Study On The Quasi-continuous Gradient Density Parts Based On SLS

With the development of the function gradient materials,parts with continuous gradient density gradually become one of the objects mostly studied.Selective laser sintering is a kind rapid prototyping technology using polymer powder materials,and it has a great advantage to sinter continuous gradient density parts.The quasi-continuous gradient density part is sintered by dividing it into several layers which are given different powers in this paper.The effect of the neighboring sintered layers is studied by simulation and experiment in this paper,and then the power of each layer in sintering is corrected to get the parts that the density of each layer meets the requirement.It has a certain guiding significance to take advantage of SLS to machining continuous gradient density parts。Firstly,the SLS molding principle,technological process and the influences of the process parameters to mechanical properties of sintered parts are analyzed.And the process of the quasi-continuous gradient density parts is put forward,at the same time,the theoretical model which uses the simplified simulated mandible as an object is built.Secondly,the neighboring layers with different powers will effect on each other is proved,the effect of layer stratification and the thickness of higher power layer on neighboring layer is studied.Then the power-density compensation factor is put forward,and the theoretical model of computing the correction power of each sintered layer is set up.Thirdly,the effects between neighboring layers are simulated by ABAQUS,including the effects of neighboring layers with same and different powers,layer stratification to heat transfer,and the increase of the thickness of higher power layer to neighboring layer。Finally,the mappings of different laser powers to different sintered density are built.The power-density compensation between neighboring layers with different powers is obtained.At last,according to the above results,the quasi-continuous gradient density parts are sintered,then the density of each layer is measured and compared with the density needed.