WO2022128800A1

WO2022128800A1 - Method for treating a surface with ir laser light

Info

Publication number: WO2022128800A1
Application number: PCT/EP2021/085237
Authority: WO
Inventors: Bettina KRÖGER-KALLIES; Stefan Kreling; Jörg IHDE; Thomas WÜBBEN; Uwe Specht; Markus VELTRUP; Daniel Lahidjanian
Original assignee: Airbus Operations Gmbh; Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2020-12-18
Filing date: 2021-12-10
Publication date: 2022-06-23
Also published as: EP4263117A1; CN115768585A

Abstract

The invention relates to a method for pretreating a polymer-coated surface (11) that comprises particles and/or pigments, wherein laser light is emitted by a laser source (110), in particular a pulsed infrared laser beam (111) in the near-infrared range with a pulse fluence of 0.01 to 50 J/cm2 is generated. The method also comprises orienting the laser light by a deflection unit (115) as a laser beam (111) towards the surface (11) and moving the laser light over the surface (11) along a path (40). The emission of the pulsed laser light comprises setting the pulse fluence so that first particles and/or pigments of the surface (11) which face the laser beam (111) absorb the pulsed infrared laser light (111), and part of the surface detaches, the layer thickness of the polymer after detachment being greater than or equal to 50%, preferably greater than or equal to 75%, particularly preferably greater than or equal to 90% of the original layer thickness of the polymer.

Description

Method of treating a surface with IR laser light

The present invention relates to a method for treating a surface with infrared laser light. More particularly, the present invention relates to a method of treating a polymer-coated surface with near-infrared laser light from a laser source having a pulse fluence of 0.01 to 50 J/cm2.

Many components must have good adhesion properties for a paint to be applied so that the paint has a long service life. Aircraft components in particular, which form an outer skin of the aircraft, are often exposed to high loads, for example strong temperature fluctuations and, of course, high overflow speeds. These outer layers of paint must adhere very well to the component over the long term. This requires the surface of the component (component material, connectors such as rivet heads, seals, hinges, etc.), but also an existing external coating (primer, antistatic paint, erosion protection, corrosion protection, previous painting, etc.) on the one hand to clean (remove adhering dirt), and on the other hand to prepare for painting, i.e. to activate the surface or outer coating.

In previous pre-treatment and cleaning processes, water or solvent-based cleaning was used, followed by a grinding process. Then grinding residues had to be removed in a final cleaning process. This very labour-intensive pre-treatment of aircraft components is not only expensive, but usually also requires the use of chemicals that have to be collected, recycled and/or disposed of accordingly. Furthermore, the thickness of the material removed during the grinding process can vary greatly, so that under certain circumstances a primer or other previously applied layers can be damaged.

DE 10 2009 029 915 A1 proposes using a CO2 laser and guiding the laser beam generated with it over the surface of a component. However, pre-treatment with a CO2 laser potentially results in greater paint removal due to the wavelength. This can lead to changes, at least in the area of the surface, which, due to the large laser spot used in DE 10 2009 029 915 A1, cause visible changes in the surface structure result, which are still visible even after applying a paint and affect the paint finish.

The invention is therefore based on the object of providing an improved method for pretreating a surface, in particular a surface coated with a polymer.

This object is achieved by a method having the features according to claim 1.

According to a first aspect for better understanding of the present disclosure, an apparatus for pretreating a surface comprises a laser source configured to emit a laser light and a deflection unit configured to direct the laser light onto the surface as a laser beam and move across the surface along a path. The laser source can be a conventional laser, for example an industrially used laser. The deflection unit can be implemented as an optical deflection unit, for example with one or more mirrors and/or prisms.

The laser source is set up to generate an infrared laser beam in the near-infrared range. In particular, the laser source can generate a pulsed infrared laser beam with which a pulse fluence of 0.01 to 50 J/cm2 is achieved. The pulse fluence is the area energy of the laser beam during a pulse, i.e. the pulse energy (J) per focus diameter (cross-sectional area of the laser beam or area of the laser spot). For example, the pulse fluence can preferably be 0.1 to 10 J/cm2 and particularly preferably 0.5 to 1 J/cm2.

This pulse fluence allows energy to be introduced into the surface in a targeted manner, for example of an aircraft component, which in fact enables the surface to be activated. However, the surface is not heated in its depth (layer thickness) and the associated component. As a result, changes in the surface due to excessive thermal stress can be avoided.

Furthermore, a near-infrared laser beam, i.e. a laser beam in the short-wavelength infrared range between 810 and 5,000 nm, offers the advantage that the thermal energy input into the entire surface to be treated is very low. A laser source can preferably be used which generates a laser beam with a wavelength between 950 and 1500 nm, particularly preferably with a wavelength of 1064 nm. By using the near-infrared laser beam in combination with a suitable processing strategy, damage or visible surface changes can be avoided. For example, the infrared laser beam can be used specifically in layers with particles that absorb infrared light to activate the layer. These layers can, for example, be heated in a targeted manner by the infrared laser beam, so that they become at least partially detached and/or at least partially detached from the underlying layers.

For example, the surface can be a polymer-coated surface, such as a painted surface and/or a surface having particles and/or pigments. In order to remove only part of the polymer layer, the pulse fluence of the laser beam can be set so that the polymer layer thickness at the point of laser exposure is >= 50%, preferably >= 75%, particularly preferably >= 90% of the original (untreated) polymer layer thickness amounts to. In other words, a maximum of 50%, preferably a maximum of 25% and particularly preferably a maximum of 10% of the original polymeric layer are removed. Of course, the entire polymeric layer can also be removed at the site where the laser has acted.

Only a very thin layer or a small outer part of an uppermost, outer layer can thus be activated by the near-infrared laser beam with the pulse fluence mentioned. Activation is understood here to mean the removal of a (very thin) outer part of a layer, as a result of which the layer acquires better adhesion properties for other layers subsequently applied thereto, for example a (further) paint finish. In other words, an existing layer is at least partially detached which, viewed from the outside, has first particles which are excited by the infrared light.

A layer that has particles is, in particular, a layer that includes a polymer, with which the surface is coated. The polymer layer can, for example, comprise fillers which bring about heterogeneous absorption of the laser light. For example, the polymer layer can be a pre-existing finish on the surface. A wide variety of particles or paint pigments are usually used here, such as titanium dioxide (for light or white colors) through to carbon black particles (for dark or black/grey colors). These particles/pigments are very well suited to absorbing the infrared laser light and thus activating the layer. With the stated pulse fluence, the particles/pigments can detach within the layer and from the layer below lead layer material. For example, the particles/pigments can change their consistency under the influence of the laser light, as a result of which part of the layer in the vicinity of the particles/pigments detaches and/or the particles/pigments (allow) to be removed from the underlying layer material. This enables a thin and even treatment of the surface.

Also, contaminants on the outermost layer of the device can be thermally activated by the near-infrared laser beam, thereby removing the contaminants. An underlying layer, in particular a layer that is transparent to infrared light, is not activated by the laser beam and thus remains on the component.

Furthermore, in the case of a primer or other base coat, the outermost surface layer can be (partially) transparent to infrared light before color pigments appear when viewed in the thickness direction of the layer. With the help of a near-infrared laser beam, the outermost transparent layer of the primer or base coat can be removed by thermally activating the "first layer" of primer up to or including the color pigments. The surface of the component pretreated in this way has very good adhesion properties for a subsequent applied paintwork.

In an implementation variant, the laser source can also be set up to adjust the infrared laser beam and/or the pulse fluence in such a way that the surface processed by the infrared laser beam has a microscopic enlargement of the effective surface by >=5%, preferably >= 25% and more preferably >= 50% learns. The microscopic enlargement of the effective surface can be seen here in comparison to the original (untreated) polymeric surface.

By way of example only, a laser source with an average power of between 5 and 1000 W, preferably a laser source with 50 to 500 W, can be used. Such a laser source is particularly compact and therefore light, which means that the device can be designed more simply overall.

In an implementation variant, the device can also comprise at least one robotic arm to which the deflection unit is attached. The at least one robotic arm can be set up to perform a movement relative to the surface. The deflection unit can thus be moved over a large area of the surface or of the component comprising the surface or the entire component move. The area on the component that can be treated is therefore not defined solely by the deflection unit. Furthermore, the deflection unit can always be optimally aligned with the surface of the component using a robot arm that can be moved around three axes. In particular, a distance between the deflection unit and the surface of the component and an angle of incidence of the laser beam on the surface of the component can be kept as constant as possible. For example, the angle of incidence of the laser beam on the surface of the component can be kept at 90° if possible, for example within a range between 85° and 95°.

Alternatively or additionally, the device can comprise a work table, to which a component comprising the surface is fastened. In this case, the work table can be set up to carry out at least one two-dimensional movement relative to the deflection unit. The movement can of course also be carried out relative to the robot arm. As a result, the area of the surface of the component that can be treated can be further increased, especially in the event that a robot arm alone cannot reach all areas of the surface of the component.

In another implementation variant, the device can also comprise an optical fiber line, which is arranged between the laser source and the deflection unit and is set up to guide the laser light of the laser source to the deflection unit. The optical fiber line can be implemented in the form of a fiber optic cable, for example. The usually heavier and more complex laser source can be locally separated from the deflection unit by the fiber line, which facilitates movement of the deflection unit over the surface of the component. An optical fiber line is particularly advantageous in interaction with a robot arm, since the optical fiber line can easily accompany the movement of the robot arm. In contrast to conventional CO2 lasers, near-infrared laser light can be guided through an optical fiber line. In addition, CO2 laser sources are usually more complex and therefore heavier in their construction. The use of near-infrared laser light proposed here thus offers many advantages, particularly when it comes to automating the pre-treatment of large aircraft components.

In an implementation variant, the laser source can also be set up to emit the infrared laser beam with a pulse length or pulse duration of 0.01 to 10,000 ns, 0.1 to 10,000 ns, 1 to 10,000 ns, 1 to 1000 ns, or 10 to 1000 ns, or a range with a combination of these range values, preferably 1 to 1000 ns. As a result, the overall power input into the surface can be more precisely controlled. In a further implementation variant, the deflection unit can also be set up to generate a laser point on the surface with a diameter of between 1 and 10,000 μm, preferably between 10 and 1,000 μm and particularly preferably between 10 and 100 μm. Such a small laser point enables the surface to be treated evenly, regardless of its surface structure. For example, aircraft components are assembled with fasteners, such as rivets. However, the rivet heads represent a bump on the surface of the aircraft component. The very small laser spot allows the laser beam to be optimally aimed at any portion of the aircraft component, including such fasteners and other elements spatially deviating from the surface. The advantage of a near-infrared laser is particularly evident in comparison to conventional grinding processes, in which more material can be removed from such elevations in the event of improper use.

Furthermore, the laser source can be set up to set an energy distribution on the laser point in the focus of the laser beam according to a specific profile. For example, the energy distribution can be set as a flattop profile or a Gaussian profile. In addition, the laser source can also be set up to set a round or angular beam profile.

In yet another implementation variant, the device can also include at least one sensor that is set up to detect a surface condition of the surface. For example, the sensor can be set up to detect and evaluate laser light that is reflected by the surface. For example, an alignment of the surface can be determined, after which an alignment of the laser beam can be adjusted. Contamination or a color of the outer layer of the surface can also be determined, after which laser parameters (frequency, pulse length, laser spot size, wavelength, fluence, etc.) can be adjusted by the laser source in order to achieve optimal processing/activation of the surface.

In a further implementation variant, the deflection unit can also be set up to move the laser point step by step along the path, with a temporally earlier laser point being spatially overlapped by a temporally subsequent laser point. The deflection unit is controlled in such a way that the laser beam always hits a point on the surface, with subsequent points having a cut surface (overlapping surface). Energy from the laser beam acts more frequently on the cut surface, since this surface is multiplied by Laser beam is treated, whereby the laser power brought onto/into the surface is accumulated. By varying the size of the cut surface, i.e. varying a step size of the step-by-step movement of the laser point, the energy input into the surface can be at least partially determined.

Alternatively or additionally, in a further implementation variant, the deflection unit can also be set up to move the laser point line by line along the path. For example, a given area can be treated by laser points arranged in rows. Consecutive laser points can be guided through the rows in a serpentine manner (i.e. along a continuous S-shaped path, with the scanning direction being reversed in adjacent rows). Alternatively, successive laser points can be guided through the lines with the same scanning direction.

Furthermore, a chronologically earlier laser point of a first line can be spatially overlapped by a chronologically subsequent laser point of a second line. In other words, a laser spot of a first line and a laser spot of an adjacent second line form an intersection (overlap area). More energy is applied to the cut surface by the laser beam because this surface is repeatedly treated by the laser beam. By varying the size of the cut surface, i.e. varying a line spacing of the line-by-line movement of the laser point, the energy input into the surface can be at least partially determined.

For example, a line spacing between two adjacent lines of the path can be between 0.001 and 10 mm, preferably between 0.01 and 1 mm, and particularly preferably between 0.01 and 0.1 mm. A small distance between the lines can be selected if the power of the laser and the resulting pulse fluence are set lower. For example, a line spacing of 0.01 mm can be set with a laser power of 10 W. In a further example, the line spacing can be set to 0.05 mm with a laser power of 100 W. With an exemplary laser spot size of 100 pm, i.e. 0.1 mm, the overlapping areas are correspondingly larger or smaller.

Of course, the line spacing can also depend on a laser point size (area or diameter of the laser point). For example, a feed between two lines can be between 5 and 95%, preferably between 30 and 60%, of the laser spot size. In another implementation variant, the laser source can also be set up to generate the pulsed laser beam with a frequency between 50 kHz and 10 MHz (10,000 kHz), preferably with a frequency of 150 kHz. The laser beam pulsed in this way enables the accumulated energy input per area (the surface) to be determined in a targeted manner. This enables an even surface treatment to be achieved.

Furthermore, for example, the deflection unit can be set up to move the laser point along the path in such a way that the pulsed laser beam is emitted onto each laser point between 1 and 15 times, preferably between 2 and 5 times. In other words, the pulsed laser beam is emitted multiple times onto a specific laser point before the deflection unit deflects the laser beam onto the next neighboring laser point. The accumulated energy input per area is also determined by the frequency with which the same area on the surface is treated with the laser beam. By varying the number of times a laser beam strikes the same laser spot (same area), the treatment of the surface can be determined.

In a further implementation variant, the deflection unit can also be set up to scan the laser beam along the path at a scanning speed of between 100 and 1,000,000 mm/s, preferably between 500 and 500,000 mm/s and particularly preferably between 500 and 500,000 mm/s move. The scanning speed of the laser beam can, for example, correspond to the movement of the laser point within a line.

Depending on the implementation variant, different path parameters and/or laser parameters can be varied in order to achieve a desired accumulated energy input into the surface. For example, a layer thickness that is removed from the surface of the component can be determined in this way. The path parameters include a progression speed of the laser (scanning speed), a distance between lines of the path, a distance between laser points along the path and thus a size of overlapping areas of adjacent laser points. The laser parameters include the fluence of the laser, a pulse length of the laser, a pulse frequency, a laser spot size (e.g. diameter), the wavelength of the laser light.

For example only, the deflection unit may be further configured to determine the path across the surface such that the laser fluence (irradiance) on the surface is between 800 and 9000 mJ/cm ² . Different can Path parameters and/or laser parameters can be varied to achieve the desired laser fluence.

In yet another implementation variant, the device can also include a suction device. In particular, the suction device can be arranged close to the deflection unit and/or close to the surface to be treated, in order to remove ablation products, ie material that detaches from the surface as a result of the laser effect. On the one hand, this reduces the subsequent cleaning effort required for the surface. On the other hand, it also prevents the deflection unit or other optical elements from getting dirty.

Furthermore, the device can also include a fan, which is arranged opposite the suction device, so that the deflection unit or at least the laser beam is/are between the fan and the suction device. This creates an airflow above the surface to ensure efficient removal of the debris.

According to a further aspect for a better understanding of the present disclosure, a method for treating a surface coated with a polymer, for example a painted aircraft component, comprises the following steps:

- emitting a pulsed laser light by a laser source arranged to generate an infrared laser beam in the near-infrared range with a pulse fluence of 0.01 to 50 J/cm2;

- directing the laser light, by a deflection unit, as a laser beam onto the surface; and

- moving the laser light, by the deflection unit, across the surface along a path.

In a further implementation variant, the method can also include generating, by the deflection unit, a laser point on the aircraft component surface with a diameter between 1 and 10,000 μm, preferably with a diameter between 10 and 1,000 μm and particularly preferably between 10 and 100 μm.

In yet another implementation variant, the method can also include the step of generating a laser point on the surface, carried out by the deflection unit. In addition, according to the method, the deflection unit can also include moving the laser point along the path in steps, where a temporally earlier laser point is spatially overlapped by a temporally subsequent laser point. Alternatively or additionally, according to the method, the deflection unit can include moving the laser point along the path in lines, with a temporally earlier laser point of a first line being spatially overlapped by a temporally subsequent laser point of a second line.

In another implementation variant, the method can also include painting an area of the surface (of the aircraft component), the area having previously been treated by the laser light. In other words, the previously performed method steps for treating the surface (of the aircraft component) with the laser light serve as a pretreatment of at least one specific area of the surface (of the aircraft component). The surface quality thus achieved in the at least one specific area enables very good adhesion properties for the painting (of the aircraft component) that is subsequently carried out. This can be achieved on the one hand by cleaning the surface (removing impurities) and on the other hand by changing the surface (activating it for subsequent painting).

Furthermore, the aspects and implementation variants described above can of course be combined without this being explicitly described. Each of the implementation variants described is therefore to be seen as optional for each of the aspects, configurations and variants or even combinations thereof. The present disclosure is therefore not limited to the individual configurations and implementation variants in the order described or to a specific combination of aspects and implementation variants.

Preferred exemplary embodiments of the invention will now be explained in more detail with reference to the accompanying schematic drawings, in which:

FIG. 1 schematically shows a device for pretreating an aircraft component surface;

FIG. 2 shows schematically different states during a treatment of a surface of an aircraft component;

Figure 3 shows schematically the movement of a laser light along a path; and FIG. 4 schematically shows a flow chart of a method for pretreating an aircraft component surface.

FIG. 1 shows a schematic of a device 100 for (pre)treating a surface 11, in particular a surface 11 of an aircraft component 10. The device 100 comprises a laser source 110 which emits pulsed laser light. The device 100 also includes a deflection unit 115 which is set up to direct the laser light from the laser source 110 as a laser beam 111 onto the surface 11 of the aircraft component 10 . Furthermore, the deflection unit 115 moves the laser beam 111 over the surface 11 of the aircraft component 10 along a path 40 (see FIGS. 2 and 3).

The deflection unit 115 can be attached to a robotic arm 150 of the device 100 . In this case, the robot arm 150 can be set up to carry out a movement relative to the aircraft component 10 . In other words, the robot arm 150 can move the deflection unit 115 relative to the aircraft component 10 so that the deflection unit 115 reaches at least part of the surface 11 of the aircraft component 10 with the laser beam 111 without the aircraft component 10 being moved.

Alternatively or additionally, the aircraft component 10 can also be moved. For example, it may be attached to or mounted on a work table 160 . The work table 160 can be set up to perform a movement relative to the deflection unit 115 or the robot arm 150 . This increases the area in which the deflection unit 115 reaches the surface 11 of the aircraft component 10, for example the entire aircraft component surface 11.

Due to the relative movement between the aircraft component 10 and the deflection unit 115, the laser beam 111 can be aligned as optimally as possible on the surface 11 of the aircraft component 10. For example, aircraft components 10 often include fasteners, such as rivets 20, protruding from the surface 11 of the aircraft component. Indentations 15 or other structural changes in the otherwise smooth and/or even surface 11 can also be present. An optimal alignment of the laser beam 111 (an optimal angle of incidence) on the surface 11 is, for example, in a range around 90° (substantially perpendicular to the surface 11). With the help of the work table 160 and/or the robot arm 150 and/or the optical components of the deflection unit 115, the laser beam 111 can also be used in the area of rivets 20, depressions 15 or other areas in which the surface 11 changes into another direction than in other areas, an optimal angle of incidence on the surface 11, 15, 20 have.

The device 100 may further comprise an optical fiber line 111 arranged between the laser source 110 and the deflection unit 115 . The laser light generated by the laser source 110 can be guided to the deflection unit 115 through the optical fiber line 116 .

The laser source 110 is set up to generate an infrared laser beam 111 in the near-infrared range. In particular, the laser source 110 can generate a laser beam 111 with a wavelength of 1064 nm. Furthermore, the laser source 110 is set up to generate the laser beam 111 with a pulse fluence of 0.01 to 50 J/cm2.

The deflection unit 115 can be set up to determine the path 40 over the surface of the aircraft component 10 in such a way that an accumulated energy input into the surface 11 of the aircraft component 10 leads to an activation of the surface. The energy thus applied to/into the surface 11 leads to the heating of the surface 11, as a result of which surface material is detached, as is illustrated schematically by an evaporation/detachment 120. FIG. This evaporation 120 of surface material corresponds to a (pre)treatment of the surface 11 of the aircraft component 10.

The ablation products generated during the evaporation 120, that is to say material which is detached from the surface 11 of the aircraft component 10 as a result of the laser effect, can be removed by a suction device 170. The suction device 170 can also be attached to a robot arm 150, for example. This can be the same robotic arm 150 to which the deflection unit 115 is attached, or a separate robotic arm (not shown).

Various treatments of the aircraft component surface 11 are shown in FIG. For example, as shown in views a) and b) of FIG. 2, contamination 30 can be present in the form of a large number of particles adhering to surface 11 . The deflection unit 115 can now guide the laser beam 111 essentially perpendicular to the aircraft component 10 along the path 40 .

The energy of the near-infrared laser beam 111 heats the particles 30, as a result of which they vaporize (120) or at least flake off the surface 11 of the aircraft component 10. Alternatively or additionally, the near-infrared laser beam 111 can also be adjusted in such a way that it penetrates an upper (outer) layer 12 on the aircraft component 10 and detaches this layer 12 (120), as shown in view c) of FIG is. Layer 12 (viewed in the direction of layer thickness, ie from top to bottom in FIG. 2) can also only be part of a layer applied to aircraft component 10, such as a thin partial area of a primer or already existing paintwork. This thin part 12 of the layer can be detached, for example, by the laser beam 111 heating the first pigments (as viewed from the outside) in the layer applied to the aircraft component 10, causing them to flake off an underlying part of the applied layer. The underlying part of the applied layer remains on the aircraft component 10. As a result, a very good activation of the surface 11 of the component 10 can be achieved for subsequent treatments, for example applying a further or renewed painting. Of course, both the particles 30 from the surface and the layer 12 can be removed by the laser beam 111 in one work step.

A treatment of the surface 11 of the aircraft component 10 is shown schematically in view d) of FIG. 2, with the laser beam 111 producing a surface structure 14 . For example, the heating 120 of the surface 11 introduced by the laser beam 111 can take place down to a specific depth. In particular, by increasing the accumulated energy introduced into the surface 11 and thus heating 120, the thickness of the layer 12 that is removed can be changed. A surface structure 14 can be produced by removing different layer thicknesses in certain areas.

In particular, the deflection unit 115 is set up to generate a laser point 111-1 to 111-n on the aircraft component surface 11 and to guide this laser point 111-1 to 111-n along a path 40, for example. This is shown in more detail in FIG. 3 by way of example. Each laser point 111-1 to 111-n can, for example, have a diameter 112 between 1 and 10,000 μm, for example a diameter

112 of 100 pm. The center of this laser point is now guided along the path 40, whereby the laser point 111-1 to 111-n is moved in steps. A chronologically earlier laser point 111-1 can be spatially overlapped by a chronologically subsequent laser point 111-2, that is to say have an overlapping area 113. Especially in the area of the overlapping area

113, the laser beam 111 hits the surface 11 several times, causing more energy in the surface 11 is introduced. In other words it can be in the surface

II introduced accumulated energy can be determined specifically by the size of the overlapping area 113, more precisely the step size between two adjacent laser points.

For example, the laser source 110 can emit the laser beam 111 as a pulsed laser beam

III generate at a frequency between 50 kHz and 10 MHz, preferably at a frequency of 150 kHz. The deflection unit 115 can move the laser point 111-1 to 111-n along the path 40 in such a way that the pulsed laser beam 111 impinges on each laser point 111-1 to 111-n with a certain number of times. For example, the laser beam 111 can be emitted onto the surface 1 to 15 times per laser point 111-1 to 111-n, preferably between 2 and 5 times, i.e. impinge on the surface 11. By way of example only, the deflection unit 115 can be set up to move the laser beam 111 along the path 40 at a scanning speed of between 100 and 1,000,000 mm/s, preferably between 500 and 500,000 mm/s and particularly preferably between 500 and 500,000 mm/s . In connection with the frequency of the laser beam 111 of the laser source 110, the frequency with which the laser beam 111 strikes a laser point 111-1 to 111-n can thus be determined.

FIG. 3 also shows that the deflection unit 115 can move the laser beam 111 line by line along the path 40 . Three lines of the path 40 are shown in FIG. 3 purely as an example. The course of the path 40 shown here in an S-shape is merely an example. Of course, each line can start on the same page, for example on the left in Figure 3.

The deflection unit 115 can move the laser beam 111 in such a way that a temporally earlier laser point 111-1 of a first line is spatially overlapped by a temporally subsequent laser point 111-m of a second line. An overlapping area 51 between adjacent laser points 111-1 to 111-n of two adjacent lines is determined by the line spacing 41 in conjunction with the diameter 112 of each laser point 111-1 to 111-n. The accumulated energy input into the surface 11 of the aircraft component 10 is also increased in this overlapping region 51 generated line by line and can be determined at least partially by the line spacing 51 .

FIG. 4 shows an exemplary method for treating a surface 11. In a first step 200, a laser source 110 emits a pulsed laser light with a pulse fluence of 0.01 to 50 J/cm2. The laser source 110 serves in particular the generation of an infrared laser beam in the near infrared range. In a further step 205, the laser light is aligned by a deflection unit 115 as a laser beam 111 onto the surface 11 (eg of the aircraft component 10). The deflection unit 115 can also move the laser light over the surface 11 along a path 40 in a further step 210 .

This surface 11 is cleaned and/or activated by the accumulated energy input into the surface 11 by means of a laser beam 111 . As a result, in a step 220, the area of the surface 11 treated in this way can be painted (again). The pre-treatment by means of a laser beam 111 significantly increases the adhesion properties of the surface 11 for (re)painting.

The exemplary embodiments and variants described above only serve to illustrate the invention. All examples, variants and individual details can be combined with one another in any way to form specific embodiments of the invention.

Claims

Claims Method for treating a surface (11) coated with a polymer and having particles and/or pigments, the method comprising:

emitting (200) a pulsed laser light by a laser source (110) configured to generate an infrared laser beam (111) in the near-infrared range with a pulse fluence of 0.01 to 50 J/cm2;

directing (205) the laser light, by a deflection unit (115), as a laser beam (111) onto the surface (11); and

Moving (210) the laser light, by the deflection unit (115), over the surface (11) along a path (40), wherein the emitting of the pulsed laser light comprises adjusting the pulse fluence so that first particles and/or particles facing the laser beam (111) or pigments of the surface (11) absorb the pulsed infrared laser light (111) and part of the surface detaches, the layer thickness of the polymer after detachment being greater than or equal to 50%, preferably greater than or equal to 75%, particularly preferably greater than or equal to 90% of original layer thickness of the polymer. The method of claim 1, wherein emitting the pulsed laser light comprises generating the infrared laser beam (111) with a pulse length or pulse duration of 1 to 1000 ns. The method of claim 2, wherein emitting the pulsed laser light comprises adjusting the infrared laser beam (111) and/or the pulse fluence such that the surface (11) processed by the infrared laser beam has a microscopic magnification of the effective surface area of greater than or equal to 5%. , preferably greater than or equal to 25% and particularly preferably greater than or equal to 50%. The method according to claim 1, further comprising:

Generating, by the deflection unit (115), a laser spot (111-1 - 111-n) on the surface (11) with a diameter (112) between 1 and 10,000 pm, preferably with a diameter (112) between 10 and 1,000 pm and more preferably between 10 and 100 µm. A method according to any one of claims 1 to 4, further comprising, by the deflection unit (115):

creating a laser spot (111-1 - 111-n) on the surface (11); and moving the laser point (111-1 - 111-n) along the path (40) in steps, wherein a temporally earlier laser point (111-1) is spatially overlapped by a temporally subsequent laser point (111-2); and or

Moving the laser spot (111-1 - 111-n) along the path (40) in rows, a temporally earlier laser spot (111-1) of a first row being spatially overlapped by a temporally subsequent laser spot (111-m) of a second row . Method according to claim 5, wherein a line spacing (41) between two adjacent lines of the path (40) is between 0.001 and 10 mm, preferably between 0.01 and 1 mm, and more preferably between 0.01 and 0.1 mm. Method (100) according to claim 5 or 6, wherein the pulsed laser beam (111) is generated with a frequency between 50 kHz and 10 MHz, preferably with a frequency of 150 kHz, and wherein preferably the laser spot (111-1 - 111- n) moving along the path (40) such that the pulsed laser beam (111) is emitted onto each laser point (111-1 - 111-n) between 1 and 15 times, preferably between 2 and 5 times. A method according to any one of claims 1 to 7, further comprising:

Painting (220) an area of the surface (11), the area having previously been treated by the laser light. A method according to any one of claims 1 to 7, wherein moving the laser spot (111-1 - 111-n) involves moving the deflection unit (115) relative to the surface (11) and/or moving the surface (11) relative to the Deflection unit (115) includes. Method according to one of Claims 1 to 8, in which moving the laser point (111-1 - 111-n) involves moving the laser beam (111) at a scanning speed of between 100 and 1,000,000 mm/s, preferably between 500 and 500,000 mm/s. s and more preferably between 500 and 500,000 mm/s, along the path (40). A method according to any one of claims 1 to 10, further comprising:

Suction by a suction device (170) of removal products from the surface

(11). 18

12. The method according to any one of claims 1 to 11, wherein the surface (11) coated with a polymer is a surface of an aircraft component.