Study on overlap ratio of pulse laser selective melting forming

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.