In the final process chain (Fig. 11), mold inserts were printed in HTM140 and LithaLox HP 500 (Fig. 12). This was done to
investigate DLP’s potential to quickly produce low-cost tooling for injection molding. The insert geometry was a direct inversion of the part geometry. No changes were made (draft angles added,etc.) to the features to facilitate molding or demolding. The HTM140 inserts were printed to size. After printing, the backs of the inserts were sanded to improve flatness and therefore conformity to the mold frame. The outer dimensions of theLithaLox inserts were oversized to compensate for shrinkage during sintering. After printing, the outer dimensions were ground to size and the ejector pin holes were reamed.