INJECTION MOLDING METHOD AND MOLD DEVICE FOR INJECTION MOLDING

• Main Authors: KUWABARA KATSUYUKI, ENDO TOYOKAZU, HAGA FUMIAKI
• Format: Patent
• Language: English
• Published: 24.07.2014
• 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 an injection molding method and a mold device for injection molding which can satisfactorily prevent generation of a weld line on the surface of a resin molded article having hole parts without complicating a mold structure, in injection molding of the resin molded article.SOLUTION: An injection molding method for molding a resin molded article having hole parts comprises: a first step of opening a valve gate 53A arranged on one side in the circumferential direction of an annular molding space 51 to inject a molding material into the annular molding space 51, branching the injected molding material into two parts along a semi-annular passage 51a to make them flow toward the other side of the circumferential direction of the annular molding space 51, and joining the two flows of the molding material on the other side of the circumferential direction of the annular molding space 51; and a second step of opening a valve gate 53B arranged on the other side in the circumferential direction of the annular molding space 51 to inject the molding material, and making the injected molding material flow between the joined molding material and a mold molding surface.