A metal additive manufacturing methodology: Pneumatic extruding direct-writing deposition

Abstract

Abstract To develop low-cost additive manufacturing for metal parts, a methodology, namely, pneumatic extruding direct-writing deposition (PEDWD), is investigated in this paper. The deposition system mainly consists of a pressure and valve controller, temperature controller, three degree-of-freedom motion platform and computer system. By adopting the pressure of compressed nitrogen, molten metal was extruded on demand and deposited onto a substrate to form metal parts along the programmed track. A throttle channel was introduced into the structure design of the nozzle, and the effect of the throttle channel on the flow of the molten metal was investigated theoretically and experimentally. A Comparison of the theoretical analysis results and the experimental results shows good agreement. The experimental measurement results suggest that the throttle channel decreases the flow of molten metal by approximately 28%. How the two key processing parameters, the velocity of the substrate and the distance between the substrate and the nozzle, affect the deposition processing of PEDWD was investigated. Based on the experimental results, when the two parameters vary in a certain range, they both affect the outflow of the molten metal and the cross-sectional size and shape of the deposited metal line. Finally, thin-walled and three-dimensional metal parts were fabricated successfully by PEDWD, and their morphological characteristics were investigated.