Device and method for runner-less molding of thermosetting resin and rubber

Abstract

A runner-less molding device for thermosetting resins and rubbers, characterized by a movable runner bush (), through which an uncured or unvulcanized fluid material kept at a low temperature supplied from a pouring nozzle () can flow, is slidably arranged in a temperature controlling bush () communicating with a gate () of a cavity (); an insulation space (A) is formed by moving the movable runner bush () apart from the gate () during heating; a valve pin () is movably inserted into said movable runner bush (); and the valve pin () is arranged so as to open and close the gate () in accordance with a pouring operation of the fluid material. A runner part of the movable runner bush containing molding material is constituted so as to move forward/backward relative to the cavity for preventing heat from conducting from the cavity, which is kept at a molding temperature, to the runner positioned apart from the gate for a long time, so that material loss generated in a sprue runner is reduced to almost null in order to reduce fabricating costs after molding and amount of wastes generated during after treatments. Thus, the improved molding device for the thermosetting resin and the rubber is obtained, and burdens on the global environment are alleviated.