Two kinds of plastic materials are molded in two parts on the same injection machine, but the product only molds once. Generally, this double injection molding process is also called double-material injection molding, usually consisting of two molds, one half mounted on a fixed plate of the machine, and the other half mounted on a rotary plate. Male molds of these two molds are the same, female molds are different. When plastic of the first color is injection molded, male and female molds are opened once. The male mold is rotated 180 degrees with the product once, reaching the position of the second color injection molding, and performed to obtain the two-color workpiece. There will be semi-finished products and finished products in each molding cycle.