采用数字化设计和组装并直接制造成形、无需实际组装工序的机构，称之为免组装机构。激光选区熔化能够直接制造冶金结合、组织致密、尺寸精度高和良好力学性能的功能零件，是直接制造免组装机构的理想技术。研究了激光选区熔化成形免组装机构的摆放方式、间隙特征的尺寸精度和表面粗糙度、间隙特征结构优化等关键技术。通过自由设计和DiMetal-100系列激光选区熔化成形设备成形了免组装的铜钱算盘和折叠算盘、平面连杆机构(曲柄滑块、曲柄摇杆、摇杆滑块)和万向节等免组装机构。研究证明，激光选区熔化不仅能够顺利成形形状很复杂的零件，也能够直接成形具有相对运动的免组装机构，为机电产品的数字化设计和一体化制造提供了一种可行的方法。

Mechanism that is designed and assembled digitally and lately manufactured directly without post-assembly is called non-assembly mechanism. Selective laser melting (SLM) is a desirable technology for manufacturing non-assembly mechanisms directly since it is able to manufacture functional parts with metallurgical bonded, relatively high density, high dimensional accuracy and favorable mechanical properties. The critical factors of manufacturing non-assembly mechanisms by SLM such as display strategy, dimensional accuracy and surface roughness of clearance character, structural optimizing of clearance character, etc are investigated. Non-assembly mechanisms such as copper cash abacus and collapsible abacus, planar linkages (slider-crank, crank-rocker, and rocker-slider) and universal joint, etc are freely designed and are manufactured by using DiMetal-100 series SLM equipment. It is shown that SLM can not only manufacture parts with complex structures successfully, but also can manufacture non-assembly mechanisms with relative motion directly. It provides a feasible method for the digital design and integrated manufacture of mechanical and electronic products.