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| Reply To: | TechNet E-Mail Forum. |
| Date: | Thu, 6 Sep 2001 11:04:11 -0500 |
| Content-Type: | multipart/mixed |
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It depends on the reason why you are cleaning no-clean. As you stated the reason you are using a no-clean is to add components that are sensitive to water. You also use a water washable in other process steps. I have seen issues were the hand cleaning operations have damaged many components that are sensitive mainly due to washing.
I have also been involved with chemistry issues due to mixing fluxes/solders.
In past lives I have seen disclaimers added to all contracts that use moisture sensitive components where the customer has made a no residue requirement even from no-clean solders. This way the customer has to acknowledge that this is not an acceptable practice for no-cleans. You can also get paid for the hand wash process.
Recently I know of an issue where a battery was installed in a hand soldering operation and the customer had a no-residue requirment (due to end user perception) was being hand washed after using a no-clean. When the operators were cleaning the two leads and got both leads wet the battery started to discharge because of the water conductivity.
I was trying to find a study that I had read about a year ago talking about the reliability issues when some no-cleans are cleaned. I thought it was on EMPF but I looked through the archives and couldn't locate it. It talked about possible contaminate entrapement if all of the residues aren't removed completely but more smeared around. It also discussed reduced life due to chemistry mismatches.
I will continue looking and if I find it I will send it to you.
Kathy
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<DIV>It depends on the reason why you are cleaning no-clean. As you stated
the reason you are using a no-clean is to add components that are
sensitive to water. You also use a water washable in other process
steps. I have seen issues were the hand cleaning operations have damaged
many components that are sensitive mainly due to washing. </DIV>
<DIV> </DIV>
<DIV>I have also been involved with chemistry issues due to mixing
fluxes/solders. </DIV>
<DIV> </DIV>
<DIV>In past lives I have seen disclaimers added to all contracts that use
moisture sensitive components where the customer has made a no residue
requirement even from no-clean solders. This way the customer has to
acknowledge that this is not an acceptable practice for no-cleans. You can
also get paid for the hand wash process.</DIV>
<DIV> </DIV>
<DIV>Recently I know of an issue where a battery was installed in a hand
soldering operation and the customer had a no-residue requirment (due to end
user perception) was being hand washed after using a no-clean. When the
operators were cleaning the two leads and got both leads wet the
battery started to discharge because of the water conductivity. </DIV>
<DIV> </DIV>
<DIV>I was trying to find a study that I had read about a year ago talking about
the reliability issues when some no-cleans are cleaned. I thought it was
on EMPF but I looked through the archives and couldn't locate it. It
talked about possible contaminate entrapement if all of the residues aren't
removed completely but more smeared around. It also discussed reduced
life due to chemistry mismatches. </DIV>
<DIV> </DIV>
<DIV>I will continue looking and if I find it I will send it to you.</DIV>
<DIV> </DIV>
<DIV>Kathy </DIV></BODY></HTML>
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