(Click to enlarge image) With Injection molding, the rubber prep is injected into the cavity forming components by a runner system. The press for this process is an injection press. The runner system can be hot, cold or valve gated. Flash control is tear-trim or trimless/flashless (ground lands) depending on the material and runner system used. Injection molds are usually 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 will have controlled rubber waste. A valve gated runner system is a no waste system. Valve gated cold runners can be more expensive than a standard cold runner system. Mold construction can be inserted or cut-in plate.