Comparative study of pattern making via single, dual-stage wax injection molding, and additive manufacturing for investment casting of stainless-steel manifold product

Pattern making is a critical stage in investment casting for producing complex components. This study evaluates a novel dual-stage wax injection moulding method against the conventional single-stage process and an additive manufacturing approach. A complex stainless steel automotive manifold was evaluated to assess dimensional accuracy, precision, and mass production viability. Results revealed that single-stage moulding exceeded the 1 mm tolerance limit. The dual-stage method significantly improved accuracy and precision, yielding target deviations of 0.09–0.46 mm with standard deviations of 0.01–0.14 mm. Although additive manufacturing achieved the highest accuracy (deviations of 0.02–0.32 mm, standard deviations of 0.01–0.08 mm), it proved inefficient for production volumes exceeding 10 units. Consequently, dual-stage injection moulding is the preferred method for high-volume production.