Patent attributes
A retractable pin reaction injection molding device and method for forming a layer on an object are disclosed and claimed. The device includes mold plates that cooperate to form a cavity. Retractable pins hold the object within the cavity. Material is inserted into the cavity under pressure to form a layer on the object. The pins are retracted and material fills the voids left by the retracted pins. A system prevents the material from flowing into the clearance between the pins and the mold plates. The system provides a counter pressure of a non-reacting gas to resist the material insertion pressure. The counter pressure may also be used to balance and control the material injection into the mold. Suitable materials for use with the apparatus and method are also disclosed.
