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相对于传统技术,3D打印技术在直接成型复杂形状金属和高分子零部件方面显示出了巨大的优越性。然而,3D打印技术在陶瓷零部件的成型方面尚存在诸多难题。为此,华中科技大学史玉升教授团队在3D打印陶瓷材料的制备及其成型技术方面做了较多研究。详细介绍了激光选区烧结(SLS)技术中复合粉体的两种主要制备方法:一种是通过机械混合法将陶瓷粉体与高分子聚合物机械混合制得SLS成型用复合粉体;另一种是通过溶解沉淀法或溶剂蒸发法将高分子聚合物包覆在陶瓷颗粒表面制得复合粉体。研究表明,采用上述两种制粉方法均可制备出具有良好流动性的适于3D打印的复合陶瓷粉体。还系统地讨论了SLS素坯的成型机理以及预热温度、激光功率和单层厚度等SLS工艺参数对陶瓷素坯的力学性能和成型精度的影响。在此基础上,采用最佳SLS工艺参数制备出传统成型工艺难以成型的具有三维孔洞结构的多孔堇青石和高岭土陶瓷零部件。此外,结合SLS工艺与冷等静压(CIP)技术提出了SLS/CIP复合成型技术,提高了SLS成型陶瓷的致密度和力学性能,制备出高性能、复杂结构的Al_2O_3、ZrO_2、Si C等致密陶瓷零部件,为采用3D打印技术制备航空航天、国防等领域用高性能陶瓷零部件打下了良好的基础。
Compared to traditional technologies, 3D printing technology has shown tremendous advantages in the direct molding of complex shaped metals and polymer parts. However, 3D printing technology still has many problems in shaping ceramic components. To this end, Huazhong University of Science and Technology Professor Shi Yusheng team in the preparation of 3D printed ceramic materials and molding technology to do more research. Two main preparation methods of composite powder in SLS technology are introduced in detail: one is that the composite powders for SLS molding are made by mechanical mixing of ceramic powder and macromolecular polymer by mechanical mixing method; the other Species by dissolving precipitation or solvent evaporation method polymer coated on the surface of ceramic particles obtained composite powder. The research shows that composite powders with good fluidity and suitable for 3D printing can be prepared by the above two milling methods. The forming mechanism of SLS slab and the influence of SLS parameters such as preheating temperature, laser power and single layer thickness on the mechanical properties and forming precision of the ceramic slab were also systematically discussed. On the basis of this, porous cordierite and kaolin ceramic parts with three-dimensional pore structure, which are difficult to be formed by the traditional molding process, are prepared by the best SLS process parameters. In addition, SLS / CIP composite molding technology is proposed by combining SLS technology and cold isostatic pressing (CIP) technology to improve the density and mechanical properties of SLS shaped ceramics and to prepare high performance and complex structures such as Al 2 O 3, ZrO 2, Si C, etc. Dense ceramic components for the use of 3D printing technology for the preparation of aerospace, defense and other fields with high-performance ceramic parts and lay a good foundation.