Gas-assisted powder injection molding: A comparison of residual wall thickness between metal cavity vs. SLA cavity and effect of mold temperature on residual wall thickness

The effects of processing variables on gas penetration depth and Residual Wall Thickness (RWT) in an aluminum (Al) cavity of Gas-Assisted Injection Molding (GAIM) were investigated with Polypropylene (PP) and Stainless Steel Powder Feedstock (SSPF). The selected processing variables were melt temperature, shot size, gas pressure, and gas delay time. By using a Taguchi L9 array, the results were compared with previous work. For PP, there were no significant differences on gas penetration depth. However, the significance of gas delay time was relatively higher in an Al cavity as compared to a Stereolithography (SLA) cavity from previous work with SSPF. The most significant parameter affecting RWT was melt temperature for PP and gas delay time for SSPF, respectively. Additionally for SSPF, we found that gas penetration depth and RWT decreased with increasing mold temperature. . Master of Science (MS), May, 2010, 65 pp., 12 Tables, 34 figures, 37 references, 33 titles.