Compression Molding

Compression molding is a manufacturing process that has been used in the pouring and forming of parts for more than 200 years. Dating back to the 1840’s, there is historical data showing that initial moldings were made of Bois, which is fine sawdust and hardwood mixed with animal blood to create a hard, polished resin. During the 1840’s, this process was used to manufacturer coins and medallions in France. And while the materials we use in the molding process have greatly evolved, the basics of manufacturing using this method are still very much the same today.  Compression molding is when you heat up a resin and pour or inject it into a preformed mold. The mold is then closed and even pressure is applied as the resin cures. The even pressure applied ensures that the resin fills all crevices of the mold to get a well-formed part. Compression molding is an inexpensive process that allows you to make many formed parts quickly and consistently.

What Type of Parts are Good Candidates for Compression Molding?

There are many different items manufactured using the compression molding process. Many compression molding companies manufacture everything from heavy machinery parts to rubber rain boots.  Some of the parts that can be made successfully using the compression molding process include formed handles, electrical receptacles, gaskets, pump parts, and spindles. Items that you need to make in bulk inexpensively are great candidates for this type of process.

Designing Parts for Compression Molding

Compression molding work begins in the design phase. Designing parts with the molding process in mind can seem a bit daunting, but the good news is that the whole design process really only uses three basic principles. These principles are part design, material selection, and plastic processing.  If you take shrinkage and warping into account during the design phase, you eliminate problems down the road when production starts.