Simulation And Experimental Research On Calcium Silicate Based Biomaterial Additive Manufacturing

With the development of modern science and technology,in order to solve the trauma or bone tumor and other orthopedic diseases caused by the increase in bone defects and other issues,implanted autologous bone or metal prosthesis is currently in clinical medicine is more common and mature bone repair.The Implanted autologous bone has good biocompatibility,biodegradability,bone conduction and other issues,but autologous bone from other parts of their own,increasing the patient's trauma area and increased patient suffering;metal prosthesis biocompatibility are relatively poor,and there are loosening or fracture and other follow-up problems.Therefore,it is the research focus and difficulty of finding suitable artificial bone replacement materials and making them into individualized implanted bone.Due to the clinical application of more mature PMMA material biodegradability and drug delivery is poor,and is not conducive to integration with healthy bone.In this paper,the calcium silicate composite bioceramic materials we selected have good biocompatibility,and the artificial bone is implanted into the human body by 3D printing technology as a result of the similar inorganic components of the bones.Which will not cause inflammation in the body.Bioceramic composites containing silicate ions can promote the formation of hydroxyapatite by silicate ions under physiological conditions,accelerate the formation of precipitated apatite layers,and release large amounts of calcium ions to promote bone formation.The cytotoxicity of the material is low,and the surrounding tissue cells have good compatibility,and the biodegradability is excellent,but the mechanical properties of the material are less difficult to break.Therefore,it is a good application prospect and research value for the design of personalized implanted bone through 3D printing design for the improvement of calcium silicate composite bone cement.In this study,we selected calcium silicate as the base material of bioceramics and propylene glycol as dispersant to study the mechanism of silica gel particle content and calcium dihydrogen phosphate on the mechanical properties,coagulation time,ductility and viscosity of calcium silicate based bioceramics.Preparation uniform,stable and suitable for 3D printing bioceramic composite slurry.The bioceramic composite slurry is a non-Newtonian fluid with the characteristics of shear thinning.Silica gel particles absorb the propylene glycol in the slurry,resulting in the decrease of the volume fraction of the liquid phase,the increase of the viscosity,the decrease of the solidification time and the flowability,but the strain increases and the toughness increases,and the degradation rate is improved in vitro.The density and viscosity of the calcium phosphate cement composite slurry were measured and the hydrodynamic simulation test was carried out by ANSYS FLUENT hydrodynamic simulation software.The effects of nozzle type,nozzle diameter and injection pressure on the injection process of cement composite slurry were studied.The pressure distribution and the flow velocity of the nozzle were obtained under different experimental parameters.In order to prepare the bioceramic stent,it is necessary to study the effect of 3D printing parameters on the slurry injection.In this study,the bioceramic composite slurry was sprayed using the pneumatic 3D printing system to study the flow of the bioceramic composite slurry under different pressures In this paper,the influence of the printing parameters on the width of the printing line is studied by combining the three-dimensional motion platform,spraying the slurry and accumulating the three-dimensional molding layer by layer.The final realization of the use of bioceramic composite slurry pneumatic jet 3D printing.