核桃壳/酚醛树脂生物质复合材料选择性激光烧结工艺参数研究

Study on Selective Laser Sintering Process Parameters of Walnut Shell/Phenolic Resin Biomass Composite Material

黑龙江省作为农林业大省,盛产核桃,这种果壳来源丰富且产量高,同时也伴随着大量农业废弃物的产生。为改善这一现状,需要对废弃核桃壳进行合理资源利用。选取废弃核桃壳作为粉末基体材料,将碳含量丰富的酚醛树脂粉作为黏结剂,制备用于选择性激光烧结的核桃壳/酚醛树脂生物质复合材料,不仅可以扩大生物质复合材料粉体的种类,还可以通过该技术的三维性,定制复杂结构的多孔碳前驱体,在海水淡化、新能源方面作出贡献。建立四因素三水平的正交试验方案,通过方差分析法和综合加权评价法,探讨激光功率、扫描速度、扫描间距和分层厚度4因素对烧结件密度、弯曲强度和Z轴精度的影响规律,确定最优激光烧结工艺参数组合,使用扫描电镜(scanning electron microscope,SEM)对成型件烧结断面进行表征。试验结果表明,激光功率对烧结件密度、弯曲强度和Z轴精度的影响最大,扫描速度对烧结件密度和弯曲强度的影响最小,扫描间距对Z轴精度影响最小;最优工艺参数组合为激光功率10 W、扫描速度2 m/s、扫描间距0.1 mm、分层厚度0.12 mm。

Heilongjiang Province,as a major agricultural and forestry province,is rich in walnuts.This kind of shell is rich in source and high in yield.At the same time,it is accompanied by a large number of agricultural wastes.In order to improve this situation,it is necessary to make rational use of waste walnut shells.In this experiment,waste walnut shell was selected as the powder matrix material,and phenolic resin powder with rich carbon content was used as the binder to prepare walnut shell/phenolic resin biomass composites for selective laser sintering.It can not only expand the types of biomass composite powder,but also customize the porous carbon precursor with complex structure through the three-dimensional nature of the technology,and contribute to seawater desalination and new energy.The orthogonal experimental scheme of four factors and three levels was established.The influence of laser power,scanning speed,scanning spacing and layer thickness on the density,bending strength and Z-axis accuracy of sintered parts was discussed by variance analysis and comprehensive weighted evaluation method.The optimal combination of laser sintering process parameters was determined,and the sintering section of the molded parts was characterized by scanning electron microscopy(SEM).The experimental results showed that the laser power had the greatest influence on the density,bending strength and Z-axis accuracy of the sintered parts.The scanning speed had the least influence on the density and bending strength of the sintered parts.The factor that had the least influence on the Z-axis accuracy was the scanning spacing.The optimal process parameter combination is:laser power 10 W,scanning speed 2 m/s,scanning spacing 0.1 mm,layered thickness 0.12 mm.