| 摘要 |
PURPOSE:To obtain a molded body having favorable filling properties even when the molded-body is thin-walled one by a method wherein expandable beads are filled in a cavity under the condition that molds are brought into the state of cracking while being kept airtight and, after that, the molds are clamped and the beads are fusion-welded together by heating. CONSTITUTION:The apparatus concerned consists of a core mold 1 and a cavity mold 2. A cavity 3 is formed between both the molds 1 and 2. Side wall parts 1c and 2c, which forms the parts of the cavity 3, are designed to be longer than normal ones. At the same time, flanges 1a and 2a are provided around the parting face (p) between the core mold 1 and the cavity mold 2 so as to hermetically engage with each other by means of packings 1b and 2b. Even under the state of cracking, the molds can be kept in airtight state by the flanges 1a and 2a through the packings 1b and 2b. Under the condition that the molds are brought into the state of cracking while being kept airtight, expandable beads are filled in the cavity under pressure or vacuum and, after that, the molds are clamped and the beads are fusion-welded together by heating. Since the expandable beads are filled under the condition that the volume of the cavity is enlarged by the amount for cracking and, after that, the molds are clamped, poor filling is prevented from occurring even at the molding of a thin-walled molded item. |
