中文摘要：

为了改善激光选区熔化成型免组装机构间隙结合处的成型质量，制造出具有高表面质量和高致密度的免组装机构，对间隙倾斜面的表面粗糙度进行了理论研究，并对间隙特征进行了设计，分析了激光表面重熔和工艺参数对间隙成型质量的影响。结果表明：间隙倾斜面的表面粗糙度（Ra）理论上由倾斜角和切片厚度两个因素决定，Ra随着倾斜角的增大和切片厚度的减小而减小。采用鼓形孔的间隙特征可以使粉末更容易去除并提高机构的稳定性；采用激光表面重熔工艺，不仅可以提高机构的致密度，也可以改善表面粗糙度。加工过程中，保持激光体能量密度在顺利成型的区域，加工到间隙顶部时，加快扫描速度，能够减少间隙处的挂渣，提高表面质量。采用以上优化条件可以顺利加工出万向节机构，其中外表面Ra=8．25肛m，间隙表面Ra=12．47μm，致密度为99．1％。

英文摘要：

To improve the clearance surface roughness of non-assembly mechanisms fabricated by selective laser melting （SLM） and to manufacture non-assembly mechanisms with good surface quality and high density, the inclined surface roughness of the clearance is studied theoretically firstly. Then the clearance junction structure is designed. The effects of laser surface remelting and process parameters on surface roughness are analyzed, respectively. Results show that the inclined surface roughness （Ra） of the clearance is affected by inclined angle and the slice thickness theoretically. R, decreases as the inclination angle increases and the slice thickness decreases. The clearance is designed as drum shaped hole to improve fabrication quality. Laser surface remelting process can not only improve the density, but also improve the surface quality. During the process, volume energy density should be controlled in success prototyping zone. When fabrication reaches the top of the clearance, the scanning speed should be increased to reduce the dross to improve surface quality. At last, the universal joint is fabricated successfully. The outside surface Ra is 8.25 μm, the clearance surface Ro is 12.47 μm. and the relatiw densitv is 99.1%