The surface quality in the mold cavity directly affects the plastic part surface quality produced by that mold. Better mold surface quality leads to better part surface quality. The quality of the mold’s finished surface is affected by the following:
- Type of mold material used.
- Mold forming method.
- Part design and application.
- Polishing method used.
Typical mold steel choices that will allow high quality surface finishes to be produced are as follows:
- Stainless steel grades 414 and 420
The polishability of steel is directly related to its quality. Defects such as pits, porosity, carbide segregation, or any inclusions must be avoided. In general, as steel hardness increases, the surface finish obtainable also increases.
Page 5 of 8