弹载SAR伺服控制焊点故障分析

针对弹载SAR伺服控制板焊点脱落故障，从整机随机振动加速度响应，单板级热应力和随机振动应力分析排查故障原因，根据仿真结果提出工艺参数优化和设计改进建议。仿真结果表明，伺服控制板的加速度响应是基础激励的1.78倍；金属陶瓷芯片采用表面贴装工艺组装时对热应力敏感，增加焊料厚度有利于降低热应力；带引脚芯片采用堆焊工艺时对振动应力敏感，在芯片与印制板之间点胶有利于降低振动应力。

Fault Analysis of Servo-control Solder Joint for Missile-borne SAR

Based on the fault of solder joint falling off in servo-control board for missile-borne SAR, the failure causes are found through the analysis of acceleration response for complete machine stochastic vibration including the analyses of stochastic vibration stress and thermal stress for printed board, the process parameters optimization and design improvement are proposed according to simulation results. Simulation results show that the acceleration response of servo-control board is 1.78 times base excitation; the ceramic-metal chip when using surface mount technology is sensitive to thermal stress, increasing solder thickness avails decreasing thermal stress; the chip with pins when using surfacing technology is sensitive to vibration stress, dispensing between chip and printed board avails decreasing vibration stress.