Experimental Study On 3D Printing Of Fe Bone Implant With Direct Ink Writing

Bone implants to repair bone defects is the focus of current medical clinical research.In the process of bone scaffolds preparation,interconnected pores and mechanical properties are two key features.Traditional methods and the current mainstream metal 3D printing methods on the market are subject to certain restrictions on the processing of metal materials,and it is impossible to process tiny pores(less than200μm)with specific properties.At the same time,the mechanical properties of bone scaffolds are highly related to their internal pores,and it is difficult for the two to meet the needs of the human body at the same time.In order to prepare an bone scaffolds with a high-precision micro-pore structure,and to prepare an bone scaffolds whose structure and performance meet the needs of the human body,this paper selects the direct ink writing technology to explore its slurry forming ability to prepare highprecision micro-pore artificial bone The scaffolds and its performance are explored.At the same time,it is proposed and proved that the use of metal pore formers to make microscopic pores,independent of structural pores to adjust its mechanical properties,to prepare bone scaffolds whose structure and performance meet the needs of the human body.It is helpful to solve the problem of the shortage of high-quality artificial bone,promote the clinical application of metal bone scaffolds,and promote the development and progress of bone tissue engineering.In this study,the direct ink writing 3D printing technology was used.Dichloromethane,polylactic acid,and Fe powder with a certain particle size were selected as the raw materials of the metal slurry.The characteristics of the materials and samples were analyzed to prove the feasibility of processing.Pneumatic extrusion,sintering and other processes prepare artificial bone implants,and print complex structures to prove its molding ability,the principle of the technology and manufacturing process section to prepare small pore samples,laying the foundation for the next experiment.Prepare high-precision bone implants with different gradient pore sizes,measure their dimensional characteristics before and after sintering,and obtain the pore size change parameters of the molded sample after design-printing,design-sintering,and according to air pressure fluctuations and nozzle manufacturing errors analyze the causes of errors by factors such as fluctuations in slurry viscosity properties,line collapse,solvent volatilization,and sintering shrinkage.The mechanical properties and biodegradability of samples with different pore sizes were measured,and the effects of different pore sizes were analyzed according to the p H value,mass loss,and degradation products on the surface of the sample.It was found that 100μm samples can not only perform at a higher rate with a high surface area ratio.The degradation reaction can also carry out high-efficiency body fluid material exchange during the degradation process.According to the change process of each material during the sintering period,it is proposed to select a suitable pore former and formulate different proportions of ink to print samples.Through the observation of the microscopic characterization of the line surface before and after sintering,the cross-sectional observation,the measurement of quality and size,and the comparison of the metal composition of the samples with different parameters,it is proved that the method can create microscopic pores in the line.The mechanical properties of the manufactured samples with different structural porosities were tested,and it was found that the increased adjustable range was beneficial to the manufacture of bone scaffolds with different porosity-mechanical properties.