EP3883721A1

EP3883721A1 - Method for the lacquer-removing laser machining of a painted workpiece

Info

Publication number: EP3883721A1
Application number: EP19809042.5A
Authority: EP
Inventors: Thomas LACOUR
Original assignee: Marelli Automotive Lighting Reutlingen Germany GmbH
Current assignee: Marelli Automotive Lighting Reutlingen Germany GmbH
Priority date: 2018-11-21
Filing date: 2019-11-21
Publication date: 2021-09-29
Also published as: CN113286678A; US20220009037A1; DE102018129329A1; WO2020104599A1

Abstract

The invention relates to a method for the material-removing laser machining of a workpiece (10), comprising a substrate element (14) made from a plastic with a surface (16), and a lacquer coating (18) applied to the surface (16) prior to the laser machining, wherein the lacquer coating (18) can be removed from a workpiece (10) with a three-dimensional extent in a large-area region of the surface (16).

Description

Process for color-removing laser processing of a painted workpiece

description

The invention relates to a method for color-removing laser processing of a painted workpiece, the carrier element made of a plastic with a

Surface and a color lacquer layer applied to the surface in advance of the laser processing. Laser processing is carried out using a

Laser processing device executed the one

Includes laser unit and a control unit for controlling the laser unit. The process includes:

- Arranging the painted workpiece in one

Processing position in a work area of the

Laser unit, - Generation of values for operating parameters for

Operating the laser unit,

- Generation and emission of a laser beam according to the

generated values for the operating parameters by the laser unit,

- Applying in the processing position

arranged lacquered workpiece with the emitted laser beam in a processing point in the area of the surface of the lacquered workpiece provided with the color lacquer layer, so that material of the color lacquer layer is removed locally in the processing point,

- Moving the laser beam and thus the

Processing point according to the generated values for the operating parameters by the laser unit relative to the painted workpiece along a work path in the

Area of the color varnish layer

Surface of the painted workpiece, so that along the working path material of the paint layer

is removed.

The invention further relates to a

Laser processing apparatus according to the preamble of claim 11 and a computer program according to the preamble of claim 16. The plastic of the carrier element can be transparent. It should also be laser-resistant (without reflections). A general material-removing laser processing of a

Workpiece is also called laser ablation or laser evaporation. It is shot at with one

Material coated surface with pulsed

Laser radiation material removed from the surface. The laser radiation used here is high

Power density and leads to a rapid heating of the material and the formation of a plasma on the

Surface. In the case of laser pulses in the nanosecond range, the energy of the laser heats up the surface (in the sense of thermal movements of the atoms) during the laser pulse. Because heat conduction is slow

The energy transport in volume is made possible

radiated energy on a very thin layer

concentrated (approx. 1 ym at 10 ns pulse length), therefore the material irradiated with the laser reaches very high

Temperatures, and the material suddenly evaporates. Through ionization (thermal, through the

Laser light or electron impact) occurs at high

Power density of the laser is a plasma of electrons and ions of the removed material.

In the context of the present invention, the painted workpiece from which the paint is to be removed comprises a carrier element made of a plastic with a surface and one on the surface prior to laser processing applied paint varnish. The plastic of the

The carrier element is preferably transparent.

The workpiece is, for example, a painted decorative element or a painted decorative panel for a motor vehicle lighting device. The interior of a headlight is, for example, lined with such trim panels (e.g. around a projection lens of a PES module or around a reflector edge of a reflection module), usually around the one behind it

Shield the unsightly mechanics and electrics of the headlamp from outside through the transparent cover panel. For various reasons, for example design aspects, it may be desirable to restore the transparency of the carrier element at least in selected areas. It would be conceivable, for example, to arrange a motor vehicle lamp behind a transparent section of the painted decorative panel, which is then replaced by the

transparent section of the painted decorative panel emits light to implement a luminaire function. It would also be easily conceivable that behind the painted

Decorative panel is positioned a light source that illuminates the area behind the painted decorative panel, so that the transparent sections of the painted decorative panel to implement a special night design

Lighting device shine. A method is already known from US Pat. No. 5,817,243 in order to remove material from various workpieces (for example metal, plastic or leather) and thereby into the

Surface of the plastic part as possible

to bring in a contrasting design or pattern. If the workpiece is a coated workpiece and part of the laser removal

Coating is removed, this is only in

Connection described for a coated metal part. If the workpiece is a transparent one

Workpiece (e.g. a cover plate of a

Motorbike headlights), it is only described that a pattern can be introduced into the transparent material of the workpiece by means of the laser. Furthermore, it is described in various places that the method has a particularly detailed, filigree pattern on the

Should produce workpiece.

The known method is therefore unsuitable for covering larger areas of a transparent plastic part provided with a color lacquer layer

Remove paint layer. In addition, the method described is not suitable for plastic parts that have a complex, three-dimensional shape.

The present invention is therefore based on the object

Reason, a process of the type mentioned to design and further develop that even with a complex three-dimensional painted

Plastic part of the paint layer material can be removed over a large area.

The invention proposes to solve this problem

Method with the features of claim 1.

In particular, it is proposed that the

Processing point at which the laser beam falls on the surface of the painted plastic part to be processed, along several adjacent ones

Working paths are moved back and forth, whereby neighboring working paths are so close together that a

Processing point of the laser beam on a work path to a processing point of the laser beam on a

Adjacent to or partially overlying the adjacent work path in order to remove material of the paint layer over a large area. Furthermore, the laser unit according to the

generated values for the operating parameters moved to change the position of the machining point and a

to follow the three-dimensional course of the surface provided with the colored lacquer layer when driving off the work paths.

The processing point of the laser beam is along

several meandering work paths lying next to each other, so that they are in the desired areas on the surface of the workpiece material of the paint layer can be removed over a large area. An angle at which the laser beam strikes the surface of the workpiece is preferably kept constant or small during the

Machining point of the laser beam the meandering

Work lanes leaves. With one in a global

Coordinate system considered three-dimensional course of the surface is a constant adaptation of the

Beam direction in a global coordinate system

required. The variation of the direction of the laser beam can be achieved in that the laser unit

has suitable deflection means (for example adjustable deflection mirrors) so that the direction of exit of the laser beam from the laser unit can be varied. But it is also conceivable that the position and orientation of the whole

Laser unit is varied, the direction of exit of the laser beam from the laser unit remains constant. The position and orientation of the laser unit follow the three-dimensional course of the surface provided with the colored lacquer layer, so that the laser beam always hits the surface at a constant angle. By using a scanner, the angle varies slightly.

It is conceivable that either the entire

Laser unit or only part of the laser unit is moved. In particular, it is conceivable that part of the

Laser unit, which comprises a laser medium and a resonator, is not moved. Moving the laser unit or a part thereof in particular comprises a linear method in an X, Y and / or Z direction. Furthermore, the movement of the laser unit or a part thereof can also include rotation about one or more of the named X, Y and / or Z axes.

The entire laser unit is preferably moved in position and orientation, following the complex one

three-dimensional course of the surface of the workpiece. The laser unit is moved depending on the generated values for the operating parameters for operating the laser unit. The operating parameters therefore include, for example, a position (X, Y, Z), a

Alignment and an adjustment speed of

Laser unit. Furthermore, the operating parameters

in particular comprise a pulse duration, a pulse frequency and a power of the laser beam or the laser unit. In particular, it is conceivable that the pulse duration, pulse frequency and power of the laser unit are set to constant values during the actual laser processing.

The power, pulse duration and pulse frequency must be set as precisely as possible so that the paint layer is as complete as possible in the desired layer thickness

is removed without damaging the carrier layer. In particular, the incomplete transparency of the carrier layer should not be impaired by the incident laser beam. The method according to the invention thus enables large-scale and precise material removal by the

Laser unit follows a three-dimensional course of the surface of the workpiece provided with the colored lacquer layer when driving along the meandering work paths.

A preferred embodiment is characterized in that the values for the operating parameters for operating the laser unit are generated and the laser unit is moved in accordance with the generated values for the operating parameters such that an angle of the laser beam in the

Machining point remains constant relative to the surface of the workpiece provided with the colored lacquer layer during the traversing of the work paths.

In an advantageous development of the invention, the

Processing point of the laser beam on the with the

Colored paint provided surface of the plastic part moved by actuators. The actuators can be designed to move the laser unit or only part of it. The entire laser unit generating the laser beam is preferably moved by means of the actuators. However, it can prove to be advantageous if only a part of the laser unit is moved by the actuators in order to change the position of the processing point. The laser unit includes, for example, suitable deflection means (for example adjustable deflection mirrors) which are moved by means of the actuators, so that the direction of exit of the laser beam from the Laser unit can be varied. The actuators are, for example, electromagnetic actuators which are designed to move the laser unit or part of the laser unit in the X, Y, Z direction and / or to one of the axes (X, Y, Z) mentioned. to turn.

The actuators are advantageously used to move the

Laser unit or a part thereof controlled by the control unit. The control takes place in particular according to the generated values for operating parameters for operating the laser unit. In particular, the control takes place according to generated values for the position (X, Y, Z)

Alignment and the adjustment speed.

In the sense of the present invention, the generation of values for the operating parameters includes both the generation of the values immediately before or during laser processing and the simple reading in of previously stored values. The values for the

Operating parameters of the laser unit immediately before or during laser processing, for example

Control loops generated. It is conceivable that the values for the operating parameters are generated automatically by the control unit, for example on the basis of sensor signals which provide information about the exact three-dimensional course of the surface. In a further advantageous embodiment of the

According to the invention, the values for the operating parameters of the laser unit are generated immediately before or during the actual laser processing in that values for the operating parameters for the respective special one that are generated and stored in time before the laser processing

Use case to be loaded into the control unit.

The values for the

Operating parameters depending on data of the workpiece (e.g. material of the support element and the

Color lacquer layer, thickness of the support element and the

Paint layer) generated. The data of the workpiece are, for example, manually created by a user

entered. Alternatively or in addition to this, it is also conceivable that the data of the workpiece are transferred to the control unit in the form of electronically stored values. In particular, data for

Various workpieces are saved and the data for the workpiece to be machined is selected and saved in the

Control unit loaded so that the laser unit is operated in this way depending on the data of the workpiece.

The values for the

Operating parameters depending on information about the three-dimensional shape of the workpiece and / or about the Processing position of the workpiece and / or information about an area of the paint layer to be removed and / or about the composition and / or thickness of the

Color lacquer layer and / or generated via material of the carrier element. Depending on the not final

enumerated information about the workpiece, the laser unit is operated adapted to the workpiece to be machined.

In an advantageous development of the method, it has proven to be advantageous that the processing position, in particular a position and / or orientation of the

Workpiece, detected by means of a sensor element and the values for the operating parameters are generated as a function of the detected position and / or orientation. Preferably, the laser unit is in this way

Depends on the position and / or orientation of the workpiece detected by the sensor element. In particular, the sensor element can be used to determine whether the workpiece is in the machining position and in the event that the workpiece is in the

Processing position, the laser unit for

Sending a laser beam can be controlled. In addition, the sensor element can be used, for example, to detect a distance from the workpiece to the laser unit and the

Power of the laser unit to be adjusted to the detected distance to the workpiece. The sensor element comprises, for example, an optical sensor, in particular one Camera or a light barrier, or a tactile sensor touch sensor. This can, for example, at the

Machining position be arranged and detect the position and orientation of the workpiece.

The laser unit is advantageously controlled as a function of a computer program that can be executed on the control unit. The computer program is programmed so that the control unit executes or controls the method according to the invention when the computer program is executed on the control unit. In this way, at least the actual laser machining of the workpiece can be automated in the context of the method according to the invention. Furthermore, it is conceivable that the generation of operating parameters takes place automatically as part of the processing of the computer program.

Another solution to the problem is a

Laser processing device for material-removing laser processing of a workpiece, which has a carrier element made of a plastic with a surface and one prior to laser processing on the surface

applied applied paint layer, proposed, wherein the laser processing device, a laser unit for generating and emitting a laser beam and a

Control unit for controlling the laser unit comprises, and the laser processing device has means for executing a method according to the invention.

The control unit advantageously comprises one

Computing unit and a computer program executable on the computing unit. The computer program is preferably programmed to enable the control unit to control the laser unit. Furthermore, that is

Computer program preferably programmed one

to enable automated execution of the method according to the invention.

The control unit is advantageously designed to generate values for operating parameters of the laser unit. The values are preferably generated in

Dependency on data of the workpiece to be machined.

The laser processing device advantageously comprises actuators for positioning and / or aligning and / or moving the laser unit. In particular, the

Actuators move the laser unit in the X, Y, Z direction and / or rotate the laser unit around one of the

mentioned axes (X, Y, Z). The laser processing device advantageously comprises at least one sensor element for detecting a position and / or orientation of the workpiece.

As yet another solution to the problem, one will

Computer program is proposed, which is programmed to execute the inventive method when it runs on a computing unit that belongs to a control unit of a laser processing device that is used for material-removing laser processing.

Further features and advantages of the invention result from the following description, in which preferred embodiments of the invention are explained in more detail with reference to the drawings. Show:

Fig. 1 an inventive

Laser processing device;

Fig. 2 is a schematic view of one in FIG

Laser processing device of Figure 1 arranged workpiece;

Fig. 3 shows a schematically illustrated sequence of a

method according to the invention;

Fig. 4 shows a schematically illustrated further process of the method according to the invention;

Fig. 5 shows a sectional view of a workpiece intended for laser processing;

Fig. 6 shows a plan view of a workpiece, and FIG. 7 shows a view of a machined workpiece.

Figure 1 shows a laser processing device for

Material-removing laser processing of a workpiece. The laser processing device is designated in its entirety by reference number 2. The

Laser processing device 2 comprises a laser unit 4 and a control unit 6 for controlling the laser unit 4. The laser unit 4 consists of a laser light source, a 2D scanner unit and a focusing unit and is designed to generate a laser beam and

send out.

In principle, the laser unit 4 can be used to generate

Laser beams include, for example, a semiconductor laser, gas laser or solid-state laser. It preferably comprises a solid-state laser. The solid-state laser is not shown separately. For example, the solid-state laser is a fiber laser.

In a fiber laser, laser radiation is guided through a fiber with a doped fiber core and at one

Resonator reinforced. Fiber lasers are generally optically pumped in that radiation from lasers, in particular diode lasers, is coupled in parallel to the fiber core in its jacket or in the fiber core itself. Known doping elements for the laser-active fiber core are erbium, ytterbium and neodymium. After emerging from the active fiber, the laser beam usually arrives in a glass fiber or in a light guide cable containing such, the glass fiber guiding the radiation, for example, to an optical element for focusing the laser beam.

The optical element is also not shown in the present invention, but it is preferably arranged in the laser unit 4. The optical element is, for example, a lens. According to the illustrated embodiment, therefore, emerges from the

Laser unit 4 a bundled laser beam.

In a work area 8 of the laser unit 4 is a

Workpiece 10 arranged in a machining position 12. The workpiece 10 can for example be manually in the

Processing position 12 can be arranged. In the context of an automated sequence of the method, however, it is also conceivable to move the workpiece 10 into the machining position 12 by means of a pick-and-place robot and to place it there in a desired position and orientation.

The workpiece 10 to be machined in the context of the present invention is shown in section in FIG. 5 and comprises a carrier element 14 made of a transparent plastic with a surface 16 and one on the surface 16

applied paint layer 18. The carrier element 14 but could also consist of a non-transparent plastic. Within the scope of the invention, the

Color lacquer layer in relatively large areas can be removed from the workpiece 10 by means of laser processing. Damage or impairment of the transparency of the carrier element 14 is to be prevented. In addition, the workpiece 10 has a relatively complex at least in the area of the surface 16 to be machined

three-dimensional shape. The workpiece 10 arranged at the machining position 12 is moved with one of the

Laser unit 4 generated and emitted laser beam 20 is applied. The area of the laser beam 20 which strikes the surface provided with the color lacquer layer 18 is referred to as the processing point 22. To the

Processing point 22 is based on one of the

Energy of the laser beam 20 caused heat development locally material of the paint layer 18 of the workpiece 10 removed. In particular, the color lacquer layer 18 is heated abruptly in the processing point 22, so that the material of the color lacquer layer 18 evaporates in the processing point 22. In order to increase the absorption of the laser beam, the color lacquer layer can be provided with an appropriate additive.

To in a desired large area of the

Removing paint layer 18 material, the

Machining point 22 moves along a working path 24 (see FIG. 2). The processing point 22 is moved by moving an impact point of the laser beam 20 on the surface 16. For this purpose, the Laser processing device 2, preferably actuators 26, by means of which the laser unit 4 is aligned and / or moved. The laser unit is moved linearly in particular in the X, Y or Z direction. Alternatively or

it is also conceivable for the laser unit to be rotated about one of the axes (X, Y, Z) mentioned.

The actuators 26 are controlled by the control unit 6

controlled. This is indicated by the dashed line 28. The control can take place, for example, via one or more data lines (not shown) or a radio link between the control unit 6 and the actuators 26. By controlling the actuators 26 with

suitable control commands or signals by the

Control unit 6, the laser unit 4 becomes like this

aligned and moved that the laser beam 20 and thus also the processing point 22 along the desired

Working path 24 is moved.

It is conceivable that both the entire laser unit 4 or only part of the laser unit 4 is aligned and moved. If only part of the laser unit 4 is moved, the laser unit includes suitable ones, for example

Deflection means (for example adjustable deflection mirrors) so that the direction of exit of the laser beam from the laser unit can be varied. The deflection means can be aligned and / or moved by means of the actuators 26. Moving and / or aligning the deflection means can in particular comprise a linear movement in the X, Y, or Z direction. Alternatively or additionally, it is conceivable that the Deflection means can be rotated around one of the axes (X, Y, Z) mentioned.

Laser processing systems of the type described here preferably have a displacement unit which has two or three degrees of translational freedom. The displacement unit can also have at least one degree of freedom of rotation. Here the workpiece or parts of the

Move the system or both. Furthermore, the system preferably has deflection means for the laser beam,

for example a 2D scan unit. An optical focusing unit is coupled to this scanning unit, which optically adjusts the distance between the

Focusing unit and the workpiece allowed. The

Shift unit now performs slow movements while the scan unit executes fast movements.

The system brings the workpiece into a defined one

Position. In this position, those areas are processed that are in the working area of the scanning unit with the focusing unit. When this area has been machined, the workpiece is moved to a next position and machining continues. The laser is switched off during the change of positions.

Alternatively, the displacement unit can be a continuous or quasi-continuous movement along one

one-dimensional line (straight line or curve), and the scanning unit moves the laser beam perpendicular to Movement generated by the displacement unit. The component is shifted in one step by the width of a strip that the laser generates. This removes material along a strip. The laser remains switched on while the system is moving. Due to the 3D contour of the component is a 2D scan unit

required around the geometric deviations

to compensate for that by projecting the geometry onto the component.

Furthermore, the laser unit 4 is controlled by the control unit 6 as part of the laser processing, so that it emits a desired laser beam 20. In particular, the power, pulse duration and pulse frequency of the laser beam 20 can be predetermined by suitable control. This control of the laser unit 4 by the control unit 6 is shown in FIG. 1 by the dashed line 30

identified. The connection between control unit 6 and laser unit 4 can be made, for example, by means of one or more data lines (not shown) or one

Radio connection (not shown) can be realized.

For this purpose, the control of the

Actuators 26 and the laser unit 4 transmit control signals to the actuators 26 and laser unit 4 by the control unit 6. These signals are particularly dependent on values for operating parameters for operating the laser unit. The operating parameters include, for example, a position (X, Y, Z), an angle of rotation, a speed at which the processing point 22 is moved over the surface 16 along the working path 24, one pulse duration, one

Pulse frequency and / or a power of the laser unit.

The values for the operating parameters can, for example, be generated by the control unit 6 itself by transferring data of the workpiece 10 to the control unit and the control unit accessing a database in which operating parameters associated with the data are stored. The data of the workpiece 10, which are transferred to the control unit 6, include, for example, information about the workpiece 10 to be machined (shape of the workpiece 10, for example as data from a CAD model, material and / or thickness of the paint layer 18, material of the

Carrier element 14), information about the

Processing position 12 of the workpiece 10, information about a region of the paint layer to be removed. The control unit 6 is connected, for example, to an operating unit (not shown). This data can be entered by a user via the control unit. Alternatively or additionally, this data can be transferred to the control unit via an electronic memory interface.

Furthermore, the values for the operating parameters can be transferred to the control unit 6, for example by loading values that have already been generated and stored before the actual laser processing. In particular, a set of operating parameters can be generated for each workpiece 10 to be machined and transferred to the control unit 6. The Operating parameters are determined, for example, by means of a computing unit based on data about the workpiece to be processed (shape of the workpiece 10, material and / or thickness of the paint layer 18, material of the carrier element 14, information about the processing position 12 of the

Workpiece 10, information about a region of the paint layer to be removed) generated. It is also conceivable that the operating parameters are based on

Expertise and experience in the field of

Laser processing can be generated. Passing the

Operating parameters take place, for example, via a

Control unit or via an electronic

Memory interface.

According to the exemplary embodiment shown in FIG. 1, the laser processing device 2 comprises

Sensor element 32. Sensor element 32 is designed, for example, to detect a position and / or an orientation of workpiece 10 arranged in work area 8. The sensor element 32 is, for example

Contact or touch sensor or a camera. A

Touch sensor could be arranged in the machining position 12 and detect the position and / or orientation of the workpiece 10 in the work area 8. For example, a camera could be at a distance from and above the

Work area 8 can be arranged and optically capture the workpiece 10. The position and / or orientation of the workpiece 10 can be determined by evaluating the camera signals. The sensor element 32 can then preferably be used to determine whether and how the workpiece 10 is attached the processing position 12 is arranged and aligned. The sensor element 32 acquires data on the position and / or the orientation of the workpiece 10 and transmits this to the control unit 6. The data transmission between the sensor element 32 and the control unit 6 is done with a

Dashed line 34 shown.

The control unit 6 comprises a computing unit 36 and a memory element 37, on which a computer program 38 is stored, which can be executed on the computing unit 36. The laser unit 4 and the actuators 26 are controlled as a function of the computer program 38.

Figure 2 shows a plan view of the one to be machined

Surface 16 of the workpiece 10. The paint layer 18 is applied to the surface 16. The processing point 22 is shown as an example, in which the laser beam 20 first strikes the workpiece 10 after the

Workpiece 10 was arranged in the machining position 12. Furthermore, an area 40 is shown as an example on the

Surface 16 of the workpiece 10 is drawn, in which the paint layer 18 has already been removed.

In addition, the paint layer 18 is now to be removed in an area 40 'on the surface 16 of the workpiece 10. As already described, the processing point 22 is moved along the working path 24. To cover large areas

To remove material of the paint layer 18, the processing point 22 is alongside one another

lying working tracks 24, 24 ', 24'',24''' moves. The working tracks 24, 24 ', 24'',24''' are so close side by side that a processing point 22 'of the

Laser beam 20 on a first working path 24 ′ adjoins the processing point 22 of the laser beam on the neighboring working path 24 or partially overlays it. The working tracks 24, 24 ', 24' ', 24' '' are selected such that a desired area 40, 40 'of the paint layer 18 is removed over a large area. The laser beam 20 is moved along the working paths 24, 24 ', 24' ', 24' '' by generating the values for the operating parameters for operating the laser unit and control signals for controlling the actuators as a function of the values of the operating parameters.

FIGS. 3 and 4 each represent a flow chart of the method according to the invention for material removal

Laser processing is shown schematically. According to FIG. 3, in a first step 50, the workpiece 10 is on a

Processing position 12 arranged in a processing area 8 of the laser unit 4. In a second step 52, values for operating parameters for operating the

Laser unit generated.

In a third step 54, the laser unit 4 emits a laser beam 20 as a function of that in the second

Step 52 generated values for the operating parameters generated and sent. In a fourth step 56, the workpiece 10 arranged at the machining position 12 is emitted at a machining point 22

Laser beam 20 is applied. This loading causes local material removal in the processing point 22. In a fifth step 58, the laser beam 20 and thus also the processing point 22 are moved according to the generated values along the working paths 24, 24 ', 24''and24''', so that a desired area 40 'of the

Color lacquer layer 18 is removed over a large area.

It should be noted here that steps 54 to 58 in particular can be carried out sequentially or simultaneously. Furthermore, step 52, which comprises the generation of values for operating parameters for operating the laser unit, can be carried out before or at the same time as the first step 50, which arranges the workpiece 10 at the machining position 12.

In Figure 4 is an example of a sequence of

The method according to the invention is shown, in which after step 50, which includes arranging the workpiece 10 in the machining position 12, in a step 60, the position and orientation of the workpiece 10 are recorded. Based on the detected position and orientation of the workpiece 10 by the sensor element 32, values for operating parameters for operating the laser unit and control signals for controlling the actuators are then in a step 62 dependent on the values of the

Operating parameters generated. The steps 54, 56, 58 already mentioned are then carried out. FIG. 5 shows a sectional view through an example of the workpiece 10 to be machined within the scope of the invention. The workpiece 10 comprises the carrier element 14 made of a transparent plastic with the surface 16 and on the surface 16 applied paint layer 18.

Areas 40 ′ are drawn in by way of example, in which the paint layer 18 is to be removed. The complex three-dimensional structure of the workpiece 10 can be clearly seen in FIG.

FIG. 6 shows another example of a workpiece 10 in its entirety. The three-dimensional shape is also clearly visible here. Figure 7 shows a section of the

Workpiece 10 from FIG. 6, in which areas 40 are applied to the surface 16 of the workpiece

Paint layer 18 was removed. The workpiece 10 in FIG. 7 is backlit by a light source. It can be clearly seen that regions of the surface 16 where the paint layer 18 is still present appear dark. In contrast, areas 40 appear where the

Color lacquer layer 18 was removed over a large area by the method according to the invention, brightly shining.

Claims

Expectations

1. A method for material-removing laser processing of a workpiece (10), which comprises a carrier element (14) made of a plastic with a surface (16) and a color lacquer layer (18) applied to the surface (16) in advance of the laser processing, the laser processing by means of a

Laser processing device (2) is executed, which comprises a laser unit (4) and a control unit (6) for controlling the laser unit (4), the method comprising:

- Arranging the workpiece (10) in one

Processing position (12) in a working area (8) of the laser unit (4),

- generation of values for operating parameters for operating the laser unit (5),

Generation and emission of a laser beam (20) according to the generated values for the

Operating parameters by the laser unit (4),

- Applying in the processing position

(12) arranged workpiece (10) with the

emitted laser beam (20) in one

Processing point (22) in the region of the surface (16) of the workpiece (10) provided with the colored lacquer layer (18), so that in the

Processing point (22) local material of the

Paint layer (18) is removed,

- Moving the laser beam (20) and thus also the processing point (22) according to the generated values for the operating parameters by the

Laser unit (4) relative to the workpiece (10) along a working path (24) in the region of the surface (16) of the workpiece (10) provided with the colored lacquer layer (18), so that material of the colored lacquer layer (18.) Along the working path (24) ) is removed, characterized in that the processing point (22) along several adjacent

Working tracks (24, 24 ', 24'',24''') is moved, adjacent working tracks (24, 24 ') being so close together that a processing point (22) of the laser beam on a working track (24) is at a processing point (22 ') of the laser beam on an adjacent work path (24') or partially superimposed on it in order to cover a large area Remove paint layer (18), and that the

Laser unit (4) is moved according to the generated values for the operating parameters to change the position of the machining point (22) and one

three-dimensional course of the with the

Color lacquer layer (18) provided surface (16) to follow when driving the work paths (24, 24 ', 24' ', 24' '').

2. The method according to claim 1, characterized in that

that the values for the operating parameters for operating the laser unit (5) are generated and the

Laser unit (4) is moved in accordance with the generated values for the operating parameters in such a way that an angle of the laser beam (20) in the processing point (22) relative to that with the color lacquer layer (18)

provided surface (16) of the workpiece (10) remains constant during the movement of the work paths (24, 24 ', 24' ', 24' ''). 3. The method according to any one of the preceding claims,

characterized in that the laser unit (4) is moved by means of actuators (26).

4. The method according to any one of the preceding claims,

characterized in that the actuators (26) for

Movement of the laser unit (4) can be controlled by the control unit (6). 5. The method according to any one of the preceding claims, characterized in that the values for the

Operating parameters of the laser unit (4) are generated ad hoc immediately before or during laser processing.

6. The method according to any one of claims 1 to 4, characterized in that the values for the

Operating parameters of the laser unit (4) immediately before or during the actual laser processing

are generated, the generation of the values for the operating parameters loading from before

Laser machining generated values includes.

7. The method according to claim 5 or 6, characterized

characterized that the values for the

Operating parameters depending on data from the

Workpiece (10) are generated.

8. The method according to claim 7, characterized in that the values for the operating parameters in

Dependence on information about the

three-dimensional shape of the workpiece (10) and / or about the machining position of the workpiece (10) and / or information about a range of

paint layer to be removed and / or material and / or thickness of the paint layer (18) and / or are generated via material of the carrier element (14).

9. The method according to any one of the preceding claims,

characterized in that a position and / or orientation of the workpiece (10) by means of a

Sensor element (34) detected and values for the

Operating parameters are generated depending on the detected position and / or orientation.

10. The method according to any one of the preceding claims,

characterized in that the control of the

Laser unit (4) depending on one on the

Control unit (6) executable program (38).

11. Laser processing device (2) for material

ablative laser machining of a workpiece (10), which has a carrier element (14) made of a plastic with a surface (16) and one in advance of the

Laser processing on the surface (16) applied paint layer (18), wherein the

Laser processing device (2) comprises a laser unit (4) for generating and emitting a laser beam (20) and a control unit (6) for controlling the laser unit (4), characterized in that the

Laser processing device (2) has means for performing a method according to any one of claims 1 to 10. 12. Laser processing device (2) according to claim 11, characterized in that the control unit (6) comprises a computing unit (36) and a computer program (38) executable on the computing unit (36).

13. Laser processing device (2) according to claim 11 or 12, characterized in that the control unit (6) is designed to generate values for operating parameters of the laser unit (4).

14. Laser processing device (2) according to one of the

Claims 11 to 13, characterized in that the laser processing device (2) actuators (26) for positioning and / or aligning and / or moving the processing point (22) of the laser beam (20)

and / or the laser unit (4).

15. Laser processing device (2) according to one of the

Claims 11 to 14, characterized in that the laser processing device (2) at least one

Sensor element (32) for detecting a position

and / or alignment of the workpiece (10) in its processing position.

16. Computer program (38) that is programmed

Execute the method according to the invention according to one of claims 1 to 10 when it is on a computing unit (36) of a control unit (6) Laser processing device (2) for material-removing laser processing runs.