Study On The Technology Of Hydroxyapatite Composite Artificial Bone Scaffold Based On SLS

Biomaterial manufacturing technology greatly facilitates the research and development of bionics and regenerative medicine.The premise of medical model diversification can be achieved through rapid prototyping technology and rapid manufacturing based on three-dimensional model.The precision,strength and shape of printed samples are more close to the actual medical model.As a kind of biomaterial manufacturing,tissue engineering scaffolds need more complex models and more strict requirements of strength and precision,so SLS technology has become one of the feasible processing methods.The material selection of SLS technology is diversified,and there is no need to add more support when printing,which reduces the processing time and improves the accuracy for making medical model.Because of the particularity of SLS,there is a new requirement for the fabrication of artificial bone scaffolds.Based on the properties and processing requirements of tissue engineering scaffolds,hydroxyapatite with strong bone induction activity and bone conduction force was selected as the matrix material,and polycaprolactone with low melting point and low temperature forming was selected as the main binder.Hydroxyapatite/polycaprolactone composite powder materials with different group distribution ratio were prepared for single-layer sintering experiment.Through single-layer sintering experiment,the feasible scheme of the ratio of hydroxyapatite/polycaprolactone composite materials was obtained.Because there is no new wave peak in the hydroxyapatite/polycaprolactone composite materials before and after printing in the infrared spectrum,it can be seen that no new group was generated.Printing The process is pure physical change.The heat transfer mode between laser and powder bed in the printing process is analyzed,and the forming mechanism of SLS is simply studied,and the heat transfer model and parameter calculation model are established.Based on the software COMSOL,the finite element heat source model and geometric model of hydroxyapatite/polycaprolactone composite powder material are established.Considering the actual physical parameters of the material and the boundary conditions of the simulation process,the multi field coupling simulation analysis of the sintering process of hydroxyapatite/polycaprolactone composite powder material is carried out and the temperature field data are obtained.The simulation of processing parameters and binder ratio is discussed The results provide theoretical support for the preparation of hydroxyapatite/polycaprolactone composite powder and the optimization of sintering parameters.Using the orthogonal test method,the hydroxyapatite/polycaprolactone composite material was sintered and formed.Taking the tensile strength,bending strength,density and dimensional accuracy as the consideration indexes,the influence trend of the four factors(laser power,scanning speed,scanning distance and layer thickness)which have great influence on the consideration indexes was analyzed,and the best SLS process parameters were obtained The feasibility analysis,design and manufacture of porous bone scaffolds with different cellulose content were carried out.The best cellulose content was selected by measuring porosity and compressive strength.