Compression Molding

Compression Molding

Quick cycle times ◾Reduced secondary operation costs

Compression molding is best used for parts that have a variable wall thickness and can be readily “split” into two to three sections to facilitate a simple mold design. The process reduces part fabrication cycle times as the material systems are designed to cure quickly when exposed to high pressure at the cure temperature. The process allows for hybrid material compression and different shapes that would otherwise have to be machined, or made as multiple pieces and then bonded, saving assembly costs in the production line.

More about Forged Composites

Compression molded composites are also known as forged composites. The process demands matched metal tooling, so these costs generally drive the need for increased part volumes of 10pcs per annum or higher to deliver the best ROI. Regardless of these challenges, Rock West Composites can deliver low-cost molding with high precision making it an excellent choice for most geometric choices that have fine detail and are less planar in nature. Rock West Composites has years of experience and know-how in the selection of the appropriate materials, processing to aerospace, precision tolerances, and functional mold designs that keep costs low and parting lines that don’t affect the cosmetics of the molded parts.

What is the compression molding process?

This is a very simple method that can be used for the most complicated parts.

  • Process starts with a matched metal mold, so all exterior surfaces are molded net
  • The mold cavity is generally split into two halves and mounted into a hydraulic press
  • The mold is set to the desired material cure temperature and the process is kept as isothermal
  • Bulk or sheet molding compound is loaded into the lower half of the mold and the press is activated to close and consolidate (or compress) the material to the net shape of the mold
  • After being held under pressure and temperature, the press is opened and the cured “part” is then ejected from the mold
  • The mold is then blown clean with filtered shop air and the molding cycle is repeated


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