Apparatus and method for runnerless injection compression molding of thermosetting materials.

摘要

The apparatus of the present invention includes a stationary assembly and a movable assembly. The stationary assembly is comprised of a stationary platen (27) which has a heat plate (29), a temperature-controlled sprue bushing (19) and a mold face (21) positioned thereon. The movable assembly is comprised of a movable platen (39) which has a heat plate (41) mounted thereon and a mold face (25), corresponding to, and adapted to be aligned with, the mold face (21) on the stationary assembly to form a partially open mold cavity (23). Means are provided to feed a supply of thermosetting molding material through the sprue bushing (19) into the partially open mold cavity (23). Means are provided to completely close the mold cavity and place the apparatus in a compression stage. In the injection and in the compression stages, the discharge end (35) of the sprue bushing (19) is in direct feed relationship with the mold cavity (23), allowing flow of molding material from the sprue bushing (19) into the mold cavity (23) in the injection stage and flow of molding material from the mold cavity (23) into the sprue bushing (19) in the compression stage. Means are also provided for the subsequent retraction of the movable assembly to allow removal of a molded article and access to the mold area.