The spiral flow analysis on the injection molding of alumina powder - An experimental design

A spiral flow analysis based on the McLean-Anderson design method was conducted in studying the influence of each formulation component on the flow of alumina feedstocks. The mixtures were composed of alumina powder (AL), polypropylene resin (PP), paraffin wax (PW) and stearic acid (SA). Fourteen different formulations were designed and tested. The spiral flow distance (SFD) of each formulation as a function of ingredient concentration was measured and analyzed. The studied ranges of AL, PP, PW and SA were 87-89, 5-9.25, 3-7.25 and 0.75-1.5 wt%, respectively. It is observed that lower alumina content or higher binder content would obtain longer SFD of feedstocks. Both PW and SA are more effective than polypropylene (PP) in enhancing SFD. For alumina content less than 88%, PW is the most effective one. In contrast, SA becomes the most effective when the powder loading is higher than 88%.