Читать книгу Plastics Process Analysis, Instrumentation, and Control - Группа авторов - Страница 31

A novel gas-assisted microcellular injection molding method was created by combining gas-assisted injection molding (GAIM) with microcellular injection molding (41). Here, with the assistance of the high-pressure gas from GAIM, the amount of the polymer melt required for fully filling the mold cavity is reduced in the gas-assisted microcellular injection molding in comparison to that in the microcellular injection molding, thus leading to a high weight reduction of the foamed part.

In addition, the high-pressure assisted gas from the GAIM can dissolve all the cells generated in the melt filling stage back into the polymer melt, thus improving the molded part’s surface appearance by eliminating the surface sliver marks. Also, the secondary foaming process in a steady state triggered by releasing the high-pressure-assisted-gas results in a foamed part with a fine cellular structure and a compact solid skin layer, which can help to enhance the part’s mechanical properties.

In order to verify the effectiveness of the gas-assisted microcellular injection molding, experiments that can compare the microcellular injection molding and the gas-assisted microcellular injection molding were conducted. The results demonstrated that the gas-assisted microcellular injection molding can not only significantly increase the weight reduction, but also greatly improve the surface appearance and the mechanical properties of the foamed part (41).