Investigation On 3D Printing Technology Of New Extrusion Metal

In recent years,metal 3D printing technology has developed rapidly in China and has been widely used in the aerospace field.In order to reduce the cost of printing materials and printing equipment,a metal 3D printer was designed in this paper,and the paste extrusion process of stainless steel 316L metal powder was studied.The research mainly includes four parts: the development of a metal 3D printer,the preparation of stainless steel 316L metal paste,the extrusion process of metal paste,and the post-processing process.The metal 3D printing equipment is based on the delta motion system.Extrusion head,extrusion screw and other components are designed in this experiment.Through the control system,the three-dimensional movement is carried out,and the extrusion system simultaneously extrudes the metal paste to realize the forming of the metal paste body.Stainless steel 316L metal paste is prepared by mixing binder and metal powder.PVA aqueous solution was used as the binder in the experiment,and the mass ratio of PVA to water was 1:10.The large particle aggregates in the binder were removed by filtration,and stirred evenly through a vacuum homogenizer.The mass ratio of stainless steel 316L metal powder to polyvinyl alcohol water solution in the metal paste was 10:1,the extrusion effect of the paste is better at this time.The extrusion process of stainless steel 316L metal paste was studied in the experiments.By adjusting the extrusion ratio,printing inclination Angle,overlap rate and other parameters,the forming quality of printing metal paste body was improved.In the actual extrusion process,when the extrusion ratio is 1.2 times of the ideal extrusion ratio,the extrusion effect is better,and when the overlap rate is increased from10% to 20%,the gap between the boundary of body and the inner filling part is reduced.The post-treatment of stainless steel paste body mainly includes drying,degreasing and sintering.Based on the TG-DSC of metal body,the suitable degreasing and sintering temperature were determined,and the mechanical properties of the metal samples at different temperatures were analyzed.