研究目的
Investigating the effects of laser surface re-melting (LSR) on the surface quality of parts fabricated via selective laser melting (SLM).
研究成果
LSR is a feasible method for improving the surface quality of parts fabricated via SLM. Repeated LSR with a moderate LED and small hatch space is recommended.
研究不足
The LSR process is still poorly understood. Numerical simulation is a helpful method for elucidating the evolution mechanism of underlying physical processes, and it accelerates the investigation process by partially avoiding traditional trial and error.
1:Experimental Design and Method Selection:
A two-dimensional numerical model involving heat transfer and fluid flow of a single-track LSR was established. Governing factors (e.g., Marangoni shear stress and damping force) were considered. The laser heat source was treated as a body heat flux with a Gaussian distribution.
2:Sample Selection and Data Sources:
The material selected to fabricate the original parts was 316 L stainless steel. The 316 L stainless steel powder particle had a near-spherical morphology with a diameter in the range of 15–53 μm.
3:List of Experimental Equipment and Materials:
The SLM system used was an EP-M250 (Beijing E-Plus 3D Tech. Co., Ltd., China). The top surface morphologies of the samples were characterized using scanning electron microscopy (ΣIGMA HDTM).
4:Experimental Procedures and Operational Workflow:
LSRs with laser powers (P) and scan speeds (v) identically to the numerical simulations were conducted. Additionally, double LSR using an LED of 225 J/m was conducted.
5:Data Analysis Methods:
The surface morphology, melt pool flow behavior, melt pool size, and thermal behavior were investigated.
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