Dust Removal System Of Selective Laser Melting Equipment

Selective laser melting(SLM),as an additive manufacturing process,has the characteristics of brilliant manufacturability for complex parts,high material availability,high precision of forming dimensions,and excellent mechanical properties of parts.Along with deepening understanding of SLM forming process,researchers have found that some by-products induced during SLM process,will directly influence the forming quality.But there are not too many studies discussed the optimization of circulation filter system and the effects of gas flow and by-products on resultant parts quality.The purpose of this paper is to systematically analyze related issues on dust gas circuits,providing with data support and reference ideas for the design of SLM system.As a result,this investigation offers a reference for scanning strategy to avoid the impact of by-products on as-built parts.The main contents and important conclusions of this work are listed as follows:(1)The gas uniformity and the pressure loss of pipes are simulated using finite volume method,under different cross-section,bending mode,bending length,transitional form,and the form of branch pipes.Two conclusions can be drawn that the flow characteristics of circular cross section pipe are better than rectangular one,and better flow characteristics can be reached at the location with longer bending length or farther from the end of the bend.(2)The critical velocity that allows common metallic powders for SLM to remain on the processing substrate,has been measured via experiments using an innovative bellows-like installation.(3)Three types of installation(divided-flow,contraposition and mobile)for blowing away by-products are discussed and classified,considering the processing dimension of individual SLM system.(4)The role of the angle ? between laser scanning path and gas flow are investigated.According to the morphology of single track and tensile strength of as-built parts,it is concluded that the resultant parts show worst performance of quality when ? = 0 and this situation should be avoided as much as possible during preliminary treatment.