Research On Lightweight Branch Structure Design Method Based On SLM

There are some structure design constraints in traditional manufacturing process.The structure with low weight and high strength hardly meet the requirements of traditional process.There are redundant materials in the traditional parts to meet these requirements.Selective laser melting technology(SLM)is one of the mainstream technologies of additive manufacturing,which produces metal functional parts directly from metal powders without use of any tools.It is suitable for producing complex and lightweight structures especially in aerospace area.However,this process requires the presence of support structures during the construction of a part.Besides,the manufacturing of cantilever structures also need plenty of support structures.Lattice supports are mostly used in SLM process,with complex design procedure,long manufacturing time and high material cost.What's more,the strength of this support is vulnerable to process defect.Lightweight and efficient support structures are desired.Current researches concentrate on optimizing part building orientation and support dense to reduce the manufacturing time.Few studies focus on the manufacturability of SLM structures and how to design new lightweight support structure based on SLM process.This paper investigates a novel lightweight branch structure design method based on SLM,according to SLM process characteristics.The main contents of this paper are as follow:1.Study the manufacture constraints of SLM.Fundamental features such as cylinder,cuboid,slit hole and cantilever structures were designed to investigate the manufacture ability of SLM.The structure design constraints of SLM process were also discussed.2.Investigate the characteristics of branch structures.The design and manufacturing of branch structures were studied.The characteristics of branch structures and traditional lattice structures were compared,especially the weight and mechanical properties.The influence of different parameters on branch structures such as branch diameter and inclined branch angle were also investigated by compression tests.3.Study the application of branch structures in SLM lightweight structure design.The design principles of freedom structures produced by SLM were researched.A lightweight structure design method based on fundamental manufacturable unit library was investigated.This method consists of two main steps: shape design and internal structure design.Internal structure design includes units selection and design.The design parameters of units such as branch support were optimized to get lightweight parts with higher strength.4.The characteristics of satellite structure design were analyzed.A satellite structure is redesigned by branch support structure according to the design principles and lightweight design method studied before.The characteristics of before and after redesigned structure are compared to verify the feasibility of this design method and the good property of branch structures.