(Click to enlarge image) In Liquid Silicone Rubber molding, the rubber prep is injected into the cavity forming components. A runner system is used to get the rubber material into the cavity. The press for this process will be an injection press. The runner system can be hot, cold, valve gated or open nozzle cold runner systems. Flash control is trimless/flashless (ground lands) or tear-trim depending on the part and runner system used. LSR injection molds are usually in groups of 4 to maintain an even balance of the runner system. Cavity counts can be between 4 and 128. Hot runner and cold runner systems do have controlled rubber waste with each cycle. A valve gated or open nozzle runner system is a no waste system. Valve gated or open nozzle can be more expensive than a standard cold runner system. Mold construction can be inserted or cut in plate.