航天电子产品中SMT焊点形态对其疲劳寿命的影响

Impact of SMT solder joint shapes on fatigue lifetime in aerospace electronic products

深入分析了航天电子产品中表面组装技术(surface mount technology,简称SMT)焊点可靠性影响因素及失效机理,研究了温度循环下SMT焊点弹塑性应力应变规律及其寿命预测方法,并在此基础上探索了元件与焊盘间隙、钎料量、外轮廓等形态对焊点热疲劳寿命的影响,揭示焊点形态与应力应变和疲劳寿命之间的对应关系,以寻求具有较为理想力学性能及热循环寿命的焊点形态.结果表明,上述理论方法为实际焊接过程中的PCB上焊盘尺寸的合理设计提供了理论支撑.

Failure mechanism and influence factors of Surface Mount Technology( SMT) of aerospace electronic products were analyzed reliability,and its elastic- plastic stress law and lifetime were researched under thermal cycling load,which was basis for exploring of thermal fatigue life under influence of clearance between component and welding plate,solder volume and external profile. This paper reveals the corresponding relationship among the shape of solder joint,stress strain and fatigue lifetime,with the intention to explore a solder joint share with relatively ideal mechanical property and thermal cycling life,and to provide theoretical basis for reasonable design of the size of solder pad on PCB,control of the quality of solder joints from the perspective of performance of joint in the actual process of soldering process.