石灰石/PES复合材料选区激光烧结温度场数值模拟与实验

Numerical Simulation and Experiment of SLS Temperature Field of Limestone/PES Composite

利用选区激光烧结技术(SLS)制备石灰石/聚醚砜树脂(PES)复合材料烧结件(LPES)时,由于粉床预热温度T直接影响烧结件的烧结质量,决定烧结件的尺寸精度和力学性能。因此,对复合材料选区激光烧结温度场进行数值模拟,探究不同预热温度下复合材料粉末颗粒的平均温度和最高温度的变化规律具有研究意义和现实价值。利用离散元模拟仿真软件EDEM构建单层烧结实验粉末颗粒的并联系统模型,并在石灰石含量(石灰石/PES质量比1∶5)16.7%,激光烧结功率12 W,扫描速度1.8 m/s,扫描间距0.1 mm,分层厚度0.1 mm时,利用SLS技术对不同预热温度T∈72~82℃的石灰石/PES复合材料进行单层烧结实验,并对LPES材料烧结件进行力学性能实验和断面微观形貌表征,探究预热温度对LPES烧结件的冲击强度、尺寸精度和显微组织的影响规律,由实验结果确定粉床最佳预热温度为80℃,验证了温度场数值模拟结果的准确性,为后续实验确定最优工艺参数组合奠定了基础。

When using selective laser sintering(SLS)to prepare limestone/polyethersulfone resin(PES)composite sintered parts(LPES),the preheating temperature(T)of the powder bed directly affected the sintering quality of the sintered parts,and determined the dimensional accuracy and mechanics performance of the sintered parts.Therefore,there were research significance and practical value to numerically simulate the temperature field of composite material selective laser sintering,and to explore the variation law of the average temperature and maximum temperature of composite powder particles under different preheating temperatures.The discrete element simulation software EDEM was used to build a parallel system model of the powder particles of the single-layer sintering test,and the limestone content(limestone/PES mass fraction ratio)was 16.7%(1∶5),the laser sintering power was 12 W,and the scanning speed was 1.8 m/s,the scanning interval was 0.1 mm,and the layer thickness was 0.1 mm,the single layer sintering experiments were carried out on limestone/PES composites with different preheating temperatures of 72~82℃using SLS technology,mechanical properties test and cross-section micro-morphology characterization of LPES sintered parts were carried out to explore the influence of preheating temperature on the impact strength,dimensional accuracy and microstructure of LPES sintered parts.The optimum preheating temperature of the powder bed was determined to be 80℃from the test results,which verified the accuracy of the numerical simulation results of temperature field,and laid a foundation for the subsequent experiments to determine the optimum process parameter combination.