在电子装联领域,焊点通常都位于PCB平面。然而,随着散热、信号屏蔽等要求越来越高,器件及通路的分散性要求焊点能够在三维结构上延伸,从而形成了三维结构的焊点。在回流焊时,垂直(Z轴)方向上的焊料必然要受到重力的影响,特别是在要求连续的线、面焊接时,控制焊料的向下流动是保证焊接质量的难点。针对这一问题,从焊膏性能、印刷工艺和回流工艺三个方面进行分析和实验,不仅获得了连续均匀焊点,而且达到了批量印刷、单次回流的工艺要求,同时减少了器件的热冲击次数。
In the field of electronic assembly, solder joints are usually located in the PCB plane. However, with the higher and higher demand of heat dissipation and signal shielding, the dispersion of device and pathways require the solder to extend in the three-dimensional structure, thus forming the solder joints of three-dimensional structure. During reflow soldering, solder on the vertical direction (Z axis) is affected by gravity. Especially in a continuous line or surface soldering, controlling the downward flow of solder is the key problem to ensure the quality. The analysis and experiments were conducted in the three aspects of properties of solder paste, printing and reflow process, which not only won the continuous uniform solder joint, but achieved the requirement of batch printing and single reflow. And also the number of thermal shock of the device was reduced.