Shape Control of Rectangular Tube Specimen Produced by Fused Spinning Deposition Method

摘要

Recently, Rapid Prototyping technology has attracted considerable attention as a new manufacturing technology for metallic molds and parts. In the present work, the metallic material was employed in order to examine the feasibility of fused spinning deposition (FSD) method for the fabrication of final metallic products. Al-4mass%Cu alloy was melted in the quartz tube with a small nozzle located at the bottom. By pressing the melt surface with argon gas pressure of 0.12～0.13 MPa, the alloy melt flowed out through the nozzle onto the copper substrate and rapidly solidified. The rectangular tube specimen was formed by moving the substrate in the X-Y horizontal direction and downwards. The shape stability and the microstructure were investigated for different moving speed of the substrate. It was found that, with increasing the moving speed of the substrate, the thickness of one layer piled up diminished and the spacing between the eutectics in the interdendritic region increased, while the width of the rectangular tube specimen was almost constant. The control of the width was attained by choosing an adequate nozzle size. For small moving speed of the substrate, a clear detached interface was observed between the layers as a result of the prolonged time interval for the successive piling up of the melt, that is, an increase in the time interval causes a reduction in the surface temperature of the lower layer and the heat capacity of the upper molten metal layer is insufficient for remelting the surface of the lower layer. Increasing the moving speed of the substrate, i.e., decreasing the time interval, the weldability between the layers was improved and the solid-liquid coexisting region was formed between the layers, resulting in a smooth side surface of the rectangular tube specimen due to the surface tension of the liquid phase.