Compression Moulding is one kind of elastomer rubber molded process, also which heat up strips of rubber compound (pre-forms) or mixed silicone rubber raw material (free-flowing granular form or a viscous material) in heated mould cavity & chamber in aim to fabricate desired elastomer rubber products by hydraulic press. Rubber compression molding process is also called vulcanization process, is performed at a mold temperature of 350 °F and mold pressure of 100 psi (180 °C and 700 kPa) with curing time about 3mins (depends on molded silicone rubber thickness and rubber materials).
Compression Moulding of rubber strip compound provide a surplus of material to be placed in the cavity, in aim to all cavities filled. Once in place, the mould is then closed, applying both heat and pressure to the rubber raw material (thermoplastics and thermoset resin) and allowing it to fill the cavity. When the cavity is filled, excess pre-form material spills out into overflow grooves. Following this step the rubber is then demolded, usually by hand, leaving us with the molded rubber product.
Benefits of Compression Moulding
Cost effective mold tooling: Sample, low-quality and mass production
Maximized cavity & chamber quantity
Economical process for medium precision
New Application: liquid silicone rubber materials compression molding & transfer-Injection molding
Compression molding can be a cost effective solution in situations where:
The tooling already exists
The cross-section of the part is very large and requires a long cure time
Removal of the rubber flash (edge) from a molded silicone rubber parts & product can be accomplished in a number of ways. Depending on the material, part size, tolerance demands and quantity deflashing methods commonly include:
Manual tear trimming