元件布局对PCB回流焊温度场的影响

针对某PCB的无铅焊料回流焊工艺,建立了元件四种不同布局条件下PCB的有限元热分析模型,运用Ansys软件,模拟获得了元件不同布局条件下的回流焊过程的温度场分布.结果表明:不同的元件布局会导致回流焊过程中温度场分布不同;将元件置于板面四角时,焊膏和BGA的回流焊峰值温度较高;元件“十”字形布局时,焊膏和BGA的回流焊峰值温度较低;在一定范围内减小元件的横向间距,对PCB回流焊接的影响不大.

Effect of Electronic Components Placements on Temperatures Field for PCB during Reflow Soldering

Based on the processes of reflow soldering for lead-free solder, four FEA models with different placements of electronic components were established to a printed circuit board. By using of Ansys, the processes of reflow soldering with different placements were simulated, and the thermal fields of all these models were analyzed. The results indicate that the distribution of temperatures would be different in the four samples. With the electronic components sit in four corners of the PCB, the highest temperatures of the soldering paste and BGA would be rise. The highest temperatures of soldering paste would be cut down, if the components were sit in cross -shaped, and decreasing the transverse spacing distance between the electronic components with limits, the effect on PCB for reflow soldering were not obvious.