关键词: 不锈钢粉末, 高分子材料, 粉体喂料3D打印机, 脱脂, 烧结

Abstract: In recent years, 3D printing is widely used in various industries due to its advantages. The traditional metal material 3D printing processes are mainly based on selective laser sintering technology. The equipments and raw materials are very expensive. Additionally, because of various limitations of the raw materials and the intensity of the laser beam, there are various problems in the processed parts and their post-treatment process. In China, the equipments for 3D printing and raw materials in the form of metal powder are mostly imported and expensive. Aiming at this situation, a new 3D printing molding?degreasing?sintering process which was based on 316L stainless steel powder and polymer material formulation was proposed in this work. Firstly, the formula material was fully mixed by the open mill, crushed and dried. The particle size of mixed material was relatively uniform. Then, the metal blank was 3D printed by using the self-developed powder feeding 3D printer, and the metal body was degreased by solvent degreasing method. Finally, the sintering experiments were carried out to study the samples obtained under different sintering conditions. The optimum sintering process was obtained through the analysis about physical and mechanical properties of the samples. The results showed that with the increase of sintering temperature, the densification degree of sintered products gradually increased, and the physical and mechanical properties were gradually improved. When the sintering temperature was 1370℃, the physical and mechanical properties of the obtained metal products were the best. The properties of metallurgical products produced by this technology are similar to those produced by traditional powder metallurgy, the sintered density reached 7.43 g/cm3, the tensile strength reached 501.2 MPa, the impact displacement reached 4.54 mm, the elongation reached 27.1%, the bending resistance reached 16.54 KN, and the hardness reached 80.74 HRB. At the same time, through micro-contrast, mechanism analysis and experimental verification, it was proved that 1370℃ was the best sintering condition, and the sintered products had the advantages of uniform composition, fine structure and stable performance. The research of this molding method was beneficial to reduce the cost of metal 3D printing and the difficulty of molding complex metal products, and the method had broad prospects.

Key words: stainless steel powder, polymer material, powder feeding 3D printer, degreasing, sintering