The effects of gas assisted injection molding on the mechanical properties of medical grade thermoplastic elastomers

Abstract

Gas-assisted injection molding (GAIM) has been demonstrated to have several advantages over traditional injection molding, including a reduction in raw material, cycle time, clamping force and injection pressure. The objective of this study was to determine the effects of GAIM parameters on the manufacturability and mechanical performance of medical grade thermoplastic elastomer injection molded parts for a bladder support device. Gas assist parts used up to 37% less raw material than conventional parts. However, GAIM methods also reduced part stiffness compared with solid parts. GAIM had a limited effect on the time dependent characteristics of creep and relaxation of each material, which are important characteristics for many medical devices. Using gas assist to manufacture flexible medical devices from thermoplastic elastomers provides an opportunity to reduce raw material and processing costs, however, predicting the effect of GAIM on part mechanics varies with each material and will require preliminary testing.