| 摘要 |
<p>Only the periphery of a portion to be prevented from decreasing in strength is solidified by local cooling before bubbles grow, thereby forming a wall for flow prevention. Thereafter, a pin (107) or the like is plunged into the molten resin present inside the periphery to reduce the volume of the cavity (3). As a result, the bubbles become small or the foaming gas is partly absorbed into the resin. Thus, the volume of the expanded bubbles is reduced to thereby inhibit the strength from decreasing.</p> |
