Compression molding is an economical process, starting with an economical way to produce a tool to make a product.
Compression molding requires a pre-formed, pre-measured amount of rubber that is placed in each cavity of the tool. The tool is closed under pressure with these pre-forms in the cavity and the material is formed in the desired shape.
This is an economical way to build a tool, as there is no need for expensive processing equipment or feed system required.
The drawbacks however is since the tool is not closed before the material enters the tool, parting lines tend to be harder to control for closure tolerance and rubber itself is a poor conductor of heat leading to extended cycle times.