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Cracked chip capacitors

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#40072

Cracked chip capacitors | 28 February, 2006

Does anyone have any insight as to the cause of cracked chip capacitors during SMT? Z-stop? Thermal shock? Any help is appreciated.

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#40077

Cracked chip capacitors | 28 February, 2006

Depaneling with the parts in question near a V-score?

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PWH

#40078

Cracked chip capacitors | 28 February, 2006

Too fast heating/cooling rate in reflow (look at mfg's spec.). Z "overdrive" on pick and place or chipshooter though unlikely I would say. Depanelization method (bending a scored board to break it is tough on things). Bad PCB design - cap. too close to board edge near depanel area. Operators putting PCB's in racks in a rough manner. Perf. tab nibbler blade chuck hitting caps near edge. Pizza cutter panel score cutter hitting parts. Washer blowing boards around so they hit on cage carriers. Might want to follow the process through thoroughly. Hopefully, could be simpler than you think.

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#40079

Cracked chip capacitors | 28 February, 2006

Steve,

I believe you hit it right on the head! Thanks!

Gary

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#40080

Cracked chip capacitors | 28 February, 2006

PWH,

Thanks for all your input. All these areas are of concern which I will look closer into. thanks!

gary

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Chunks

#40095

Cracked chip capacitors | 1 March, 2006

Round cracks that look like it's from a placement are generally from a too big Delta T in wave (been there done that). All other cracks are anomalies. Ya gotta see it find it.

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inds

#40118

Cracked chip capacitors | 2 March, 2006

jagman,

take a hard look at a capacitor under the high mag microscope before you start assembling it.. I remembering seeing cracks even before the assembly. apparently all chip capacitors have crack at the intersection between the capacitor head and body.. and the cracks expands due to all the effects mentioned above

inds

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