| 摘要 |
<p>PURPOSE:To make it possible to mold a resin molded item having a through hole and a resin molded item having no through hole in the same mold by a method wherein both a first position, at which the tip face of an insert is flush with the inner face of one mold, and a second position, at which the tip face of the insert nearly abuts against the inner face of the other mold to leave a gap allowing no influx of molten resin therein between the faces, can be realized. CONSTITUTION:An insert 5, which is provided, for example, in the core 3 of a mold 1, is advanced and retreated by means of a hydraulic device 10. When the molding of a molded item having a through hole is intended, injection molding is done under the condition that the insert 5 is moved to the position at which its tip face 5a nearly abuts against the inner face 2a of a cavity 2. When the molding of a molded item the requirement of which is favorable quality external appearance, such as a bumper, is intended, a slight gap G, which allows no influx of molten resin, is left between the tip face 5a and the inner faced 2a of the cavity 2 in order to prevent mark from developing. When the molding of a molted item having no through hole is intended, injection molding is done under the condition that the insert 5 is moved to the position at which its tip face 5a is flush with the inner face 3a of a core 3. When the difference in level is within a certain range, the luster non-uniformity of the surface of a product is brought in the allowable range.</p> |
