The main purpose of electroplating is to:
1. Protect the surface of metal parts and prevent corrosion.
2. Decorate the appearance of parts to make them beautiful.
3. Improve the working performance of parts.

The selection of electroplating layer type and thickness mainly depends on the following factors:
1. Working environment of parts.
2. Type, material and properties of parts to be plated.
3. Properties and uses of electroplated layers.
4. Tolerances on the structure, shape and size of parts.
5. Materials and properties of the coating and the metal in contact with each other.

Requirements for electroplating layers:
1. There should be good bonding between the coating and the base metal, and between coatings.

2. The coating should be finely crystallized, flat, and even in thickness.
3. The coating should have the specified thickness and as few pores as possible.
4. The coating should have various specified indicators, such as brightness, hardness, conductivity, etc.