Compression molding

[1] The process employs thermosetting resins in a partially cured stage, either in the form of granules, putty-like masses, or preforms.

Advanced composite thermoplastics can also be compression molded with unidirectional tapes, woven fabrics, randomly oriented fiber mat or chopped strand.

However, compression molding often provides poor product consistency and difficulty in controlling flashing, and it is not suitable for some types of parts.

Fewer knit lines are produced and a smaller amount of fiber-length degradation is noticeable when compared to injection molding.

Compression-molding is also suitable for ultra-large basic shape production in sizes beyond the capacity of extrusion techniques.

Materials that are typically manufactured through compression molding include: Polyester fiberglass resin systems (SMC/BMC), Torlon, Vespel, Poly(p-phenylene sulfide) (PPS), and many grades of PEEK.

[2] Compression molding is commonly utilized by product development engineers seeking cost effective rubber and silicone parts.

Manufacturers of low volume compression molded components include PrintForm, 3D, STYS, and Aero MFG.

The more evenly the feed material is distributed over the mold surface, the less flow orientation occurs during the compression stage.

[3] Compression molding is also widely used to produce sandwich structures that incorporate a core material such as a honeycomb or polymer foam.

Thermoplastic matrices with an inherent indefinite shelf-life and shorter cycle molding times are widely used and examples are shown in Ref 3.

The landed plunger type mold must have an accurate charge of plastic, and no flash is produced.