激光透射焊接聚碳酸酯的有限元分析

Finite element analysis of laser transmission welding of polycabonate

为了研究激光透射焊接塑料过程中温度分布对焊接显微结构和强度的影响,采用ABAQUS软件,建立了使用激光透射焊接技术焊接聚碳酸酯(PC)的三维有限元热分析模型,通过子程序DFLUX和FORTRAN语言编程实现超高斯型热源的动态加载,有限元分析得到激光透射连接过程中温度场的分布。结果表明:当激光功率P=40 W,焊接速度v=40 mm/s时,焊接温度达到333.8℃,焊接强度最高(1.3 k N),焊接质量最好;当焊接速度v=10 mm/s时,最高温度达到589.5℃,拉伸强度为0.4 k N。当激光功率为40 W,焊接速度为100 mm/s时,焊接温度达到165.5℃,拉伸强度为0.74 k N。焊缝成形的好坏主要与焊接温度有关,可通过选择合适的工艺参数对这些缺陷进行控制。

A three-dimensional finite element analysis thermal model for laser transmission welding technique of polycarbonate （PC） was developed. Power distribution of moving heat source was implemented into DFLUX subroutine, written in FORTRAN programming language to simulate the temperature distribution during the laser transmission welding process. The effect of process parameters on the weld strength and weld width was analyzed. Data gained by numerical simulation was compared to data obtained by laser transmission welding experiments, and good agreement was found between the two trends. It was observed that for a particular value of the laser power, good bonding between two thermoplastic materials is a function of laser scanning speed. Too high speed will not produce any significant increase in temperature at the two material interfaces to have a good chemical bonding. On the other hand, too slow speed will cause excessive increase in temperature resulting in burnout condition for polycarbonate. For the ranges of parameters investigated in the current study, it was observed that for a laser heat flux of 40 W, good bonding occurs for a laser scanning of 40 mm/s. This shows that the finite element analysis can be used for optimization of process parameters.