Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Lead shift

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Lead shift | 15 November, 2010

Hello. We encountered a SMD problem on PCB. It is that the lead of photocoupler is shifted after reflow and don't meet the minimum requirement of side joint length. I know this is a defect but what i want to hear the reason and the solution to prevent this problem in the future.Our SMD operator is saying that this may be caused by the larger pad length than the PC's lead. But i don't think so. What is the root cause why the PC's lead is shifted? How can i avoid this problem? FYI. The defect rate is about 32 ~35% and Side solder joint of good part is about 120% of lead lenght (PC)


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Lead shift | 15 December, 2010

We side with your operator. Poor pad design is the largest contributor to component shift.

If you posted pictures, we might have a livelier discussion about alternate explanations.

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