| 摘要 |
PURPOSE:To easily mass-produce a double structural body by extruding a right sheet and a left sheet independently from simple dies by a structure wherein a male and a female molds, on which small holes for vacuum forming are provided and over the domain ranging from their shoulders to the whole surface or uneven portion of cavities of which small local vacuum holes are provided, are employed. CONSTITUTION:First, a thick sheet 14 which is extruded through the port 22 of a die 5a is supplied between the open space of a mold clamping space having a male mold 17 and a female mold 18. Secondly, the thick sheet is pushed by advancing the male mold 17 and, after that, vacuum-formed along the wall surface of a female cavity 16 by means of small diameter suction holes 19 which are connected with a vacuum pump 11. Thirdly, a thin sheet 13 is extruded ahead of the male mold and attracted onto a male cavity 15. Fourthly, mold clamping is performed in such a manner that the thin sheet 13 is pushed into the male mold side by the female mold under the state that the molded thick sheet is held in the female mold. Immediately after clamping, air under pressure of about 7kg/cm<2> is poured through an air supplying pin into the hollow part between the sheets 13 and 14, which are vacuum- formed from the backs on the cavities 15 and 16 by means of vacuum pumps 11 and pipings 12. After that, the male and female molds are clamped to the parting line and both the inner and outer walls of a molded part are formed precisely by means of pressure and vacuum. |
