PRODUCTION OF RESIN PRODUCT HAVING COMPLICATED INNER SURFACE SHAPE

摘要

PURPOSE: To efficiently produce a resin product of high quality by a reduced number of processes by integrally molding a resin product having a complicated inner surface shape such as an impeller by injection molding. CONSTITUTION: A water-soluble resin core 2 is set in a mold 1 so as to leave a cavity 3 for molding an impeller for a pump having a predetermined shape. Next, a synthetic resin molding material for injection molding excellent in abrasion resistance such as a polyamide or polyacetal type synthetic resin molding material is injected into the cavity 3 to mold the molded object 10 of the impeller for the pump integrated with the molten resin core 2 in the cavity 3. Next, upper and lower molds 1a, 1b are opened to demold the molded object 10 integrated with the water-soluble resin core 2 from the mold 1. Finally, the molded object 10 is put in a water tank to remove the water-soluble resin core 2 integrated with the molded object 10. By this constitution, the impeller for the pump of high quality having a predetermined dimension is easily and integrally molded by a plastic injection molding method.