Surface treatment is widely used in many objects, from traditional industry to high-tech industry, from metal surface to plastic surface. All processes, which are made to change the material surface's physical, mechanical and chemical properties, is called Surface Treatment. 
A mold surface treatment is processed to improve surface finish of injection molded parts. It makes materials more corrosion-resistant, wear-resistant and heat-resistant. Also it prolongs the lifetime of materials, and add add value of products through improving the surface characteristics of materials and gloss beauty.

The purpose of surface treatment in plastic injection mold can be divided into four categories:
1) Aappearance;
2) Protection;
3) Special surface properties;
4) Mechanical or engineering properties.