Abstract: This paper reported a structure design of injection mold with one mold, one cavity and three plates for the plastic part of purifier framework. In this mold, the mold cavity was designed with a 5-point gate, and the cooling system was designed with cooling water wells and pipes. The full ejection of plastic parts was arranged by an improved cylinder head type ejector pin. Aiming at the difficulty in demolding of plastic parts, two types of core-pulling mechanisms were set for demolding with a characteristic side edge, in which one was a compound secondary core-pulling mechanism of slider ejector and another was a bending pin slider core-pulling mechanism. A delay ejector on the side slider was set in the compound secondary core-pulling mechanism of slider ejector needle, and a push rod block on the fixed mold was designed in the ejector rod. The delayed ejection ensured the core-pulling of the side forming block at first and then the core-pulling of the side ejector pin on the slider. Such a design avoids the deformation of plastic parts when the side core-pulling is one-off. The structure design of this mechanism is exquisite and the structure of the mold is reasonable. This may provide a useful reference for the design of mold for the plastic parts with the same structures.

Key words: injection mould;three plate mould;delayed ejection, slider mechanism, structural design