Investigation of Mold Filling Simulation, Segregation, and Rheological Properties in Low Pressure Injection Molding of Alumina Parts

Abstract

Advanced ceramics are widely used in various industries like medical, automotive, and aerospace. Production of ceramic components has been constrained due to challenging machining procedures and the difficulty of forming complicated parts. Powder injection molding is one of the suitable methods to produce complex ceramics and overcome the difficulties of producing these parts. This paper investigates the effect of micro and nano powder addition on the rheological properties, segregation, and imbalance filling. For this purpose, different amounts of nano and micro SiC powder (5 wt%, 10 wt%, 15 wt%, and 20 wt% of micro SiC and 1-3 wt% of nano alumina) were added to alumina powder and the prepared feedstocks were injected at various flow rates. Rheological properties of feedstocks and segregation phenomenon in the green parts were investigated by rotational rheometer and thermogravimetric analyzer, respectively. As well as, mold filing, segregation and distribution of temperature during filling were simulated using Moldflow Synergy (Autodesk) 2019 software and compared to the experimental results. It was found that feedstocks containing 15 wt% micro SiC and 2 wt% nano SiC showed the best rheological behavior. The segregation phenomenon was observed in samples injected at flow rate of 15 cm3/s. No imbalance filling was observed in none of the samples, but by increasing the flow rate the segregation was intensified.