MOLD FOR INJECTION MOLDING, INJECTION MOLDING APPARATUS, AND INJECTION MOLDING METHOD

• Main Author: MOGI ATSUSHI
• Format: Patent
• Language: English
• Published: 03.02.2014
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

PROBLEM TO BE SOLVED: To provide a mold for injection molding to collapse weld lines, prevent product strength weakening, and improve product appearance failure by a simple mechanism enabling stable operation.SOLUTION: A mold 10 is of a two-gate structure in which molten resin comes together almost at the center of a cavity C. At both sides of the plane of the resin 20 coming together, one resin pool 24, 32 is provided for each side respectively. Movable core pins 28, 36 are provided thereinside. After the resin 20 has been supplied from gates 16, 18 to the cavity C and the resin pools 24, 32, the volume of the resin pool 24 is compressed by driving the core pin 28 with a compression unit 30. Another core pin 36, working together with movement of the core pin 28, is pulled down by a pulling-down unit 38, in the direction to expand the volume of the resin pool 32. Because of occurrence of internal resin flow in the cavity C, weld lines are collapsed, and, in the case of material containing fiber, elongation of fiber in the direction lowering product strength is prevented.