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Tombstone 0402 Caps......

techknow..

#34702

Tombstone 0402 Caps...... | 2 June, 2005

Placement looks good...paste to pad coverage good..correct profile used and verified by tracker. The problem being that this one cap is tombstoning at the same place every time. The placement is central. The part is near the edge at the break off.

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jimmygam

#34703

Tombstone 0402 Caps...... | 2 June, 2005

run the board thru both backward and sideways and see what happens

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PWH

#34704

Tombstone 0402 Caps...... | 2 June, 2005

Could also be a ground plane under one of the terminations of the cap causing heat sink troubles during reflow. One pad liquifies/solidifies before the other. Don't know a good solution for this outside of reworking them.

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peter ng

#34963

Tombstone 0402 Caps...... | 14 June, 2005

the pcb pad design problem?(the component able to fully located at the pad?).....or maybe the component(cap)problem?try to exchanged the part and reverse the pcb direction of the reflow entering.

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GS

#34967

Tombstone 0402 Caps...... | 14 June, 2005

On top to above suggestions,Round pad designe (where possible to get) helps to solve tombstoning pbm.

Regards

GS

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#35044

Tombstone 0402 Caps...... | 21 June, 2005

Curious... are you running any N2 in your reflow? If so what ppm level? I have worked with some reflow users that low ppm levels (< 100 ppm) would actualy cause tombstone, this was more random in nature though. This would occur due to the higher wetting forces with N2 and also ground plane in product. Your occurence with the same component and same place, the other recomendations to check out seem more reasonable.

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KT

#35162

Tombstone 0402 Caps...... | 24 June, 2005

Also check for any Vian-in-pad designs that could cause the problem.

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