Preparation,microstructure And Properties Of Titanium Alloy Denture Based On RE And SLM

There are a large number of patients with tooth loss in China and the world,and the market potential of dental prosthesis is huge.However,the speed and quality of dental prosthesis prepared by traditional technology can not keep up with the development trend of the times.In this paper,based on Reverse Engineering（RE）and Selective Laser Melting（SLM）technology,three-dimensional denture crown model was established by RE technology combined with gemmer software,and then TC4 alloy powder was selected to print denture crown by SLM technology.Firstly,the point cloud data of human first molar crown surface was obtained by scanner,and the point cloud was processed by gemmer software.The crown 3D model data of growth×width×height was 10.2mm×10.2mm×8.1mm.The maximum size difference between the reverse crown 3D model and the initial crown point cloud was2.93×10^-2mm,which met the medical standard.Then,the finite element analysis of the three-dimensional crown model under the actual occlusal condition（200N-600N load）was carried out.It is found that the crown deformation increases with the increase of the load.The maximum deformation of the crown occurs at the tip of the tooth under each loading condition.When the load is 600N,the maximum deformation of the crown is 2.41×10^-4mm,which meets the requirements.The reverse obtained crown is the printed geometric size.Then,in order to prepare qualified denture crown,the SLM molding process parameters were studied.Firstly,the effect of process parameters on the morphology of weld bead was studied.When P=300W,V=1200mm/s,D=0.11mm,the weld bead with good quality was obtained respectively.When H=0.05mm,the weld bead without obvious defects was obtained.Then,the orthogonal experiment was used to optimize the process parameters,and the optimum densification process parameters were determined as follows:P=250W,V=1050mm/s,H=0.07mm,D=0.07mm,the densification of the formed sample reached 99.92%;the optimum roughness process parameters were determined as follows:P=350W,V=1050mm/s,H=0.09mm,D=0.11mm,and the surface roughness of the formed sample was 6.74μm.Finally,the samples formed by the best densification process were annealed at different temperatures to explore the influence of annealing system on the properties of the samples.The results show that when the annealing temperature reaches 850℃,theα’phase in the as cast sample transforms into（α+β）phase,and the coarse columnar crystal dissipates;when the annealing temperature reaches 950℃,theαphase of the sample grows obviously,the orientation tends to be equiaxed;with the increase of annealing temperature,the hardness and strength of the sample decrease,but the plasticity is obviously improved;the comparison between the as cast crown and the as annealed crown at 950℃is made The results show that the size error of 950℃annealed crown is smaller than that of as cast crown.