RIM (REACTION INJECTION MOLDING)

摘要

PURPOSE:To evacuate completely the gas in a cavity of a mold, by setting a gas-evacuating pipe located at an appropriate point on the wall of the cavity, led to the outside of the mold and having a taper part whose inner diameter becomes larger at the cavity side and by setting a pin inserted through the hole of the gas-evacuating pipe and having an expansion contacted with the taper part. CONSTITUTION:A gap 7 between the taper part 5 and the expansion 42 is formed by moving the pin 4 downward. After the pipeline is open to the atmosphere, the mold 1 and 2 are clamped and a urethane resin is then introduced to the cavity 3 from the gate. The resin completely filled the cavity 3 while performing reaction and the gas is evacuated outside the gas-evacuating pipe 11 through the gap 7 formed between the upper part of the expansion 42 and the taper part 5. When the gas in the cavity 3 has been evacuated and the resin has filled the cavity, the pin 4 is pushed upwards by the expansion of the resin till the expansion 42 and the taper part 5 contact with each other.