激光熔融喷射焊接系统的设计及实验研究

发布时间：2018-11-29 10:57

【摘要】：随着电子元器件引脚数量增加、引脚间距减小,现代电子制造业对焊锡材料和设备工艺提出了更高的要求。而目前市场上的主流材料无铅焊料存在熔点高、润湿性差等缺点。传统的回流焊和手工锡焊工序复杂、效率低,且使用无铅焊料进行焊接时整体焊点质量难以保证、良品率较低。为解决上述问题,本文提出了一种激光熔融喷射焊接系统,利用全新的非接触式喷射焊接技术,提高焊接质量和效率,满足现代电子制造业的需求,促进行业的发展,具体研究内容如下:首先确定了锡球材质、直径和物性参数的影响因素,在理论上分析了锡球加热熔化过程中,锡球对激光器的激光能量吸收率和锡球由于热辐射、热传导向外界热量散失;考察了表面张力、喷嘴结构参数、工作气压和锡球大小等因素对熔融锡球脱离喷嘴时平均速度的影响;分析了熔融锡球在焊件上最大铺展直径和破裂飞溅的影响因素。在理论分析的基础上,运用有限元分析软件对锡球加热过程、熔融锡球喷射和焊接过程进行模拟仿真,对喷嘴的结构参数、喷嘴和熔融锡球之间的润湿角、工作气体压力、工作气体作用时间、激光器加热功率和锡球加热温度等参数进行优化分析,并依次确定了设备配套零部件的结构和型号,为后续的整机结构设计奠定基础。对激光熔融喷射焊接系统进行整机结构设计、制作整机并搭建实验平台,进行实验探究,首先考察了电机转速对锡球输送成功率和稳定性的影响,确定最佳电机转速为0.25r/s,然后依据仿真和理论的结果对激光熔融喷射部分进行了实验测试,确定激光器输出功率为90W,激光器作用时间为20ms,工作氮气压力为5500Pa,工作氮气压力作用时间为6.2ms,喷嘴口直径为0.5mm,锡球直径为0.76mm时,可以形成比较优质的焊点。并以此参数设置为基础,通过单因素法实验考察电机转速、工作气体压力、激光器加热功率等工作参数对锡球输送性能和熔融锡喷射效果的影响特性。
[Abstract]:With the increase of the number of pins and the decrease of pin spacing, modern electronic manufacturing industry has put forward higher requirements for solder materials and equipment processes. At present, the mainstream materials in the market lead-free solder has high melting point, poor wettability and other shortcomings. The traditional reflow welding and manual tin welding processes are complex and inefficient, and the quality of solder joint is difficult to guarantee and the rate of good products is low when using lead-free solder. In order to solve the above problems, a laser melt jet welding system is proposed in this paper. The new non-contact spray welding technology is used to improve the welding quality and efficiency, to meet the needs of the modern electronic manufacturing industry, and to promote the development of the industry. The specific research contents are as follows: firstly, the factors affecting the material, diameter and physical properties of the tin ball are determined, and the laser energy absorption rate of the tin ball to the laser and the thermal radiation of the tin ball due to thermal radiation are analyzed theoretically during the heating and melting process of the tin ball. Heat conduction to the outside heat loss; The effects of surface tension, nozzle structure parameters, working pressure and tin ball size on the average velocity of molten tin ball were investigated, and the factors affecting the maximum spreading diameter and rupture spatter of molten tin ball were analyzed. On the basis of theoretical analysis, the finite element analysis software is used to simulate the heating process of the tin ball, the spray and welding process of the molten tin ball, the structure parameters of the nozzle, the wetting angle between the nozzle and the molten tin ball, and the working gas pressure. The operation time of the gas, the heating power of the laser and the heating temperature of the tin ball are optimized and analyzed, and the structure and model of the matching parts of the equipment are determined in turn, which lays a foundation for the subsequent structural design of the whole machine. The structure of the laser melt jet welding system is designed, the whole machine is made and the experimental platform is built. The influence of motor speed on the success rate and stability of tin ball transportation is investigated. The optimum motor speed is 0.25 r / s, and the laser melt injection part is tested according to the simulation and theoretical results. The laser output power is 90 W, the laser operating time is 20 Ms, and the working nitrogen pressure is 5 500 Pa. When the working time of nitrogen pressure is 6.2 Ms, the nozzle diameter is 0.5 mm and the diameter of tin ball is 0.76mm, a better solder joint can be formed. On the basis of this parameter setting, the effects of motor speed, working gas pressure and laser heating power on the transport performance of tin ball and the effect of molten tin injection were investigated by single factor method.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG439.4

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