Characterizations of polymer injection molding tools with conformal cooling channels fabricated by direct and indirect rapid tooling technologies

The molds or dies with complex conformal cooling channel (CCC) can be manufactured by the metal powder additive manufacturing (AM). However, the metal powder AM approaches have a high initial cost of the capital equipment and maintenance. Wax injection molding is a frequently applied manufacturing technique for the production of investment casting wax patterns because of time efficiency. This study demonstrates low-cost alternatives for fabricating wax patterns economically and efficiently was developed via both direct tooling (DT) and indirect tooling (IDT). The Nine pairs of injection mold (IM) containing CCC were manufactured and the cooling performance was evaluated. The characteristics of IM fabricated by DT and IDT were analyzed. The most suitable methods of making injection molding tools fabricated by direct and indirect rapid tooling technologies have been demonstrated based on total production costs, cooling time as well as flexural strength. It was found that there is no significant difference in the cooling time of the molded products fabricated by IM made with virgin polylactic acid filament with different layer thicknesses. The IM fabricated by DT is sensitive to the coolant temperature. The IM fabricated by IDT is not sensitive to the coolant temperature. In addition, there is no significant difference in the cooling time of the molded products by changing the coolant volumetric flow rate.