基于选区激光烧结工艺的多孔尼龙制备及性能

Fabrication Process and Properties of Porous Polyamide Produced by Selective Laser Sintering

提出一种基于选区激光烧结的多孔材料成型方法,利用增材制造技术控形、控性的优势,实现多孔材料结构与功能的可控设计。采用尼龙与水溶性致孔剂Na Cl为原材料,通过改变致孔剂含量和工艺参数,实现多孔材料的孔隙率、渗透性及力学性能的可控调节。实验结果表明,多孔材料的孔隙率、渗透性随着致孔剂含量的增大而增大;在相同的致孔剂含量下,其孔隙率和渗透性随着激光能量密度的增加呈下降趋势,分层厚度增加,孔隙率和渗透性明显增加;制备的多孔材料最高孔隙率达到59%,渗透率达0.312 m L/(mm2·s),弯曲强度可达44 MPa。以陶瓷高压注浆成型多孔树脂模具为例,开展多孔材料的功能验证,获得厚度为10 mm、含水率为20%的陶瓷坯体,为该模具的快速制造提供了一种新手段。

A peculiar method based on selective laser sintering（SLS） to fabricate porous materials was proposed, which utilized the characteristic of structure and property control derived from additive manufacturing（AM） to realize the controllable structure and function design. The composite powders used for SLS were prepared by mechanically mixing polyamide12 （PA12） with the water-soluble pore-foaming agent （NaCl）. The controllable porosity, permeability and mechanical property were achieved by changing NaCl contents and processing parameters. Experiment results show the porosity and permeability both increase with increasing NaCl contents. The maximum porosity, permeability and flexural strength reach 59%, 0.312 mL/（mm2·s） and 44 MPa, respectively. The application research is performed on the porous PA mould for ceramic pressure slip casting. A green body with the wall thickness up to 10 mm and moisture content of 20% is obtained, which can meet basic requirements of slip casting process. This work offers an alternative approach for the rapid manufacturing of porous resin moulds and personalized customization of porcelain products.