Research On Melt Differential 3D Printing Technology Of Metal Powder

With the development of 3D printing technology,3D printing composite materials have become the focus of current research.Scholars in various countries have studied the 3D printing composites very deeply,especially the composite materials available for molten deposition molding(FDM),including glass,ceramic and metal composites.This topic mainly studies the 3D printing of metal composite materials.With the self-made metal composite material as the experimental material,the metal parts are finally obtained by 3D printing,degreasing and sintering process by the self developed melt differential 3D printing equipment.The metal powder composites studied in this paper are mainly composed of copper powder and adhesive,and have two kinds of PLA/Cu,PW+PP+SA/Cu.The melt differential 3D printing equipment has a certain fluidity for the requirements of the composite material.In order to keep the shape and the products after the sintering can meet certain performance requirements during the sintering process,the metal content in the composite is a critical proportion.So the feeding part mainly studies the metal and adhesive formula that can meet the requirements.The experimental results show that the most suitable mass ratio of the printed PLA/Cu composite is 1:8;the mass ratio calculated in the PW+PP+SA/Cu composite material is 1:10.The mass ratio of the binder and copper powder that can be printed into the type of PW+PP+SA/Cu composite is 1:7.In this paper,a polymer melt differential 3D printer is used for printing and molding.The influence of different printing parameters on the molding quality is studied,and the printing parameters suitable for each metal composite are obtained.The printing parameters for PLA/Cu composites are:0.4mm for the nozzle,0.3mm for the layer height,1600mm/min for the print speed,2.5r/min for the extrusion motor,0.25r/min for the extrusion screw and the temperature of screw section is 180 ?.The printing parameters for PW+PP+SA/Cu composites are:0.3mm for layer height,1600mm/min for printing speed,2r/min for extrusion screw and the temperature of screw section is 166 ?,the temperature of screw section is 112?.The degreasing process is a link which must be carried out to improve the final effect of the experiment.This paper selects the heating and degreasing mode according to the properties of the adhesive,and also selects the degreasing atmosphere wrapped with ash powder.Then according to the results of the thermogravimetric analysis and SEM analysis of each composite,the number of degreasing parameters is designed.At the same time,the different degreasing temperature and addition are studied.The effect of heat speed,heat preservation time and cooling mode on the experimental results was determined.Finally,the most suitable degreasing experimental parameters of the metal composite material were determined.Finally,the degreasing parts were obtained through the experiment,and the removal ratio reached 98.5%.The research principle of the sintering process is the same as degreasing,and the influence of different sintering temperature,heating rate,heat preservation tmme and cooling mode on the experimental results is studied.Finally,the optimum sintering parameters suitable for the metal composite material are determined.At the same time,the sintering parts which meet the requirements of the experiment are obtained with this parameter,and the final test of the sintering sample is drawn.Extend the strength.The experimental results show that the sintering method suitable for the metal composite material is low temperature long maintenance(low temperature,long time heat preservation),and the metal composite material mixed with a kind of low melting point metal will improve the result of final sintering experiment.