| 摘要 |
PURPOSE:To prevent sinking from developing without being effected by the height of a boss and at the same time under the state that the height of the boss is stabilized by a structure wherein a slit, which is provided along the outer periphery at the root of the boss and through which the pressure of gas or liquid is applied, and a fluid circuit, by which said slit is connected to the outside of a mold, are provided. CONSTITUTION:Molten resin is filled through a sprue 5 in a product part 7 and a boss part 8. If cooling proceeds as is, sinking develops on the surface 23 of the boss 8 due to the shrinkage of the resin. However, when high gas or liquid pressure is applied to a core fluid circuit 22 from the outside of a mold after the filling of the resin, said pressure is transmitted through a fluid circuit 21 and a slit 20 to the root of a boss 8 so as to press the resin at the root. Thus, said resin is pressed to a cavity side, resulting in preventing sinking from developing. In addition, since the slit 20 is fine, no resin enters the slit and consequently no clogging of the slit occurs. |
