Compression Molds

Compression molding or press molding is a lower cost, more commonly used approach to rubber molding. Compared to other methods, such as injection molding, Compression molding requires less materials and is a great low-cost approach for low production runs for composite components.

The Process

The Compression molding process is when a thermosetting plastic material is placed in an open, heated mold cavity. There are two different molding processes than can take place depending on material.

• Hot compression – This process is more commonly used and occurs by applying heat to the mold. A molding compound is charged into the mold and both halves of the materials are closed. Once the mold is closed both pressure and temperature are applied. Depending on the thickness of the material, the cooldown process can vary in time. Once the cooldown has occurred, the component can be ejected from the mold.
• Cold compression – Unlike the hot compression process, during cold compression the curing process takes place at room temperature and only involves pressure and not heat.

Tools Used:

Compression molding is used to produce composite parts for a multitude of products. The great thing about compression molding is fewer parts are used, making the process cheaper. The most common materials used for this process is:

• Bulk Molding Compound (BMC) – BMC offers stronger materials and a lighter weight option to other metals.

These two compounds are applied to the mold by pressure. They are then heated until the curing reaction occurs.

Compression molds are used to produce a number of different products across multiple industries like:

• Automotive parts
• Aerospace materials (satellites, etc.)
• Stadium seating
• Kitchenware (bowls, plates, etc.)

The Toolroom offers compression molding and can build compression molds. Give us a call today and let us help you with your next project!