Metal wire drawing line appearance process

Abstract

According to the metal wiredrawing line appearance process, stress is relieved through a plastic part, internal stress is reduced, and an electroplated product is prevented from deforming; the microcosmic roughness of the surface of the plastic part is increased through coarsening, and the contact area of an electroplated surface and the part is increased; the colloid palladium is exposed and has catalytic activity by removing the activating solution on the surface; the deposition speed is accelerated; a plating layer with good conductivity is formed through chemical plating, and it is guaranteed that a circuit can form a loop, so that the plastic part has conductivity; metal wire drawing lines are formed on the surface of plastic through composite electroplating of three metals of copper, nickel and chromium; compared with a traditional silver paint spraying and IML technology, the metal wire drawing line appearance technology has higher durability and better appearance effect; finer and more uniform metal wiredrawing textures can be realized through fine pretreatment and accurate electroplating control; the process provided by the invention not only improves the quality and performance of the product, but also reduces the production cost and shortens the production cycle.

Description

Technical Field

[0001] The invention relates to the technical field of metal brushed pattern appearance processing, and in particular to a metal brushed pattern appearance process. Background Art

[0002] Metal brushing is very common in products, such as buildings, daily products, and electronic products. However, due to the high cost of metal brushing products, most of them are used in mid-to-high-end products. Therefore, low-cost plastic parts with visual effects similar to metal brushing are gradually produced. Not only are they beautiful and have a metal-like texture, but they are also relatively low in cost.

[0003] A deep-drawn metal wire drawing process proposed in Chinese invention patent application number: CN202110178307.0 belongs to the field of metal wire drawing. A deep-drawn metal wire drawing process comprises the following steps: S1, using a flat-pressed abrasive belt for wire drawing, first fixing the workpiece on a mold, and rotating the abrasive belt at high speed. The pressure block on the back of the abrasive belt presses down to grind the workpiece, and sprays grinding liquid and grinding particles while grinding. This process improves the wire drawing effect by adding grinding particles, deepens the depth of the texture to make it clearer, and the grinding auxiliary aggregate effectively removes welds, residues and scratches on the surface of the workpiece, improves the uniformity of the workpiece surface, and the texture friction aggregate effectively deepens the texture depth. At the same time, during the wire drawing process, the grinding particles also release passivators and antioxidants, thereby achieving the purpose of wire drawing and processing at the same time.

[0004] Traditional metal wire drawing process: Silver paint spraying requires a deeper wire drawing texture and a less delicate texture;

[0005] Specific shortcomings of silver paint spraying process:

[0006] Texture depth and fineness: The brushed metal texture formed by the silver spray paint process is deep and not fine enough, making it difficult to achieve high-quality appearance requirements.

[0007] Poor durability: The spray coating is easy to wear and fade, especially under frequent use or harsh environment, its durability is poor, affecting the service life and appearance of the product.

[0008] The IML process is relatively expensive, and involves printing texture on the membrane - forming the membrane - punching the membrane - integral injection molding of the membrane and plastic parts - taking out the product. The process is complex and the cost is relatively high.

[0009] The specific shortcomings of the IML process are as follows:

[0010] Complex process: The IML process involves multiple steps, including film printing texture, molding, punching and one-piece injection molding. The process is complex and requires high-precision equipment and technology.

[0011] High cost: Due to the complex process, high material and production costs, the total cost of the product is increased, which is not conducive to large-scale production.

[0012] Long production cycle: The series connection of multiple processes makes the production cycle longer, which is not conducive to quickly responding to market demand and shortening product development time.

[0013] Therefore, we made improvements to this and proposed a metal brushed texture appearance process. Summary of the invention

[0014] The purpose of the present invention is to solve the problems in the existing background technology. In order to achieve the above invention purpose, the present invention provides the following technical solutions: a metal brushed appearance process, including the following process steps: S1, plastic part stress relief: stress relief of the internal stress of the plastic after injection molding;

[0015] S2, degreasing / deoiling: remove grease from plastic parts, degreasing / deoiling uses medium and low temperature alkaline liquid cleaning;

[0016] S3, Roughening: The strong acidity of the roughening liquid dissolves the butadiene component in the ABS plastic, so that microscopic rough dovetail-shaped holes are formed on the surface of the part to increase the contact area between the electroplating surface and the part;

[0017] S4, Neutralization and reduction: Remove strong acid and oxide impurities remaining on the surface of plastic parts; reduce and remove chromic acid hidden on the surface of parts through the reducing property of the solution;

[0018] S5, Pre-dip: Pre-dip allows divalent tin ions to attach to the surface of the plastic parts and further clean the chromium residue;

[0019] S6. Activation / sensitization palladium deposition: a layer of catalytically active metal layer is adsorbed on the surface of the plastic part; the catalytic substance in the solution - colloidal palladium (Pd) is evenly adsorbed in the dovetail-shaped holes on the surface of the part, providing a catalytic center for the occurrence of chemical nickel reaction;

[0020] S7, Reduction: After activation and cleaning, reduction treatment is required to remove the activation liquid on the surface; the colloidal palladium adsorbed on the surface of the parts in the catalytic liquid does not have catalytic activity, and the colloidal palladium is surrounded by divalent tin ions (Sn2+). The degumming process dissolves the divalent tin around the palladium to make it naked and catalytically active;

[0021] S8, chemical plating: a conductive coating is formed on the surface of plastic parts, the coating is uniform and continuous, so that the circuit forms a loop. After the chemical reaction, the surface of the parts is covered with a conductive nickel / phosphorus alloy layer, making the plastic parts that were not conductive before become conductors;

[0022] S9. Electroplating: Electroplating uses copper, nickel and chromium as a composite to electroplate on the plastic surface to form a metal brushed pattern on the surface.

[0023] As the preferred technical solution of the present invention, S1, stress relief requirements during stress relief of plastic parts: ABS: temperature 70°C, time 4-6h; PC+ABS: temperature 90°C, time 4-6h Stress test requirements: soak in glacial acetic acid for 5 minutes, and no whitening is required.

[0024] As a preferred technical solution of the present invention, in S2, the degreasing and oil removal process, the concentration of the degreasing powder is 30-50 g / L, the temperature is 55° C.-60° C., and the time is 3-5 minutes.

[0025] As the preferred technical solution of the present invention, S3, during the roughening process, -OH, -SO3H, >C=0 polar hydrophilic groups are generated on the surface of the part, making the surface of the part hydrophilic; the solution concentration cr03 is 380-420g / L; H2S04 is 390-420g / L; cr3+≦25g / L; the temperature is 68-72°C, and the time is 8-12 minutes.

[0026] As a preferred technical solution of the present invention, S3, the roughening liquid in the roughening process includes a perchromic acid solution.

[0027] As a preferred technical solution of the present invention, in S4, the hydrochloric acid content is 25%, the reducing agent content is 10%, the neutralization and reduction temperature is room temperature, and the chromic acid reduction removal time is 1 minute.

[0028] As a preferred technical solution of the present invention, S6, activation / sensitization palladium precipitation: comprises the following steps:

[0029] S61. Ensure that the concentration of colloidal palladium solution is 500-1000 mg / L; control the solution temperature at 25-30°C to ensure the best adsorption effect;

[0030] S62. Immerse the plastic part completely in the colloidal palladium solution; use a stirrer to gently stir the solution to keep the solution uniform and avoid excessively high or low concentration in some areas; adjust the immersion time range to 5-10 minutes according to the size and shape of the plastic part;

[0031] S63. Take out the plastic parts to avoid damaging the catalytic layer on the surface; gently rinse the plastic parts with deionized water to remove the colloidal palladium that is not adsorbed on the surface; place the plastic parts in a dust-free environment to dry naturally or use mild hot air to blow dry.

[0032] As a preferred technical solution of the present invention, S7, reduction treatment is further performed after reduction activation cleaning to remove the activation liquid on the surface, which specifically includes the following steps:

[0033] According to the needs, prepare dilute hydrochloric acid with a concentration of 5-10% mg / L; control the temperature of the reducing agent solution at room temperature 20-25°C;

[0034] Immerse the plastic parts completely in the reducing agent solution; use a stirrer to gently stir the solution to keep it uniform and avoid excessively high or low concentrations in some areas;

[0035] Adjust the soaking time range to 1-3 minutes according to the size and shape of the plastic part; take out the plastic part to avoid damaging the catalytic layer on the surface.

[0036] As a preferred technical solution of the present invention, S8, during the chemical plating process, the surface of the part is covered with a conductive nickel / phosphorus alloy layer with a thickness of 0.2 um.

[0037] As a preferred technical solution of the present invention, the specific steps of S9, electroplating are as follows:

[0038] S91. Ensure that the electroplating tank is clean and free of pollution, and add copper, nickel and chromium electroplating solutions respectively;

[0039] S92. Set electroplating parameters:

[0040] S921, set the current density to 2-4A / dm according to the process requirements 2 ;

[0041] S922, setting the electroplating time according to the thickness of the coating, the electroplating time for each layer of metal is 10-30 minutes;

[0042] S923, controlled at room temperature to 50°C;

[0043] S93, copper electroplating: place the plastic part in the copper electroplating tank; turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic part and wash it with deionized water;

[0044] S94, nickel electroplating: put the cleaned plastic parts into the nickel electroplating tank, turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic parts and wash them with deionized water;

[0045] S95, chromium electroplating: put the nickel-plated plastic parts into the chromium electroplating tank; turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic parts and wash them with deionized water;

[0046] S96, Final cleaning: After all electroplating layers are completed, thoroughly clean the plastic parts with deionized water to remove the residual electroplating solution on the surface;

[0047] S97, Drying: Place the cleaned plastic parts in a dust-free environment to dry naturally or use mild hot air to dry;

[0048] S98. Inspection: Evaluate the appearance quality of brushed metal patterns by visual inspection and microscopic observation, including uniformity, gloss, and adhesion of the metal layer.

[0049] Compared with the prior art, the invention has the following beneficial effects: In the scheme of the invention: The invention reduces internal stress by stress relief of plastic parts, and prevents deformation of products after electroplating. Improves product stability and durability. Increases the microscopic roughness of the surface of plastic parts by roughening, and increases the contact area between the electroplated surface and the parts. Enhances the adhesion and durability of the coating.

[0050] Remove residual strong acid and oxide impurities through neutralization and reduction, improve the affinity of plastic parts, ensure the smooth progress of subsequent processes, and improve product quality. Activation / sensitization palladium deposition: adsorb a layer of catalytically active metal layer on the surface of plastic parts to provide a catalytic center for chemical nickel reaction, and improve the reaction efficiency and quality of chemical plating.

[0051] By removing the activation liquid on the surface, the colloidal palladium is exposed and has catalytic activity. The deposition speed is accelerated and the quality of the coating is improved. A coating with good conductivity is formed by chemical plating to ensure that the circuit can form a loop. The plastic parts are made conductive to prepare for subsequent electroplating. Electroplating uses copper, nickel and chromium three metal composite electroplating to form metal brushed patterns on the plastic surface. It has beautiful appearance, strong durability and good metal texture.

[0052] Compared with the traditional silver spray paint and IML process, the metal brushed texture appearance process of the present invention has higher durability and better appearance effect. Through meticulous pre-treatment and precise electroplating control, a finer and more uniform metal brushed texture can be achieved. The process of the present invention not only improves the quality and performance of the product, but also reduces the production cost and shortens the production cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A process flow chart provided by the present invention;

[0054] Figure 2 This is an experimental data diagram provided by the present invention. DETAILED DESCRIPTION

[0055] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0056] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. 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. It should be noted that the embodiments of the present invention and the features and technical solutions in the embodiments can be combined with each other without conflict. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0057] Example 1: Please refer to Figure 1-Figure 2 , a metal brushed pattern appearance process, comprising the following process steps: S1, plastic part stress relief: stress relief of the internal stress existing after plastic injection molding;

[0058] S2, degreasing / deoiling: remove grease from plastic parts, degreasing / deoiling uses medium and low temperature alkaline liquid cleaning;

[0059] S3, Roughening: The strong acidity of the roughening liquid dissolves the butadiene component in the ABS plastic, so that microscopic rough dovetail-shaped holes are formed on the surface of the part to increase the contact area between the electroplating surface and the part;

[0060] S4, Neutralization and reduction: Remove strong acid and oxide impurities remaining on the surface of plastic parts; reduce and remove chromic acid hidden on the surface of parts through the reducing property of the solution;

[0061] S5, Pre-dip: Pre-dip allows divalent tin ions to attach to the surface of the plastic parts and further clean the chromium residue;

[0062] S6. Activation / sensitization palladium deposition: a layer of catalytically active metal layer is adsorbed on the surface of the plastic part; the catalytic substance in the solution - colloidal palladium (Pd) is evenly adsorbed in the dovetail-shaped holes on the surface of the part, providing a catalytic center for the occurrence of chemical nickel reaction;

[0063] S7, Reduction: After activation and cleaning, reduction treatment is required to remove the activation liquid on the surface; the colloidal palladium adsorbed on the surface of the parts in the catalytic liquid does not have catalytic activity, and the colloidal palladium is surrounded by divalent tin ions (Sn2+). The degumming process dissolves the divalent tin around the palladium to make it naked and catalytically active;

[0064] S8, chemical plating: a conductive coating is formed on the surface of plastic parts, the coating is uniform and continuous, so that the circuit forms a loop. After the chemical reaction, the surface of the parts is covered with a conductive nickel / phosphorus alloy layer, making the plastic parts that were not conductive before become conductors;

[0065] S9. Electroplating: Electroplating uses copper, nickel and chromium as a composite to electroplate on the plastic surface to form a metal brushed pattern on the surface.

[0066] S1. Stress relief requirements during the stress relief process of plastic parts: ABS: temperature 70℃, time 4-6h; PC+ABS: temperature 90℃, time 4-6h Stress test requirements: Soak in glacial acetic acid for 5 minutes, and no whitening is required.

[0067] S2. During the degreasing and oil removal process, the concentration of the degreasing powder is 30-50 g / L, the temperature is 55°C-60°C, and the time is 3-5 minutes.

[0068] S3. During the roughening process, -OH, -SO3H, >C=0 polar hydrophilic groups are generated on the surface of the part, making the surface of the part hydrophilic; the solution concentration cr03 is 380-420g / L; H2S04 is 390-420g / L; cr3+≦25g / L; the temperature is 68-72℃, and the time is 8-12 minutes.

[0069] S3. During the roughening process, the roughening liquid includes a perchromic acid solution.

[0070] S4. During the chromic acid reduction removal process, the hydrochloric acid content is 25%, the reducing agent content is 10%, the neutralization and reduction temperature is room temperature, and the chromic acid reduction removal time is 1 minute.

[0071] S6, activation / sensitization palladium precipitation: comprising the following steps:

[0072] S61. Ensure that the concentration of colloidal palladium solution is 500-1000 mg / L; control the solution temperature at 25-30°C to ensure the best adsorption effect;

[0073] S62. Immerse the plastic part completely in the colloidal palladium solution; use a stirrer to gently stir the solution to keep the solution uniform and avoid excessively high or low concentration in some areas; adjust the immersion time range to 5-10 minutes according to the size and shape of the plastic part;

[0074] S63. Take out the plastic parts to avoid damaging the catalytic layer on the surface; gently rinse the plastic parts with deionized water to remove the colloidal palladium that is not adsorbed on the surface; place the plastic parts in a dust-free environment to dry naturally or use mild hot air to blow dry.

[0075] S7, reduction and activation After cleaning, reduction treatment is required to remove the activation liquid on the surface, which specifically includes the following steps:

[0076] S71. Prepare dilute hydrochloric acid with a concentration of 5-10% mg / L as required; control the temperature of the reducing agent solution at room temperature 20-25°C;

[0077] S72. Immerse the plastic part completely in the reducing agent solution; use a stirrer to gently stir the solution to keep the solution uniform and avoid excessively high or low concentration in some areas;

[0078] S73. Adjust the soaking time to 1-3 minutes according to the size and shape of the plastic part; take out the plastic part to avoid damaging the catalytic layer on the surface.

[0079] S8. During the chemical plating process, the surface of the parts is covered with a conductive nickel / phosphorus alloy layer with a thickness of 0.2um.

[0080] S9. The specific steps of electroplating are as follows:

[0081] S91. Ensure that the electroplating tank is clean and free of pollution, and add copper, nickel and chromium electroplating solutions respectively;

[0082] S92. Set electroplating parameters:

[0083] S921, set the current density to 2-4A / dm according to the process requirements 2 ;

[0084] S922, setting the electroplating time according to the thickness of the coating, the electroplating time for each layer of metal is 10-30 minutes;

[0085] S923, controlled at room temperature to 50°C;

[0086] S93, copper electroplating: place the plastic part in the copper electroplating tank; turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic part and wash it with deionized water;

[0087] S94, nickel electroplating: put the cleaned plastic parts into the nickel electroplating tank, turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic parts and wash them with deionized water;

[0088] S95, chromium electroplating: put the nickel-plated plastic parts into the chromium electroplating tank; turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic parts and wash them with deionized water;

[0089] S96, Final cleaning: After all electroplating layers are completed, thoroughly clean the plastic parts with deionized water to remove the residual electroplating solution on the surface;

[0090] S97, Drying: Place the cleaned plastic parts in a dust-free environment to dry naturally or use mild hot air to dry;

[0091] S98. Inspection: Evaluate the appearance quality of brushed metal patterns by visual inspection and microscopic observation, including uniformity, gloss, and adhesion of the metal layer.

[0092] Stress relief for plastic parts: reduce internal stress and prevent deformation of products after electroplating. Improve product stability and durability.

[0093] Degreasing / deoiling: Remove grease from the surface of plastic parts to ensure uniform contact of the roughening liquid. Improve the effect and quality of subsequent processes.

[0094] Roughening: Increase the microscopic roughness of the plastic surface, increase the contact area between the electroplated surface and the part, and enhance the adhesion and durability of the coating.

[0095] Neutralization and reduction: remove residual strong acid and oxide impurities, improve the affinity of plastic parts, ensure the smooth progress of subsequent processes and improve product quality.

[0096] Pre-immersion: prepare for activation and further clean chromium residues; ensure the effectiveness of the activation process.

[0097] Activation / sensitization palladium deposition: adsorb a catalytically active metal layer on the surface of the plastic part to provide a catalytic center for the chemical nickel reaction. Improve the reaction efficiency and quality of chemical plating.

[0098] Reduction: Remove the activation liquid on the surface to expose the colloidal palladium and make it catalytically active. Accelerate the deposition speed and improve the quality of the coating.

[0099] Chemical plating: forms a coating with good conductivity to ensure that the circuit can form a loop. Make the plastic parts conductive and prepare for subsequent electroplating.

[0100] Electroplating: copper, nickel and chromium are used for composite electroplating to form metal brushed lines on the plastic surface. It has beautiful appearance, strong durability and good metal texture.

[0101] Compared with traditional silver spray paint and IML processes, the metal brushed appearance process has higher durability and better appearance. Through meticulous pre-treatment and precise electroplating control, a finer and more uniform metal brushed texture can be achieved.

[0102] The process of the invention not only improves the quality and performance of the product, but also reduces the production cost and shortens the production cycle.

[0103] Example 2: A metal brushed appearance process, stress relief for plastic parts: Since there is internal stress after plastic injection molding, in order to reduce the deformation of the product after electroplating, the internal stress must be removed. Stress relief requirements: ABS: temperature 70℃, time 4-6h; PC+ABS: temperature 90℃, time 4-6h Stress inspection requirements: Soak in glacial acetic acid for 5 minutes, no whitening is required.

[0104] Degreasing / deoiling: In order to ensure uniform contact with the solution during roughening, the grease on the plastic parts must be removed first, generally using a medium to low temperature alkaline liquid.

[0105] Cleaning; degreasing powder: 30-50g / L temperature: 55-60℃, time 3-5 minutes.

[0106] Roughening: The purpose is to ensure the contact area between the plastic parts and the liquid. Generally, a perchromic acid solution is used. The strong acidity of the roughening solution dissolves the B (butadiene) component in the ABS plastic, so that the surface of the parts forms microscopic rough "swallowtail" holes to increase the contact area between the electroplating surface and the parts. In addition, some -OH, -SO3H, >C=0 polar hydrophilic groups are generated on the surface of the parts, making the surface of the parts hydrophilic. Solution concentration cr03380-420g / L; H2S04 390-420g / L; cr3+≦25g / L; temperature: 68-72℃, time 8-12 minutes.

[0107] Neutralization and reduction: remove the strong acid and oxide impurities remaining on the surface of plastic parts to improve the affinity of plastic parts; use the reducing property of the solution to reduce and remove the chromic acid retained on the surface of parts. These retained chromic acids have an adverse effect on the subsequent processes and must be neutralized. Hydrochloric acid 25% reducing agent 10%, room temperature, 1 minute.

[0108] Pre-preg: To allow divalent tin ions to attach to the surface of plastic parts in preparation for activation; mainly to further clean chromium residues.

[0109] Activation / sensitization palladium deposition: In order to meet the needs of metal electroplating, a catalytically active metal layer needs to be adsorbed on the surface of the plastic part; the catalytic substance in the solution - colloidal palladium (Pd) is evenly adsorbed in the dovetail-shaped holes on the surface of the part, providing a catalytic center for the subsequent chemical nickel reaction.

[0110] Reduction: After activation and cleaning, reduction treatment is required to improve surface activity, accelerate deposition, and remove the activation liquid on the surface to prevent it from being brought into the chemical plating solution and causing decomposition. The colloidal palladium adsorbed on the surface of the parts in the catalytic liquid does not have catalytic activity because it is surrounded by divalent tin ions (Sn2+). The degumming process is required to dissolve the divalent tin around the palladium to expose it and make it truly catalytically active.

[0111] S8, chemical plating: The purpose is to form a good conductive coating on the surface of the plastic parts, the coating is uniform and continuous, and the circuit can form a loop to ensure the smooth progress of the next step; all the processes before this process are in preparation for the smooth progress of this process. After the chemical reaction, the surface of the part is covered with a layer of conductive nickel / phosphorus alloy layer (0.2um), which makes the plastic parts that were not conductive before become conductors, making the subsequent series of electroplating (copper, nickel, chromium) processes a reality. For the mechanism of chemical nickel, according to the "atomic hydrogen state theory", the following series of redox reactions occur in the presence of a catalyst:

[0112] H2PO2﹣+H2O→H++HPO3 2﹣+2H

[0113] △Ni2﹢+2H→Ni+2H﹢

[0114] H2PO2﹣+H→P+H2O+OH﹣

[0115] △H2PO2﹣+H2O→H+HPO3 2﹣+H2↑

[0116] Ni-P alloy and hydrogen are mainly produced during the reaction.

[0117] S9. Electroplating: Generally, copper, nickel and chromium are used as composite electroplating on the plastic surface to form a metal brushed effect.

[0118] The method of depositing a metal or alloy layer on the surface of a conductor by electrolyzing a solution with the help of external direct current is called electroplating.

[0119] The main cathode reaction:

[0120] Cu2++2e-→Cu anode main reaction:

[0121] Cu→Cu2++2e-

[0122] Cathode side reaction:

[0123] 2H3O++2e-→H2+2H2O Anode side reaction:

[0124] 6H2O→O2+4H3O++4e-.

[0125] Experimental example

[0126] Purpose:

[0127] Evaluate the effect of different process parameters on the appearance of brushed metal texture, especially the changes in degreasing powder concentration and roughening temperature.

[0128] Materials and Methods

[0129] Experimental group settings:

[0130] Experimental group A: ABS material, 30g / L degreasing powder, 68℃ roughening temperature;

[0131] Experimental group B: ABS material, 50g / L degreasing powder, 72℃ roughening temperature;

[0132] Experimental group C: PC+ABS material, 30g / L degreasing powder, 68℃ roughening temperature;

[0133] Experimental group D: PC+ABS material, 50g / L degreasing powder, 72℃ roughening temperature.

[0134] Neutralization, reduction (S4) to electroplating (S9): All steps are performed according to standard operations.

[0135] Evaluation criteria: Evaluate the clarity, uniformity and adhesion of the metal brushed texture by visual inspection and observation under a microscope.

[0136] Experimental data:

[0137]

[0138]

[0139] Observations:

[0140] Inspection after stress relief: No whitening was found on all samples after being immersed in glacial acetic acid for 5 minutes.

[0141] Degreasing / oil removal effect: The surface of samples treated with high concentration of oil removal powder (experimental groups B and D) is cleaner and has less grease residue.

[0142] Roughening effect: The samples treated at 72°C (experimental groups B and D) have more obvious micro-roughness than the samples treated at 68°C (experimental groups A and C).

[0143] Appearance after electroplating: The samples using 50g / L degreasing powder and roughened at 72°C (experimental groups B and D) showed the best metal brushed texture effect, with clear and uniform texture.

[0144] Inspection after stress relief: No whitening was found on all samples after being immersed in glacial acetic acid for 5 minutes.

[0145] Degreasing / oil removal effect: The surface of the sample treated with high-concentration oil removal powder is cleaner and has less grease residue.

[0146] Roughening effect: The samples treated at 72 °C have more obvious microscopic roughness than those treated at 68 °C.

[0147] Appearance after electroplating: The sample using 50g / L degreasing powder and roughened at 72℃ showed the best metal brushed texture effect, with clear and uniform texture.

[0148] Experimental conclusion:

[0149] 1. Increasing the concentration of degreasing powder can effectively improve the degreasing effect, thereby improving the surface treatment quality of subsequent processes.

[0150] 2. Increasing the temperature of the roughening step can enhance the micro-roughness of the plastic surface, which is conducive to forming a more obvious metal brushed texture.

[0151] 3. Considering the above factors, the best metal brushed texture appearance effect was obtained by using 50g / L degreasing powder and 72℃ roughening samples.

[0152] This experiment shows that by fine-tuning specific steps in the metal brushed appearance process, the appearance quality of the final product can be significantly affected. In particular, in the degreasing / deoiling and roughening steps, appropriate parameter adjustment is essential to obtain the desired surface effect. Future research can further explore the optimal process parameters under different materials and conditions to achieve more diverse product requirements.

[0153] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the above specific implementation methods. Therefore, any modification or replacement of the present invention; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the invention are included in the scope of the claims of the present invention.

Claims

1. A metal brushed appearance process, characterized in that: The process steps include: S1. Stress relief for plastic parts: relieve the internal stress of plastic after injection molding; S2, degreasing / deoiling: remove grease from plastic parts, degreasing / deoiling uses medium and low temperature alkaline liquid cleaning; S3, Roughening: The strong acidity of the roughening liquid dissolves the butadiene component in the ABS plastic, so that microscopic rough dovetail-shaped holes are formed on the surface of the part to increase the contact area between the electroplating surface and the part; S4, neutralization and reduction: remove strong acid and oxide impurities remaining on the surface of plastic parts; The chromic acid hidden on the surface of the parts is reduced and removed through the reducing property of the solution; S5, Pre-dip: Pre-dip allows divalent tin ions to attach to the surface of the plastic parts and cleans the chromium residue; S6. Activation / sensitization palladium deposition: a catalytically active metal layer is adsorbed on the surface of the plastic part; the catalytic substance in the solution - colloidal palladium (Pd) is evenly adsorbed in the dovetail-shaped holes on the surface of the part, providing catalysis for the occurrence of chemical nickel reaction; S7, Reduction: After activation and cleaning, reduction treatment is required to remove the activation liquid on the surface; the colloidal palladium adsorbed on the surface of the parts in the catalytic liquid does not have catalytic activity, and the colloidal palladium is surrounded by divalent tin ions Sn2+. The degumming process dissolves the divalent tin around the palladium to make it naked and catalytically active; S8, Chemical plating: A conductive coating is formed on the surface of the plastic part, so that the circuit forms a loop. After a chemical reaction, the surface of the part is covered with a conductive nickel / phosphorus alloy layer, making the originally non-conductive plastic part a conductor; S9. Electroplating: Electroplating uses copper, nickel and chromium as a composite to electroplate on the plastic surface to form a metal brushed pattern on the surface.

2. A metal brushed appearance process according to claim 1, characterized in that: S1. Stress relief requirements during stress relief of plastic parts: ABS: temperature 70°C, time 4-6h; PC+ABS: temperature 90℃, time 4-6h. Stress test requirements: soak in glacial acetic acid for 5 minutes, no whitening.

3. The metal brushed appearance process according to claim 1, characterized in that: S2. During the degreasing and oil removal process, the concentration of the degreasing powder is 30-50 g / L, the temperature is 55°C-60°C, and the time is 3-5 minutes.

4. The metal wire drawing process according to claim 1, characterized in that: S3. During the roughening process, -OH, -SO3H, >C=0 polar hydrophilic groups are generated on the surface of the part, making the surface of the part hydrophilic; the solution concentration cr03 is 380-420g / L; H2S04 is 390-420g / L; cr3+≦25g / L; the temperature is 68-72℃, and the time is 8-12 minutes.

5. The metal brushed appearance process according to claim 1, characterized in that: S3. During the roughening process, the roughening liquid includes a perchromic acid solution.

6. The metal wire drawing appearance process according to claim 1, characterized in that: S4. During the chromic acid reduction removal process, the hydrochloric acid content is 25%, the reducing agent content is 10%, the neutralization and reduction temperature is room temperature, and the chromic acid reduction removal time is 1 minute.

7. The metal wire drawing appearance process according to claim 1, characterized in that: S6, activation / sensitization palladium precipitation: comprising the following steps: S61, the concentration of colloidal palladium solution is 500-1000 mg / L; the solution temperature is controlled at 25-30°C; S62, completely immersing the plastic part in the colloidal palladium solution; stirring the solution with a stirrer, and adjusting the immersion time range to 5-10 minutes according to the size and shape of the plastic part; S63. Take out the plastic parts and gently rinse them with deionized water to remove the unabsorbed colloidal palladium on the surface; place the plastic parts in a dust-free environment to dry naturally or use mild hot air to dry them.

8. The metal wire drawing appearance process according to claim 1, characterized in that: S7, reduction and activation After cleaning, reduction treatment is required to remove the activation liquid on the surface, which specifically includes the following steps: S71, prepare dilute hydrochloric acid with a concentration of 5-10% mg / L; control the temperature of the reducing agent solution at room temperature 20-25°C; S72. Completely immerse the plastic part in the reducing agent solution; gently stir the solution using a stirrer; S73. Adjust the soaking time range to 1-3 minutes according to the size and shape of the plastic part; and take out the plastic part.

9. The metal wire drawing appearance process according to claim 1, characterized in that: S8. During the chemical plating process, the surface of the parts is covered with a conductive nickel / phosphorus alloy layer with a thickness of 0.2um.

10. The metal brushed appearance process according to claim 1, characterized in that: S9. The specific steps of electroplating are as follows: S91. Ensure that the electroplating tank is clean and free of pollution, and add copper, nickel and chromium electroplating solutions respectively; S92. Set electroplating parameters: S921, set the current density to 2-4A / dm according to the process requirements 2 ; S922, setting the electroplating time according to the thickness of the coating, the electroplating time for each layer of metal is 10-30 minutes; S923, controlled at room temperature to 50°C; S93, copper electroplating: place the plastic part in the copper electroplating tank; turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic part and wash it with deionized water; S94, nickel electroplating: put the cleaned plastic parts into the nickel electroplating tank, turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic parts and wash them with deionized water; S95, chromium electroplating: put the nickel-plated plastic parts into the chromium electroplating tank; turn on the power supply, adjust the current density and electroplating time; use a stirrer to keep the electroplating solution uniform; after the electroplating is completed, take out the plastic parts and wash them with deionized water; S96, Final cleaning: After all electroplating layers are completed, thoroughly clean the plastic parts with deionized water to remove the residual electroplating solution on the surface; S97, Drying: Place the cleaned plastic parts in a dust-free environment to dry naturally or use mild hot air to dry; S98. Inspection: Evaluate the appearance quality of the metal brushed pattern by visual inspection and microscopic observation, including the uniformity, gloss and adhesion of the metal layer.

Images