【摘要】 小芯片部件在利用焊膏进行回流焊时会出现"翘曲"现象。翘曲的问题在于芯片部件凸起,一端与印刷电路板分离,而相反的另一端粘连在电路板上。翘曲产生的原因在于焊接时间的不同,也就是部件相对两端的焊膏在回流炉中遇热溶化的时间不同。与处在芯片部件一端的的焊膏比,在另一端的的焊膏溶化得较早,溶化较早的焊膏通过软焊料表面拉力作用使先端下拉,就这样,翘曲问题在印刷电路板分装过程中产生了。更多还原

【Abstract】 Small chip components may have "tombstone" problems during reflow process by the solder paste. Tombstone is a defect that the chip components are raised and detached from the printed circuit board (PCB) at one end while remaining bonded to the circuit board at the opposite end. Tombstone is caused by difference in soldering time when the solder paste is melted at opposite ends of the component during heated in a reflow furnace. When the melting of solder paste adhering to the first electrode at one end of the chip component occurs earlier than that one adhering to the second electrode located at the opposite end, the earlier melted solder paste acts to pull down the first electrode by the surface tension force of the molten solder, thus tombstone problems are generated during PCBs sub-assembly process.更多还原