What are the functions of surface treatment technology for plastic injection molds

Plastic injection mold is a vital tool in the production process of plastic products. Its quality directly affects the molding quality and production efficiency of plastic products. In order to improve the service life and production efficiency of plastic injection molds, surface treatment technology is becoming more and more important. Not only that, with the diversification of plastic products and the improvement of quality requirements, the requirements for surface treatment technology of plastic injection molds are also getting higher and higher.

1. Chrome plating treatment
Chrome plating is a commonly used surface treatment technology. Its main function is to form a uniform and smooth chromium layer on the surface of the mold to improve the wear resistance and corrosion resistance of the mold. Chrome plating can be carried out in two ways: electroplating and chemical plating.
Electroplating chromium plating is to place the mold in an electrolyte containing chromate, and through the action of electric current, chromium ions are deposited on the surface of the mold to form a uniform chromium layer. This method can control the thickness and uniformity of the chromium layer to ensure the quality of the mold surface. Electroless chromium plating is to place the mold in a solution containing chromium complex, and under a certain temperature and pressure, the chromium complex is deposited on the surface of the mold to form a chromium layer. Compared with electroplating, the advantage of electroless plating is that it can form a uniform chromium layer on the surface of complex-shaped molds, but its cost is higher.
Chrome plating can improve the surface hardness and wear resistance of the mold, reduce the friction between the mold and the plastic material, and extend the service life of the mold. In addition, the chromium plating layer has good corrosion resistance and can protect the mold surface from chemical corrosion, thus improving the stability and reliability of the mold.

2. Nitriding treatment
Nitriding treatment is a surface treatment technology that forms a nitride layer on the surface of the mold. Its main function is to improve the hardness, wear resistance and corrosion resistance of the mold. Nitriding treatment can be carried out in two ways: gas nitriding and ion nitriding.
Gas nitriding is to place the mold in a high-temperature environment containing nitrogen gas (such as ammonia), so that nitrogen atoms penetrate into the surface of the mold and react chemically with the iron elements in the mold matrix to form a nitrided layer with higher hardness. This method can form a uniform nitride layer on the surface of the mold and improve the hardness and wear resistance of the mold. Ion nitriding uses ion beam bombardment to form a uniform and dense nitride layer on the surface of the mold. Compared with gas nitriding, ion nitriding can be performed at a lower temperature, and the nitrided layer is denser and has higher hardness and corrosion resistance.
The nitrided layer has high hardness and wear resistance, which can effectively improve the service life and corrosion resistance of the mold. At the same time, the nitride layer also has excellent heat resistance and remains stable in high temperature environments, so it can also play a good protective role during the injection molding process.

3. Sand blasting
Sandblasting is a commonly used surface treatment technology. Its main function is to form a layer of texture with moderate roughness on the surface of the mold to improve the slip resistance and adhesion of the mold. Sandblasting can be carried out in two ways: mechanical sandblasting and chemical sandblasting.
Mechanical sandblasting uses a high-speed sandblasting machine to spray abrasive particles onto the surface of the mold, causing impact and grinding to form a surface with a certain roughness. This method can sandblast complex-shaped mold surfaces and control the roughness of the sandblasting to meet the requirements of different plastic materials. Chemical sandblasting uses chemical solutions to corrode the surface of the mold to form a surface with a certain roughness. Compared with mechanical sandblasting, chemical sandblasting can control the depth and shape of the sandblasting, thereby more finely adjusting the texture of the mold surface.
Sandblasting can increase the friction coefficient of the mold surface, improve the adhesion between the mold and the plastic material, prevent the plastic material from slipping during the injection molding process, thereby improving the dimensional accuracy and surface quality of the product. In addition, sandblasting can also eliminate the smoothness of the mold surface, which is beneficial to the filling and cooling of plastic materials on the mold, thereby improving the molding efficiency of the product.

4. Oxidation treatment
Oxidation treatment is a surface treatment technology that forms an oxide layer on the surface of the mold. Its main function is to improve the corrosion resistance and surface hardness of the mold. Oxidation treatment can be carried out in two ways: thermal oxidation and chemical oxidation.
Thermal oxidation is to heat the mold to a certain temperature so that the surface of the mold reacts with oxygen to form a dense oxide layer. This method can enhance the corrosion resistance of the mold surface and prevent the mold surface from being corroded by chemical substances. Chemical oxidation is to place the mold in a solution containing an oxidant, and at a certain temperature and time, the surface of the mold reacts with the oxidant to form an oxide layer. Compared with thermal oxidation, chemical oxidation can control the thickness and uniformity of the oxide layer, thereby more finely adjusting the properties of the mold surface.
The oxide layer has good corrosion resistance and can protect the mold surface from chemical erosion, thus improving the stability and reliability of the mold. At the same time, the oxide layer can also increase the hardness of the mold surface and improve its wear resistance, thus extending the service life of the mold.