A method for selectively removing transparent coating on workpiece surface by laser scanning

Abstract

The present invention discloses a method for selectively removing a transparent coating on a workpiece surface by laser scanning. First, a transparent flexible film is covered on the transparent coating on the workpiece surface, and photosensitive glue is filled between the transparent flexible film and the workpiece. Then, an ultraviolet laser is used to pass through the transparent flexible film to solidify the photosensitive glue of the custom pattern part. Subsequently, an infrared laser is used to heat the solidified photosensitive adhesive layer so as to conduct heat to the transparent coating to soften it and further bond the two. Finally, the transparent flexible film is peeled off, and the transparent coating of the custom pattern part is removed together. The method realizes rapid and accurate selective removal of the transparent coating on the workpiece surface without damaging the workpiece surface. It is convenient and fast, highly safe, and environmentally friendly and pollution-free.

Description

Technical Field

[0001] The invention relates to the technical field of surface engineering, and in particular to a method for selectively removing a transparent coating on a workpiece surface by laser scanning. Background Art

[0002] Varnish is a transparent coating mainly used to protect and decorate the surface of objects. It is a coating composed of resin as the main film-forming substance, solvents and additives. Varnish is applied to the surface of an object and forms a smooth film after drying, which can show the original texture of the surface. Varnish has the advantages of high transparency, good gloss, fast film formation, good weather resistance, high hardness, and good scratch resistance. It is widely used in coating on wood, metal, plastic, glass, stone, leather and other surfaces.

[0003] Varnishes are mainly divided into two categories: thermosetting varnishes and thermoplastic varnishes. Thermosetting varnishes are a type of coating that cures by reaction at high temperatures. Its curing process is irreversible and produces chemical chains to form a hard coating. Thermoplastic varnishes are a type of coating that partially softens at high temperatures and has strong plasticity. It can be heated and cooled repeatedly but will not react chemically. Varnishes are resistant to wear, water, heat and corrosion. However, in some cases, it may be necessary to remove the varnish from the surface of the workpiece.

[0004] Commonly used varnish removal methods in the prior art include physical methods, chemical methods, and biological methods. Physical methods for removing varnish mainly remove the varnish from the surface of the workpiece through mechanical action, such as sanding, scraping with a scraper, blowing with hot air, etc. Chemical methods for removing varnish use chemical reagents to react with the varnish components on the workpiece to achieve the removal effect. Common chemical methods include organic solvent dissolution, alkaline solution cleaning, etc. Common biological methods include microbial degradation, enzyme preparation cleaning, etc., which use the action of microorganisms or enzyme preparations to decompose the varnish on the workpiece into soluble substances or small molecules.

[0005] However, the above varnish removal method has the following defects when applied specifically:

[0006] (1) Physical methods may damage the workpiece surface, and it is difficult to ensure complete removal of complex surface workpieces;

[0007] (2) Chemical methods require the use of certain chemical reagents, which may cause damage to the surface of some workpieces. In addition, some of the chemical reagents used are toxic or flammable, and their safety is poor;

[0008] (3) Biological methods require certain time and humidity conditions and may not be effective in some special environments or severely contaminated workpiece surfaces. At the same time, the cost of biological methods is relatively high. Summary of the invention

[0009] In order to solve the technical defects of the existing methods for removing varnish from the surface of workpieces, the purpose of the present invention is to provide a method for selectively removing the transparent coating on the surface of workpieces by laser scanning, which can achieve rapid and accurate selective removal of the transparent coating on the surface of the workpiece without damaging the surface of the workpiece, is convenient and fast, highly safe, and environmentally friendly and pollution-free.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] The present invention provides a method for selectively removing a transparent coating on a workpiece surface by laser scanning, comprising the following steps:

[0012] S1. A transparent flexible film is laminated on the transparent coating on the surface of the workpiece, and a photosensitive glue is coated between the transparent flexible film and the transparent coating on the surface of the workpiece to form a photosensitive glue layer;

[0013] S2, using ultraviolet laser to scan the transparent flexible film according to a preset pattern, and curing the photosensitive glue of the laser-irradiated part;

[0014] S3, scanning with infrared laser according to the preset pattern in step S2, the photosensitive adhesive layer of the cured part absorbs heat and conducts the heat to the transparent coating on the surface of the workpiece, the transparent coating softens and bonds with the photosensitive adhesive layer of the cured part;

[0015] S4, peeling off the transparent flexible film from the surface of the workpiece, and the transparent coating of the preset pattern portion in step S2 is bonded and taken away by the transparent flexible film.

[0016] Using the above technical solution:

[0017] Since the transparent coating has a low absorption rate for laser, it is not possible to directly use laser ablation to remove the transparent coating on the surface of the workpiece. In view of the problem that the transparent coating on the surface of the workpiece (especially the complex-shaped workpiece) is difficult to selectively remove, the present invention provides a method for removing the transparent coating of a custom pattern or area by selectively scanning with a laser. First, a transparent flexible film is covered on the transparent coating on the surface of the workpiece, and photosensitive glue is filled between the transparent flexible film and the workpiece. Then, an ultraviolet laser is used to pass through the transparent flexible film to cure the photosensitive glue of the custom pattern part. Subsequently, an infrared laser is used to heat the cured photosensitive glue layer so as to transfer the heat to the transparent coating to soften it and further bond the two. Finally, the transparent flexible film is peeled off, and the transparent coating of the custom pattern part is removed together.

[0018] The present invention adopts a combination of ultraviolet laser and infrared laser to achieve accurate and selective removal of the transparent coating on the surface of the workpiece, without causing damage to the surface of the workpiece, and can process complex shapes; through the combined use of a transparent flexible film (low laser absorption and high heat resistance) and a photosensitive glue (high laser absorption), an innovative solution is provided for laser energy conduction and selective removal of the transparent coating, ensuring that heat is effectively conducted to the transparent coating and softened, while protecting the surface of the workpiece from damage; the method avoids the use of chemical reagents, which not only reduces environmental pollution, but also improves the safety of operation, and does not damage the surface of the workpiece, ensuring the integrity of the workpiece; by utilizing the conformability of the transparent flexible film and the flexibility of laser scanning, the method of the present invention can effectively process workpieces of various complex surfaces, solving the problem that traditional methods are difficult to ensure complete removal effects; through the use of laser technology, rapid and accurate selective removal of the transparent coating on the surface of the workpiece is achieved without damaging the surface of the workpiece, which is convenient, fast, safe, environmentally friendly and pollution-free.

[0019] In this application, the selection of ultraviolet laser and infrared laser is based on their specific absorption characteristics and energy transfer efficiency. In practical applications, other types of lasers (such as green laser, blue laser, etc.) can be selected according to the material and thickness of the transparent coating on the surface of the specific workpiece, as long as these lasers can be effectively absorbed by the transparent flexible film and photosensitive glue, and transfer enough heat to soften the transparent coating on the surface of the workpiece.

[0020] This application adopts a two-step processing method of UV laser curing photosensitive glue and infrared laser softening transparent coating. In specific applications, the laser power, wavelength, scanning speed and other parameters can be adjusted according to the specific material and thickness of the transparent coating, or other types of laser processing methods (such as pulsed laser, continuous laser, etc.) can be used to achieve the best processing effect.

[0021] In the present application, the size of the transparent flexible film can be customized according to the size of the transparent coating to be removed from the workpiece surface, rather than being limited to the situation where the size of the transparent flexible film is completely matched with the size of the transparent coating to be removed from the workpiece surface. This can provide greater flexibility to accommodate workpieces of different sizes and shapes.

[0022] In the present application, the photosensitive glue can be applied by a soft brush or other coating methods (such as spraying, dipping, rolling, etc.) to the transparent coating on the surface of the workpiece or to one side of the transparent flexible film.

[0023] In the present application, the laser scanning system adopts a two-dimensional galvanometer laser scanning system which is an effective processing method, but other types of laser scanning systems, such as a direct writing laser processing head, etc., may also be considered.

[0024] After removing the clear coat, the workpiece sometimes needs further processing, such as cleaning, polishing, etc.

[0025] Furthermore, in the step S2, after the photosensitive glue of the preset pattern part is completely cured by using ultraviolet laser, the operations in step S3 and step S4 are performed in sequence.

[0026] Furthermore, in the step S2, the photosensitive glue of the preset pattern part is cured step by step in different areas by using ultraviolet laser, and the operations in the steps S3 and S4 are then performed on the photosensitive glue layer of the cured part.

[0027] That is to say, the ultraviolet curing operation in step S2 is performed while the infrared scanning film peeling operation in steps S3 and S4 is performed, that is, ultraviolet laser scanning curing is performed in the front and infrared scanning film peeling is performed in the back, thereby improving work efficiency.

[0028] Furthermore, in the step S1, the absorption rate of the transparent flexible film to ultraviolet laser and infrared laser is lower than 5%, and the heat-resistant temperature of the transparent flexible film is higher than 200°C.

[0029] Preferably, the transparent flexible film includes but is not limited to a polyimide film (PI), a polyethylene terephthalate film (PET), a polyurethane film or a flexible transparent conductive oxide film (ITO).

[0030] In the prior art, other materials having similar optical properties and heat resistance as the above-mentioned transparent flexible film may also be used as alternatives, such as specially synthesized polymer materials or composite materials, which have better performance or lower cost.

[0031] Furthermore, in step S2, the absorption rate of the photosensitive glue to ultraviolet laser and infrared laser is greater than 50%.

[0032] Preferably, after curing, the bonding strength between the photosensitive glue, the transparent flexible film and the workpiece is greater than the bonding strength between the transparent coating on the surface of the workpiece and the surface of the workpiece.

[0033] Further preferably, the photosensitive glue includes but is not limited to UV epoxy resin glue, UV acrylic resin glue or polyurethane glue with added absorbers (ultraviolet absorber and infrared absorber).

[0034] Other types of glue in the prior art can be selected for use as long as they can meet the requirements of high laser absorption rate and strong bonding force between the transparent flexible film and the workpiece.

[0035] Wherein, in the step S3, the temperature of the cured portion of the photosensitive adhesive layer reaches 90-150° C. after absorbing heat.

[0036] Furthermore, the workpiece is a workpiece with a complex surface.

[0037] The shapes of industrial products can be roughly divided into two categories:

[0038] One category is composed only of elementary analytical surfaces such as planes, cylinders, cones, spheres, etc. Most mechanical parts belong to this category. Descriptive geometry and mechanical drawing can be used to clearly express and convey all the shape information contained.

[0039] The other type is complex surfaces, also known as free-form surfaces, which cannot be composed of elementary analytical surfaces, but are curved surfaces that change freely in complex ways, such as airplane wings or car shapes, injection molds, turbine blades, ship propellers, and various toy molding plastic molds.

[0040] The material of the workpiece to be processed needs to be heat-resistant to withstand the temperature changes caused by the curing of the photosensitive glue and the heating of the infrared laser. Suitable materials include metal, glass, ceramic or some plastics.

[0041] The transparent coating on the surface of the workpiece must have appropriate bonding strength, and the coating should have heat resistance of 60 to 90°C to ensure that it will not be completely peeled off during the curing and softening of the photosensitive glue.

[0042] The thickness of the transparent coating on the workpiece surface can be controlled to be between tens of microns and hundreds of microns, ensuring that the laser can effectively conduct heat to the bonding area.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention uses a combination of ultraviolet laser and infrared laser, and uses a transparent flexible film (low laser absorption and high heat resistance) in combination with a photosensitive glue (high laser absorption). This method is simple and easy to operate, and solves the problem that the traditional laser method cannot remove the transparent coating on the surface of the workpiece;

[0045] (2) Ability to accurately and quickly remove clear coatings from custom patterns or areas, with patterns that can be imported in a variety of formats via the galvanometer software;

[0046] (3) The paint removal is highly accurate. When removing the transparent coating with a thickness of only tens of microns, there is no damage to the surface of the workpiece, which ensures the integrity of the workpiece. It will not cause mechanical damage to the workpiece itself, nor will it produce chemical reactions to corrode the workpiece;

[0047] (4) It will not generate a large amount of dust or solid waste, which is more environmentally friendly;

[0048] (5) By utilizing the conformability of the transparent flexible film and the flexibility of laser scanning, the transparent coating can be effectively removed from complex surface workpieces, solving the problem that traditional mechanical methods are inefficient and easily cause damage when processing coatings on the surfaces of complex surface workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Figure 1 This is a flow chart of the laser scanning method for selectively removing the transparent coating on the surface of a workpiece in the present invention.

[0051] Figure 2 This is a physical picture of the workpiece sample after removing the transparent varnish in Example 1.

[0052] Figure 3 These are microscope magnified images of the workpiece sample after the transparent varnish is removed in Example 1, A is a photo magnified X2 times, and B is a photo magnified X3 times. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] A method for selectively removing a transparent coating on a workpiece surface by laser scanning of the present invention, such as Figure 1 As shown, the following steps are included:

[0055] S1. Prepare a transparent flexible film. The size of the transparent flexible film can be customized according to the size of the transparent coating to be removed on the surface of the workpiece, such as the size of the transparent flexible film completely matches the size of the transparent coating to be removed on the surface of the workpiece or the size of the transparent flexible film is larger than the transparent coating to be removed on the surface of the workpiece. The selected transparent flexible film is required to have an absorption rate of less than 5% for ultraviolet laser and infrared laser, and a heat-resistant temperature of more than 200°C. Specifically, the transparent flexible film includes but is not limited to polyimide film (PI), polyethylene terephthalate film (PET), polyurethane film or flexible transparent conductive oxide film (ITO). In the prior art, other materials with similar optical characteristics and heat resistance as the above-mentioned transparent flexible film can also be used as alternatives, such as specially synthesized polymer materials or composite materials, which have better performance or lower cost.

[0056] S2. Pre-coat a layer of photosensitive glue on the transparent coating on the surface of the workpiece or on one side of the transparent flexible film with a soft brush or other coating methods (such as spraying, dipping, rolling, etc.). The absorption rate of the photosensitive glue to ultraviolet laser and infrared laser is required to be greater than 50%, and the bonding strength between the photosensitive glue and the transparent flexible film and the workpiece after curing is greater than the bonding strength between the transparent coating on the surface of the workpiece and the surface of the workpiece. Photosensitive glue includes but is not limited to UV epoxy resin glue, UV acrylic resin glue or polyurethane glue with added absorbent (ultraviolet absorber and infrared absorber). Other types of glue in the prior art can be selected for use as long as they can meet the requirements of high absorption rate of laser and strong bonding with transparent flexible film and workpiece.

[0057] S3, placing the transparent flexible film in contact with the transparent coating on the surface of the workpiece, forming a photosensitive adhesive layer between the transparent flexible film and the transparent coating on the surface of the workpiece, and using a roller to press the transparent flexible film to remove residual air in the photosensitive adhesive layer.

[0058] S4. Starting from one end of the transparent flexible film, an ultraviolet laser is used to perform pixel raster scanning on the transparent flexible film according to a preset pattern, and the photosensitive glue in the laser irradiated part is effectively cross-linked and cured, and the transparent flexible film and the photosensitive glue at this part are cured and bonded.

[0059] S5. Use infrared laser to perform laser scanning according to the preset pattern in step S4. The photosensitive adhesive layer of the cured part absorbs heat and becomes higher in temperature (90-150°C), and transfers the heat to the transparent coating on the surface of the workpiece. The transparent coating softens and bonds with the photosensitive adhesive layer of the cured part.

[0060] S6. After the transparent coating is softened, when its bonding force with the paint layer below is weaker than its bonding force with the photosensitive adhesive layer, a peeling action is performed on the transparent flexible film to peel the transparent flexible film off the surface of the workpiece. The transparent coating of the preset pattern portion in step S4 is bonded and taken away by the transparent flexible film. After removing the transparent coating, the workpiece may sometimes need to be further processed, such as cleaning, polishing, etc.

[0061] There are two specific operations of steps S4 to S6. Method 1 is: in step S4, ultraviolet laser is used to cure all the photosensitive glue of the preset pattern part, and then the infrared scanning and film peeling operations in steps S5 and S6 are performed in sequence.

[0062] The second method is: in step S4, the photosensitive glue of the preset pattern part is cured step by step by area using ultraviolet laser, and the photosensitive glue layer of the cured part is immediately subjected to the operations in step S5 and step S6. That is to say, the ultraviolet curing operation in step S4 is performed while the infrared scanning film peeling operation in step S5 and step S6 is performed, that is, the ultraviolet laser scanning curing is performed in the front and the infrared scanning film peeling is performed in the back, which improves the work efficiency.

[0063] Among them, the shapes of industrial products can be roughly divided into two categories:

[0064] One category is composed only of elementary analytical surfaces such as planes, cylinders, cones, spheres, etc. Most mechanical parts belong to this category. Descriptive geometry and mechanical drawing can be used to clearly express and convey all the shape information contained.

[0065] The other type is complex surfaces, also known as free-form surfaces, which are curved surfaces that cannot be composed of elementary analytical surfaces but are freely changing in complex ways, such as airplane wings, car shapes, injection molds, turbine blades, ship propellers, and various toy molding plastic molds.

[0066] The workpiece in the present invention can be an elementary analytical surface or a complex surface. By utilizing the conformability of the transparent flexible film and the flexibility of laser scanning, it can be effectively applied to the complex surface workpiece to selectively remove the transparent coating on the surface of the complex surface workpiece.

[0067] The material of the workpiece to be processed must be heat-resistant to withstand the temperature changes caused by the curing of the photosensitive glue and the heating of the infrared laser. Suitable materials include metal, glass, ceramic or some plastics. The transparent coating on the surface of the workpiece must have appropriate bonding strength, and the coating should have a heat resistance of 60 to 90°C to ensure that it will not be completely peeled off during the curing and softening of the photosensitive glue. The thickness of the transparent coating on the surface of the workpiece can be controlled to be tens of microns to hundreds of microns to ensure that the laser can effectively conduct heat to the bonding area.

[0068] In the present invention, a two-step processing method of UV laser curing photosensitive glue and infrared laser softening transparent coating is adopted. In specific applications, the laser power, wavelength, scanning speed and other parameters can be adjusted according to the specific material and thickness of the transparent coating, or other types of laser processing methods (such as pulsed laser, continuous laser, etc.) can be used to achieve the best processing effect, or other types of lasers (such as green laser, blue laser, etc.) can be selected, as long as these lasers can be effectively absorbed by the transparent flexible film and photosensitive glue, and transmit enough heat to soften the transparent coating on the surface of the workpiece.

[0069] Regarding the requirements for laser power: The power of the UV laser must be high enough to ensure that the photosensitive glue can quickly reach the curing threshold required for photosensitivity curing, usually between a few hundred milliwatts and a few watts. The infrared laser power should be adjusted according to the thermal characteristics of the transparent coating and the photosensitive glue to avoid overheating and material damage or insufficient heat that fails to soften the transparent coating. Regarding the requirements for laser wavelength: The wavelength of the UV laser should match the photosensitivity of the photosensitive glue, usually in the range of 355nm to 405nm; the wavelength of the infrared laser needs to be selected in a range suitable for partial absorption of the cured photosensitive glue layer, and the common wavelength is 1064nm. Regarding the laser scanning speed: The scanning speed should match the laser power to ensure that the photosensitive glue has enough time to cure. The optimal speed needs to be determined through experiments to avoid incomplete curing due to excessive speed.

[0070] In the present invention, the laser scanning system generally adopts a two-dimensional galvanometer laser scanning system, which is an effective processing method, but other types of laser scanning systems, such as a direct writing laser processing head, etc., may also be considered.

[0071] The present invention adopts a combination of ultraviolet laser and infrared laser to achieve accurate and selective removal of the transparent coating on the surface of the workpiece, without causing damage to the surface of the workpiece, and can process complex shapes; through the combined use of a transparent flexible film (low laser absorption and high heat resistance) and a photosensitive glue (high laser absorption), an innovative solution is provided for laser energy conduction and selective removal of the transparent coating, ensuring that heat is effectively conducted to the transparent coating and softened, while protecting the surface of the workpiece from damage; the method avoids the use of chemical reagents, which not only reduces environmental pollution, but also improves the safety of operation, and does not damage the surface of the workpiece, ensuring the integrity of the workpiece; by utilizing the conformability of the transparent flexible film and the flexibility of laser scanning, the method of the present invention can effectively process workpieces of various complex surfaces, solving the problem that traditional methods are difficult to ensure complete removal effects; through the use of laser technology, rapid and accurate selective removal of the transparent coating on the surface of the workpiece is achieved without damaging the surface of the workpiece, which is convenient, fast, safe, environmentally friendly and pollution-free.

[0072] Example 1

[0073] A carbon fiber automobile rearview mirror shell with a length, width and height of 120 mm × 200 mm × 300 mm was selected as a complex surface workpiece sample, and its surface was coated with a thermosetting resin transparent varnish with an average thickness of 25 μm.

[0074] The method for selectively removing the transparent coating on the surface of a workpiece by laser scanning in the present invention is used for paint removal, which specifically comprises the following steps:

[0075] (1) Use deionized water to clean the surface of the workpiece sample to remove dust on the surface of the workpiece sample;

[0076] (2) Use a soft brush to apply polyurethane photosensitive glue on the surface of the workpiece sample, take a polyimide film with a length, width and height of 500 mm × 500 mm × 1 mm and cover it on the surface of the workpiece sample coated with photosensitive glue, and use a steel roller to roll on the transparent flexible film to remove the residual air in the photosensitive glue layer;

[0077] (3) Input the processing pattern in DXF format into the software as the preset graphic;

[0078] (4) Starting from one end of the polyimide film, a UV nanosecond pulse laser with a wavelength of 355 nm, a pulse width of 1.5 ns, and a power of 30 W is used to process according to a preset pattern through a two-dimensional galvanometer. The photosensitive glue at the laser irradiated area is photocured, so that the polyimide film at that location is cured and bonded with the transparent varnish;

[0079] (5) Using an infrared continuous laser with a wavelength of 1064 nm and a power of 500 W, a laser scan is performed for about 30 seconds through a two-dimensional galvanometer according to the preset pattern in step (3). The temperature of the cured photosensitive adhesive layer rises to about 120° C. The heat is transferred to the transparent varnish, causing the transparent varnish to soften.

[0080] (6) After the transparent varnish softens, when its bonding strength with the paint layer below is weaker than its bonding strength with the photosensitive adhesive layer, the polyimide film is peeled off to remove the transparent varnish on the processed pattern part.

[0081] Figure 2 This is a physical picture of the workpiece sample after removing the transparent varnish. It can be seen that the transparent varnish on the surface of the workpiece sample has been accurately removed according to the preset pattern, with clear edges, and other parts of the transparent varnish still remain on the surface of the workpiece sample. Figure 3 This is a microscope magnified image of the workpiece sample after the transparent varnish is removed. It can be seen that the number of broken carbon fiber bundles on the surface of the workpiece is less than 10 / bundle, indicating that the method of the present invention will not cause damage to the workpiece itself when removing the transparent varnish.

[0082] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for selectively removing a transparent coating on a workpiece surface by laser scanning, characterized in that: The following steps are involved: S1. A transparent flexible film is laminated on the transparent coating on the surface of the workpiece, and a photosensitive glue is coated between the transparent flexible film and the transparent coating on the surface of the workpiece to form a photosensitive glue layer; S2, using ultraviolet laser to scan the transparent flexible film according to a preset pattern, and curing the photosensitive glue of the laser-irradiated part; S3, scanning with infrared laser according to the preset pattern in step S2, the photosensitive adhesive layer of the cured part absorbs heat and conducts the heat to the transparent coating on the surface of the workpiece, the transparent coating softens and bonds with the photosensitive adhesive layer of the cured part; S4, peeling the transparent flexible film from the surface of the workpiece, and the transparent coating of the preset pattern portion in step S2 is bonded and taken away by the transparent flexible film; In step S2, the absorption rate of the photosensitive glue to ultraviolet laser and infrared laser is greater than 50%; After the photosensitive glue is cured, the bonding strength between the transparent flexible film and the workpiece is greater than the bonding strength between the transparent coating on the surface of the workpiece and the surface of the workpiece.

2. The method for selectively removing a transparent coating on a workpiece surface by laser scanning according to claim 1, characterized in that: In the step S2, after the photosensitive glue of the preset pattern part is completely cured by using ultraviolet laser, the operations in steps S3 and S4 are performed in sequence.

3. The method for selectively removing a transparent coating on a workpiece surface by laser scanning according to claim 1, characterized in that: In the step S2, the photosensitive glue of the preset pattern part is cured step by step in different areas by using ultraviolet laser, and the operations in the steps S3 and S4 are then performed on the photosensitive glue layer of the cured part.

4. The method for selectively removing a transparent coating on a workpiece surface by laser scanning according to any one of claims 1 to 3, characterized in that: In the step S1, the absorption rate of the transparent flexible film to ultraviolet laser and infrared laser is lower than 5%, and the heat-resistant temperature of the transparent flexible film is higher than 200°C.

5. The method for selectively removing a transparent coating on a workpiece surface by laser scanning according to claim 4, characterized in that: The transparent flexible film is a polyimide film, a polyethylene terephthalate film, a polyurethane film or a flexible transparent conductive oxide film.

6. The method for selectively removing a transparent coating on a workpiece surface by laser scanning according to claim 1, characterized in that: The photosensitive glue is UV epoxy resin glue, UV acrylic resin glue or polyurethane glue with added absorbent.

7. The method for selectively removing a transparent coating on a workpiece surface by laser scanning according to claim 1, characterized in that: In the step S3, the temperature of the cured portion of the photosensitive adhesive layer reaches 90-150° C. after absorbing heat.

8. The method for selectively removing a transparent coating on a workpiece surface by laser scanning according to claim 1, characterized in that: The workpiece has a complex surface.

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