What is a Compression Mold?

A compression mold is an open, heated mold. The material being molded usually is preheated, then poured into the mold. Pressure is applied to force the material into the entire mold, then heat and pressure is kept until the molded material is cured.

Compression molding is useful for manufacturing large batches of large, intricate parts, such as automotive parts like hoods, fenders, and spoilers. This method of molding also works for smaller, more intricate parts. It is less expensive than injection molding or transfer molding. Two types of materials used in compression molding are high-strength fiberglass and thermoplastics. The molding materials are either sheets of material or granules. Granules can be poured into a mold and sheets of material can be laid between the mold and the plug and squeezed into the mold.

Another advantage to compression molding is that it wastes relatively little material, which helps when using expensive molding material. Where compression molding comes up short is in product inconsistency and lack of flashing control.

Our automotive customers find compression molding a particularly useful process, since it keeps the cost down and quickly produces large batches of parts. If you think compression molding might be the right process for creating your parts, contact us to discuss your project more. We can work with our customers to determine the best method and materials for making compression molds that ultimately optimize the parts that are fabricated from those molds.