Abstract
When a thermoplastic resin is molded in an injection molding machine, the molten resin is packed into a mold under high pressure, so the resin shrinks during cooling down to room temperature in the mold. In general, the pressure in the mold decreases along the flow direction during the hold pressure, thus the pressure does not become uniform in the cavity up to the solid state. Therefore, the molded shape is almost never equal to the cavity shape.
In this study, one part of the mold has been made up of a flexible wall in order to produce very accurately moldings. When a part of the filled molten resin has been solidified in the cavity, the gate has been shut and the flexible wall has been deformed by controlling oil pressure. Consequently, it is clarified that uniform thickness moldings can be obtained by using this flexible mold.
