Method for embedding metal piece on appearance surface of carbon fiber woven prepreg composite workpiece

Abstract

The invention discloses a method for embedding a metal part on the appearance surface of a carbon fiber woven prepreg composite part. The method comprises the following steps: step 1, engraving a groove in the surface of the composite part by using an ultraviolet laser engraving machine; secondly, roughening treatment is conducted on the surface area of the groove; thirdly, after the groove is cleaned, resin is brushed, the insert is pressed in, the beautiful seam is filled with the resin, and the surface is stricken to be flat; 4, baking the whole product to cure the resin; (5) post-treatment: polishing a resin filling area around the insert until the resin filling area is integrally flat with the surface of the composite product; and sixthly, appearance spraying is conducted. The metal insert is embedded in the surface of the composite material in the semi-finished product stage, so that a client can directly use the metal insert, and secondary labeling operation is avoided. And moreover, by adopting ultraviolet light, only high-energy ablation is realized on a processed part, a divergence phenomenon does not occur around light spots, the periphery is not heated to yellow and gasified, heat damage does not occur around a processing path, and fiber burrs and burrs are not formed.

Description

Technical Field

[0001] The invention relates to the field of composite materials, and in particular to a method for embedding a metal part in the appearance surface of a carbon fiber woven prepreg composite part. Background Art

[0002] Composite materials are currently widely used in automotive exteriors, interiors, and structural parts. Automotive decorative parts usually carry automotive brand logos to convey the visual image and concept of the automotive brand, helping companies achieve brand communication and improve brand value. Currently, logos are usually attached to the surface of parts or embedded in parts using adhesives.

[0003] In the form of external attachment, the logo will protrude from the surface of the product, lacking integrity and being easily removed. The preparation methods for embedding metal parts such as car logos on the exterior surface of carbon fiber composite parts usually include: (1) Metal parts and SMC compression molding: Using the molding fluidity of SMC to wrap the metal parts. However, this method requires that the metal parts have a certain thickness, strength, and fixed structure (such as positioning holes, threaded holes, etc.) to meet the positioning requirements and withstand the compression molding pressure. Therefore, it is only applicable to products with metal parts as structural parts; and it cannot be applied to the preparation of composite embedded metal parts with woven prepreg; (2) After the metal parts and woven prepreg are laid together, they are cured and formed: When the prepreg is laid, the metal parts are fixed on the mold, the prepreg is laid around the metal parts, and then they are cured and formed together. This method also requires that the metal parts have a certain thickness, strength, and fixed structure (such as positioning holes, threaded holes, etc.), meet the positioning requirements and be able to withstand the pressure of the curing process. It is only applicable to products with metal parts as structural parts; (3) Processing grooves on the surface of composite products and bonding metal parts with glue: Processing grooves by laser engraving or CNC processing, and then bonding metal parts with glue. However, there are the following disadvantages: burrs are inevitably generated on the processed edges, especially for processing very shallow grooves (grooves <1mm), and the burrs cannot be polished and removed after processing to meet the precision requirements, especially for curve processing such as engraving letters; after glue bonding, it cannot be integrated with the composite product body due to different systems, colors, and thermal stability, resulting in uneven surfaces and cannot meet the A-level appearance requirements of low film thickness and high-transparency varnish. Therefore, this solution is suitable for the installation and fixation of single-structure metal parts with a certain thickness, and the appearance spraying of color paint to cover defects; it cannot be used for very thin (0.1mm) character logos with complex curves and high-transparency varnish products with A-level appearance requirements. Summary of the invention

[0004] The present invention aims to provide a method for embedding a metal part on the appearance surface of a carbon fiber woven prepreg composite part, which can solve the defects of burrs and flashes in the processing of carbon fiber composite materials in the prior art.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for embedding a metal part on the exterior surface of a carbon fiber woven prepreg composite part, comprising: Step 1: Use a laser engraving machine to engrave grooves on the surface of the composite material workpiece. The laser light source is ultraviolet light with a wavelength of 350-380nm; the laser beam must be perpendicular to the processing position; Step 2: roughening the surface area of ​​the groove; Step 3: After cleaning the groove, apply resin, press in the insert, fill the seam with resin, and scrape the surface; Step 4: baking the composite material product obtained in step 3 as a whole to solidify the resin; Step 5: Post-processing: polish the resin-filled area around the insert until it is flat with the surface of the composite product; Step 6: Appearance spraying.

[0006] In the above technical solution, by embedding the metal insert into the surface of the composite material at the semi-finished stage, the client can use it directly, avoiding secondary labeling. And by using ultraviolet light, high-energy ablation is only achieved on the processing area, and there is no divergence around the light spot, which will not cause yellowing and gasification of the surrounding area due to heat, and no thermal damage will occur around the processing path, and no fiber burrs or burrs will be formed.

[0007] In another technical solution, the resin in step 3 includes component A and component B, calculated by weight: The component A comprises 60-80 parts of epoxy resin, 19-39 parts of modified polyurethane-based epoxy resin, 0.1-0.5 parts of defoaming agent, and 0.1-0.5 parts of thixotropic agent; The B component includes 65-99 parts of curing agent, 3-10 parts of curing agent accelerator, 0.2-0.5 parts of antioxidant, and 0.2-0.5 parts of ultraviolet absorber; The epoxy resin is bisphenol A epoxy resin; the viscosity of the modified polyurethane-based epoxy resin is in the range of 200-300 mPa·s.

[0008] The modification method of the modified polyurethane-based epoxy resin comprises the following steps: Step 1: by weight, place 100 parts of polyether polyol, 2-28 parts of tertiary amino polyether alcohol, and 10-50 parts of epoxy resin under vacuum and 120-130° C., dehydrate for 1-2 hours, and then cool for standby use; Step 2: Evenly mix the dehydrated and cooled tertiary amino polyether alcohol and epoxy resin, and then heat to 100° C. for pre-reaction, then add polyether polyol, stir evenly, and heat to 70° C., then drop 20-40 parts by weight of MDI to react to obtain a polyurethane prepolymer; Step 3: Mix the polyurethane prepolymer with 10-35 parts by weight of hydroxy acrylate to obtain a modified polyurethane-based epoxy resin.

[0009] In the above technical solution, the metal insert is embedded in the surface of the composite material product by using a highly transparent resin, so that it is integrated with the composite material product itself, and an A-level appearance can be achieved.

[0010] Beneficial effects of the present invention: (1) The logo of the present invention is embedded in the surface of the product at the semi-finished stage, and the exterior painting operation will be carried out after the embedding process. It is a product with a logo completed at the production end of the product, and the client can use it directly, avoiding secondary operations; (2) The logo of the present invention is embedded in the body and flush with the surface of the product, which is more complete and beautiful than the common external protruding logo on the product surface; (3) Traditional watermarks, screen printing and other logos have a dull luster, while the logo of the present invention has a metallic luster, which is more beautiful, more three-dimensional and more technological; (4) The logo of the present invention is integrated with the finished product. Removing the logo will damage the product. It has the property of protecting the customer's logo and preventing piracy, imitation and tampering. 5) The present invention is applicable to both flat and curved surfaces, and the product has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Attached Figure 1 It is a schematic diagram of a workpiece embedded with a metal nickel mark; Attached Figure 2 A photograph of the groove engraved by ultraviolet light of the present invention; Attached Figure 3 This is an electron microscope image of the groove engraved by ultraviolet light of the present invention; Attached Figure 4 This is a comparative infrared engraved groove photograph.

[0012] Among them: 1- non-appearance surface of the part, 2- appearance surface of the part; 3- metal nickel mark. DETAILED DESCRIPTION

[0013] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention. Example

[0014] In this embodiment, the carbon fiber woven prepreg composite parts are shown in the attached Figure 1, comprising a non-exterior surface 1 to be installed with the vehicle and an exterior surface 2 that is visible after installation, and a metal nickel mark 3 is embedded on the exterior surface 2.

[0015] A method for embedding a metal part on the exterior surface of a carbon fiber woven prepreg composite part, comprising: Step 1: Use an ultraviolet engraving machine to laser engrave grooves on the surface of the composite product that are compatible with the metal nickel label characters. The width of the groove is 0.3±0.1mm greater than the character, and the depth is 0.35±0.1mm greater than the character thickness. The wavelength of the ultraviolet light is 355nm. Step 2: Use 400# metallographic sandpaper to grind the surface of the groove to roughen the surface, remove dust after roughening, and wipe with alcohol to clean; Step 3: Apply highly transparent thermosetting epoxy resin in the groove, press the metal parts completely into the corresponding groove, fill the seams with resin, and smooth the surface; Step 4: Place the composite part with the embedded metal part in an oven for baking to cure the resin at a temperature of 80 ± 5 ° C for 10-12 hours; Step 5: Use 400# and 600# metallographic sandpaper to polish the filled seam area after curing, so that the filled resin area and the composite material surface are flat as a whole and reach the spraying surface, and the metal parts shall not be polished; Step 6: Perform conventional exterior surface spraying operations, specifically spraying transparent varnish with a thickness of 150-200 μm.

[0016] The resin in step 3 includes component A and component B, which are calculated by weight: component A includes 60-80 parts of epoxy resin, 19-39 parts of modified polyurethane-based epoxy resin, 0.1-0.5 parts of defoaming agent, and 0.1-0.5 parts of thixotropic agent; component B includes 65-99 parts of curing agent, 1-35 parts of curing agent accelerator, 0.2-0.5 parts of antioxidant, and 0.2-0.5 parts of ultraviolet absorber; The epoxy resin is bisphenol A epoxy resin; the viscosity of the modified polyurethane-based epoxy resin is in the range of 200-300 mPa·s.

[0017] The modification method of the modified polyurethane-based epoxy resin comprises the following steps: Step 1: by weight, place 100 parts of polyether polyol, 2-28 parts of tertiary amino polyether alcohol, and 10-50 parts of epoxy resin under vacuum and 120-130° C., dehydrate for 1-2 hours, and then cool for standby use; Step 2: Evenly mix the dehydrated and cooled tertiary amino polyether alcohol and epoxy resin, and then heat to 100° C. for pre-reaction, then add polyether polyol, stir evenly, and heat to 70° C., then drop 20-40 parts by weight of MDI to react to obtain a polyurethane prepolymer; Step 3: Mix the polyurethane prepolymer with 10-35 parts by weight of hydroxy acrylate to obtain a modified polyurethane-based epoxy resin.

[0018] In this embodiment, the ultraviolet laser used has good beam focusing and small spot, which can realize ultra-fine marking and micron-level cutting accuracy. The high-energy spot only realizes high-energy ablation at the processing location, and there is no divergence around the spot. The surrounding area is not heated to yellow and gasify, and the thermal damage around the processing path is minimal. For photos of the engraved grooves, please refer to the attached Figure 2 , see attached electron microscope image Figure 3 It can be seen that the resin and fiber are ablated and cut off along the path of the UV laser, and the edges are smooth without defects such as fiber burrs and burrs.

[0019] Comparative Example The difference from the embodiment is that the carbon fiber composite material part is a flat plate, which is engraved by an infrared laser light source with a laser wavelength of 1064nm. Figure 4 In the photo, the cut edge of the workpiece has defects such as yellowing, unevenness, and burrs. This is because the infrared wavelength is large, and the high energy of the laser spot will cause local heating and combustion or vaporization of the workpiece, and the energy at the center of the spot is high, while the energy at the edge is low, which will cause the resin at the edge of the spot to vaporize and appear yellow edges; in addition, the spot is relatively large and cannot be focused with high precision, resulting in a large heating area. The fiber can be cut in the area with high energy in the center of the spot, but cannot be cut in the area with low energy at the edge of the spot, forming fiber burrs and burrs.

Claims

1. A method for embedding metal parts on the exterior surface of a carbon fiber woven prepreg composite part, characterized in that include, Step 1: Carve grooves on the surface of the composite material part using an ultraviolet laser engraving machine; Step 2: roughening the surface area of ​​the groove; Step 3: After cleaning the groove, apply resin, press in the insert, fill the seam with resin, and smooth the surface; Step 4: baking the composite material product obtained in step 3 as a whole to solidify the resin; Step 5: Post-processing: polish the resin-filled area around the insert until it is flat with the surface of the composite product; Step 6: Appearance spraying.

2. The method for embedding metal parts on the exterior surface of a carbon fiber woven prepreg composite part according to claim 1, characterized in that: The wavelength of the ultraviolet laser in step 1 is 350-380nm.

3. The method for embedding metal parts on the exterior surface of a carbon fiber woven prepreg composite part according to claim 1, characterized in that: The resin in step 3 includes component A and component B, calculated by weight: The component A comprises 60-80 parts of epoxy resin, 19-39 parts of modified polyurethane-based epoxy resin, 0.1-0.5 parts of defoaming agent, and 0.1-0.5 parts of thixotropic agent; The B component includes 65-99 parts of curing agent, 3-10 parts of curing agent accelerator, 0.2-0.5 parts of antioxidant, and 0.2-0.5 parts of ultraviolet absorber.

4. The method for embedding metal parts on the exterior surface of a carbon fiber woven prepreg composite part according to claim 3, characterized in that: The epoxy resin is bisphenol A epoxy resin; the viscosity of the modified polyurethane-based epoxy resin is in the range of 200-300 mPa·s.

5. The method for embedding metal parts on the exterior surface of a carbon fiber woven prepreg composite part according to claim 3, characterized in that: The modification method of the modified polyurethane-based epoxy resin comprises the following steps: Step 1: by weight, place 100 parts of polyether polyol, 2-28 parts of tertiary amino polyether alcohol, and 10-50 parts of epoxy resin under vacuum and 120-130° C., dehydrate for 1-2 hours, and then cool for standby use; Step 2: Evenly mix the dehydrated and cooled tertiary amino polyether alcohol and epoxy resin, and then heat to 100° C. for pre-reaction, then add polyether polyol, stir evenly, and heat to 70° C., then drop 20-40 parts by weight of MDI to react to obtain a polyurethane prepolymer; Step 3: Mix the polyurethane prepolymer and 10-35 parts by weight of hydroxy acrylate to obtain a modified polyurethane-based epoxy resin.

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