Constrained forming

In constrained forming, the plasticizing, filling and curing reactions of materials are all carried out in the mold. In this process, three technical parameters, namely, mold temperature, forming pressure and forming time, are mainly controlled.

In constrained forming, the mold is usually preheated to 140-18090. Because the constrained time, shortening rate, electrical function and appearance of plastic parts are directly related to the mold temperature. The mold temperature is too low, the movement resistance of the plastic is added, and the mobility becomes poor. Even if the forming pressure is improved, it is difficult to fill the mold cavity; The mold temperature is too high, which accelerates the curing of the plastic, but the internal plastic curing is slow, the generated gas is not easy to escape, and the surface of the plastic parts is swollen or blistered.

Forming pressure is an important condition for the plastic part to obtain the same shape as the cavity; In addition, since low molecular volatiles occur during the forming process, the pressure can withstand the pressure caused by the gas and avoid foaming of plastic parts. The type of filler, mold temperature and preheating method of forming pressure are different from the shape of plastic parts.

Source: Jiangmen engineering plastics http://www.wywantong.com/