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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


capacitor shelf life

zam_bri

#5918

capacitor shelf life | 10 April, 2001

Hi..

What is the typical shelf life for chips capacitor 0603/0402 and what is the consequences of using the capacitor which more than 1 year old esplly on double reflow process. Pls help and thank you in advance.

cheers

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Steve Brown

#5921

capacitor shelf life | 11 April, 2001

Most of the component vendors I've dealt with will guarantee the solderability of the terminations for three years if the components are still packaged in a full reel. If the reel is part used we've kept them for 1 year and then used a wetting balance such as a Must II or a Meniscograph to check the solderability of the terminations. I haven't seen any problems on components over 12 months old, but this depends very much on the environment they have been stored in. Is the temperature and Relative humidity controlled in your stores. Were the reels loose or in seperate bags, did the bags contain any strips to maintain solderability. The best thing to do is to get the solderability checked and make sure that a good wetting force is achieved in the timescales required by your manufacturing process.

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Steve Brown

#5922

capacitor shelf life | 11 April, 2001

Most of the component vendors I've dealt with will guarantee the solderability of the terminations for three years if the components are still packaged in a full reel. If the reel is part used we've kept them for 1 year and then used a wetting balance such as a Must II or a Meniscograph to check the solderability of the terminations. I haven't seen any problems on components over 12 months old, but this depends very much on the environment they have been stored in. Is the temperature and Relative humidity controlled in your stores. Were the reels loose or in seperate bags, did the bags contain any strips to maintain solderability. The best thing to do is to get the solderability checked and make sure that a good wetting force is achieved in the timescales required by your manufacturing process.

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#5923

capacitor shelf life | 11 April, 2001

What's the issue? Solderability or performance of the component <= tantalium caps

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zam_bri

#5933

capacitor shelf life | 11 April, 2001

Thank you for the feedback guys. The concerns I have is related to components' performance as well as chipped-off & cracks. Does the performance also degrading over the time?

thx

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#5940

capacitor shelf life | 12 April, 2001

Tantalum caps degrade over time.

You should not be seeing "chipped-off & cracks" regardless of the age. This should not be a shelf-life issue, unless you are storing them in an aquarium. Tell us the story.

Solderability is a shelf-life issue and [as others have aptly stated] it depends.

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zam_bri

#5942

capacitor shelf life | 13 April, 2001

Hi Dave,

Thanx for your reply.

What is it in the process of manufacturing the capacitor that can go wrong until it can caused the chips to be chipped-off or cracks. I've encountered alot of this problem lately. First I thought it was our process that causing all these problem, until one day I went and pulled one reel for inspections. To my suprise, about 3% of the chips were cracked and chipped-off, while it is in the reels itself. I would appreciate it if you could share with me or let me know where can I pull the articles on Cap's manufacturing process.

cheers..

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#5946

capacitor shelf life | 13 April, 2001

I'll respond directly to your question about capacitor fabrication in a later posting, but more importantly and possibly more directly in response to the situation many hands touch your capacitors before you do. Each of these stockroom personnel, UPS truck drivers, distributor shipping types, distributor stock pickers, distributor inventory stockers, distributor in-bound material receivers, and on and on have the potential to damage your parts.

It seems like you have a fairly pervasive problem. Can you narrow it down to a supplier, date code, value, etc?

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#5951

capacitor shelf life | 13 April, 2001

root around the following site

http://www.faradnet.com/

... you should find some good stuff on capacitors

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zam_bri

#5956

capacitor shelf life | 13 April, 2001

cheers...

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