Patent attributes
A mold for injection molding includes a male mold portion, and a female mold portion mating with the male mold portion to define a parting face therebetween. The female mold includes a mold cavity defined at the parting face, an injection aperture communicated with the mold cavity, an air channel defined at the parting face and evenly spaced from and partially surrounding the mold cavity, a spacing portion formed between the mold cavity and the air channel, and a gap formed between the male mold portion and the spacing portion for transmitting air from the mold cavity to the air channel during injection of molten plastic. When injecting molten plastic, air in the mold cavity can be expelled in time under pressure of the molten plastic and through the air channel. Therefore, the surface quality of the molded product can be improved, by avoiding formation of air holes, fissure.