锌合金熔融沉积三维打印工艺

针对现有金属件增材制造技术存在设备开发及运行成本高、成形效率低的问题，提出新的低成本且适用于中、低熔点金属材料的增材制造技术--熔融沉积3D打印成形，介绍了该技术原理.采用自主开发的成形设备，开展锌合金熔融沉积3D打印成形工艺试验，研究喷嘴高度、扫描速度和搭接率对成形效果的影响.研究结果表明：金属熔融沉积单道轨迹宽度与高度成反比例关系；当喷嘴高度为25~35 mm，扫描速度为8 mm/s时，所得的单道轨迹质量较好；当路径搭接率为35%~40%时，沉积单层表面质量较好；采用熔融沉积三维打印工艺所成形锌合金实体的致密度可以达到97%以上；通过提高坩埚加热温度、成形基板温度、退火温度和退火时间，可以显著增强成形件的致密度；采用金属熔融沉积三维打印工艺，可以实现具有复杂形状内流道模具的成形，不仅可以降低加工难度，还可以提高成形效率；熔融沉积三维打印成形锌合金实体的抗拉强度为198 MPa，屈服强度为140 MPa，伸长率为0.453%，拉伸性能与传统挤压铸造工艺相当，实体的显微组织呈现更细化的树枝状.

Three-dimensional printing technology of zinc alloy fused and deposition

A new three-dimensional printing technology based on fused and deposition was proposed in order to solve the high cost and low efficiency problems of the existing additive manufacturing technologies for metal parts. The technology is suitable for medium and low melting point metal material. The principle of the technology was introduced. The three-dimensional printing process of zinc alloy was conducted by using the self-developed equipment in order to analyze the effects of nozzle height, scanning speed and lapping rate on the forming effect. The width of single track was inversely proportional to height. When the nozzle height was 25~35 mm and the scanning speed was 8 mm/s, the single track quality was better. The surface quality of the deposited monolayer was better when the overlap ratio was 35%~40%. The density of the zinc alloy can be more than 97% by using the three-dimensional printing technology based on fused and deposition, and the density of the formed part can be enhanced by increasing the melting temperature, the temperature of the substrate, annealing temperature and annealing time. The technology can be used to realize the forming of the inner flow channel die with complex shape, which can reduce the processing difficulty and improve the forming efficiency. The tensile strength of zinc alloy solid was 198 MPa, the yield strength was 140 MPa, and the elongation was 0.453%, which were equivalent to those of conventional squeeze casting process. The microstructure of the zinc alloy solid was more refined.