非均匀分布双面SMT及PBGA焊后塌陷高度控制

Double-Sided SMT of Unbalanced Distribution and Collapse Height Control of PBGA After Soldering

为了将大型计算机内部的热量及时传导出去 ,需采用一种新型的散热器 ,并将印制板上的发热元件集中安放在某一面 ,因此要求严格控制PBGA焊后塌陷高度 ,以保证散热器的合理安装和紧密接触。此外 ,如何保证非均匀分布印制板双面焊接的可靠性 。

For transmitting the heat from inside a supercomputer in time,a kind of new heat sink is needed and all exothermic devices and chips are required to be placed on one side of PCB Therefore the collapse height of PBGA must be controlled strictly in order to ensure heat sink to be packed and impinged properly Besides,it is also a hard problem in the SMT process to assure the soldering reliability of unbalanced distributed double sided PCBs