Design, manufacture and testing of titanium EBM insert for injection molding

Abstract

Rapid tooling technologies allow for quick fabrication of injection molding tools directly from Computer-Aided Design (CAD) data. In this study, the capability of producing tool inserts with freeform channels and the required finish and accuracy was examined. The investigation started with the design, manufacture and post-processing and ended with the testing of the tool inserts for injection molding process. Using the Electron Beam Melting (EBM) process, the restriction of drilling straight routes could be eliminated and freeform channels with sufficient powder removal were achieved. The choice of electron beam parameters and preheating sequence strongly influence the sintering levels of adjacent powder next to solidified tool inserts. Despite the very low heat conductivity of the new tool inserts made from titanium alloy Ti6Al4V Eli, the cooling performance was the same as for the conventional cavity inserts. However, titanium alloys have a high corrosion resistance that can prevent corrosion in injection molding process e.g. due to cooling medium or corrosive gas released by the polymer to be processed