Affiliation: College of Mechanical Engineering, Tianjin University of Technology and Education, Tianjin, 300222, P.R. China.
The plasticizing and injection devices are among the main components of injection molding machines. The injection seat moves forward by injection-shift oil cylinders to joint the nozzle and the gate of mould tightly. The single oil cylinder and the double oil cylinders are adopted in the traditional injection molding machine. The paper reviews various patents of injection-shift structures through adopting new structures and new devices in recent years. A new type of the single injection-shift structure of injection molding machines is invented to solve high injection pressure, long-time holding pressure, the warpage of the nozzle and the joint fracture of shift piston rod for the traditional injection-shift device. The new type of the injection-shift structure is more compacted, reliable and especially suitable for multiple material injection molding. Moreover, when the length of injection-shift rod is shortened, the cost will be reduced.