| 摘要 |
PURPOSE:To prevent the generation of bubbles in a product as well as the missing of the product and eliminate large fins, remaining on the product, by a method wherein resin is poured into a cavity simultaneously through gates provided independently at both sides of the split faces of two pieces of molds respectively. CONSTITUTION:A heat radiating plate 25 is set in the recess 13 of a bottom force 11, a top force 31 is mated with the bottom force 11 and fixed, then, both of them are kept in a predetermined temperature and plasticated resin is poured forcibly into a runner 2 through spruces communicating with the runner 2 provided in the top force 31. The resin R1, entered through a gate 14, fills mainly a recess 13 at the lower side of the heat radiating plate 25 while the resin R2, entered into a cavity 3 through the gate 34, fills mainly the recess 33 at the upper side of the heat radiating plate 25. In this case, turbulence in the flow of resins R1, R2 is small and it will never generate bubbles by including air. A transistor element 44 is taken out, thereafter, gate pieces 41, 43 are separated from the transistor element 44, however, the sectional area of connecting part of both parts is small, therefore, fins will never remain and the element 44 will never be notched. |
