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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Ron Beasley

#12100

Catastrophic failure of solid tantalum smt caps | 31 March, 1999

Has anyone heard of a problem with catastrophic failure of large value (200uF) solid tantulum capacitors that have been exsposed to high humdity.

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AF Ng

#12101

Re: Catastrophic failure of solid tantalum smt caps | 1 April, 1999

| Has anyone heard of a problem with catastrophic failure of | large value (200uF) solid tantulum capacitors that have been | exsposed to high humdity. | I suppose that with water moisture seep in the capacitor, the risk is very high that abrupt outgassing at either reflow or solder pot zone would cause capcitor crack. Of course , the scenario would be worsen with poor preheating.

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Ron Beasley

#12102

Re: Catastrophic failure of solid tantalum smt caps | 1 April, 1999

| | Has anyone heard of a problem with catastrophic failure of | | large value (200uF) solid tantulum capacitors that have been | | exsposed to high humdity. | | | I suppose that with water moisture seep in the capacitor, the risk is very high that abrupt outgassing at either reflow or solder pot zone would cause capcitor crack. Of course , the scenario would be worsen with poor preheating.

|This failure occurs in the field after processing and test

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P.L. Sorenson - Technical Consultant

#12103

Re: Catastrophic failure of solid tantalum smt caps | 2 April, 1999

| | | Has anyone heard of a problem with catastrophic failure of | | | large value (200uF) solid tantulum capacitors that have been | | | exsposed to high humdity. | | | | | I suppose that with water moisture seep in the capacitor, the risk is very high that abrupt outgassing at either reflow or solder pot zone would cause capcitor crack. Of course , the scenario would be worsen with poor preheating. | | |This failure occurs in the field after processing and test | More information would be helpful to solve this problem.

1. Was failure analysis performed and if so, what was the result? 2. Has the manufacturer been contacted, provided samples of failed items, and provided a response? 3. Have you conducted in-house burn in tests for extended periods of time under various environmental conditions to duplicate the failures? 4. Is power quality in the field a possible contributing factor? 5. How have you concluded that humidity is the primary factor resulting in failure. 6. What is the typical time to failure in calendar and operating hours? 7. Are the failed capacitors from a single lot or from various lots? 8. Are the failed capacitors from a single manufacturer or from various sources? 9. Is the failed item being used within the environmental and functional limitations of its specifications? 10. What is the history of this design? (is this a new product)

These are the types of questions I have asked myself on more occasions than I care to recall. I hope some of them provide new ideas to solve this problem.

Regards, Pete Sorenson Phone (414)238 1731

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