Laser processing machine, in particular laser plotter or flatbed laser plotter, and method for operating a laser processing machine

Abstract

The invention describes a method and a laser processing machine (1), in particular a laser plotter (2a) or flatbed laser plotter (2b), for performing at least one job (18) for cutting, engraving, marking and / or inscribing a preferably flat workpiece (7), which forms at least one housing (3) having a processing chamber (8) for positioning a workpiece (7) on a processing table (9), wherein it has at least one radiation source (4) in the form of a laser (5, 6), and a control unit (13) for controlling the slide (14) which, operated via preferably a belt drive, can be adjusted along a y-axis and has a focusing unit (12) or laser head (12) which is movably arranged thereon and can be adjusted in an x-axis, wherein a plurality of installed mirrors (30, 31, 32) are arranged for guiding a freely propagating laser beam (10) from the laser (5, 6) to the workpiece (7). In order for an increased amplitude or width (44) of the laser beam (10) to be formed, that is to say in order for what is known as "wobbling" of the laser beam (10), the last mirror (32) in the focusing unit (12) for deflecting the laser beam (10) in the direction of the lens (28) and / or a preceding mirror (30, 31) for deflecting the laser beam (10) in the direction of the focusing unit (12) are / is mounted rotatably and are / is connected to at least one actuator (41), in particular a piezo element or a piezo stack, with the result that the mirror (30, 31, 32) can be adjusted via the actuator (41) mechanically (in particular a mechanical deflection) by loading the actuator (41) with energy.

Description

[0001] Laser processing machine, in particular laser plotter or flatbed laser plotter, and method for operating a laser processing machine

[0002] The invention relates to a laser processing machine, in particular a laser plotter or flatbed laser plotter, and to methods for operating a laser processing machine for executing at least one job for cutting, engraving, marking and / or inscribing a preferably flat workpiece, as described in claims 1 and 10.

[0003] Please note that the focusing unit can also be a laser head, or vice versa. The same applies to the light source, which can be a laser pointer.

[0004] Laser processing machines are already known from the prior art in which the laser beam is wobbled to increase its amplitude, particularly the laser spot. During wobbling, i.e., oscillation, a deflection unit on the mirror or other optical elements in the laser beam path is designed to subject the laser beam to periodic, particularly sinusoidal or circular, fluctuations / deflections. This means that a very thin laser line, especially a very thin line width, is significantly broadened by the oscillating movement of the deflection unit or mirror.

[0005] For example, DE 102018221203 A1 discloses a laser processing machine with a wobble scanner. According to the invention, a deflection unit is used that deflects the beam axis of the laser beam in a one- or two-dimensional oscillating manner, parallel to the actual beam axis, or that displaces the end of a laser fiber in a one- or two-dimensional oscillating manner by means of a displacement unit.

[0006] Likewise, DE 1020131 10523 B3 discloses a laser processing machine in which a mirror deflecting the laser beam toward the workpiece is deflected in an oscillating manner to create a thick laser beam for welding. EP 4032652 A1 discloses a system for material processing using a laser beam, in which a deflection unit for deflecting the laser beam and a wobble unit connected to it are provided to transmit a wobble motion with a wobble pattern and a wobble frequency.

[0007] Trumpf Laser Welding also uses a wobbled mirror in a laser head for welding on a robot, as shown in the video at httDs: / / www.youtube.com / watch?v=6i3m0qHT3dE. In this application, the laser beam is guided to the laser head via a fiber optic cable, where it is deflected toward the workpiece by a deflection unit or mirror. A mirror is adjusted in an oscillating manner to wobble the laser beam. A deflection mirror in front of the mirror wobbles to deflect the laser beam toward the lens and workpiece, creating the widest possible laser beam.

[0008] In addition, wobbling is also used in other fields. For example, EP 1469 304 A2 discloses an X-ray optical system that includes a wobbling device that causes the X-ray optical element to oscillate during the measurement.

[0009] Generally speaking, such systems are already known from the state of the art, but they are usually used in galvo-like laser applications or where the laser head structure is very complex. This makes such a laser head very heavy, making it impossible to use it in laser plotters, where the laser head or focusing unit needs to be as lightweight as possible to enable rapid movements (acceleration and deceleration).

[0010] The object of the invention is to provide a laser processing machine, in particular a laser plotter or flatbed laser plotter, and a method for operating a laser processing machine for processing at least one job for cutting, engraving, marking, and / or inscribing a preferably flat workpiece, which, on the one hand, avoids the aforementioned disadvantages and, on the other hand, achieves the simplest possible design of the laser head or focusing unit. This object is achieved by the invention. Advantageous embodiments and / or method measures are described in the subclaims.

[0011] The object of the invention is achieved by a laser processing machine, in particular a laser plotter or flatbed laser plotter, in which, in order to form an increased amplitude or width of the laser beam, i.e. for the so-called "wobbling" of the laser beam, the last mirror for deflecting the laser beam in the direction of the lens and / or a preceding mirror for deflecting the laser beam in the direction of the focusing unit is rotatably mounted in the focusing unit and is connected to at least one actuator, in particular a piezo element or a piezo stack, so that the mirror can be mechanically adjusted via the actuator, in particular a mechanical deflection, by applying energy to the actuator.

[0012] The advantage here is that the use of actuators, in particular piezo elements or piezo stacks, to adjust the mirror creates a very simply constructed focusing unit whose weight is only slightly higher than the weight of a conventional focusing unit in a laser plotter. All that is necessary is that the mirror is in contact with the actuator (piezo element or piezo stack) on the back, so that when energy is applied to the actuator, it expands and the mirror is pivoted about the fixed pivot axis. This means that by constantly switching the energy on and off, the actuator adjusts the mirror in an oscillating manner, in particular moving it back and forth. The deflection of the actuators and thus the adjustment angle or angle of the mirror can be influenced depending on the amount of energy applied.

[0013] An advantage of adjusting the additional mirrors outside the focusing unit is that, on the one hand, there is no increase in the mass or weight of the focusing unit and, on the other hand, the deflection angle or angle of the mirror is significantly smaller because the length of the path is increased due to the additional mirrors or deflections of the laser beam.

[0014] A further advantage is that for the first time with laser plotters, large, homogeneous fill areas, for example on laminates where the sharpness of the engraving is not so important due to a distant viewing distance, can be created with laser lines or laser beams of up to 2.0 mm. This significantly shortens processing times when producing large signs / boards. If a large sign / board were created without wobbling the laser beam, a laser line (laser beam) of, for example, 0.1 mm to 0.5 mm would be created in one work cycle, meaning that numerous laser lines (work cycles) would have to be arranged next to one another to create a corresponding fill area. With a wobbled laser beam, where the laser beam reaches a width of, for example, 2.0 mm, considerably fewer work cycles (laser lines arranged next to one another) are necessary to engrave a corresponding fill area.Both raster engraving and vector engraving are possible, although raster engraving, i.e. line by line, is preferred for large areas, where the carriage is adjusted line by line, whereas with vector engraving the carriage is moved according to the specified contour, i.e. not line by line.

[0015] An advantageous design is one in which the mirror is mounted at least twice over two axes of rotation and is connected to two or more actuators to achieve different functions or motion sequences for the swept laser beam, such as sine or trochoid, etc. This allows the mirror to be deflected in multiple directions. This allows different wobbling movements of the mirror for the laser beam. This allows the optimal function or motion sequence to be selected depending on the resolution. The wobbling function can be selected in the software, for example.

[0016] A design in which the deflection or angle of the last mirror in the focusing unit is controlled by the actuator in the y-direction is advantageous. This allows for a simpler design and thus only slightly increases the mass or weight of the focusing unit. In this case, only an actuator is installed, which is supplied with power via cables from the base unit, i.e., the housing. The necessary components can be installed in the housing.

[0017] An advantageous design is one in which the deflection of the actuators, in particular the width of the laser beam, is adjustable as a function of the x and y position of the focusing unit. This ensures that a constant engraved line width can be generated on the workpiece. This is particularly necessary when a mirror in front of it, rather than the last mirror, is designed to wobble, as this can result in different lengths of the freely running laser beam between the mirrors. If the actuator control is not adjusted, the mirror would always be deflected the same, which would lead to different widths in material processing (e.g. engraving) if the free running laser beam had different lengths.

[0018] An advantageous embodiment is one in which the amplitude, in particular the deflection or width, of the laser beam or laser spot can be freely adjusted by entering a parameter, in particular in the software. This enables the user to influence the deflection of the mirror by entering or selecting a corresponding parameter, so that the width of the swept laser beam can be individually adjusted. This is possible because, by using actuators, in particular piezo components, the deflection of the mirror can be easily controlled by applying more or less energy, in particular voltage. In particular, the extent of the extension of the actuators can be influenced by the amplitude of the voltage, so that applying a greater voltage results in a greater extension of the actuator, which in turn causes a greater deflection of the mirror, thus increasing the width of the swept laser beam.This makes it easy to adjust the width of the laser beam.

[0019] A design in which the frequency of the wobbled mirror is freely selectable and the actuators follow the frequency up to the tens of kHz range is advantageous. This enables high-frequency movements, enabling rapid modulation of the laser beam, and also allows adjustment of the acceleration, constant speed, and deceleration of the laser head.

[0020] An advantageous embodiment is one in which the actuator(s) is / are configured for adaptive control depending on the lens used or set, in particular 1.5" or 2.0" or 2.5" or 4.0" lenses, to achieve a preset amplitude or width. This ensures that the various lenses can be used and, at the same time, a set width of the laser beam is achieved during wobbling. Thus, a standardized or wobbled machining process can be carried out with such a focusing unit.

[0021] An embodiment is advantageous in which the laser beam is arranged or designed to run freely between at least three mirrors, the first mirror being positioned in the housing and deflecting the laser beam coming from the laser along the y-direction of the machining table in the direction of the second play, the second mirror being coupled to the carriage and thus being adjustable along the y-direction with the carriage, the third mirror being arranged in the focusing unit so that the laser beam can be deflected from the second mirror in the x-direction to the third mirror in the focusing unit. This enables simple guidance of the laser beam without an optical fiber, the carriage and the focusing unit being freely adjustable in their position.

[0022] An advantageous embodiment is one in which the laser beam is arranged or configured to run freely between two mirrors, wherein a laser, in particular a diode laser, is positioned in the housing such that it emits the laser beam along the y-direction of the machining table in the direction of the first mirror, wherein the first mirror is coupled to the carriage and the carriage can thus be adjusted along the y-direction with the carriage, wherein the second mirror is arranged in the focusing unit such that the laser beam can be deflected from the first mirror in the x-direction to the second mirror in the focusing unit. This results in a simple structure.

[0023] Furthermore, the object of the invention is also achieved by a method for operating a laser processing machine, in particular a laser plotter or a flatbed laser plotter, in which, in order to form an increased amplitude or width of the laser beam, i.e. for the so-called "wobbling" of the laser beam, the last mirror for deflecting the laser beam in the direction of the lens and / or a preceding mirror for deflecting the laser beam in the direction of the focusing unit is rotatably mounted and is connected to at least one actuator, in particular a piezo element or a piezo stack, so that the mirror is adjusted mechanically via the actuator, in particular a mechanical deflection, by applying energy to the actuator.

[0024] The advantage here is that for the first time, a laser plotter can be used for wobbling, whereby the properties of the laser plotter remain unchanged thanks to the simple and lightweight design with actuators, in particular piezo elements or piezo stacks. As already mentioned, a significant reduction in processing time is advantageously achieved when producing large surfaces, especially large signs / boards. If a large surface were created on a sign / board without wobbling the laser beam, a laser line (laser beam) of, for example, 0.1 mm to 0.5 mm would be generated in one work cycle, meaning that numerous laser lines (work cycles) would have to be arranged next to one another to create a corresponding fill area. With a wobbled laser beam, where the laser beam reaches a width of, for example, 2.0 mm, significantly fewer laser lines are required to engrave a corresponding fill area.

[0025] Advantageous measures include subjecting the mirror to an oscillating or fluctuating movement by applying pulsed and / or modulated energy, in particular current and voltage, to the actuator(s). This ensures that the frequency and / or voltage level of the supplied energy is adjusted for each set width or amplitude of the laser beam, ensuring that with a correspondingly set travel speed of the focusing unit, a sufficiently rapid oscillation of the mirror is generated to achieve the width of the laser beam, i.e. that the user can set the width of the swept laser beam and other parameters such as travel speed, laser power, etc., whereupon the software, in particular the user software or the software of the control unit, calculates the energy to control the actuator(s) and executes it if necessary.

[0026] Advantageous are the measures in which the mirror is adjusted around the rotation axis at a defined angle by the actuator. This results in a very simple and cost-effective design.

[0027] Advantageous are the measures in which the deflection of the preferably last mirror around a rotational axis is carried out by the actuator in the y-direction. This ensures that only a very few and very lightweight components are required, allowing for use in the focusing unit or laser head.

[0028] Advantageous measures are those in which the mirror is deflected around two axes of rotation using two actuators in the x and y directions. This makes it possible to generate a wide variety of laser beam movements, such as a sine or a trochoid, etc., thus improving the quality of such wobbled lines. Advantageous measures are those in which the control of the actuator or actuators varies depending on the lens used or set, in particular 1.5", 2.0", 2.5", or 4.0" lenses, to achieve a preset amplitude or width. This ensures that the advantages of using different lenses are retained while still enabling wobbling.

[0029] Advantageous measures include the laser beam running freely between at least three mirrors. The first mirror is positioned in the housing and deflects the laser beam coming from the laser along the y-direction of the machining table toward the second mirror. The second mirror, which is coupled to the carriage and adjusted with it, then deflects the laser beam in the x-direction toward the third mirror in the focusing unit. The third mirror then deflects the laser beam in the y-direction toward the lens. This allows adjustment of the carriage and the focusing unit while the laser beam is running freely.

[0030] Advantageous measures include the laser beam running freely between the at least two mirrors. A laser is positioned in the housing and the laser beam is emitted along the y-direction of the machining table toward the first mirror. The first mirror, which is coupled to and adjusted by the carriage, deflects the laser beam in the x-direction toward the second mirror in the focusing unit. The second mirror deflects the laser beam in the z-direction toward the lens. This results in a simple and cost-effective design.

[0031] Advantageous measures include recording and evaluating the distances of the laser beam between the mirrors during the wobble of the first or second mirror. The deflection or angle of the wobbled mirror is then adjusted by adjusting the actuator energy accordingly to achieve a constant line width, especially the width, of the laser beam. This configuration ensures that no increase in mass or weight occurs on the focusing unit. Furthermore, sufficient space is available in the area of ​​the mirrors in the housing of the laser processing machine.

[0032] Finally, measures involving a laser beam surrounding a wobbled surface, especially an engraved surface, are advantageous. This improves the resolution of the engraved surface, particularly by sharpening it. However, if the actuator is not energized, the actuators hold the mirror in its original position, and normal machining can be carried out.

[0033] The invention is described below in the form of an embodiment, whereby it is pointed out that the invention is not limited to the illustrated and described embodiment or solution.

[0034] They show:

[0035] Fig.1 is a diagrammatic representation of a laser plotter with an inserted workpiece to be engraved during the machining process, in a simplified, schematic representation;

[0036] Fig. 2 is a diagrammatic top view of the laser plotter without a cover with a schematically drawn laser beam path, in a simplified schematic representation;

[0037] Fig. 3 is a diagrammatic representation of the focusing unit without additional components, in particular without an ultrasonic sensor, but with a laser beam drawn in, in a simplified schematic representation;

[0038] Fig. 4 is a sectional view through the focusing unit according to Figure 3 with the wobble unit deactivated, in a simplified schematic representation;

[0039] Fig. 5 is a sectional view through the focusing unit according to Figure 4 with activated wobble unit, in a simplified schematic representation;

[0040] Fig. 6 is a diagrammatic representation of a flatbed laser plotter, in a simplified, schematic representation;

[0041] Fig.7 shows a further embodiment of a diagrammatic plan view of a laser plotter with a wobbled second mirror, in a simplified, schematic representation;

[0042] Fig.8 shows another embodiment of a diagrammatic plan view of the laser plotter without a cover with a laser, in particular a diode laser, instead of the first mirror, in a simplified schematic representation;

[0043] Fig. 9 is a simplified, schematic representation of a swept laser beam or path in which the laser was activated only at the required times to generate a line; Fig. 10 is a simplified, schematic, distorted representation illustrating a control of the laser to form a preferably straight line.

[0044] By way of introduction, it should be noted that in the various embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the described figure and, if the position changes, must be applied analogously to the new position.

[0045] Figures 1 to 10 show an exemplary embodiment of a laser processing machine 1 or a laser device 1, in particular a laser plotter 2a and / or a flatbed laser plotter 2b. Of course, application with other laser processing machines, in particular with a galvo laser, is also possible.

[0046] In the laser plotter 2a shown in Fig. 1, at least one, preferably two, radiation source(s) 4 or laser sources 4 in the form of lasers 5, 6 are arranged in a housing 3. The lasers 5 and 6 preferably act alternately on a workpiece 7 to be processed. The workpiece 7 is or will be positioned in a processing space 8 of the laser plotter 2a, in particular on a processing table 9, wherein the processing table 9 is preferably adjustable in height. A laser beam 10 emitted by a radiation source 4, in particular the laser 5 or 6, is directed via deflection elements 11 to at least one movable focusing unit 12 or

[0047] Laser head 12, from which the laser beam 10 is deflected towards the workpiece 7 and focused for processing. The control, in particular the position control of the laser beam 10 to the workpiece 7, is carried out via software running in a control unit 13, wherein the workpiece 7 is processed by adjusting a carriage 14, on which the focusing unit 12 or the laser head 12 is also arranged for movement, preferably via a belt drive in the xy direction. It is possible, for example, that in the "engraving" processing process, the adjustment of the carriage 14 takes place line by line, whereas in the "cutting" processing process the carriage 14 is moved according to the contour to be cut, i.e., not line by line. In such laser processing machines 1, in particular laser plotters 2a, it is necessary for safety reasons that a cover 15 orDoor 15, which is preferably at least partially transparent, must be closed, as shown in Fig. 1. The operating personnel can then manually or automatically position the laser point or a light source 16, for example in the form of a laser pointer 16, in particular light beam 17 or laser pointer point 17, which is preferably coupled into the beam path of the laser 5, 6 and is deflected towards the machining table 8 via the focusing unit 12, on the inserted workpiece 7, whereupon a job 18 for machining the workpiece 7 can be started. At the end of the job 18, the carriage 14 and the focusing unit 12 are then preferably moved to the starting position so that the finished workpiece 7 can be removed, whereupon a new machining process can be started by inserting a new workpiece 7 to be machined or a blank 7.It is advantageous if the end of processing is indicated visually or acoustically, so that the user does not have to constantly monitor the laser machine, in particular the laser plotter 1. For the sake of completeness, it should be mentioned that the adjustment of the focusing unit 12 with the activated light beam 17 is also possible when the cover 17 is open, but the laser 5, 6 cannot be activated. Furthermore, it is possible for the laser processing machine 1 to be equipped with a camera system 19, which is preferably arranged in the cover 15 and with which the processing space 8 can be recorded with the cover 15 closed and open.

[0048] For the sake of completeness, it should be noted that the laser processing machine 1 is or can be equipped with connections or lines for power supply or for connection to the intranet and / or internet 20. In this case, it is possible to connect to external components 22, such as a laptop 22a or computer, an automatic feed unit, a conveyor belt, a removal robot, etc., via a line 21 or wirelessly via WLAN or Bluetooth, so that data can be transmitted from the external components 22, in particular the laptop 22a. For this purpose, for example, a graphic 23 and / or text 23 is created or displayed on the external component 22, in particular a computer, laptop 22a or a control unit, using commercially available software 24, such as CorelDraw, Paint, etc., or using the company's own application software 24, in particular Ruby.loaded, which is exported or transferred to the control unit 13 of the laser device 1, preferably in the form of the job 18. Preferably, the data to be transferred is converted by the same or different software so that the control unit 13 can process the job 18. Of course, it is also possible for the input to be made directly on the laser processing machine 1 via the existing input means 25, such as a touchscreen or input keys, or for a corresponding job 18 to be loaded from a storage medium, such as a cloud 26, a USB stick 27, etc. After the data, in particular the job(s) 18, have been transferred or have been created directly or loaded from the storage medium, the job 18 is processed by the laser processing machine 1, in particular its control unit 13.It is possible for multiple jobs 18 to be stored simultaneously in the laser processing machine 1 and processed sequentially. Furthermore, it is also possible for the application software 24 to be installed in the cloud 26 and to be accessed from the cloud 26 via a web browser.

[0049] Furthermore, in Figure 1, the focusing unit 12 is equipped with an inserted lens 28 and an additional device 29, namely an ultrasonic measuring device, with which the distance between the workpiece surface of the inserted workpiece 7 and the focusing unit 12 can be automatically determined, so that the correct table height for an inserted lens 28 can be determined, calculated, and adjusted. This additional device 29 has been omitted from the following figures for the sake of clarity.

[0050] As can now be seen more clearly from Figure 2, in laser processing machines 1 of this type the laser beam 10 is guided from the laser 5, 6 to the focusing unit 12 via deflection elements 11 which are permanently installed according to the prior art. The deflection elements 1 are formed by at least three mirrors 30, 31 and 32, between which the laser beam 10 runs freely, i.e. the laser beam 10 is not bound or coupled in a light guide, but rather the laser beam 10 runs freely in the atmosphere / air, wherein the laser beam 10 can be surrounded by a housing, preferably for protection. The first mirror 30 is fixedly positioned in the housing 3 and deflects the laser beam 10 coming from the laser 5, 6 along the y-direction of the processing table 9. The second mirror 31 is coupled to the carriage 14 and is thus moved or guided along the y-direction with the carriage 14.adjusted, with the laser beam 10 running freely between the first mirror 30 and the second mirror 31. From the second mirror 31, the laser beam 10 is deflected freely in the x-direction to the focusing unit 12, so that the focusing unit 12 can be moved in the x-direction on the carriage 14. The third mirror 32 is arranged in the focusing unit 12, which now deflects the laser beam 12 deflected by the second mirror 31 by 90° in the z-direction to the lens 28 and subsequently to the workpiece 7. This makes it possible for the carriage 14 to be moved in the y-direction and the focusing unit 12 on the carriage 14 to be moved in the x-direction, with the last mirror 32 in the focusing unit 12 deflecting the laser beam 12 towards the workpiece 7, i.e. in the z-direction, i.e.that in such laser plotters 2a, 2b the laser beam 10 always runs freely between the at least three mirrors 30-32 and not, as in welding applications, the laser beam is guided to the laser head via a fiber optic cable.

[0051] Figure 3 shows an external view of the focusing unit 12 of a laser plotter 2a in order to show the difference of the simple weight-saving design of the focusing unit 12 compared to laser welding heads known from the prior art.

[0052] It is essential that the focusing unit 12 or laser head 12 of such laser processing machines 1 is designed to be as lightweight as possible in order to achieve a very high speed of up to 4.32 m / sec and thus be able to accelerate and decelerate quickly (currently 5 g). For this reason, the focusing unit 12 should be as lightweight as possible in order to be able to move the focusing unit 12 across the processing table 9 along the x- and y-axes.

[0053] The focusing unit 12 has a base housing 33, to which a nozzle 34 is connected, in particular screwed, to. Furthermore, a lens housing 35 with a lens 28 inserted therein is inserted into a lens receptacle of the base housing 33. In order to remove or replace the lens 28 or the lens housing 35, this exemplary embodiment provides that a fastening wheel 36 is first loosened so that the lens housing 34 with the lens 28 can then be removed. For this purpose, the fastening wheel 36 is preferably rotated upwards so that the fastening wheel 36 releases the clamping of the lens housing 35 and the lens housing 35 can be pulled out of the lens receptacle. Furthermore, the base housing 33 has an opening 37 through which the laser beam 10 can pass from the second mirror 31 to the third mirror 32, which is positioned in the base housing 33 (see Figures 4 and 5).The third mirror 32 in the base housing 33 then deflects the laser beam 10 in such a way that the laser beam 10 travels in the z-direction through the inserted lens 28 to the nozzle 34 and from the nozzle 34, in which an opening 38 is provided, to the workpiece 7. The laser beam 10 is focused by the lens 28 in such a way that the optimal focal point is formed at a specific distance 39, depending on the lens 28 used, at which the best possible energy is introduced into the workpiece 7. Basically, it is mentioned that the machining table 9 is adjusted to this distance 39 manually or automatically, so that preferably the surface of the workpiece 7 is at exactly the distance 39 to the inserted lens 36, or that the distance 39 is selected to be smaller in order to achieve a greater machining depth of the laser beam 10.For example, in the illustrated embodiment, a 1.5" lens 28 is used, which requires a distance 39 of, for example, 40mm. Typically, different lenses 28 are used in laser plotters 2a, namely 1.5" or 2.0" or 2.5" or 4.0" lenses 28, so that the distance 39 is adjusted accordingly. It is also possible for the different lenses 28 to be arranged in different positions in the focusing unit 12, so that the distance 39 can then remain constant.

[0054] Some customers have found that they prefer milling the engraving material, preferably purchased from Trotec Laser GmbH, rather than laser processing it. Especially for large signs that don't require high resolution, a milling cutter is considerably faster due to its significantly higher line width of 2 mm to 10 mm than a laser beam 10 with a line width of 0.1 mm to 0.5 mm, as is the case with state-of-the-art laser plotters 2a or flatbed laser plotters 2b. The low resolution of milling is not a significant disadvantage, as the resulting signs often only need to be readable from a relatively long distance.

[0055] According to the invention, it is now provided that for the first time a laser plotter 2a or flatbed laser plotter 2b is equipped with the "wobbling" function, in which at least one mirror 30, 31 or 32 is subjected to an oscillating or fluctuating movement, so that a widening of the laser line width of, for example, up to 2 mm is achieved, ie that the laser beam 10 in the focusing unit 12 follows a sinusoidal or helical path instead of a straight path, whereby the laser beam 10, in particular the laser line width, appears optically wider.

[0056] In order to make the focusing unit 12 as light and simple to construct as possible, i.e. without heavy components, it is provided that, for example, the last mirror 32 is mounted rotatably about a rotation axis 40 and the mirror 32 is coupled or connected on the back to an actuator 41, in particular a piezo element or a piezo stack 41a or piezo stack, i.e. that the last mirror 32 has an actuator 41 which deflects the laser beam 10 parallel to the y-axis of the processing field. For this purpose, the actuator 41 is supplied with preferably pulsed and / or modulated energy via lines 42 (as shown schematically), so that the actuator 41 enlarges or expands and / or reduces orcontracts and thus adjusts the mirror 32 around the axis of rotation 40 at a defined angle 43, whereby the laser beam 10 deflected in the y-direction to the workpiece 7 is deflected in such a way that it hits the workpiece 7 offset by a width 44, as can be seen in Figure 5, i.e. the piezo or piezo stack expands when a voltage is applied (shown in solid lines in Figure 5), whereby when the polarity of the applied voltage is exchanged or reversed the piezo or piezo stack contracts (shown in dashed lines in Figure 5). When the application of energy is stopped, the actuator 41 returns to its original size and the mirror 32 is returned to its starting position, as shown in Figure 4. Thus, by applying the energy (current and voltage) alternatively, sinusoidal or circular fluctuations / deflections, i.e. wobbling, of the laser beam 10 can be achieved.This creates an optical impression of a wide laser beam or laser line width, so that when a line is executed, due to the very fast oscillating movement of the laser beam 10, a very wide machining of the material of the workpiece 7 is carried out in a line or row of the focusing unit 12 and thus the next line or row can preferably be executed with a width 44 next to it, ie that the focusing unit 12 executes the engraving line by line, wherein due to the wobbled laser beam 10 the line has a width 44.

[0057] The wobble mode can be activated or configured such that a separate color is used for the graphic 23 and / or text 23 in the software 24, allowing wobble processing to be combined with normal laser processing, since only those lines created with the corresponding color are wobbled. Alternatively or additionally, it is also possible to activate a corresponding "wobble" parameter, in particular by checking it, which then wobbles the entire text 23 and / or graphic 23. Preferably, the laser processing machine 1 remains in engraving mode (line-by-line processing), whereby an increased production increase is achieved due to the wobble and the quality of the contours is acceptable.

[0058] Furthermore, a design is possible in which the preferably last mirror 32 in front of the lens 28 is again rotatably mounted and is deflected about two axes of rotation 40 by means of two actuators 41. The deflection occurs such that the workpiece 7 is deflected along the x and y directions parallel to the x and y directions of the processing field or the processing table 9, i.e., the mirror 32 is pivoted in two directions, with an actuator 41 required for each direction. This allows a wide variety of movements of the laser beam 10, such as a sine or a trochoid, etc., to be generated, so that the quality of such wobbled lines can be improved. The amplitude or width 44 can be freely selected between 0 (operation as before - without wobbling of the laser beam 10) and, for example, 1 mm, whereby with 1 mm deflection or width 44 an optically perceivable line width of the laser beam 10 of 2 mm is achieved, ieBecause of the law of reflection, the mechanical angular deflection is only half the optical angle change. However, the perceptible line width value is usually set in the software.

[0059] For example, with a 1.5" lens 28 at a distance 39 of 40mm, an amplitude of 1mm is achieved when the mirror 32 is mechanically deflected at an angle 43 of 0.7°. However, if other lenses 28, such as 2.0", 2.5", or 4.0" lenses 28, are used, a smaller deflection is required with a longer focal length. One could also say that in order to achieve a 1 mm deflection at the target, i.e. at the workpiece 7, with a 1.5" lens 28, a mechanical deflection at the edge of the mirror 32 of 0.16 mm (with a mirror diameter of 1") or of 0.08 mm (with a mirror diameter of 0.5") is necessary. Such slight deflections of the mirror 32 can be easily achieved with actuators 41, in particular piezo elements or piezo stacks. The speed is also an important factor in controlling the actuator 41 with an appropriate frequency.For example, to achieve a speed of 100 mm / s, 200 m / s or 400 mm / s on the target or workpiece 7 with a 1.5" lens 28, a frequency of approximately 500 Hz, 1000 Hz or 2000 Hz is necessary for switching the actuator 41 on and off. At the maximum speed of the applicant's laser plotter 2a of 4320 mm / s, a frequency of 21600 Hz is required. Such actuators 41 for these frequencies are available, for example, as piezo (stack), so that an application of wobbling by means of actuators 41 is possible, ie that both the deflection in the range of 0.1 mm to 0.2 mm and the frequency of up to approximately 22000 Hz can be achieved by piezo actuators 41. Since the actuators 41 exert high forces, the force acting on the mirror 32 can be close to on the rotation axis 40 in order to achieve the same deflection angle 43 with a small deflection distance.In principle, it can be said that the frequency is freely selectable, and the actuators 41 can follow frequencies up to the tens of kHz range. When processing large, fully engraved surfaces, it is important that the frequency increases proportionally to the speed during the acceleration phases of the laser head 12. This ensures that the surface energy applied to the workpiece 7 is homogeneous and that the sine wave (wobble), for example, has the same wavelength everywhere.

[0060] Figure 6 shows an embodiment with a flatbed laser plotter 2b, in which a large sign is to be engraved as workpiece 7. The difference from the previously described laser plotter 2a is that the flatbed laser plotter 2b does not have a cover, but is equipped with a safety shield 45 that can be retracted and extended. Furthermore, the processing table 9 is permanently integrated into the housing 3, and the height is adjusted by adjusting the height of the laser plotter or the focusing unit 12. Otherwise, the flatbed laser plotter 2b essentially has the same elements / assemblies, such as the carriage 14, focusing unit 12, laser 5, control unit 13, etc., which, however, can be adapted to the circumstances.For example, an extraction system is integrated directly in the carriage 14, which is connected to the laser plotter 12, so that the smoke generated during processing is directly extracted, which is usually not the case with the other laser plotters 2a, since there the processing chamber 9 is closed with the cover 15 and thus an extraction system is integrated in the housing 3. For the sake of completeness, it should be mentioned that with the laser plotter 2a and the flatbed laser plotter 2b, the applied frequency is freely selectable and the stacks or actuators 41 can follow up to the tens of kHz range. When processing large, fully engraved surfaces, it is important that the frequency in the acceleration and braking phases of the laser head 12 increases proportionally to the speed. This ensures that the surface energy introduced on the workpiece 7 is homogeneous and the, for example,Sinusoidally wobbled laser beam 10 has the same wavelength everywhere, as is done analogously with the control of the laser power: If the laser head 12 is still slow, the laser power is also reduced so that the energy per unit length remains constant.

[0061] As in the previously described Figures 1 to 5, in the flatbed laser plotter 2b, the laser beam 10 is guided from the laser 5, 6 to the laser plotter 12 via at least three mirrors 30 to 32 (not shown), so that wobbling can also be performed here. For this purpose, a machining process with a wobbled laser beam 10 is shown, with which four lines 45a - 45d were engraved on the workpiece 7. It can be seen that, due to the wobbled laser beam 10, a line thickness of, for example, 1 mm is achieved and thus, with four engraved lines 45a - 45d, a very large area was machined, something otherwise only possible with state-of-the-art milling cutters.

[0062] Figure 7 shows another embodiment in which the last mirror 32 is no longer rotatably mounted and adjusted by an actuator 41, but in which the actuator 41 is mounted on the first or second mirror 30, 31, in particular on the first mirror 30, ie the last mirror 32 is now fixedly installed and at least one of the two further mirrors 30, 31, in particular the first mirror 30, is designed to wobble by means of actuators 41.

[0063] This ensures that the angular deflection, or angle 43, leads to a larger absolute deflection at the workpiece 7 with increasing length of the optical path (laser beam 10). For this purpose, deflection 2 and 3, i.e., mirrors 31 and 32, each double the deflection angle. The angular deflection or the angle 43 is therefore an order of magnitude smaller than when controlling the last mirror 32, whereby in this case with a 1.5" lens 28 only about 1 pm to 20 pm needs to be deflected. However, in order to achieve a homogeneous line width with the laser beam 10 in this embodiment, it is necessary for the deflection of the actuator 41 to be regulated as a function of the position of the carriage 14 and the focusing unit 12, i.e. the x and y position of the laser head 12, i.e. that the distances of the laser beam 10 between the mirrors 30 - 32 are recorded and evaluated, whereupon the deflection orThe angle 43 for the wobbled mirror 31, 32 is adjusted by appropriately adjusting the energy for the actuator 41 in order to achieve a constant line width of the laser beam 10. The essential advantage of such a solution is that this configuration does not result in an increase in the mass or weight of the focusing unit 12. Furthermore, there is sufficient space in the area of ​​the mirrors 30 and 31 in the housing 3 of the laser processing machine 1 as an extension of the focusing unit 12.

[0064] The described "wobble" system partially combines the advantages of laser plotters and galvo lasers. It can also be used specifically with large cutting plotters, such as the flatbed laser plotter 2b, to process large-area engraving jobs significantly faster than before, as it allows for significantly thicker line widths for the laser beam 10. These engraving jobs should be convertible to vectors and therefore have a lower resolution. However, to improve the resolution and / or ensure sharper contours, it is possible for each wobbled hatch area to be framed without wobble, i.e., without dynamic mirror movement. This means that the engraving area is first created with the wobbled laser beam 10 activated, and then the edge or circumference is processed again with a normal laser beam 10, creating a very precise and sharp engraving finish.This subsequent bordering can be switched on or off, for example, in the software 24 by activating or checking a parameter.

[0065] It is mentioned that several mirrors 30, 31, 32 can also be rotatably mounted and connected to actuators 41 in order to jointly generate a wobbled laser beam 10.

[0066] Figure 8 shows a further embodiment of a laser processing machine 1, in which a laser 5, 6 in the form of a solid-state laser or diode laser is arranged instead of the first mirror 30. The other mirrors 31, 32, in particular the second mirror 31, which is adjusted with the carriage 14, and the third mirror 32, which is arranged in the focusing unit 12 and adjusted with it, are still present. This ensures that the laser beam 10 is sent directly from the laser 5, 6 to the second mirror 31, with the laser beam 10 being sent from the second mirror 31 to the third mirror 32. The third mirror 32 deflects the laser beam 10 in the direction of the lens 28 and the workpiece 7. Thus, the mirrors 31 and 32 are available for wobbling, wherein at least one mirror 32 or 31 is mounted rotatably and is coupled to an actuator 41, in particular a piezo element.

[0067] Furthermore, Figure 9 shows a schematic embodiment of an application of engraving on a workpiece 7, wherein three wobbled lines 47, 48, and 49 are shown. The lines 47, 48, 49 have a wobbled width 44 of, for example, four normal individual lines 50a-d, as indicated by dashed lines, meaning that with one wobbled line 47, 48, 49, the laser head 12 must normally execute four lines.

[0068] In the first line 47, a full-surface engraving was created, so that the laser 5, 6 is constantly activated, in particular in a pulsed manner, and the engraving was created across the entire wobbled width 44 of the laser beam 10 through a sinusoidal waveform by wobbling at least one mirror 30-32. In the second and third lines 48, 49, no full-surface engraving was performed, but the laser 5, 6 was only activated selectively so that a line 51 was engraved, i.e., although the mirror 30-32 was wobbled, the laser 5, 6 was only activated at specific times to engrave the drawn line 51. This ensures that the laser head 12 creates a line 51 across the four individual lines 50a-d in one work step (arrow), i.e., in a line 48 or 49, so that it can be said that the working speed of such an engraving is significantly increased due to the wobbling.The disadvantage here is that increased demands are placed on the real-time control of the xy position of the focusing unit as well as on the piezo deflection(s).

[0069] Figure 10 schematically shows how and when the laser 5, 6 is activated and how the mirror 30-32 is positioned to engrave a preferably straight line 51. In this case, wobbling is again activated, so that the laser beam 10 can extend over a width 44 when activated. Points 52a-d are schematically plotted in each individual line 50a-d, which, for example, correspond to 4 individual lines without wobbling. At the first point 52a, the mirror 30-32 is positioned over the actuator(s) 41 in such a way that it deflects the laser beam 10 to the right, i.e., forwards. Subsequently, at point 52b, the mirror 30-32 is in its original position and the laser beam 10 travels straight downwards. The mirror 30-32 is then adjusted to the left, i.e., trailing, in order to deflect the laser beam 10 to the left at the two points 52c and 52d.By precisely controlling the mirrors 30-32 via the actuator(s) 41 and activating the laser 5, 6, it is possible to generate a line 51 with a wobbled laser beam 10. This is possible because the control unit 13 can control the individual components so quickly, i.e., the control technology controls one or two actuators 41, particularly piezos, in addition to the x- and y-motors for the carriage 14 and the focusing unit 12, and the laser 5, 6 is activated in a synchronized manner.

[0070] In principle, a piezoelectric sensor behaves like a single-axis galvo, although the working field is significantly smaller than with a conventional galvo deflection. However, the dynamics are much higher, and the manufacturing costs and, above all, the weight are much lower with a piezo (actuator)-controlled mirror (30, 31, 32) than with a galvo system. A mirror control with two piezoelectric or actuator mirrors corresponds to a 2-axis galvo system with a smaller working field. The small working field is conveyed across the entire processing area by the standard laser plotter (2a) or flatbed laser plotter (2b).

[0071] It should be noted that the drawings shown are merely schematic examples for the simplified description of the invention.

[0072] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure of the laser processing machine 1 and its components or parts, some of the figures are not to scale and / or enlarged and / or reduced in size and, above all, are only shown schematically.

[0073] Furthermore, individual features or combinations of features from the different embodiments shown and described can also form independent, inventive or inventive solutions.

Claims

P a t e n t a n s p r ü c h e :

1. Laser processing machine (1), in particular a laser plotter (2a) or flatbed laser plotter (2b), for processing at least one job (18) for cutting, engraving, marking and / or inscribing a preferably flat workpiece (7), which forms at least one housing (3) with a processing space (8) for positioning a workpiece (7) on a processing table (9), said housing having at least one radiation source (4) in the form of a laser (5, 6) and a control unit (13) for controlling the carriage (14) which is adjustable along a y-axis and is preferably operated by a belt drive, with a focusing unit (12) or laser head (12) which is arranged displaceably thereon and is adjustable in the x-axis, wherein a plurality of built-in mirrors (30, 31, 32) are arranged for guiding a freely running laser beam (10) from the laser (5, 6) to the workpiece (7), characterized in that in order to form an increased amplitude orWidth (44) of the laser beam (10), i.e. for the so-called "wobbling" of the laser beam (10), in the focusing unit (12) the last mirror (32) for deflecting the laser beam (10) in the direction of the lens (28) and / or a preceding mirror (30, 31) for deflecting the laser beam (10) in the direction of the focusing unit (12) is rotatably mounted and is connected to at least one actuator (41), in particular a piezo element or a piezo stack, so that the mirror (30, 31, 32) can be adjusted mechanically, in particular a mechanical deflection, by applying energy to the actuator (41).

2. Laser processing machine according to claim 1, characterized in that the mirror (30, 31, 32) is mounted at least twice over two axes of rotation (40) and is connected to two or more actuators (41) for achieving different functions or movement sequences for the wobbled laser beam (10), such as sine or trochoid, etc.

3. Laser processing machine according to claim 1 or 2, characterized in that in the focusing unit (12) the deflection or an angle (43) of the last mirror (32) is formed by the actuator (41) in the y-direction.

4. Laser processing machine according to one of the preceding claims, characterized in that the deflection of the actuators, in particular the width (44) of the laser beam (10), is adjustable as a function of the x and y positions of the focusing unit (12).

5. Laser processing machine according to one of the preceding claims, characterized in that by entering a parameter, in particular in the software (24), the amplitude, in particular the deflection or width (44), of the laser beam (10) or laser spot can be freely adjusted.

6. Laser processing machine according to one of the preceding claims, characterized in that the frequency of the wobbled mirror (30-32) is freely selectable and the actuators (41) follow up to the tens of kHz range.

7. Laser processing machine according to one of the preceding claims, characterized in that the actuator (41) or the actuators (41) are designed for adapted control depending on the lens (28) used or set, in particular 1.5" or 2.0" or 2.5" or 4.0" lenses (28), in order to achieve a preset amplitude or width (44).

8. Laser processing machine according to one of the preceding claims, characterized in that the laser beam (10) is arranged or designed to run freely between at least three mirrors (30 to 32), the first mirror (30) being positioned in the housing (3) and deflecting the laser beam (10) coming from the laser (5, 6) along the y-direction of the processing table (9) in the direction of the second slide (31), the second mirror (31) being coupled to the slide (14) and the latter thus being adjustable along the y-direction with the slide (14), the third mirror (32) being arranged in the focusing unit (12) so that the laser beam (10) can be deflected by the second mirror (31) in the x-direction to the third mirror (32) in the focusing unit (12).

9. Laser processing machine according to one of the preceding claims, characterized in that the laser beam (10) is arranged or designed to run freely between two mirrors (30 to 32), wherein a laser (5, 6), in particular a diode laser, is positioned in the housing (3) in such a way that it directs the laser beam (10) along the y-direction of the processing table (9) in the direction of the first mirror (31). emits, wherein the first mirror (31) is coupled to the carriage (14) and the carriage (14) is thus adjustable along the y-direction with the carriage (14), wherein the second mirror (32) is arranged in the focusing unit (12) so that the laser beam (10) can be deflected by the first mirror (31) in the x-direction to the second mirror (32) in the focusing unit (12).

10. Method for operating a laser processing machine, in particular a laser plotter (2a) or a flatbed laser plotter (2b), for processing at least one job (18) for cutting, engraving, marking and / or inscribing a preferably flat workpiece (7), in which at least one beam source (4) in the form of a laser (5, 6) is used in a housing (3) of the laser processing machine (1), which beam source acts on the workpiece (7) to be processed, the workpiece (7) being deposited in a defined manner in a processing space (5) and a laser beam (10) emitted by the beam source (4) being sent via deflection elements or mirrors (30, 31, 32) to a focusing unit (12) or laser head (12), from which the laser beam (10) is directed in the direction of the workpiece (7) via deflection elements or mirrors.Mirrors (32) and focused for processing, wherein a control unit (13), in particular the position control to the workpiece (7), is carried out by running software, so that the workpiece (7) is preferably processed line by line by adjusting a carriage (14) via preferably a belt drive in the xy direction, characterized in that in order to form an increased amplitude or width (44) of the laser beam (10), i.e. for the so-called "wobbling" of the laser beam (10), in the focusing unit (12) the last mirror (32) for deflecting the laser beam (10) in the direction of the lens (28) and / or a preceding mirror (30, 31) for deflecting the laser beam (10) in the direction of the focusing unit (12) is rotatably mounted and is connected to at least one actuator (41), in particular a piezo element or a piezo stack orPiezo stack, so that the mirror (30,31,32) is adjusted mechanically, in particular a mechanical deflection, by applying energy to the actuator (41) via the actuator (41). 11 .Method according to claim 1 , characterized in that by applying pulsed and / or modulated energy, in particular current, to the actuator(s) (41) and voltage, the mirror (30,31,32) is subjected to an oscillating or fluctuating movement.

12. Method according to claim 1 or 2, characterized in that the mirror (30, 31, 32) is adjusted about the axis of rotation (40) at a defined angle (43) by the actuator (41).

13. Method according to one of the preceding claims, characterized in that the deflection of the preferably last mirror (30, 31, 32) about an axis of rotation (40) is carried out by the actuator (41) in the y-direction.

14. Method according to one or more of the preceding claims, characterized in that the deflection of the mirror (30, 31, 32) about two axes of rotation (40) is carried out with two actuators (41) in the x and y directions.

15. Method according to one or more of the preceding claims, characterized in that the control of the actuator (41) or the actuators (41) is carried out differently depending on the lens (28) used or set, in particular 1.5" or 2.0" or 2.5" or 4.0" lenses (28), in order to achieve a preset amplitude or width (44).

16. Method according to one or more of the preceding claims, characterized in that the laser beam (10) runs freely between the at least three mirrors (30 to 32), the first mirror (30) being positioned in the housing (3) and deflecting the laser beam (10) coming from the laser (5, 6) along the y-direction of the machining table (9) in the direction of the second play (31), whereupon the second mirror (31), which is coupled to the slide (14) and is adjusted with it, deflects the laser beam (10) in the x-direction to the third mirror (32) in the focusing unit (12), and in that the third mirror (32) deflects the laser beam (10) in the z-direction to the lens (28).

17. Method according to one or more of the preceding claims, characterized in that the laser beam (10) runs freely between the at least two mirrors (30 to 32), wherein a laser (5, 6) is positioned in the housing (3) and the laser beam (10) is emitted by the laser (5, 6) along the y-direction of the machining table (9) in the direction of the first mirror (31), whereupon the first Mirror (31), which is coupled to the carriage (14) and is adjusted with it, deflects the laser beam (10) in the x-direction to the second mirror (32) in the focusing unit (12), and that the second mirror (32) deflects the laser beam (10) in the z-direction to the lens (28).

18. Method according to one or more of the preceding claims, characterized in that when the first or second mirror (30, 31) is wobbled, the distances of the laser beam (10) between the mirrors (30, 31, 32) are detected and evaluated, whereupon the deflection or the angle (43) for the wobbled mirror (30, 31, 32) is adjusted by appropriately adjusting the energy for the actuator (41) in order to achieve a constant line thickness, in particular width (44), of the laser beam (10).

19. Method according to one or more of the preceding claims, characterized in that a wobbled surface, in particular an engraving surface, is outlined with a laser beam (10).

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