Compression molding has been used to mold rubber parts since the beginning of the silicone products manufacturing industry. It is one of the oldest methods still used to mold rubber parts. Seehope is a silicone molding company that has utilized compression molding since the year 2008.
Compression Molding is the simplest form of thermal set molding. Compression molds vary considerably in size, shape, and complexity and also contain from one to a very high number of cavities. The Compression Molding process is as follows: “An uncured rubber preform, which is often shaped to the approximate size & configuration of the desired finished part, is placed directly in the mold cavity prior to mold closure”.
During the molding process, silicone rubber is compressed (squeezed) between the Top and Bottom plates. The uncured preform must weigh more than the finished part in order for air to be driven out of the mold cavity during mold closure. If the preform weighs the same or less than the finished part; voids, air traps or non-fills will appear on the finished product. The excess rubber will flow into the overflow or flash groove. Two, three or more mold plates may be used depending upon part configuration and complexity. The silicone rubber is then Vulcanized(cured) utilizing both heat and pressure. The end result is a Silicone Rubber Products that will meet your specifications.