Insert molding apparatus with movable flash barrier

Abstract

A molding press for insert molding of composite articles. The press has upper and lower plates movable between open and closed positions, and a die set positioned between the plates. The die set includes a core member with surfaces defining a portion of the molding cavity and another surface for receiving and supporting the insert. The core member also includes means defining a part of an area for receiving a charge of curable material and a part of a scrap forming cavity. A second mold member has surfaces defining a second portion of the article forming cavity and a second portion of said strap forming cavity, and the second mold member also includes means for engaging the insert and cooperating with it to form an axially movable flash barrier. The second mold part also has means cooperating with the insert to form a second, stationary flash barrier on an angularly related surface of the insert. The third mold member is adapted to reciprocate relative to the first and second members and has one surface for engaging a portion of said charge of moldable material for moving it from the receiving area through the scrap forming area and into the molding cavity. The first and third elements also include surfaces lying opposite each other in the closed position of said mold which serve to define a slightly spaced apart, substantially circumferentially continuous passage of reduced cross-section which separates scrap forming area from the article forming cavity. The second and third mold members are resiliently urged, in the closed position of the mold towards the first member by separate sets of resilient means interposed between portions of the second and third members and portions of the top mold plate. The method includes establishing a movable flash barrier by engaging an axial insert surface during mold closure. A seal with a unitary body, having two or more lips and a deep axial cross-section, is also described.