積層金型のベント穴付き射出成形型への応用

抄録

We describe the results of manufacturing a laminated mold provided with air vents for injection molding. Since this mold is made by diffusion bonding laminated metal sheets on which microgrooves have been fabricated, micro-air vents can be provided at any place on the forming surface without a restriction. The contours of the metal sheets, together with channels for circulating a coolant, were cut by laser. Microgrooves of 60μm depth and 565μm width were fabricated by electrolyte jet machining. The results of forming showed that the air vents are effective in improving the flowability of resin and prevent short shots. It was also found that the air vents can reduce the negative pressure generated inside the space between the mold and the molded part when the molded part is released from the mold. As a result, deformation of the molded part was decreased and molding accuracy was improved. Furthermore, the effects of the size of the air vents on the appearance of the molded parts and clogging of the air vents owing to resin penetration were evaluated.