Benchmarking of three processes for producing castings incorporating micro/meso-scale features with a high aspect ratio

This paper investigates the capabilities of three different process chains for vacuum investment casting of parts incorporating micro/mesoscale features. The first two process chains employ the classical Lost Wax Process and make use of layer-based manufacturing technologies, ThermoJet and PatternMaster respectively, to create patterns out of a thermoplastic material, while the third one, Fcubic, produces directly a casting tree in zirconia ceramics. The study involves the manufacture of test parts in aluminium/zinc alloys and stainless steel with microfeatures in the range of 250 to 700 μm and aspect ratios up to 50. The dimensional accuracy, surface quality, and production costs of the investigated manufacturing routes are compared. A metallographic analysis is performed on castings in aluminium to investigate the evolution of the dendrite structure and eutectic clusters of microfeatures as a function of their aspect ratios together with their influence on the parts' mechanical properties. Conclusions are drawn about the applicability of the studied three processes for casting parts with micro/mesoscale features