Research On 3D Printing Process Of Metal-ceramic Composites

Cermet composite materials have the advantages of both metal and ceramic,and combine the toughness and bending resistance of metal with the heat resistance and oxidation resistance of ceramic,which are widely used in many fields.3D printing technology,based on digital model files,uses printing molding equipment to print layer by layer,and finally completes the target product.The traditional metal printing equipment based on laser sintering principle is expensive,the cost of consumables is high,and is limited by metal materials.The pulp direct writing printing equipment has many advantages such as simple structure,low cost and no preheating in the forming process.In view of the wide application prospect of cermet composites,this paper will carry out research from the following three aspects: the construction and improvement of the printing device,the preparation of cermet composites paste,degreasing and sintering process.The main research contents and conclusions are as follows:(1)Based on the principle of direct writing 3D printing of paste,the material extrusion driving mode and the movement mode of equipment were determined.The experimental platform of direct writing printing of cermet paste was designed and built,and the printability was tested,realizing the low-cost printing of cermet composite material at room temperature;(2)In-depth study of the direct writing 3D printing process of cermets,the most suitable cermets paste for printing is obtained through experimental comparison,and the optimal ratio is 95:5,density is3.1523g/cm3,viscosity is 134.37 Pa.s,and the orthogonal test is used to further explore the influence of printing parameters on the forming size and quality.The optimal forming process parameters of cermet slurry were as follows: nozzle aperture was 0.41 mm,extrusion pressure was 0.5mpa,printing speed was 20mm/s,printing height was 0.37 mm and hot bed temperature was60℃.(3)Through the thermogravimetric analysis of the printed body,the influence of heating rate and holding time on the product degreasing,the best process parameters of cermet degreasing process: heating rate is 5℃/min,from room temperature to 800℃,holding for 1h;At the same time,the optimal process parameters of sintering process were determined by exploring:the heating rate in the low temperature stage was 10℃/min,rising from room temperature to 1400℃,and the heating rate in the high temperature stage was5℃/min,rising from 1400℃ to 2000℃ for 2h.