为了探究脉冲式激光选区熔化成形过程中的搭接率与搭接特性, 采用了弓形与抛物线形搭接理论模型, 并设计了单熔点、单熔道和多层块体的成形实验, 获得了不同条件下较优的搭接率。结果表明,单熔点熔宽随曝光时间增大而增大; 单熔道实验中, 曝光时间为40μs～60μs时, 单熔点间较合理的搭接率约为30%; 曝光时间为80μs时, 搭接率约为50%; 曝光时间为100μs～120μs时, 搭接率约为60%; 多层块体实验中, 单熔道间的搭接率为50%时, 块体表面形貌较好; 通过对块体进行致密度、缺陷、微观组织和拉伸性能分析可知, 当功率200W、层厚50μm、曝光时间100μs、点距65μm、线间距77μm时, 可得到致密度最高为99.99%的样件。该研究对认识脉冲式激光选区熔化成形过程中的搭接特性和搭接率选取是有帮助的。

In order to study overlap ratio and overlap characteristics during pulse laser selective melting forming process, the overlap theoretical models of bow and parabola were adopted, and the forming experiments of single melting point, single cladding and multi-layer block were designed under different conditions to obtain the optimal overlap ratio. The results show that the width of single melting point increases with the increase of exposure time. The optimal overlap ratio between two melting tracks is 30% in the single cladding experiment when exposure time is 40μs～60μs. The overlap ratio is 50% when exposure time is 80μs. The overlap ratio is 60%, when exposure time is 100μs～120μs. The surface morphology of block is slat in the multi-layer block experiment when overlap ratio between two melting tracks is 50%. After the analysis of block density, defect, microstructure and tensile properties, sample density is up to 99.99%, when laser power is 200W, layer thickness is 50μm, exposure time is 100μs, point distance is 65μm and line spacing is 77μm. The research is helpful for understanding overlap characteristics and overlap ratio selection in pulse laser selective melting.