Abstract: A water soluble thermoplastic wiring board spacer for temporarily supporting an electrical component in fixed spaced relation to a printed wiring board which comprises a toroidally shaped spacer composed of a water soluble injection molded thermoplastic material. The material is preferably a polymer and the preferred polymer is a blend of partially hydrolyzed polyvinyl alcohol resin and fully hydrolyzed polyvinyl alcohol resin. The spacer has a melting temperature determined by the ratio of partially hydrolyzed polyvinyl alcohol resin to fully hydrolyzed polyvinyl alcohol resin and a solubility rate in water determined by the ratio of partially hydrolyzed polyvinyl alcohol resin to fully hydrolyzed polyvinyl alcohol resin. The spacer can have a plurality of spaced apart ridges and recessed surfaces on a surface thereof.

Abstract: Thermoplastic printed wiring board spacers are fabricated by providing a water soluble partially hydrolyzed polyvinyl alcohol resin or fully hydrolyzed polyvinyl alcohol resin or a blend of partially hydrolyzed polyvinyl alcohol resin and fully hydrolyzed polyvinyl alcohol resin, the ratio thereof depending upon (1) the degree of hydrolyzation of the polyvinyl alcohol resins, (2) crystallinity associated with particular polyvinyl alcohol resins, (3) the fabrication temperatures of the printed wiring board to avoid spacer melting and (4) the degree of solubility in water of the spacer. The spacers are fabricated by injection molding the polyvinyl alcohol resins or desired polyvinyl alcohol resin mixture to provide a molded configuration having a runner system with spacers attached to a sub runner system by a very thin gate.

Abstract: A method of degating molded parts including the steps of providing a water soluble molding material, molding a configuration from the molding material including parts secured to a runner system by gates of the molding material having a cross-section substantially thinner than any cross-section of the molded configuration, cooling the surfaces of the configuration to a temperature and for a time until only the gates becomes brittle, preferably by spraying liquid nitrogen over the surface of the configuration and applying an impact to the configuration to cause the configuration to sever at the gates, preferably by tumbling the cooled configuration, whereby the severed parts are separated from the runner system.

Abstract: Thermoplastic printed wiring board spacers are fabricated by providing a water soluble partially hydrolyzed polyvinyl alcohol resin or fully hydrolyzed polyvinyl alcohol resin or a blend of partially hydrolyzed polyvinyl alcohol resin and fully hydrolyzed polyvinyl alcohol resin, the ration thereof depending upon (1) the degree of hydrolyzation of the polyvinyl alcohol resins, (2) crystallinity associated with particular polyvinyl alcohol resins, (3) the fabrication temperatures of the printed wiring board to avoid spacer melting and (4) the degree of solubility in water of the spacer. The spacers are fabricated by injection molding the polyvinyl alcohol resins or desired polyvinyl alcohol resin mixture to provide a molded configuration having a runner system with spacers attached to a sub runner system by a very thin gate.