stitching errors can generally be caused by incorrect alignment of the scan fields relative to each other, for example, due to relative angles or inappropriate lateral offset distances between the scan fields. This can result in the workpiece not being machined at all in a specific area, even though it is intended to be, or being machined incorrectly. To counteract these stitching errors, several different strategies are explained below, which can be used individually or in any combination to avoid such errors.

[0019] Optionally, the scan fields can be aligned relative to each other based on the calibration parameters in such a way that the relative angle between scan field pairs is negligible. This means that rotations between the scan fields caused by external influences can be compensated for using the calibration parameters. Furthermore, the scan fields can also be aligned relative to each other based on the calibration parameters in such a way that a target relative offset between adjacent scan field positions is ensured, at least after repeated passes of the laser beams and different positioning using the first, second, and third motion devices, such that the adjacent scan field positions have a target overlap area. This ensures that every workpiece position within the total machining area can be processed by at least one laser beam.The target relative offset provides a tolerance range regarding misalignment of the scan fields. The target relative offset also enables specific measures to counteract potential stitching errors, as will be explained in detail below.

[0020] In some embodiments, the calibration parameters include at least local coordinate transformations that depend on the positions of the motion devices. For example, the motion devices exhibit tolerances with respect to their guides. These tolerances can result in a position-specific influence on the alignment of the scan fields, depending on the position of a motion device. Therefore, for example, the axes of the motion devices can be measured volumetrically with respect to one, and generally every, scan field. This results in calibration parameters for each scan field for each target position of a scan field, which can be used to align the scan fields.

[0021] Similarly, the calibration parameters can also be incorporated into the local coordinate transformations, which describe and compensate for the varying influence of at least the motion devices on the scan fields, depending on their position. The local coordinate transformations allow for artificial, yet convenient, manipulation of the scan field alignment. This reduces the alignment effort. Optionally, the local coordinate transformations can also depend on other factors.

[0022] In general, incorrect alignment of the scan fields can be compensated for using hardware or software. The approaches described above involve, on the one hand, adjusting the control of the motion devices to align the scan fields relative to each other. On the other hand, software-based intervention is possible, for example, through appropriate coordinate transformations that adjust the originally misaligned scan fields to each other, ensuring the desired alignment between the scan fields and / or a target relative offset. Coordinate transformation also allows for convenient compensation of deviations between the actual position of a scan field and its target position.

[0023] Alternatively, instead of a software-based coordinate transformation, a software-based limitation of the achievable processing areas of the workpiece and / or the scan fields for different laser beams can be implemented. This means that the actually achievable processing areas of the workpiece for different laser beams and / or their scan fields can be artificially limited to enforce specific orientations. For example, prefactors for the different coordinates can be used for this purpose.

[0024] The software-based control of the processing areas and / or scan fields by the control unit also enables rotations of the scan fields, which, from a hardware perspective, would only be achievable, if at all, by simultaneous displacement along two mutually orthogonal axes using the corresponding motion devices. Especially for rotations of the scan fields relative to each other, software-based control is a far more convenient approach that also requires less effort to implement.

[0025] In addition, the software-based control unit allows for other modifications, particularly to the scan fields. For example, the scan fields can be stretched or compressed through coordinate transformation, depending on the application requirements.

[0026] Preferably, a scan field is three-dimensional, corresponding to a Cartesian coordinate system. A scan field then has a length, a width, and a height. The height is essentially determined by a length along the laser beam along which the laser spot changes only slightly. In other words, a laser beam has a focal point. Along the laser beam, the beam changes only slightly at a certain distance from the focal point, thus limiting the height of the scan field. Typically, the height of the scan field is limited by the Rayleigh length of the laser beam, corresponding to its wavelength and focal diameter. The height allows, for example, a scan field to be tilted relative to a plane for some applications. Alternatively, the scan field can also be considered two-dimensional if the effect of the scan field height is neglected.

[0027] Optionally, a scan field associated with a laser beam is generated by a scanner associated with the laser beam, in particular a galvanometer scanner (also called a beam positioning unit). Galvanometer scanners are known from the prior art.

[0028] The scanner, particularly a galvanometer scanner, is designed to guide a laser beam across the workpiece according to the processing program received from the control unit. To achieve this, the galvanometer scanner can project corresponding laser spots onto the workpiece. In other words, the processing program includes a desired trajectory and at least some parameters specifying a desired pulse energy, scan speed, and repetition rate, which the laser beam must deliver to a specific position on the workpiece for processing (also called a spot pattern). Based on the respective spot pattern, the scanner can execute a simultaneous and synchronous positioning movement of the laser beam projected onto / into the workpiece, controlled by the processing program from the control unit.Additionally, the processing program can include a displacement function, which is ensured by the motion devices and is executed simultaneously and synchronized with the scanner's function. The scanner can, in particular, ensure the trajectory, including the orientation and duration of the irradiation. Intensity and frequency (corresponding to power) are controlled separately, as explained below.

[0029] In some embodiments, different scanners are assigned to different laser beams. While a scanner can generally be used to provide multiple laser beams, the variability is increased by assigning each beam to an individually assigned scanner.

[0030] In general, the scanners have optical components, such as mirrors or the like, to allow the laser beams to be deflected onto the workpiece.

[0031] Preferably, the scanners incorporate beam shaping systems. Alternatively or cumulatively, the scanners feature fixed optics. This allows the focusing characteristics of the laser beam to be varied.

[0032] Preferably, the control unit is configured to operate the motion devices and the scanners of different laser beams in synchronization with each other.

[0033] For example, the superpositioned drives of the scanners and the motion devices can preferably be moved simultaneously, for example as a so-called XLScan with multi-systems.

[0034] Optionally, sub-control units can be assigned to the motion devices and the scanners (galvanometer scanners). These sub-control units can then be synchronized with the control unit.

[0035] In some embodiments, the laser device can include a focusing unit for focusing the laser radiation of a laser beam onto / into the workpiece. This means that each laser processing head has at least one

[0036] is assigned to the focusing unit.

[0037] Preferably, the control unit is configured to control each laser processing head according to an individual processing program for a scan field, such that the workpiece can be processed by the different laser beams according to individual trajectories. These trajectories can also be understood as "passages" across the workpiece. In this way, a multitude of different and complex processing geometries can be realized across the entire surface of the workpiece, depending on the specific user requirements.

[0038] In some embodiments, the control unit is set up to coordinate the processing programs in such a way that the boundary areas of the scan fields vary when the laser beams repeatedly pass over the same workpiece positions.

[0039] The scan fields have corresponding boundaries to which adjacent scan fields connect. These boundary areas can vary with repeated passes. This means that the scan fields assigned to individual laser beams can be varied for successive passes, particularly by the control unit. For example, an offset between the boundary areas of the processing zones of different passes can be used for this purpose, which is varied with each pass.

[0040] As previously explained, for the homogeneity of the machining process, it is crucial that no unmachined areas of the workpiece remain where machining is planned. It is also important that individual workpiece areas are not machined by different laser beams per pass, even though this is not intended. External influences, such as temperature drift effects, can affect the alignment of the scan fields. The control unit can now vary the scan fields during repeated passes, particularly with regard to their boundaries, so that the boundary areas of adjacent scan fields vary with each pass. As a result, machining errors resulting from alignment errors are prevented from accumulating over repeated passes. In this way, defective machining areas caused by boundary areas are distributed across the workpiece.This increases the homogeneity of the machining process. In particular, it helps prevent individual, but pronounced, defects on the workpiece.

[0041] Preferably, the control unit is configured to coordinate the processing programs in such a way that scan fields assigned to different laser beams have different, irregular contours. This can be achieved, for example, using so-called Voronoi segments (Voronoi scan fields). This prevents the previously described boundary areas of adjacent scan fields from being arranged according to a regular pattern, grid, or similar configuration. As a result, the irregularity of any processing defects that may occur can be increased, which corresponds to greater homogeneity across the workpiece surface, especially if the contours are repeatedly changed according to different irregular contours for repeated passes.

[0042] Optionally, the control unit is configured to coordinate the processing programs in such a way that the scan lines of different scan fields, along which the laser beams are guided across the workpiece, are at least partially aligned and / or at least partially parallel to each other. This means that the scan lines of a laser in a first scan field align with (or are oriented parallel to) the scan lines of a laser in an adjacent scan field, so that the scan lines appear to extend continuously beyond the boundaries of the scan fields. This ensures that the workpiece is processed homogeneously, as no area of ​​the workpiece is missed, at least not unless this is desired. In some embodiments, the scan fields can be processed parallel to each other, i.e., simultaneously, by the respective laser beams.

[0043] Alternatively, a specific processing sequence or direction can be defined, which is used to process the scan fields sequentially or according to a specific direction, for example, to trace specific scan lines that extend across multiple scan fields in a specific sequence, direction, or similar manner. The control unit can adjust the processing programs accordingly.

[0044] In some embodiments, scan lines can extend beyond the boundaries of individual scan fields. In this case, the control unit can adjust the machining programs so that at least some ends of the scan lines do not coincide with the boundaries of the scan fields, nor with the edge regions of the scan fields. Ultimately, the scan lines then terminate, at least partially, within the interior of the scan fields. The ends of adjacent scan lines can differ from one another. This means that the adjacent ends of neighboring scan lines can be offset relative to each other along a direction of extension of the scan lines. This effectively leads to an interlocking of the scan lines, as they terminate neither at the boundaries of the scan fields nor adjacent to the ends of neighboring scan lines. This further increases the irregularity in the machining of the workpiece, thereby improving the homogeneity of the machining process.

[0045] Preferably, the control unit is configured to coordinate the processing programs in such a way that the scan fields of different laser beams have boundary areas arranged to coincide with areas of the workpiece that are not to be processed. If there are areas of the workpiece that are not to be processed anyway, the scan fields can be dimensioned so that their boundaries fall within these areas. This eliminates potential misalignments in the boundary areas that could lead to "double processing" or even no processing at all, because no laser or more than one laser can reach the relevant boundary area. In this way, at least some processing errors can be avoided.

[0046] In some embodiments, the control unit is set up to adapt the processing programs in such a way as to take into account efficient traversing, processing and measuring strategies that aim for the highest possible duty cycle of laser processing or a minimization of the total throughput time for manufacturing (including component qualification).

[0047] Optionally, the control unit is configured to perform a calibration procedure, at least for the first, second, and third motion devices, and to consider the calibration parameters from this procedure, at least when controlling the motion devices. The calibration procedure can identify misalignments of the motion devices, guide carriages, bridges, and / or scan fields relative to each other. These misalignments can result, for example, from nonlinearities in the control or actuation, friction effects, vibrations, drift effects, or similar factors. As a result of the calibration procedure, the control unit determines calibration parameters based on which the misalignments of the motion devices, guide carriages, bridges, and / or scan fields relative to each other are compensated.The calibration parameters are then taken into account when controlling the relevant components, such as the motion devices. This increases the precision when machining the workpiece.

[0048] In some embodiments, the laser device includes at least one calibration measuring box for performing the calibration procedure. The calibration measuring box is arranged and configured such that a measuring plane parallel to the support surface is provided, or that a measuring area of ​​the calibration measuring box maps the support surface. The calibration measuring box allows the scan fields to be measured with high precision relative to each other with respect to the beam caustics of the laser beams, for example, using volumetric measurement, so that corresponding calibration parameters can be determined. Due to the arrangement of the calibration measuring box, the effects on the position of the workpiece can be determined directly or at least by an approximation or interpolation method (parallel measuring plane), since laser beams propagate linearly.

[0049] The calibration process enabled by the calibration measuring box can, for example, be based on the active introduction of specific features, such as those incorporated into a design to be manufactured (so-called fiducial marks). Such fiducial marks can be positioned, for example, on the edge or on the surface of the workpiece being actively machined and can be added and removed as needed during machining.

[0050] Alternatively or cumulatively, the calibration procedure can be based on repeatedly detecting specific features of the ablation structure in their position. This allows the relative orientation of the scan fields to be determined and also how this orientation develops over time.

[0051] The calibration measuring box can optionally be retracted. This allows it to be removed during the actual machining of the workpiece to prevent any interference with the machining process.

[0052] Alternatively, the calibration measuring box can also be permanently present, but positioned below or above the support surface.

[0053] In some embodiments, the laser device comprises at least one or more laser beam sources, in particular ultrashort pulse laser beam sources. The one or more laser beam sources are arranged and configured such that they each output at least one source beam for at least one laser beam.

[0054] Alternatively, the laser device has at least several laser beam sources, in particular several ultrashort pulse laser beam sources, which are arranged and configured such that they each output a source beam for at least one, in particular exactly one, laser beam.

[0055] The laser beam source can be, in particular, a high-power laser beam source. The average power that the individual laser beams may have is regularly limited by thermal effects. This means that the average power must not be too high to prevent the workpiece from overheating locally. Therefore, the maximum possible cooling capacity (e.g., cooling by convection) must be taken into account during processing. The cost of individual laser beam sources for each laser beam is relatively high, especially the cost per watt of laser power. It can therefore be advantageous to use a high-power laser beam source to output a single source beam from which multiple laser beams can be fed. For example, it can be advantageous for structural and economic reasons to divide the power of a high-power laser and assign it to different scanners.From an economic perspective, the cost per watt of laser power for a high-power ultrashort pulse (USP) laser is significantly lower than for the same power output generated by a combination of medium-power laser sources. For structural reasons, it can also be advantageous to position the laser beam source centrally rather than distributing numerous individual laser beam sources throughout the laser device. An ultrashort pulse laser beam source combines high laser power with high scalability for supplying multiple laser beams.

[0056] Optionally, the laser device includes at least one beam splitting module (BSM). The beam splitting module is coupled to the at least one laser beam source, in particular the ultrashort pulse laser beam source, and configured to split the source beam generated by the at least one laser beam source (ultrashort pulse laser beam source) into multiple laser beams. This ensures that multiple laser beams can be efficiently fed from a single source beam.

[0057] In some embodiments, the laser device has a modulation device assigned to each laser beam. The modulation device is coupled to the control unit and configured to vary the parameters of the respective laser beam. This allows the parameters of each laser beam to be varied to ensure specific processing of a particular workpiece area according to specific processing programs. The control signals for varying and setting the parameters of the respective laser beam can also be part of the processing program, which includes corresponding commands from the control unit for the respective modulation device. The modulation device enables the time-dynamic power modulation of each laser beam and thus processing with a scanner, for example, a galvanometer scanner, depending on an external modulation signal from the control unit.For example, the focal point of the laser beam, the laser power, the pulse energy, the temporal modulation of the laser radiation, the activation / deactivation of a laser beam, and other parameters can be adjusted.

[0058] Preferably, the modulation device comprises an acousto-optic or electro-optic modulator (AOM: acousto-optic modulator, EOM: electro-optic modulator). This allows the frequency and intensity of the laser beam to be adjusted as required.

[0059] Optionally, the laser device includes at least one beam alignment module (also called a BAM). The beam alignment module is arranged between the at least one laser beam source, for example, an ultrashort pulse laser beam source, and the beam splitting module. Alternatively or cumulatively, beam alignment modules can also be provided, each individually arranged between a modulation device and a scanner associated with that modulation device. All beam alignment modules are coupled to the control unit and configured to adjust the source beam generated by the laser beam source (ultrashort pulse laser beam source) with respect to at least one beam position along a beam path. This allows the beam position to be adjusted, thereby minimizing beam losses. In other words, the beam alignment module ensures the optimal adjustment of the source beam with respect to the

[0060] Coupling into the beam splitting module.

[0061] The beam balancing module can be designed as a beam position adjustment module. This ensures the correct positioning of the beam.

[0062] In some embodiments, the laser device includes at least one camera and / or a measuring system. The camera and / or measuring system are coupled to the control unit and configured to detect the beam position of the source beam generated by the at least one laser beam source (ultrashort pulse laser beam source), at least along the beam path. This allows any deviation of the beam position from a target position to be determined. This deviation can then be taken into account by the control unit when controlling the beam alignment module. This increases the positional accuracy of the laser beam on the workpiece. Furthermore, deviations and / or fluctuations in the position of the laser focus on the workpiece caused by temporal changes in the position of the laser beam (drift and pointing), as well as by a change in the relative position of the laser beam to the scanning system during an axis shift (e.g.,(through a movement device) avoided, or at least reduced.

[0063] Preferably, at least one laser processing head is configured to direct two to one hundred laser beams towards the support surface. This enables a faster processing process, as the same processing area of ​​the workpiece can be processed by multiple laser beams.

[0064] It can be advantageous if at least two of the multiple laser processing heads can be moved together along at least one axis of motion using their respective motion devices. This simplifies the setup. Alternatively, at least two of the multiple laser processing heads can be moved relative to each other along at least one axis of motion, with each of the at least two laser processing heads having a separate motion device for its respective axis. This further increases the flexibility of the processing operation.

[0065] The third motion device can comprise a third guide carriage on which the at least one laser processing head is arranged, a third guide along which the third guide carriage is guided, and a third drive device for driving the third guide carriage. The second motion device can comprise a second guide carriage that includes the third guide, a second guide along which the second guide carriage is guided, and a second drive device for driving the second guide carriage. The first motion device can comprise a first guide carriage that includes the second guide, a first guide along which the first guide carriage is guided, and a first drive device for driving the first guide carriage.This creates a preferred design that is simple in construction and enables reliable guidance along the three axes of movement.

[0066] The first guide preferably has two parallel first guide rails, which are preferably connected to the support table, with the bearing surface extending between the two first guide rails, and the first guide carriage preferably has a bridge with a first bridge end guided on one of the first guide rails and an opposite second bridge end guided on the other of the two first guide rails. To achieve the highest possible stiffness, it may be advantageous if the bridge is made of granite.

[0067] The at least one process parameter preferably comprises at least one of the following: laser power, relative velocity to the workpiece, number of pulses per burst, pulse amplitude in a burst, repetition rate, wavelength, pulse energy, focus diameter, energy amplitude of the pulses in the burst, and pulse duration. By individually modifying one or more process parameters, a desired processing result (e.g., a defined surface structure) can be achieved. Gradual adjustment of the process parameters to different workpiece materials would also be possible.

[0068] Preferably, an acousto-optic modulator (AOM) or an electro-optic modulator (EOM) is provided for each of the individually adjustable laser beams. AOMs and EOMs have proven advantageous for rapidly and individually changing the process parameters of the laser beams and, in particular, for quickly switching the individual laser beams on and off.

[0069] It can be advantageous if the support surface has multiple suction openings, if the laser device includes a vacuum pump connected to these openings to generate suction pressure, and if the vacuum pump is controllable by the control unit. This allows the workpiece to be held against the support surface by the generated suction pressure.

[0070] Alternatively, the vacuum pump and intake ports can interact in such a way that they can also be used as blow-out ports. An air cushion can then be created through these blow-out ports to position the workpiece, thus greatly simplifying the positioning process, for example in the case of heavy workpieces.

[0071] Alternatively or additionally, it can be advantageous if the support table includes a number of rotatable rollers that can be moved between a rolling position, in which the rollers protrude from the support surface, and a rest position, in which the rollers are recessed into the support surface. This allows the workpiece to roll on the rollers and be easily positioned on the support surface by sliding them. The rollers can be moved manually or, if necessary, by means of one or more suitable electrically controlled actuators that can be controlled by the control unit.

[0072] It is advantageous if at least one laser processing head includes a scanner and / or at least one sensor device and / or an optical unit for adjusting the focus position of at least one laser beam. The scanner enables rapid and precise adjustment of one or more laser beams. The sensor device can acquire a desired measurement variable, which can then be processed by the control unit to control the laser device. The optical unit allows for easy adjustment of the focus of one or more laser beams, thereby influencing the surface structuring.

[0073] The scanner preferably comprises a number of adjustable mirrors for deflecting the at least one laser beam, each adjustable mirror having a galvanometric mirror drive for adjusting the mirror, which can be controlled by the control unit. The scanner allows the at least one laser beam to be moved within a defined processing area on the workpiece. The processing area can, for example, be rectangular and have a size of 100 x 100 mm.

[0074] The optical unit can comprise two optical elements, in particular lenses, that are linearly movable relative to each other, and an actuator for changing the distance between the optical elements, which can be controlled by the control unit. Alternatively or additionally, the optical unit can comprise two rotatably mounted mirrors and a parabolic mirror, each of the two mirrors having a galvanometric mirror drive for adjusting the mirror, which can be controlled by the control unit. The embodiment with a parabolic mirror allows for a faster change of focus due to the rotary movement compared to linear adjustment.

[0075] The scanner's number of movable mirrors can include a first mirror for moving the at least one laser beam in a first deflection direction relative to the support surface, preferably parallel to the first axis of movement. Alternatively or additionally, the scanner's number of movable mirrors can include a second mirror for moving the at least one laser beam in a second deflection direction relative to the support surface, preferably parallel to the second axis of movement.

[0076] The at least one sensor device of the laser processing head preferably comprises at least one of the following sensors: distance sensor, position sensor, laser power sensor, CMOS camera, CMS camera, camera, first photodiode for detecting a back reflection of the laser intensity of the at least one laser beam, second photodiode for detecting heat radiation from the workpiece. This allows relevant measured variables of the processing process to be acquired and, if necessary, used for control or regulation.

[0077] The laser device can also include an extraction system designed to extract material from the workpiece that has been removed by at least one laser beam, and which can be controlled by the control unit. This allows for the removal of potentially disruptive contaminants and can improve the quality of the machining process.

[0078] The laser device preferably comprises a laser beam source for generating at least one laser beam, wherein the laser beam source is connected to at least one laser processing head by means of an optical connection. The optical connection can, for example, comprise a suitable optical fiber or optics. The laser beam source can be arranged at a suitable location within the laser device, for example, on the support table (stationary) or on the bridge (movable).

[0079] The laser device is preferably used by positioning a workpiece, which has a basic gloss level and / or a basic surface structure, on the support surface such that the at least one laser processing head and / or the plurality of laser processing heads, as well as the first and / or the second and / or the third motion unit, are controlled by the control unit in such a way that a gloss level different from the basic gloss level is produced in at least one defined processing area of ​​the surface and / or material from the workpiece is removed in such a way that a predetermined surface structure is created. For example, a product or a press tool mentioned above can be used as the workpiece.

[0080] According to an advantageous embodiment, a decorative image to be generated is transmitted to the control unit, preferably in the form of a grayscale file or a black and white file, whereupon the control unit assigns different gloss levels or different surface structures to areas with different grayscale levels or to the black and white areas, and whereupon the control unit controls the at least one laser processing head and / or the plurality of laser processing heads as well as the first motion device and / or the second motion device and / or the third motion device in such a way that an image synchronous with the predetermined decorative image is generated on the surface of the workpiece, which has the assigned gloss levels or surface structures.This allows different colors of a decorative image to be essentially "translated" into different gloss levels or different surface textures in the image on the workpiece.

[0081] According to a further aspect of the invention, several of the laser devices according to the invention can be combined to form a modular laser system by coupling the support tables of adjacent laser devices in such a way that the support surfaces form a common overall support surface. This allows, for example, the processing of larger workpieces than with a single laser device. Depending on the size of the workpiece, the laser system can be configured modularly.

[0082] It can be advantageous if the control units of the majority of laser devices are connected or connectable via a primary data communication link, with one control unit being selectable as the master control unit and the remaining control units being selectable as slave control units. The laser system can then be controlled via the master control unit, and the slave control units are controlled by the master control unit. Alternatively, the laser system can also include a higher-level system control unit that is connected or connectable to the control units of the majority of laser devices via a secondary data communication link. In this case, the laser system can be controlled via the system control unit, and the control units can be controlled by the system control unit.

[0083] To better understand the invention, it is explained in more detail with reference to the following figures.

[0084] They each show, in a highly simplified, schematic representation:

[0085] - Fig. 1 shows a laser device in an exemplary first embodiment in top view,

[0086] - Fig. 2 shows the laser device of the first embodiment in side view,

[0087] - Fig. 3 shows a laser processing head with a scanner and a sensor device,

[0088] - Fig. 4a shows an exemplary workpiece after processing by the laser device,

[0089] - Fig. 4b shows an exemplary workpiece after processing by the laser device,

[0090] - Fig. 5 shows a sequence of an advantageous use of the laser device,

[0091] - Fig. 6 shows a laser device in an exemplary second embodiment in top view,

[0092] - Fig. 7 shows the laser device of the second embodiment in side view,

[0093] - Fig. 8 shows a laser device in an exemplary third embodiment in top view,

[0094] - Fig. 9 shows the laser device of the third embodiment in side view,

[0095] - Fig. 10 shows a laser device in an exemplary fourth embodiment in top view,

[0096] - Fig. 11 shows the laser device of the fourth embodiment in side view, - Fig. 12 shows a laser system of an exemplary embodiment in top view,

[0097] - Fig. 13 shows a laser device according to one embodiment,

[0098] - Fig. 14 Varying limit ranges during repeated crossings according to one embodiment,

[0099] - Fig. 15 Scan fields with differing, irregular contours according to one embodiment,

[0100] - Fig. 16a specifically coordinated scan lines of different scan fields according to one embodiment,

[0101] - Fig. 16b shows a specific sequence of scan lines of different scan fields according to one embodiment,

[0102] - Fig. 17 Interlocking scan lines of different scan fields according to one embodiment,

[0103] - Fig. 18 shows scan fields adapted to areas of the workpiece not to be machined, according to one embodiment,

[0104] - Fig. 19 Scan fields that show alignment errors,

[0105] - Fig. 20 Scan fields that can be variably positioned within more accessible processing areas, and

[0106] - Fig. 21 Scan fields for which an offset is taken into account during repeated passes in order to ensure varying limit areas.

[0107] It should be noted at the outset that in the differently described embodiments, identical parts are provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these positional designations must be applied analogously to the new position if the position changes.

[0108] FIGURE DESCRIPTION

[0109] In Fig. 1, a laser device 2 according to the invention is shown as an exemplary first example.

[0110] The embodiment is shown in a top view. Fig. 2 shows the laser device 2 in a side view. The laser device 2 is designed for processing a surface 31 of a workpiece 3 using at least one laser beam 4. As mentioned at the outset, the workpiece 3 is preferably a product (e.g., laminate flooring, material sheet, etc.) or a pressing tool for manufacturing the product (e.g., press plate, embossing roller, etc.).

[0111] The laser device 2 comprises a support surface 6 for arranging the workpiece 3. The support surface 6 is provided here by a generally optional support table 5. The support table 5 can, for example, be made of a suitable metal, granite or a granite-based material, or, if applicable, a suitable plastic. The support surface 6 lies on a first plane El, which is preferably horizontally oriented during operation of the laser device 2.

[0112] Furthermore, the laser device 2 in the illustrated example comprises a (single) laser processing head 7, which is configured to direct two laser beams 4a, 4b towards the support surface 6. The laser device 2 also comprises a first motion device 8, which is configured to move the laser processing head 7 along a first axis of motion X parallel to the first plane El, a second motion device 9, which is configured to move the laser processing head 7 along a second axis of motion Y parallel to the first plane El, and a third motion device 10, which is configured to move the laser processing head 7 along a third axis of motion Z. The axes of motion X, Y, Z are preferably perpendicular to each other.

[0113] The laser device 2 further comprises a control unit 11, which is configured to control the laser processing head 7, the first motion unit 8, the second motion unit 9, and the third motion unit 10. The control unit 11 can control the laser processing head 7 such that the value of at least one process parameter of the laser beams 4a, 4b can be individually changed in order to create areas with different surface structures, e.g., different gloss levels or different roughness. By way of example only, the laser power can be individually changed as a process parameter.Alternatively or additionally, one or more of the following process parameters could be individually set: A relative speed between laser beam 4 and workpiece 3, the number of pulses per burst, the energy amplitude of pulses in a burst, the repetition rate, the wavelength, the pulse energy, the focus diameter, a pulse duration of the pulses.

[0114] In the context of the invention, "individual" means that the process parameters of the two laser beams 4a and 4b can be set independently of one another. For example, a first value of a process parameter can be set for the first laser beam 4a, and a second value of the respective process parameter, different from the first value, can be set for the second laser beam 4b. For example, a first laser power can be set for the first laser beam 4a, and a higher or lower second laser power for the second laser beam 4b. Similarly, one or more of the other process parameters mentioned can also be set individually.

[0115] Individual settings allow for the simultaneous processing of non-periodic structures. For individual control of the laser beams, preferably one acoustoptic modulator (AOM) or one electro-optic modulator (EOM) is provided per laser beam, along with sufficiently powerful control electronics for controlling the AOMs or EOMs.

[0116] The illustrated embodiment with two laser beams 4a, 4b is, of course, only exemplary, and the invention is naturally not limited to two laser beams 4a, 4b. If the laser processing head 7 is configured to generate more than two laser beams 4a, 4b, ... 4i, then the process parameters of the multiple laser beams, or at least of each group of laser beams, can be individually adjusted. The laser processing head 7 can, for example, be configured to generate up to one hundred laser beams. Simultaneously, the control unit 11 can control the motion devices 8, 9, 10 so that a desired processing area 32 of the surface 31 of the workpiece 3 is processed. The material can, for example, be removed layer by layer by cyclically moving the laser beam 4 over the same areas.It is also possible to create a predefined pattern by coordinating the movements along the X, Y, and Z axes of motion.

[0117] In the illustrated example, the first motion device 8 comprises a first guide carriage 16 and a first guide 42 along which the first guide carriage 16 is guided, here along the horizontal X-axis. A first drive device 17 is also provided for driving the first guide carriage 16 along the first guide 42.

[0118] The second motion device 9 similarly comprises a second guide carriage 14 and a second guide 41 along which the second guide carriage 14 is guided, here along the horizontal Y-axis. Furthermore, a second drive device 15 is provided for driving the second guide carriage 14 along the second guide 41.

[0119] The third motion device 10 comprises a third guide carriage 12, on which the laser processing head 7 is arranged, and a third guide 40 along which the third guide carriage 12 is guided, here along the vertical Z-axis. A third drive device 13 is also provided for driving the third guide carriage 12 along the third guide 40. The third guide 40 is arranged on the second guide carriage 14, and the second guide 41 is arranged on the first guide carriage 16.

[0120] The guides 40, 41, 42 can each comprise a suitable guide rail along which the respective guide carriage 16, 14, 12 is guided. The drive devices 13, 15, 17 can each comprise a suitable electric drive unit, e.g., an electric motor. Optionally, one or more suitable power transmission means (not shown), e.g., toothed belts, gears, racks, etc., can also be provided. The motion devices 8, 9, 10 can, for example, each also comprise a linear motor, in particular a long-stator linear motor.

[0121] In the illustrated example, the first guide 42 has two parallel first guide rails 18, between which the support surface 6 extends. The first guide rails 18 can be connected to the support table 5, e.g., attached to it, or possibly be integrally formed with the support table 5. The first guide carriage 16 here comprises a bridge 19 with a first bridge end 20 and an opposing second bridge end 21. The first bridge end 20 is guided on one of the first guide rails 18, and the second bridge end 21 is guided on the other of the two first guide rails 18. The bridge 19 can, for example, be made of granite, which achieves high rigidity. However, other materials with sufficiently high strength, e.g., a suitable metallic material, would also be conceivable.

[0122] The bridge 19 can be positioned at a fixed, i.e., constant, distance LB from the support surface 6. Alternatively, the distance LB between the bridge 19 and the support surface 6 could also be variable. A suitable adjustment device 22 can be provided for adjusting the distance LB, which can be controlled by the control unit 11. The adjustment device 22 can include an electric drive unit, e.g., an electric motor, and optionally one or more power transmission means, e.g., toothed belts, gears, racks, etc. Optionally, the adjustment device 22 can also be operated manually, e.g., via a suitable crank drive.

[0123] In the example shown, a plurality of suction openings 23 are provided in the support surface 6, and a vacuum pump 24 is provided which is connected to the suction openings 23 to generate suction pressure. The vacuum pump 24 can be controlled by the control unit 11. This allows the workpiece 3 to be drawn towards the support surface 6 and held in position. The suction openings 23 are shown in Fig. 1 and Fig. 2 only as examples in a small area of ​​the support surface 6 or the support table 5. Of course, the suction openings 23 can extend over a larger area or preferably over the entire support surface 6, contrary to the illustration.

[0124] The intake openings 23 can, for example, be integrated directly into the support table 5 and connected to the vacuum pump 24 via one or more suitable lines. The vacuum pump 24 can be arranged at a suitable location on the laser device 2. The intake openings 23 are shown only as examples of straight bores connecting the support surface 6 to an underside of the support table 5. Contrary to the illustration, the intake openings 23 could also be shaped differently and, for example, connected to a side surface of the support table 5.

[0125] Alternatively or additionally, other fixing means could be provided to fix the workpiece 3 to the support surface 6, e.g. clamping elements.

[0126] The support table 5 can also comprise a plurality of rotatable roller bodies 49, which can be positioned between a rolling position in which the roller bodies 49 are removed from the

[0127] The rollers 49 protrude from the support surface 6 and can be moved to a rest position in which they are recessed in the support surface 6. The rollers 49 are shown in Fig. 2 as an example for a limited area. In reality, the rollers 49 are preferably arranged over a larger area of ​​the support surface 6, contrary to the illustration. The rollers 49 can, for example, be in the form of balls or rollers.

[0128] The four rollers 49 shown on the left are in the rolling position. In the rolling position, the workpiece 3 rests on the rollers 49 and can roll off them. This allows the workpiece 3 to be positioned very easily and flexibly in the first level El. The four rollers 49 shown on the right are in the rest position. In the rest position, the rollers 49 are recessed in the support table 5, so that the workpiece 3 rests on the support surface 6. The rollers 49 can be moved between the rolling position and the rest position manually, for example. However, one or more suitable (not shown) electrically controlled actuators could also be provided to move the rollers 49 between the rolling position and the rest position. The actuator(s) can be controlled by the control unit 11.

[0129] As shown in Fig. 1, the rolling elements 49 could optionally be pre-tensioned in the rolling position by means of suitable springs. The rolling elements 49 could be moved into the rest position by applying a sufficiently high force to the workpiece 3 and then held in the rest position, for example, by the clamping elements mentioned above. After the load is released, the rolling elements 49 can be returned to the rolling position by the spring force.

[0130] The laser processing head 7 can include a scanner 25 and / or a sensor device 26. The scanner 25 and the sensor device 26 are shown schematically in Fig. 2.

[0131] Fig. 3 shows a schematic representation of an exemplary laser processing head 7, which includes a scanner 25 and a sensor device 26. The scanner 25 can comprise a number of adjustable mirrors 27 for deflecting a laser beam 4, each mirror 27 having a galvanometric mirror drive 28 for adjusting the mirror 27, which can be controlled by the control unit 11. In Fig. 3, an exemplary mirror 27 is shown which can be rotated about a rotary axis by means of the associated galvanometric mirror drive 28. By rotating the mirror 27, the laser beam 4 can be moved relative to the support table 6 or the workpiece 3 arranged on it.

[0132] Depending on the arrangement of the mirror 27, the movement of the laser beam 4 can occur in a specific direction. For example, a first mirror 27 can be provided to move the respective laser beam 4 in a first deflection direction relative to the support surface 6. The first deflection direction can, for example, run parallel to the first axis of movement X. Alternatively or additionally, a second mirror 27 can be provided to move the laser beam 4 in a second deflection direction relative to the support surface 6. The second deflection direction can, for example, run parallel to the second axis of movement Y, as shown in Fig. 3. A third mirror 27 can also be provided, if necessary, to move the laser beam 4 in a third deflection direction relative to the support surface 6, and so on.

[0133] The laser device 2 preferably also includes a laser beam source 30 for providing at least one laser beam 4. The laser beam source 30 can be connected to the laser processing head 7 by means of a suitable optical connection 50. The optical connection 50 can, for example, comprise one or more suitable optical fibers or suitable optics that deflect the laser beam 4 appropriately from the laser beam source 30 to the laser processing head 7. Optionally, the laser beam source 30 can first generate and output a source beam, which is then split into different laser beams 4, as will be explained in detail later. The laser beam source 30 can be arranged at a suitable location within the laser device 2, either stationary or movable. A stationary arrangement could, for example, be implemented by connecting the laser beam source 30 to the support table 5. A movable arrangement could, for example,This can be achieved by placing the laser beam source at bridge 19.

[0134] The sensor device 26 can, for example, comprise one or more sensors suitable for detecting a specific measured quantity. For example, a distance sensor can be provided, which is configured to detect the distance of the laser processing head 7 in the Z-direction from the support surface 6. Alternatively or additionally, a position sensor could also be provided. This would allow, for example, the detection of the position of the laser processing head 7 in the first plane El (X / Y plane). The position could, for example, be determined as a relative position of the laser processing head 7, in particular of the laser beam 4, to a defined reference point.

[0135] The reference point can be fixed or variable. For example, the reference point can be defined at the support surface 6. Depending on the desired measurement, a sensor with a suitable measuring principle can be used, e.g., an optical sensor, in particular a CMS camera, a capacitive sensor, an inductive sensor, etc. Such sensors are known in the prior art. It would also be possible to provide a distance or position sensor for each motion device 8, 9, 10 in order to determine the distance or position of the respective guide carriage 12, 14, 16 relative to a defined reference point.

[0136] Other advantageous sensors include, for example, a laser power sensor for measuring the power of the laser beam 4, a CMOS camera (CMOS = "Complementary Metal Oxide Semiconductor") for measuring the diameter of the laser beam 4, a macro camera for process observation, a first photodiode for detecting a back reflection of the laser beam 4 intensity (in the range of lpm), or a second photodiode for detecting heat radiation from the surface of the workpiece 3 (in the range of 8-10 pm). Several of the aforementioned sensors can, of course, be combined.

[0137] In general, the sensor device 26 can transmit a sensor signal as the actual value of the respective measured quantity to the control unit 11, and the control unit 11 can use the actual value and a predefined setpoint value to control the laser device 2. For example, a suitable controller can be implemented in the control unit 11 to regulate, for example, the distance in the Z direction, a position in the first plane El (X / Y), or one of the other measured quantities mentioned.

[0138] The sensor device 26 could also be configured to determine the bridge spacing LB. The control unit 11 could then, for example, use the determined bridge spacing LB as an actual value for controlling the bridge spacing. Using a suitable controller, the control unit 11 can, for example, determine a manipulated variable from the actual value and a predefined setpoint and use it to control the adjustment device 22.

[0139] The laser processing head 7 can further comprise an optical unit (not shown in Fig. 3) for adjusting the focus position of the laser beam 4 (or, more generally, at least one laser beam). If a scanner 25 is provided, the optical unit is preferably positioned upstream of the scanner 25. This means that the corresponding laser beam 4 first passes through the optical unit. In a first advantageous embodiment, the optical unit can comprise two optical elements, in particular lenses, that are linearly movable relative to each other, and an actuator for changing the distance between the optical elements. The actuator can be suitably connected to and controlled by the control unit 11. The optical elements can, for example, each have a defined focal length and aperture. One of the two optical elements can be fixedly arranged on the laser processing head 7 so that its position relative to the laser processing head 7 is unchangeable.The second element can be moved linearly relative to the first element by means of the actuator. By changing the distance between the two optical elements, the focus position in the Z direction can be changed.

[0140] According to a second advantageous embodiment, the optical unit can comprise two rotatably mounted mirrors and a parabolic mirror. Each of the two mirrors includes a galvanometric mirror drive for adjusting the mirror's position. The galvanometric mirror drives are suitably connected to the control unit 11 and can be controlled by it. By means of the movable mirrors, the laser beam 4 can be directed to a desired point on the parabolic mirror. The point of impact on the parabolic mirror defines the focus position in the Z-direction. The second embodiment is more dynamic than the first because the rotary adjustment is faster than the linear adjustment.

[0141] The laser device 2 can also include an extraction device 29, which is configured to extract material from the workpiece 3 ablated by one or more laser beams 4a, 4b. The extraction device 29 can be controlled by the control unit 11. For this purpose, the extraction device 29 can be appropriately connected to the control unit 11. For example, the extraction device 29 can include an extraction nozzle and an associated extraction pump. Optionally, a container can also be provided to collect the extracted material. Figures 4a and 4b each show a schematic representation of a workpiece 3 that has been processed with the laser device 2. The workpiece 3 can, for example, be plate-shaped. "Plate-shaped" means that the length and width of the workpiece 3 are many times greater than its thickness. The workpiece 3 can, in particular, be a material plate or a floor element comprising a coated wood-based material.The workpiece 3 may be laminated with a foil, pressed with a resin film, in particular a melamine resin film, or lacquered.

[0142] In the example shown in Fig. 4a, the surface 31 of the workpiece 3 has a basic gloss level. Gloss is generally an optical property of a surface, its ability to reflect light completely or partially specularly. If a surface is not glossy because it reflects light diffusely, this is called matte. Just like color, gloss is a property that contributes to the visual appearance of a surface. To make the gloss of surfaces technically comparable, reflectometers are used to measure the gloss level. In the example shown in Fig. 4b, the surface 31 of the workpiece 3 has a basic structure, which can, for example, be modeled on a wood grain.

[0143] For processing the workpiece, the workpiece 3 can first be positioned on the support surface 6 of the laser device 2 and preferably fixed in place. For fixing, the workpiece 3 can, for example, be drawn towards the support surface 6 via the suction openings 23. The surface 31 of the workpiece 2 to be processed faces away from the support surface 6.

[0144] The laser processing head 7 and the motion devices 8, 9, 10 can then be controlled by the control unit 11 such that a gloss level different from the base gloss level is produced in at least one defined processing area 32 of the surface 31 (Fig. 4a). The produced gloss level can be more matte or glossier than the base gloss level.

[0145] Alternatively, the laser processing head 7 and the motion devices 8, 9, 10 can be controlled by the control unit 11 such that a defined surface structure is generated in at least one defined processing area 33 of the surface 31. The generated surface structure can, for example, have a greater or lesser roughness than the surrounding base structure. The base structure can also be superimposed with the generated surface structure.

[0146] The machining areas 32, 33 are shown as rectangular shapes in Figs. 4a and 4b for illustrative purposes only. The shape and size of the machining areas 32, 33 can be defined essentially arbitrarily and can naturally vary. Of course, multiple machining areas 32 and / or multiple machining areas 33 could be defined on the surface 31 of a workpiece 3. Within any two machining areas 32, 33, identical or different gloss levels or identical or different surface textures can be produced. For example, lettering could be produced, with each letter being a separate machining area 32, 33.

[0147] With reference to Fig. 5, a further advantageous use of the laser device 2 is described below. In a first step S1, a decorative image 34 can be transmitted to the control unit 11, which is to be generated by means of the laser beam 4 in a processing area 32, 33 of the surface 31 of the workpiece 3.

[0148] The decorative image 34 can preferably be provided in the form of a grayscale file 44 or a black and white file. A color file would also be conceivable in principle. In the example shown, the decorative image 34 has a wood grain design. At the pixel level, the decorative image 34 shown has several areas 43 with different shades of gray, white areas, and black areas, as can be seen in Detail A.

[0149] In a further step S2, the control unit 11 can assign different gloss levels G to the areas 43 with different shades of gray, or to the black and white areas. Suitable software can be implemented for this purpose. However, manual assignment by a user would also be conceivable, for example via a user interface (not shown).

[0150] In a further step S3, the control unit 11 can control the at least one laser processing head 7 as well as the motion devices 8, 9, 10 (generally the laser device 2) in such a way that in a defined processing area 32 of the surface 31 of the workpiece 3 a synchronous image 35 is generated to the specified decorative image 34, which has the assigned gloss levels G.

[0151] Alternatively, in step S2, the control unit 11 can assign different surface structures 0, e.g., with different depth information, such as different roughnesses, to the different areas 43. In step S3, the control unit 11 could control the laser device 2 accordingly, so that in a defined processing area 33 of the surface 31 of the workpiece 3, an image 35 synchronous with the specified decorative image 34 is generated, which has the assigned surface structures 0.

[0152] Figure 6 shows a top view of a laser device 2 according to the invention, representing an exemplary second embodiment. Figure 7 shows a side view of the laser device 2. The same reference numerals and component designations are used for identical parts as in Figures 1 and 2. To avoid unnecessary repetition, only the differences are described in detail below. Unless explicitly stated otherwise, reference is made to the above descriptions regarding the other features, which also apply to the second embodiment.

[0153] The laser device 2 shown in Fig. 6 and Fig. 7 comprises a support table 5 with a support surface 6 for arranging the workpiece 3 and a control unit 11 for controlling the laser device 2. Furthermore, the laser device 2 comprises a laser processing head 7 and a first motion device 8 for moving the laser processing head 7 along the first axis of motion X, a second motion device 9 for moving the laser processing head 7 along the second axis of motion Y, and a third motion device 10 for moving the laser processing head 7 along the third axis of motion Z.

[0154] In contrast to the first embodiment according to Fig. 1 and Fig. 2, the laser processing head 7 is designed to direct more than two laser beams 4a, 4b, here by way of example eight laser beams 4a-4h, towards the support surface 6. The arrangement of the laser beams 4a-4h relative to each other can be arbitrarily defined, for example parallel, at an angle, or offset from each other. The enclosing geometry of the laser beams can be, for example, round, rectangular, square, triangular, etc. In the illustrated example, the laser beams 4a-4h are only arbitrarily aligned essentially parallel to each other.

[0155] The number of laser beams 4a-4h can, as already mentioned, also be larger and up to one hundred, preferably 10, 20, 30, 40, 50, 60, 70, 80, or 90, or an intermediate number. The control unit 11 can, in turn, control the laser processing head 7 so that the process parameters of the laser beams 4a-4h can be set individually, i.e., independently of each other. Thus, for example, a laser power and / or a different focus diameter, etc., could be set for each of the eight laser beams 4a-4h.

[0156] It is also possible to define multiple groups of laser beams and set different process parameters for each group. In the illustrated embodiment, for example, a first value of a process parameter could be set for a first group consisting of four laser beams 4a-4d, and a second value of a process parameter could be set for a second group consisting of the remaining four laser beams 4e-4h. Of course, other groupings would also be possible.

[0157] Due to the larger number of laser beams 4a-4h, the same processing area on the workpiece 3 can be traversed multiple times, thus reducing the processing time compared to using a single laser beam 4. The processing area may, for example, depend on the design of the scanner 25 and be 100 x 100 mm. With the eight laser beams 4a-4h shown as an example, each individual laser beam therefore only needs to process 1 / 8 of the processing area (e.g., 12.5 x 100 mm). With a higher number of laser beams, the required processing area per laser beam 4 decreases accordingly.

[0158] Detail B schematically shows a top view (in the Z direction) of the processing area of ​​the laser processing head 7. The laser processing head 7 here comprises, as an example, eight laser beams 4a-4h, arranged in a grid pattern. On the left, two laser beams 4 are arranged side by side along the first axis of movement X, and four laser beams 4 are arranged side by side along the second axis of movement Y. On the right, four laser beams 4 are arranged side by side along the first axis of movement X, and two laser beams 4 are arranged side by side along the second axis of movement Y. Of course, the arrangement of the laser beams 4a-4h shown is only an example, and other orientations would also be conceivable, for example, round or square, as mentioned above.

[0159] Figure 8 shows a top view of a laser device 2 according to the invention, representing an exemplary third embodiment. Figure 9 shows a side view of the laser device 2. The same reference numerals and component designations are used for identical parts as in the previous figures. To avoid unnecessary repetition, only the differences are described in detail below. Unless explicitly stated otherwise, reference is made to the above descriptions regarding the remaining features, which also apply to the third embodiment.

[0160] The laser device 2 shown in Figs. 8 and 9 again comprises a support table 5 with a support surface 6 for arranging the workpiece 3 and a control unit 11 for controlling the laser device 2. In contrast to the first embodiment according to Figs. 1 and 2, the laser device 2 here comprises two laser processing heads 7a, 7b, each configured to direct at least one laser beam 4a, 4b towards the support surface 6. Thus, the laser device 2 comprises at least two laser beams 4a, 4b in total. The two laser processing heads 7a, 7b can be individually controlled by the control unit 11, so that the process parameters of the at least two laser beams 4a, 4b can be individually adjusted. Of course, the two laser processing heads 7a, 7b could also be configured to generate multiple laser beams, e.g., two to one hundred laser beams.To avoid repetition, details are referred to the above explanations of the first embodiment, which is valid in an analogous manner.

[0161] In the example shown, the two laser processing heads 7a, 7b have a common first motion device 8, by which they can be moved together along the first axis of motion X. The first motion device 8 in turn comprises a bridge 19, which can be moved along two parallel first guide rails 18.

[0162] In contrast, the two laser processing heads 7a, 7b each include their own second motion device 9a, 9b for moving the respective laser processing head 7a, 7b along the second axis of motion Y, as well as their own third motion device 10a, 10b for moving the respective laser processing head 7a, 7b along the third axis of motion Z. This allows the laser processing heads 7a, 7b to be moved relative to each other along the second axis of motion Y and along the third axis of motion Z. This enables a significantly higher degree of freedom in the processing, as the surface 31 of the workpiece 3 can be processed simultaneously by both laser processing heads 7a, 7b.

[0163] The second motion devices 9a, 9b each comprise a second guide carriage 14a, 14b. A second guide 41 is provided on the bridge 19, along which the two second guide carriages 14a, 14b are movable. The third motion devices 10a, 10b each comprise a third guide carriage 12a, 12b. A third guide 40a, 40b is provided on each of the second guide carriages 14a, 14b, along which the two third guide carriages 12a, 12b are movable. Each motion device again comprises a suitable drive device (not shown in Figs. 8 and 9). To avoid repetition, reference is made to the description of the first embodiment. Fig. 10 shows a top view of a laser device 2 according to the invention, an exemplary fourth embodiment. Fig. 11 shows a side view of the laser device 2. The same reference numerals are used for identical parts.Component designations are used as in previous figures. To avoid unnecessary repetition, only the differences are described in detail below. Unless explicitly stated otherwise, reference is made to the above descriptions regarding the remaining features, which also apply to the fourth embodiment.

[0164] The laser device 2 shown in Figs. 10 and 11 comprises a support table 5 with a support surface 6 for arranging the workpiece 3, and a control unit 11 for controlling the laser device 2. The laser device 2 includes four laser processing heads 7a-7d, each configured to direct at least one laser beam 4a-4d towards the support surface 6. The four laser processing heads 7a-7d can be individually controlled by the control unit 11. This allows different process parameters to be set for each laser beam 4a-4d, if necessary.

[0165] The four laser processing heads 7a-7d share a common first motion device 8, which allows them to be moved together along the first axis of motion X. The first motion device 8 in turn comprises a bridge 19, which is movable along two parallel first guide rails 18. Each pair of laser processing heads 7a, 7b or 7c, 7d shares a common second motion device 9a, 9b for moving the respective pair of laser processing heads 7a, 7b or 7c, 7d along the second axis of motion Y, and a common third motion device 10a, 10b for moving the respective pair of laser processing heads 7a, 7b or 7c, 7d along the third axis of motion Z. This allows the laser processing heads 7a, 7b to be moved along the second axis of motion Y and along the third axis of motion Z relative to the laser processing heads 7c, 7d. This enables a significantly higher degree of freedom in the processing.Regarding the design of the movement devices 8, 9a, 9b, 10a, 10b, reference is made to the above description of Fig. 8 & Fig. 9.

[0166] It should be noted that the four embodiments shown are only examples and not intended to be limiting. The embodiments can, of course, be combined and / or extended as desired. For example, a second identically designed bridge 19 (including the respective motion devices and laser processing heads) could be provided, or a bridge 19 according to one of the other embodiments (including the respective motion devices and laser processing heads) could be provided. A person skilled in the art can assemble a suitable embodiment.

[0167] Figure 12 shows a top view of a laser system 1 of an exemplary embodiment of the invention. The laser system 1 comprises a plurality of laser devices 2a-2e, each of which can be configured according to a previously described embodiment. The laser system 1 has a modular design in that the support tables 5a-5e of adjacent laser devices 2a-2e can be coupled to one another, so that the support surfaces 6a-6e form a common overall support surface 36. Due to the modular design, the laser system 1 can be very flexibly configured from several individual laser devices.

[0168] 2 can be assembled. This allows, for example, a larger workpiece to be combined.

[0169] 3 can be processed as with only one laser device 2.

[0170] For coupling, the laser devices 2a-2e can each have a suitable coupling device 45. An exemplary embodiment of the coupling device 45 is shown in Figs. 6 and 7. The coupling device 45 shown comprises a coupling element 47 and a coupling opening 48 on each of the end faces 6 of the support table 5. Two adjacent laser devices 2 can be coupled by inserting the coupling elements 47 into the corresponding coupling openings 48. For fixing, a suitable locking device (not shown) can optionally be provided, such as detent elements that engage in detent openings. A screw connection or another type of detachable connection would also be conceivable. The first laser device 2a and the third laser device 2c in Fig. 12 are designed by way of example according to the third embodiment (Figs. 8 and 9). The second laser device 2b in Fig. 12 is designed by way of example according to the first embodiment (Figs. 1 and 2).2) designed. The fourth laser device 2d and the fifth laser device 2e in Fig. 12 are designed by way of example according to the fourth embodiment (Fig. 10 + Fig. 11). Of course, fewer or more laser devices 2 can be provided than shown. Likewise, the laser devices 2 can also be designed differently, possibly identically.

[0171] In the coupled state of the laser system 1, the movement ranges of the bridges 19 of adjacent laser devices 2 can, for example, overlap. This means that, for instance, the bridge 19a of the first laser device 2a could utilize at least part of the first guide 42b of the second laser device 2b, and the bridge 19b of the second laser device 2b could utilize part of the first guide 42a of the first laser device 2b.

[0172] The control units 11a–Ile of the laser devices 2a–2e can be connected, for example, by means of a first data communication link 37. The link can be parallel or, if necessary, serial. One of the control units 11a–Ile, for example, the control unit 11a of the first laser device 2, can be designated as the master control unit M. The remaining control units 11b–Ile can be designated as slave control units S. The laser system 1 can then be controlled via the master control unit M, with the slave control units S being controlled by the master control unit M.

[0173] Optionally, the laser system 1 could also include a higher-level system control unit 38, which can be connected to the control units 11a-11e of the laser devices 2a-2e by means of a second data communication link 39, as indicated by dashed lines in Fig. 12. In this case, the laser system 1 can be controlled via the system control unit 38, with the individual control units 11a-11e being controlled by the system control unit 38. Fig. 13 shows a laser device 2 according to one embodiment. The laser device 2 has a laser beam source 30 that generates and emits a source beam 52. According to this embodiment, the laser beam source 30 is designed as an ultrashort pulse laser beam source. Other types of laser beam sources 30 can also be used, e.g. nanosecond lasers, quasi-continuous wave fiber lasers (QCW lasers) and continuous wave lasers (CW lasers).

[0174] The laser device 2 comprises a beam alignment module 54 (BAM) downstream of the laser beam source 30, which is configured here as a beam position adjustment module. According to this embodiment, the beam alignment module 54 includes a camera device 56 and a measuring system 58.

[0175] In other embodiments, the camera device 56 and the measuring system 58 can also be arranged separately from the beam balancing module 54.

[0176] The beam balancing module 54, the camera device 56 and the measuring system 58 are coupled to the control unit 11.

[0177] Using the camera system 56 and the measuring system 58, the beam position of the source beam 52 is detected and transmitted to the control unit 11. Based on the detected beam position of the source beam 52, the control unit 11 then determines any deviation of the source beam 52's position from a target position. To compensate for this positional deviation, the control unit 11 outputs a control signal to the beam alignment module 54, thereby correcting the alignment of the source beam 52. This ensures, in particular, that the source beam 52 is precisely aligned with respect to the downstream beam splitting module 60.

[0178] The beam splitting module 60 (BSM) is also coupled to the control unit 11 and configured to split the source beam 52. Thus, the beam splitting module 60 allows several individual laser beams 4 to be fed from a single source beam 52. This reduces the power consumption per watt of laser power (sum of the powers of the individual laser beams 4) because only a single laser beam source 30 is required, for example, an ultrashort pulse laser beam source.

[0179] Downstream of the beam splitting module 60, a modulation device 62 is arranged for each laser beam 4. According to this embodiment, the modulation device 62 is designed as an acousto-optic modulator. The modulation devices 62 are also coupled to the control unit 11. The modulation devices 62 receive control signals from the control unit 11 and, based on these signals, vary the parameters of the individual laser beams 4, for example, the focal point of a laser beam 4 or the power of the respective laser beam 4 by varying the frequency and / or intensity. This ensures that laser beams 4 can have individual properties.

[0180] The laser device 2 comprises, downstream of each modulation device 62 for each laser beam 4, a further beam balancing module 54 (BAM), which here is configured as a beam position adjustment module. According to this embodiment, the additional beam balancing module 54 also includes a camera device 56 and a measuring system 58.

[0181] In other embodiments, the camera device 56 and the measuring system 58 can also be arranged separately from the beam balancing module 54.

[0182] The beam balancing module 54, the camera device 56 and the measuring system 58 are coupled to the control unit 11.

[0183] Using the camera system 56 and the measuring system 58, the beam position of the respective source beams 52 is recorded (technically, the laser beams 4 are only referred to as such at the output of the scanner 25) and transmitted to the control unit 11. Since the individual source beams 52 are guided along different axis systems, for example, the motion devices 8, 9, 10, to different laser processing heads 7, individual beam paths are established. Therefore, the different source beams also exhibit different deviations of their respective beam positions from their respective target positions.

[0184] The control unit 11 subsequently determines, based on the detected beam position of each source beam 52, any deviation of the beam position of the respective source beam 52 from a target position. To compensate for the positional deviation, the control unit 11 then outputs a control signal to the beam balancing module 54, thereby correcting the alignment of the respective source beam 52. This ensures, in particular, that the respective source beam 52 is precisely aligned with respect to the downstream scanner 25.

[0185] Downstream of the modulation devices 62, a scanner 25, in particular a galvanometer scanner, is arranged for each laser beam 4. The scanners 25 are also coupled to the control unit 11.

[0186] The scanners 25 receive corresponding control signals from the control unit 11, which indicate how the respective laser beam 4 should be influenced by the scanner 25 assigned to it, in order to ensure a specific orientation of the laser beam 4 with respect to the workpiece 3.

[0187] The scanners 25 are part of one or more laser processing heads 7. The orientation of at least one laser processing head 7 can also be influenced by the motion devices 8, 9, 10 coupled to it, which are also coupled to the control unit 11.

[0188] The laser processing heads 7 can enable the processing of the workpiece 3 simultaneously, but can also generally be operated sequentially.

[0189] Subsequently, the laser device 2, depending on the control signals of the control unit 11, ensures a processing area 66 on the workpiece 3 for each laser beam 4, which is generally reachable by the respective laser beam 4. Unless the processing area 66 is artificially limited by corresponding control signals from the control unit 11, the processing area 66 corresponds to a scan field 68, which indicates the area actually processed on the workpiece 3 by the respective laser beam 4. However, the control unit 11 can provide that the scan field 68 is artificially limited, for example, by prefactors in the control of the scanners 25 and / or the motion devices 8, 9, 10, which will be explained in more detail below.

[0190] In general, each scan field 68 is three-dimensional according to a Cartesian coordinate system, where the height along the Z-direction corresponds to a length along the laser beam 4, along which the laser beam 4 changes only negligibly in the vicinity of the focal point. For simplicity, the height along the Z-direction can be neglected. Then each scan field 68 can be considered two-dimensional.

[0191] The entirety of all control signals that the control unit 11 outputs to the various components with respect to a single laser beam 4 is referred to as a processing program 70. The processing programs 70 also include variations of the control signals, for example, those output to the scanners 25 and / or the motion devices 8, 9, 10, so that a single laser beam 4 is moved on the workpiece according to a specific trajectory 72.

[0192] A processing program 70 can also include all the control signals that the control unit 11 outputs to control the laser beams 4 of a single laser processing head 7.

[0193] Figure 13 shows a single laser beam source 30 of the laser device 2. Generally, a laser device 2 can, of course, also have several laser beam sources 30. In this case, only a single laser beam 4 can be fed from each source beam 52. Furthermore, a single laser beam source 30 can also be used for laser beams 4 from different laser devices 2 of the laser system 1. However, the laser system 1 generally also has only a single control unit 11, which sends the processing programs 70 with the corresponding control signals for the different components to all

[0194] provides 4 laser beams.

[0195] A fundamental challenge now is to arrange and align the different scan fields 68 over the workpiece 3 in such a way that the entire machining area of ​​the workpiece 3 is completely covered by the scan fields 68.

[0196] The control unit 11 can exert influence on the machining programs 70 either through hardware, for example by controlling the motion devices 8, 9, 10 accordingly, which cause a translation of the scanners 25 and thus also a corresponding translation of the scan fields 68. As a result, the control of the motion devices 8, 9, 10 ensures that the scan fields 68 completely cover the entire machining area of ​​the workpiece 3, at least after repeated passes over the workpiece 3.

[0197] On the other hand, the control unit 11 can exert influence via software. The processing programs 70 can then be adjusted so that, for example, based on prefactors, the scan fields 68 are limited compared to the processing areas 66 reachable by the laser beams on the workpiece 3. This means that the generally maximum possible orientation that the scanners 25 allow is not (fully) utilized. Ultimately, this can be seen as a local coordinate transformation for each laser beam 4, or rather its scan field 68. In this way, it can also be ensured that the scan fields 68 completely cover the total processing area of ​​the workpiece 3, at least after repeated passes over the workpiece 3.

[0198] While the motion devices 8, 9, 10 essentially enable translations along directions orthogonally oriented to each other (corresponding to a Cartesian coordinate system), the adaptation of the scanner control 25 also allows rotations of individual scan fields 68 relative to others, for example, to neighboring scan fields 68. In this way, nonlinearities in the alignment of the laser beams 4, thermal drift effects, and other external influences can be compensated for, in particular by means of appropriate calibration parameters. This also ensures that the entire workpiece 3 can be processed homogeneously by the different laser beams 4, according to the respective desired trajectories 72.

[0199] To detect the deviations and relative orientations of the scan fields 68 relative to each other, the laser device 2 has a calibration measuring box 74. At least one measuring plane of the calibration measuring box 74 is arranged parallel to the support surface 6 of the workpiece 3 or forms the support surface 6. According to the present embodiment, the calibration measuring box 74 is retractable, i.e., it can be removed, for example, so that the workpiece 3 can be positioned on the support table 5 instead of the calibration measuring box 74.

[0200] The calibration measuring box 74 is coupled to the control unit 11. The control unit 11 can use the calibration measuring box 74 to perform a calibration procedure that determines calibration parameters specifying the relative orientations of the scan fields 68 to each other. The control unit 11 then takes these calibration parameters into account when controlling the motion devices 8, 9, 10 and the scanners 25 within the respective machining programs 70. This ensures complete coverage of the entire machining area of ​​the workpiece 3 by the scan fields 68, at least after repeated passes over the workpiece 3.

[0201] Fig. 14 shows varying boundary regions 76 of the scan fields 68 during repeated passes according to one embodiment. In this context, Fig. 21 also shows varying boundary regions 76 of the scan fields 68 during repeated passes according to one embodiment. By combining the multiple scan fields 68, which together cover the workpiece 3, the total processing area of ​​the workpiece 3 is divided into the different scan fields 68. The scan fields 68 are also referred to as "patches". The scan fields 68 have boundary regions 76 that define the outer contour of the respective scan field 68. Within each scan field 68, the respective laser beam 4 follows the respective trajectory 72.

[0202] If the scan fields 68 are not optimally aligned with each other, for example, not gap-free, then due to a misalignment of adjacent scan fields 68 (see Fig. 19), repeated passes of the laser beams 4 over the same areas of the workpiece 3 can lead to certain areas of the workpiece 3 not being processed by any laser beam 4 at all, or by several laser beams 4, although both situations may be undesirable for the respective application. For example, the misalignment can also lead to scan lines 84 being interrupted or exhibiting errors, even though this is not intended.

[0203] Using the aforementioned calibration parameters, which are determined by a calibration procedure carried out using the calibration measuring box 74, such misalignments of the scan fields 68 can be compensated.

[0204] The scan fields 68 generally enable sequential or parallel processing of the workpiece 3 by the different laser beams 4. The alignment of adjacent scan fields 68, which represents a partial division of the entire processing area of ​​the workpiece 3, is also referred to as "stitching." This is illustrated by way of example in Fig. 20. In general, the individual scan fields 68A, 68B, which are assigned to a specific laser beam 4, can be arranged within a corresponding reachable processing area 66A, 66B. With repeated passes of the lasers 4, the scan fields 68A, 68B can be repositioned according to different scan field positions 69. This allows the entire processing area of ​​the workpiece 3 to be completely covered after a corresponding number of passes by the scan fields 68.The scan field positions 69 can be selected such that an overlap 71 between adjacent scan field positions 69A, 69B is ensured. This ensures that every position on the workpiece 3 can be processed by at least one laser beam 4. Stitching errors can occur due to deviations or misalignments of adjacent scan fields 68, the guide devices 16, 17, 18, the motion devices 8, 9, 10, and the bridges 19. The overlap 71 also ensures that additional techniques (explained below) can be used to counteract stitching errors, such as interlocking the scan fields 68.

[0205] One measure to counteract this effect is to vary the boundary areas 76 of the scan fields 68 during repeated passes (N = 1, 2, 3, ...) of the same areas of the workpiece 3. This means that a boundary area 76 of a second pass (N = 2) has an offset 78 along at least one direction compared to a boundary area 76 of the first pass (N = 1). During a third pass (etc.), the offset 78 can be varied further.

[0206] Fig. 21 shows that the offset 78 also leads to scan fields

[0207] 68 of an accessible processing area 66, which includes multiple scan field positions

[0208] 69 exhibits, after the changed offset 78 exhibits boundary areas 76 that differ from those of the previous pass; compare the situations for n = 1, 2. Since, in addition, the reachable machining areas 66 overlap, here indicated by Sx for scan fields 68, which are covered by a specific scanner 25 with x = 1 - 4, it is possible that every workpiece position of the workpiece 3 is reachable for one pass. Furthermore, the varying boundary areas 76 prevent machining errors from accumulating at individual workpiece positions.

[0209] Alternatively or cumulatively, variations in the trajectories 72 of the different passes can also be provided. For example, a rotation angle 80° can be taken into account, which is varied between different passes (N = 1, 2, 3, ...). Both measures ensure that processing errors during the laser treatment of the workpiece 3 do not accumulate in isolated, limited areas of the workpiece 3, but are distributed over the entire surface of the workpiece 3, thereby increasing the homogeneity of the processing of the workpiece 3. For example, the local, maximum surface roughness of the workpiece 3 can be reduced in this way.

[0210] The adjustment of the boundary areas 76 can be taken into account by the control unit 11 within the framework of the processing programs 70, whereby the boundary areas 76 of adjacent scan fields 68 are of course coordinated with each other for repeated passes, so that scan fields 68 are as gap- and overlap-free as possible are ensured for each pass.

[0211] Fig. 15 shows scan fields 68 with differing, irregular contours 82 according to one embodiment.

[0212] While Fig. 14 illustrates an approach in which the boundary regions 76 of the different scan fields 68 have identical contours (rectangles), adapting the scan fields 68 so that they generally have non-uniform, varying contours 82 results in potential machining defects occurring less uniformly on the workpiece 3. In other words, the irregularity of potential machining defects caused by scan fields 68 that are not optimally aligned with each other can be further increased by the differing, irregular contours 82 of the different scan fields 68, here exemplified as "patches" PI, P2, P3. This prevents, for example, potential machining defects from occurring according to local, regular patterns. The homogeneity of the machining of the workpiece 3 is further increased.The differing contours 82 can be taken into account by the control unit 11 within the framework of the different machining programs 70.

[0213] Fig. 16a shows specifically coordinated scan lines 84 of different scan fields 68 according to one embodiment. A further approach to ensuring the most uniform processing of the workpiece 3 is achieved by coordinating the scan lines 84 of adjacent scan fields 68. The scan lines 84 describe the trajectory 72 along which a laser beam 4 is guided within a scan field 68. The scan lines 84 of adjacent scan fields 68 can now be coordinated such that, at least sectionally viewed across the workpiece 3, they are either aligned with each other and / or parallel to each other.

[0214] Four scan fields 68 (patches 1 to 4) are shown here as examples, for which the scan lines 84 are all aligned parallel to each other. Additionally, the scan lines 84 of patch pairs 1 and 2, and of patch pairs 3 and 4, are aligned so that they are in line with each other. The direction of movement of the scan lines 84 is maintained across the boundary areas 76 of the scan fields 68, which are defined by the corresponding contours 82 of the scan fields 68, as indicated by the arrows.

[0215] This leads to a further increase in the homogeneity during the machining of the workpiece 3. To achieve the specific alignment of the scan lines 84, the control unit 11 can adjust the machining programs 70 accordingly.

[0216] Fig. 16b shows a specific sequence 86 of scan lines 84 of different scan fields 68 according to one embodiment.

[0217] A specific sequence 86 (indicated here by arrows) can, for example, lead to increased homogeneity in the laser processing of workpiece 3 if certain areas 88 are not to be processed. The scan fields 68 can then be arranged and aligned around these areas 88. As a result of the adapted sequence 86, jumps in the processing of the different scan fields 68 can be avoided, so that workpiece areas to be processed (here, for example, patches 2 and 3) are processed uniformly one after the other. Adapting the sequence 86 also enables the adapted processing of scan lines 84 that extend across multiple scan fields 68.

[0218] Specific sequences 86 can be taken into account by the control unit 11 based on the processing programs 70.

[0219] Fig. 17 shows interlocking scan lines 84 of different scan fields 68 according to one embodiment.

[0220] A further measure to ensure optimal stitching and avoid processing errors in the boundary areas 76 of the scan fields 68 is achieved by adjusting the scan lines 84 of different scan fields 68 in such a way that the ends 90 of the scan lines 84 do not overlap with the boundary areas 76. Instead, the scan lines 84 can be adjusted so that their respective ends 90 fall at least partially within an interior space 92 defined by a scan field 68. Ultimately, this means that the processing areas 66 reachable by the respective laser beams 4 overlap at least partially, but the scan fields 68 do not.

[0221] Furthermore, the scan lines 84 can be adjusted such that adjacent ends 90 are offset relative to each other along the direction of extension of the scan lines 84, which can, for example, be arranged parallel to each other. This creates an offset 94 between the ends 90 along the direction of extension of the scan lines 84, resulting in an "interlocking" of the scan lines 84 perpendicular to their direction of extension. Consequently, potential machining errors that may result from suboptimally aligned scan fields 68 are distributed even more homogeneously across the workpiece 3.

[0222] Specific ends 90 of the scan lines 84 can be taken into account by the control unit 11 based on the machining programs 70. Fig. 18 shows scan fields 68 adapted to workpiece areas not to be machined, according to one embodiment.

[0223] In general, the workpiece will have 3 areas to be processed (96) by the laser beams (4) and areas not to be processed (88) by the laser beams (4). The areas to be processed (96) can, for example, imitate the grain of the workpiece (3). This could be a wood grain.

[0224] Another approach to ensuring the "stitching" involves aligning the boundary areas 76 of the scan fields 68 such that the boundary areas 76 coincide with areas 88 (here white surfaces) of the workpiece 3 that are not to be processed. In contrast, areas 96 of the workpiece 3 that are to be processed (here black surfaces that imitate a grain, in particular a wood grain) are completely enclosed by the boundary areas 76, so that they correspond to a respective interior space 92 of a scan field 68.

[0225] The adjustment of the limit areas 76 can be ensured by the control unit 11, which adapts the machining programs 70 accordingly. In doing so, the control unit 11 will take into account a higher-level machining specification that indicates how the workpiece 3 is to be machined in general, for example, which structures are to be created. The scan fields 68 can have different sizes, formats, geometries, or similar characteristics.

[0226] The approaches shown in Figures 14 to 18 for ensuring "stitching" or for avoiding individual, pronounced processing errors can be taken into account by the control unit 11, either individually or in any combination, for controlling the relevant components in connection with a single laser beam 4, based on the individual processing programs 70. This allows the product quality to be increased after laser processing.

[0227] The exemplary embodiments show possible embodiment variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiment variants, but rather various combinations of the individual embodiment variants are also possible and this possibility of variation lies within the skill of the person skilled in this technical field due to the teaching on technical action by the present invention.

[0228] The scope of protection is defined by the claims. However, the description and drawings must be consulted for the interpretation of the claims. Individual features or combinations of features from the different embodiments shown and described can, in themselves, represent independent inventive solutions. The problem underlying these independent inventive solutions can be found in the description.

[0229] All references to value ranges in this description are to be understood as encompassing any and all sub-ranges thereof, e.g., the reference 1 to 10 is to be understood as including all sub-ranges, starting from the lower limit 1 and the upper limit 10, i.e., all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g., 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0230] Finally, for the sake of clarity, it should be noted that, for a better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced in size.

[0231] Reference symbol list

[0232] Laser system 29 extraction unit

[0233] Laser device 30 Laser beam source

[0234] Workpiece 31 surface

[0235] Laser beam 32 processing area

[0236] Support table 33 processing area

[0237] Surface area 34 Decorative image

[0238] Laser processing head 35 image

[0239] First movement device 36 Total contact area

[0240] Second movement device 3? First data communication device

[0241] Third movement device connection

[0242] Control unit 38 System control unit

[0243] Third Command Center _ Q Second data communication

[0244] Third drive unit connection

[0245] Second command facility 40 Third command

[0246] Second drive unit 41 Second guide

[0247] First leadership facility 42 First leadership

[0248] First drive unit areas with different

[0249] 43

[0250] First guidance facility Greyscale

[0251] Bridge 44 grayscale file

[0252] First bridge end 45 coupling device

[0253] Second bridge end 46 Front surface

[0254] Adjustment device 47 coupling element

[0255] Intake opening 48 Coupling opening

[0256] Vacuum pump 49 rolling elements

[0257] Scanner 50 Optical connection

[0258] Sensor device 52 Source beam

[0259] Mirror 54 Beam balancing module Mirror drive 56 Camera device

[0260] Measurement system offset between

[0261] 78

[0262] Beam splitting module, boundary areas

[0263] Modulation device 80° rotation angle

[0264] 82 Contour reachable 84 Scan line

[0265] Processing area 86 sequence

[0266] Scan field 88 areas not to be processed

[0267] Scan field position 90 End of a scan line

[0268] Editing program 92 Interior

[0269] Overlap 94 Offset between ends

[0270] Trajectory 96 areas to be processed

[0271] Calibration measuring box

[0272] Border area

Claims

Patent claims 1. Device for processing a surface (31) of a workpiece (3), wherein the device is configured as a laser device (2) which is set up to process the surface (31) by means of a number of laser beams (4), wherein the laser device (2) comprises a support surface (6) for arranging the workpiece (3), wherein the support surface (6) lies in a first plane (El), preferably horizontal, wherein the laser device (2) comprises at least one laser processing head (7) configured to direct a plurality of laser beams (4) towards the support surface (6) and / or comprises a plurality of laser processing heads (7a, 7b), each configured to direct at least one laser beam (4a, 4b) towards the support surface (6), wherein the laser device (2) comprises a first movement device (8) configured to move the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b)7b) to move along a first axis of motion (X) parallel to the first plane (El), comprising a second motion device (9) configured to move the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b) along a second axis of motion (Y) parallel to the first plane (El) and preferably normal to the first axis of motion (X), and comprising a third motion device (10) configured to move the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b) along a third axis of motion (Z) normal to the first plane (El) and preferably normal to the first axis of motion (X) and second axis of motion (Y), and wherein the laser device (2) comprises a control unit (11) configured to control the first motion device (8), the second motion device (9) and the third motion device (10), and further configured toat least one to control the laser processing head (7) and / or the plurality of laser processing heads (7a, 7b) in such a way that at least one process parameter of the at least two laser beams (4, 4a, 4b) can be individually changed and / or the at least two laser beams (4, 4a, 4b) can be individually switched on and off.

2. Laser device (2) according to claim 1, characterized in that the laser device (2) comprises a support table (5) which has the support surface (6).

3. Laser device (2) according to claim 1 or 2, characterized in that each laser beam (4) directed at the workpiece (3) is assigned a scan field (68) which can be variably positioned within a processing area (66) of the workpiece (3) reachable by the respective laser beam (4) by means of the first, second and third movement device (8, 9, 10), and that the control unit (11) is configured to control at least the first, second and third movement device (8, 9, 10) in such a way that a total processing area of ​​the workpiece (3) to be processed is completely covered by scan fields (68) of the laser beams (4), at least after repeated passes of the laser beams (4) and different positioning by means of the first, second and third movement device (8, 9, 10).

4. Laser device (2) according to claim 3, characterized in that the control unit (11) is configured to ensure alignment of the scan fields (68) of the different laser beams (4) based on individual processing programs (70), wherein the individual processing programs (70) have at least positioning signals for the first, second and third motion device (8, 9, 10) and calibration parameters by means of which alignment of the scan fields (68) relative to each other is ensured.

5. Laser device according to claim 4, characterized in that the scan fields (68) are relative to the calibration parameters. are alignable to each other, that a relative angle between scan field pairs (68) is negligible, and that a target relative offset between adjacent scan field positions of the scan fields (68), at least after repeated passes of the laser beams (4) and different positionings based on the first, second and third movement device (8, 9, 10), is ensured such that the adjacent scan field positions of the scan fields (68) have a target overlap area.

6. Laser device according to claim 5, characterized in that the calibration parameters comprise at least local coordinate transformations that depend at least on positions of the motion devices (8, 9, 10).

7. Laser device (2) according to one of claims 3 to 6, characterized in that a scan field (68) associated with a laser beam (4) is generated by a scanner (25) associated with the laser beam (4), in particular a galvanometer scanner.

8. Laser device (2) according to claim 7, characterized in that different laser beams (4) are assigned to different scanners (25).

9. Laser device (2) according to one of claims 4 to 8, characterized in that the control unit (11) is configured to control each laser processing head (7) according to an individual processing program (70) of a scan field (68) such that the workpiece (3) can be processed by the different laser beams (4) according to individual trajectories (72).

10. Laser device (2) according to one of claims 4 to 9, characterized in that the control unit (11) is configured to coordinate the processing programs (70) such that boundary areas (76) of the scan fields (68) are repeatedly passed over the Laser beams (4) vary over the same workpiece positions of the workpiece (3).

11. Laser device (2) according to one of claims 4 to 10, characterized in that the control unit (11) is configured to coordinate the processing programs (70) such that scan fields (68) assigned to different laser beams (4) have different, irregular contours (82).

12. Laser device (2) according to one of claims 4 to 11, characterized in that the control unit (11) is configured to coordinate the processing programs (70) such that scan lines (84) of different scan fields (68), along which the laser beams (4) are guided over the workpiece (3), are aligned at least partially with each other and / or are aligned at least partially parallel to each other.

13. Laser device (2) according to claim 12, characterized in that the control unit (11) is configured to coordinate the processing programs (70) such that the ends (90) of the scan lines (84) coincide, wherein adjacent ends (90) of adjacent scan lines (84) are arranged offset relative to each other along a direction of extension of the scan lines (84).

14. Laser device (2) according to one of claims 4 to 13, characterized in that the control unit (11) is configured to coordinate the processing programs (70) such that scan fields (68) of different laser beams (4) correspond to a specific processing sequence or processing direction.

15. Laser device (2) according to one of claims 4 to 14, characterized in that the control unit (11) is configured to coordinate the processing programs (80) such that scan fields (68) of different laser beams (4) boundary areas (76) exhibiting which are arranged in such a way that they correspond to non-machinable workpiece areas (88) of the workpiece (3).

16. Laser device (2) according to one of the preceding claims, characterized in that the control unit (11) is configured to perform a calibration procedure at least with regard to the first, second and third motion device (8, 9, 10) and to take into account calibration parameters from the calibration procedure at least when controlling the motion devices (8, 9, 10).

17. Laser device (2) according to claim 16, characterized in that the laser device (2) has at least one calibration measuring box (74) for carrying out the calibration procedure, wherein the calibration measuring box (74) is arranged and set up such that a measuring plane parallel to the support surface (6) is provided, or that a measuring area of ​​the calibration measuring box (74) maps the support surface (6).

18. Laser device (2) according to one of the preceding claims, characterized in that the laser device (2) has at least one or more laser beam sources (30) which are arranged and configured such that they each output at least one source beam (52) for at least one laser beam (4).

19. Laser device (2) according to claim 18, characterized in that the laser device (2) has at least one beam splitting module (60) which is coupled to the at least one laser beam source (30) and is configured to split the source beam (52) generated by the at least one laser beam source (30) for several laser beams (4).

20. Laser device (2) according to one of the preceding claims, characterized in that the laser device (2) has for each laser beam (4) a modulation device (62) associated with the laser beam (4), which is coupled to the control unit (11) and which is configured to vary parameters of the respective laser beam (4).

21. Laser device (2) according to claim 20, characterized in that the laser device (2) has at least one beam balancing module (54) arranged between the at least one laser beam source (30) and the beam splitting module (60), and / or that the laser device (2) has several beam balancing modules (54) each arranged individually between a modulation device (62) and a scanner (25) associated with the respective modulation device (62), wherein each beam balancing module (54) is coupled to the control unit (11) and configured to adjust the source beam (52) generated by the laser beam source (30) at least with respect to a beam position along a beam path.

22. Laser device (2) according to one of claims 18 to 21, characterized in that the laser device (2) has at least one camera device (56) and / or a measuring system (58) which is coupled to the control unit (11) and is configured to detect the beam position of a source beam (52) generated by the at least one laser beam source (30) at least along the beam path.

23. Laser device (2) according to one of the preceding claims, characterized in that at least one laser processing head (7, 7a, 7b) is configured to direct two to one hundred laser beams in the direction of the support surface (6).

24. Laser device (2) according to one of the preceding claims, characterized in that at least two laser processing heads (7a, 7b) of the plurality of laser processing heads (7a, 7b) are jointly movable at least along an axis of movement (X) by means of the respective movement device (8).

25. Laser device (2) according to one of the preceding claims, characterized in that at least two laser processing heads (7a, 7b) of the plurality of laser processing heads (7a, 7b) are at least along a The axes of movement (Y) are movable relative to each other, with each of the at least two laser processing heads (7a, 7b) having a separate Movement device (9a, 9b) for the respective axis of movement (Y) has.

26. Laser device (2) according to one of the preceding claims, characterized in that the third motion device (10) comprises a third guide carriage (12) on which the at least one laser processing head (7) is arranged, a third guide (40) along which the third guide carriage (12) is guided, and a third drive device (13) for driving the third guide carriage (12), that the second motion device (9) comprises a second guide carriage (14) which includes the third guide (40), a second guide (41) along which the second guide carriage (14) is guided, and a second drive device (15) for driving the second guide carriage (14), and that the first motion device (8) comprises a first guide carriage (16) which includes the second guide (41), a first guide (42),along which the first guide carriage (16) is guided and comprises a first drive device (17) for driving the first guide carriage (16).

27. Laser device (2) according to claim 26, characterized in that the first guide (42) comprises two parallel first guide rails (18), wherein the support surface (6) extends between the two first guide rails (18), and that the first guide carriage (16) comprises a bridge (19) with a first bridge end (20) which is guided on one of the first guide rails (18) and an opposite second bridge end (21) which is guided on the other of the two first guide rails (18).

28. Laser device (2) according to claim 27, characterized in that the bridge (19) is spaced at a defined bridge distance (LB) from the support surface (6) or that a bridge distance (LB) between the bridge (19) and the support surface (6) is variable, wherein the laser device (2) for adjusting the bridge distance (LB) preferably comprises an adjustment device (22) which can be controlled by the control unit (11) or operated manually.

29. Laser device (2) according to one of the preceding claims, characterized in that the at least one process parameter comprises at least one of the following parameters: laser power, Relative velocity to the workpiece, number of pulses per burst, amplitude of pulses in a burst, repetition rate, wavelength, pulse energy, focus diameter, energy amplitudes of the pulses in the burst, pulse duration of the pulses.

30. Laser device (2) according to one of the preceding claims, characterized in that an acousto-optic modulator or an electro-optic modulator is provided for each of the individually adjustable laser beams (4, 4a, 4b).

31. Laser device (2) according to any of the preceding claims 2 to 30, insofar as related back to claim 2, characterized in that a plurality of suction openings (23) are provided in the support surface (6), that the laser device (2) comprises a vacuum pump (24) which is connected to the suction openings (23) to generate a suction pressure, and that the vacuum pump (24) can be controlled by the control unit (11), and / or the suction openings (23) can be used as blow openings to generate an air cushion for positioning the workpiece (3), and / or that the support table (5) comprises a plurality of rotatable roller bodies (49) which can be displaced between a rolling position in which the roller bodies (49) protrude from the support surface (6) and a rest position in which the roller bodies (49) are recessed in the support surface (6).

32. Laser device (2) according to one of the preceding claims, characterized in that at least one laser processing head (7, 7a, 7b) has a scanner (25) includes and / or that at least one laser processing head (7, 7a, 7b) includes at least one sensor device (26) and / or that at least one laser processing head (7, 7a, 7b) includes an optical unit for adjusting a focus position of at least one laser beam (4, 4a, 4b).

33. Laser device (2) according to claim 32, characterized in that the scanner (25) comprises a number of adjustable mirrors (27) for deflecting the at least one laser beam (4), wherein the number of adjustable mirrors (27) each have a galvanometric mirror drive (28) for adjusting the mirror (27) which can be controlled by the control unit (11) and / or that the optical unit comprises two optical elements, in particular lenses, which are linearly movable relative to each other and an actuator for changing a distance between optical elements which can be controlled by the control unit (11) and / or that the optical unit comprises two rotatably mounted mirrors and a parabolic mirror, wherein the two mirrors each have a galvanometric mirror drive for adjusting the mirror which can be controlled by the control unit (11).

34. Laser device (2) according to claim 33, characterized in that the number of movable mirrors (27) comprises a first mirror (27) for moving the at least one laser beam (4) in a first deflection direction, preferably parallel to the first axis of movement (X), relative to the support surface (6) and / or a second mirror (27) for moving the at least one laser beam (4) in a second deflection direction, preferably parallel to the second axis of movement (Y), relative to the support surface (6).

35. Laser device (2) according to one of claims 32 to 34, characterized in that the at least one sensor device (26) comprises at least one of the following sensors: distance sensor, position sensor, laser power sensor, CMOS camera, CMS camera, camera, first photodiode for detecting a back reflection of a laser intensity at least one laser beam (4, 4a, 4b), second photodiode for detecting heat radiation from the workpiece (3).

36. Laser device (2) according to one of the preceding claims, characterized in that the laser device (2) comprises an extraction device (29) which is designed to extract material from the workpiece (3) removed by at least one laser beam (4, 4a, 4b), wherein the extraction device (29) can be controlled by the control unit (11).

37. Laser device (2) according to one of the preceding claims, characterized in that the laser device (2) comprises a laser beam source (30) for providing at least one laser beam (4), wherein the laser beam source (30) is connected to at least one laser processing head (7) by means of an optical connection (50).

38. Use of a laser device (2) according to one of the preceding claims, characterized in that a workpiece (3) having a basic gloss level and / or a basic structure on its surface (31) is arranged on the support surface (6), that the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b), the first movement device (8) and / or the second movement device (9) and / or the third movement device (10) are controlled by the control unit (11) in such a way that in at least one defined processing area (32, 33) of the surface (31) a gloss level different from the basic gloss level is produced and / or material of the workpiece (3) is removed in such a way that a predetermined surface structure is created.

39. Use according to claim 38, characterized in that a decorative image (34) to be generated is transmitted to the control unit (11), preferably in the form of a grayscale file (44) or a black and white file, and that the control unit (11) assigns different gloss levels or different surface structures to areas with different grayscale levels (43) or to the black and white areas. assigns and that the control unit (11) controls the at least one laser processing head (7) and / or the plurality of laser processing heads (7a, 7b), the first motion device (8) and / or the second motion device (9) and / or the third motion device (10) in such a way that an image (35) synchronous with the specified decorative image (34) is produced on the surface of the workpiece (3) which has the assigned gloss levels or surface structures.

40. Laser system (1) comprising a plurality of laser devices (2a-2e), characterized in that the plurality of laser devices (2a-2e) are each designed according to one of claims 2 to 37, insofar as related back to claim 2, and that the laser system (1) is modularly constructed in that the support tables (5a-5e) of adjacent laser devices (2a-2e) can be coupled in such a way that the support surfaces (6a-6e) form a common overall support surface (36).

41. Laser system (1) according to claim 40, characterized in that the Control units (lla-lle) of the majority of laser devices (2a- 2e) are connected or connectable by means of a first data communication link (37), wherein one control unit (11a) can be selected as the master control unit (M) and the remaining control units (llb-lle) can be selected as slave control units (S), wherein the laser system (1) can be controlled via the master control unit (M) and the slave control units (S) can be controlled by the master control unit (M), or that the laser system (1) comprises a superior system control unit (38) which is connected or connectable to the control units (lla-lle) of the plurality of laser devices (2a-2e) by means of a second data communication link (39), wherein the laser system (1) can be controlled via the system control unit (38) and the control units (lla-lle) can be controlled by the system control unit (38).

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