| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a sprue made of a resin which can realize successful productivity while further improving dimensional molding precision, and a sprue obtained by this method. SOLUTION: In this manufacturing method, a molten resin 60 is injected into a cavity 53 from a resin fluidization flow path 57c, while a gate 52a is opened. After the cavity 53 is sufficiently filled with the molten resin 60, a valve gate pin 56 is advanced toward the cavity 53 inside the gate 52a. Consequently, further pressure is applied to the molten resin 60 inside the cavity 53 and the axial end part of a molded object (sprue) is molded by means of the end surface 56a of the valve gate pin 56. The axial end part of the sprue is a contact surface, which comes into contact with a plunger, of a solenoid valve. Thus it is possible to mold the axial end part of the sprue only by injection molding without the necessity to perform an after-processing such as cutting or polishing in the way described above, although there is the need to secure high dimensional precision. COPYRIGHT: (C)2006,JPO&NCIPI |
