Surface treatment method for mobile phone battery cover mold

Abstract

The invention relates to the technical field of mold treatment, in particular to a surface treatment method for a mobile phone battery cover mold. The surface treatment method comprises the following steps that cleaning treatment, polishing treatment, pattern turning treatment, chemical nickel layer electroplating and cleaning and drying are sequentially conducted on the surface of the mold. According to the surface treatment method, the extremely thin nickel layer is chemically electroplated on the surface of the mold, it is ensured that the surface of an injection product is free of water marks, black marks and other defects, the nickel layer has high hardness and corrosion resistance, mechanical abrasion in the injection molding process can be effectively resisted, the service life of the mold is prolonged, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of mold treatment, and particularly relates to a surface treatment method for a mobile phone battery cover mold. Background Art

[0002] There are turning fine lines on the surface of the mobile phone battery cover mold. During the injection molding production process, defects such as water lines and black marks are likely to appear, resulting in a decline in the surface quality of the injection molded products. Traditional methods usually adopt polishing or coating treatment. For example, the Chinese invention patent with the application number 202111322718.9 discloses spraying gel coat on the mold surface and then performing water grinding and polishing, which can solve the problem of poor surface appearance of the injection molded products. However, these methods have problems such as insufficient mold hardness, poor corrosion resistance, and short service life, and cannot fundamentally solve the influence of mold surface defects on the injection molded products. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a surface treatment method for a mobile phone battery cover mold with high hardness and strong corrosion resistance.

[0004] To solve the above technical problem, the technical solution adopted by the present invention is: A surface treatment method for a mobile phone battery cover mold, comprising the following steps: sequentially performing cleaning treatment, polishing treatment, turning treatment, chemical electroplating nickel layer, and cleaning and drying on the mold surface.

[0005] The beneficial effect of the present invention lies in that: Through the surface treatment method of the present invention, by sequentially performing cleaning treatment, polishing treatment, turning treatment, chemical electroplating nickel layer, and cleaning and drying on the mold surface, an extremely thin nickel layer is chemically electroplated on the mold surface, ensuring that there are no defects such as water lines and black marks on the surface of the injection molded products. This nickel layer has high hardness and corrosion resistance, can effectively resist mechanical wear during the injection molding process, extend the service life of the mold, and reduce production costs. Detailed Embodiment

[0006] To illustrate the technical content, achieved objectives, and effects of the present invention in detail, the following is described in conjunction with the embodiments.

[0007] A surface treatment method for a mobile phone battery cover mold, comprising the following steps: sequentially performing cleaning treatment, polishing treatment, turning treatment, chemical electroplating nickel layer, and cleaning and drying on the mold surface.

[0008] As can be seen from the above description, the beneficial effects of the present invention are as follows: In the surface treatment method of the present invention, the surface of the mold is first cleaned and polished to remove oil stains and oxide layers on the surface and ensure surface smoothness, which is beneficial for subsequent chemical electroplating treatment; then graining is carried out to obtain fine patterns; the nickel layer is chemically electroplated on the grained mold, significantly improving the hardness, corrosion resistance and service life of the mold; after electroplating is completed, cleaning and drying treatments are carried out to ensure that the surface of the nickel layer is bright and defect-free. The mold after surface treatment is used for the injection molding production of mobile phone battery covers, and there are no defects such as water streaks and black marks on the surface of the injection molded products. The mold after the surface treatment method of the present invention is not only applicable to the injection molding of mobile phone battery covers, but also applicable to the injection molding of any surface fine pattern products.

[0009] Among them, cleaning is carried out first, and it is easier to carry out polishing treatment after removing impurities and oxide layers.

[0010] Further, the cleaning treatment includes the following steps: alkaline cleaning and acid cleaning are sequentially carried out on the surface of the mold.

[0011] As can be seen from the above description, alkaline cleaning can remove oil stains, and then acid cleaning is beneficial for removing the oxide layer under the oil stains.

[0012] Further, the cleaning solution used for alkaline cleaning contains at least one of sodium hydroxide, sodium carbonate and sodium phosphate.

[0013] Further, the cleaning solution used for acid cleaning contains at least one of sulfuric acid, hydrochloric acid and phosphoric acid.

[0014] Further, the surface smoothness of the mold after polishing treatment reaches Ra≤0.1μm.

[0015] As can be seen from the above description, when the surface smoothness of the mold reaches Ra≤0.1μm, the accuracy of graining and the flatness of the subsequent electroplated nickel layer are improved.

[0016] Further, the graining treatment includes the following steps: pattern processing is carried out on the surface of the mold, and the depth of the pattern is 0.025~0.03mm.

[0017] As can be seen from the above description, the depth of the pattern is 0.025~0.03mm, and this depth can ensure clear patterns without greatly affecting the overall strength of the mold.

[0018] Further, the chemical electroplated nickel layer includes the following steps: nickel sulfate, sodium hypophosphite, sodium citrate and a stabilizer are mixed to form a chemical electroplating solution, and the grained mold is immersed in the chemical electroplating solution to form a nickel layer with a thickness of 0.003~0.005mm on the surface of the mold.

[0019] From the above description, it can be seen that forming a nickel layer on the mold surface by chemical reduction reaction is simple and efficient. The nickel layer of this thickness is relatively thin, which can improve the hardness and corrosion resistance of the mold and have little effect on the depth of the texture.

[0020] Furthermore, the pH value of the chemical plating solution is 4.0-5.5, and the temperature is 70-90°C.

[0021] From the above description, we can see that when the pH value is 4.0-5.5, the reducing ability of hypophosphite is moderate, and it can stably release electrons to convert Ni 2+ If the alkalinity increases, the hypophosphite may spontaneously decompose, causing the plating solution to be unstable (such as the precipitation of nickel-phosphorus particles) or even causing the plating solution to self-decompose.

[0022] Furthermore, the chemical plating solution includes 25-35 g / L nickel sulfate, 15-25 g / L sodium hypophosphite, 5-15 g / L sodium citrate and 0.5-1.5 g / L stabilizer.

[0023] Furthermore, the material of the mold is bronze.

[0024] From the above description, we can see that the material is easy to process and the surface texture is clear after turning.

[0025] Embodiment 1 of the present invention is: a surface treatment method for a mobile phone battery cover mold, the steps are as follows: S1: The mold surface is cleaned with an ultrasonic cleaning machine. The bronze mold is immersed in a sodium hydroxide solution with a pH of 10 for ultrasonic cleaning for 8 minutes. After water washing, it is immersed in a sulfuric acid solution with a pH of 4 for ultrasonic cleaning for 15 minutes. Then, it is washed with water and then ultrasonically cleaned with deionized water.

[0026] S2: The mold surface is polished with a polishing machine. After polishing, the surface finish of the mold reaches Ra≤0.1μm.

[0027] S3: The mold surface is textured, and the depth of the texture is 0.027 mm.

[0028] S4: Prepare a chemical plating solution, which consists of 30 g / L nickel sulfate, 30 g / L sodium hypophosphite, 10 g / L sodium citrate, 1 g / L citric acid and deionized water. The pH value of the chemical plating solution is 5 and the temperature is 80°C. Immerse the mold after the car graining treatment in the chemical plating solution to form a nickel layer with a thickness of 0.003 mm on the surface of the mold.

[0029] S5: Clean the mold surface with deionized water and then dry it with a hot air dryer.

[0030] Comparative Example 1 of the present invention is: The difference between Comparative Example 1 and Example 1 is only that: step S4 is not included.

[0031] Use the molds of Example 1 and Comparative Example 1 to injection mold 10 PC (polycarbonate) mobile phone battery covers respectively. The injection molding conditions are: melt temperature is 230 °C, injection pressure is 40 bar, holding pressure is 50 MPA, holding time is 10 s. Detect the mold and the injection molded products, and the detection results are shown in Table 1.

[0032] Table 1

[0033] Example 2 of the present invention is: a surface treatment method for a mobile phone battery cover mold, and the steps are as follows: S1: Use an ultrasonic cleaning machine to clean the surface of the mold. Immerse the bronze mold in a sodium carbonate solution with a pH of 10 and ultrasonically clean for 8 min. After water washing, immerse it in a hydrochloric acid solution with a pH of 4 and ultrasonically clean for 15 min. Then wash with water and ultrasonically clean with deionized water.

[0034] S2: Use a polishing machine to polish the surface of the mold. After polishing, the surface finish of the mold reaches Ra ≤ 0.1 μm.

[0035] S3: Perform texture processing on the surface of the mold, and the depth of the texture is 0.025 mm.

[0036] S4: Prepare a chemical electroplating solution. The chemical electroplating solution consists of 25 g / L nickel sulfate, 15 g / L sodium hypophosphite, 5 sodium citrate, 0.5 g / L citric acid and deionized water. The pH value of the chemical electroplating solution is 5.5, and the temperature is 70 °C; immerse the mold after thread turning in the chemical electroplating solution to form a nickel layer with a thickness of 0.004 mm on the surface of the mold.

[0037] S5: Wash the surface of the mold with deionized water, and then use a hot air dryer for drying treatment.

[0038] Example 3 of the present invention is: a surface treatment method for a mobile phone battery cover mold, and the steps are as follows: S1: Use an ultrasonic cleaning machine to clean the surface of the mold. Immerse the bronze mold in a sodium phosphate solution with a pH of 10 and ultrasonically clean for 8 min. After water washing, immerse it in a phosphoric acid solution with a pH of 4 and ultrasonically clean for 15 min. Then wash with water and ultrasonically clean with deionized water.

[0039] S2: Use a polishing machine to polish the surface of the mold. After polishing, the surface finish of the mold reaches Ra ≤ 0.1 μm.

[0040] S3: Perform texture processing on the surface of the mold, and the depth of the texture is 0.03 mm.

[0041] S4: Configure the electroless plating solution. The electroless plating solution is composed of 35 g / L nickel sulfate, 25 g / L sodium hypophosphite, 15 g / L sodium citrate, 1.5 g / L citric acid, and deionized water. The pH value of the electroless plating solution is 4.0, and the temperature is 90 °C. Immerse the die after the knurling treatment into the electroless plating solution to form a nickel layer with a thickness of 0.005 mm on the surface of the die.

[0042] S5: Wash the surface of the die with deionized water, and then perform drying treatment using a hot air dryer.

[0043] In summary, for the surface treatment method of the mobile phone battery cover die provided by the present invention, by making patterns on the surface of the die and electroless plating a nickel layer with a thickness of 0.003 - 0.005 mm, the hardness, corrosion resistance, and service life of the die are significantly improved. At the same time, the surface quality of the injection molded product is improved. This method is applicable to the surface treatment of mobile phone battery cover dies, can effectively protect the surface patterns of the die, and ensure that there are no defects such as water streaks and black marks on the surface of the injection molded product.

[0044] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent transformations made using the description of the present invention, directly or indirectly applied in related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A surface treatment method for a mobile phone battery cover mold, characterized in that, It includes the following steps: The mold surface is successively subjected to cleaning treatment, polishing treatment, texturing treatment, chemical electroless nickel plating treatment, and cleaning and drying treatment.

2. The surface treatment method according to claim 1, characterized in that, The cleaning treatment includes the following steps: successively performing alkaline cleaning and acid cleaning on the mold surface.

3. The surface treatment method according to claim 2, characterized in that, The cleaning solution used for the alkaline cleaning contains at least one of sodium hydroxide, sodium carbonate, and sodium phosphate.

4. The surface treatment method according to claim 2, characterized in that The cleaning solution used for the acid cleaning contains at least one of sulfuric acid, hydrochloric acid, and phosphoric acid.

5. The surface treatment method according to claim 1, wherein After the polishing treatment, the surface finish of the mold reaches Ra≤0.1μm.

6. The surface treatment method according to claim 1, characterized in that, The texturing treatment includes the following steps: performing texture machining on the mold surface, and the depth of the texture is 0.025 - 0.03mm.

7. The surface treatment method according to claim 1, characterized in that The chemical electroless nickel plating treatment includes the following steps: mixing nickel sulfate, sodium hypophosphite, sodium citrate, and a stabilizer to form a chemical plating solution, immersing the mold after the texturing treatment in the chemical plating solution, and forming a nickel layer with a thickness of 0.003 - 0.005mm on the mold surface.

8. The surface treatment method according to claim 7, characterized in that, The pH value of the chemical plating solution is 4.0 - 5.5, and the temperature is 70 - 90°C.

9. The surface treatment method according to claim 7, wherein The chemical plating solution includes 25 - 35g / L of nickel sulfate, 15 - 25g / L of sodium hypophosphite, 5 - 15g / L of sodium citrate, and 0.5 - 1.5g / L of stabilizer.

10. The surface treatment method according to claim 1, characterized in that, The material of the mold is bronze.

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