Liquid silicone rubber molding is a rapidly growing niche market with new applications appearing regularly. The molding process is rather unique, but not so different than the plastic molding process of thermoplastic, except that it is the opposite!
Custom injection molders everywhere are looking for markets to penetrate, and this is an opportunity for a molder who is willing to learn new technologies and invest in a white room. It is also advisable to have put into place your lean manufacturing process. Besides the fact that it just makes good business sense, medical companies are very demanding of protocol, order, cleanliness, and accountability.
LSR molding is somewhat like baking a cake: the material is injected in a cold state, then heated up in with mold. This is one reason it flashes so easily.
Liquid Silicone Molding is like baking
Liquid silicone molding is very similar to conventional plastic injection molding, with one major difference: with silicone the barrel is cooled and the mold is heated! Just exactly opposites. Because the parts are injection molded, they are clean and hopefully flash-free. This offers several benefits such as lower cost per part, better quality control, and contamination free parts. This makes it ideal for molded medical parts.
Molders who can have a Class 10,000 Cleanroom for high cleanliness sensitive parts are able to mold U.S.P. Class VI Medical and Food Grade materials. While this demands a high level of investment and sophistication, the payoff can be great. This is also a strategy some custom injection molders use to win domestic work. You can also use your usual injection mold making team, though there is quite a learning curve, due to the exacting tolerances. The mold making process is very similar, with tougher steels and tighter tolerances.
LSR molded parts
Many gaskets and “o” rings used in assembly are made of silicone rubber. Other medical rubber parts can be made out of Viton, Nitrile, Neoprene, Fluorosilicone,and Ethylene Propylene. Because the molding is done without contaminants in the plastic, seals and gaskets of silicone are ideal for medical products.
LSR mold making is not for everyone, to put it diplomatically. The tolerances are extremely tight and the steel is nasty: D2
Besides the medical market, there are numerous other industries served by LIM™. Aerospace, automotive, electronics manufacturers, firefighters, divers, and many other specialized industries are included. This represents a good opportunity for injection molders who want to diversify
LSR products are found on most military aircraft such as special helicopters, bombers, in-flight refueling craft, and jet fighters. Nearly all commercial aircraft use elastomeric molded parts as well. Every year more and more applications are being developed.