Bob sent me a picture of what the wipes look like after the acetone wipes. 
 I have forwarded it to Steve, and with Bob's permission, to put on Steves 
web page.

There is some serious schmutz here.  Bob, a couple of questions - is the 
solder mask dark in color or is it the garden variety green?  Are the 
legend and marking inks dark and are they smeared or blurred after the 
acetone wipe?  Is it a light wiping with low pressure, done by Millie the 
Mouse, or heavy cleaning by Magilla the Gorilla?

Has anyone thought to analyze the wipe cloths by FTIR to see what the 
chemical signature of the schmutz is?

Doug Pauls



From:   Robert DeQuattro <[log in to unmask]>
To:     <[log in to unmask]>
Date:   02/20/2014 12:19 PM
Subject:        Re: [TN] Acetone as a cleaning agent for PCBA's
Sent by:        TechNet <[log in to unmask]>



Thanks all on the comments.

This is a picture of what the residue looks like from the acetone cleaning 
process.



[cid:[log in to unmask]]



Based upon the replies at this point to this thread, it appears:

1.       Using the acetone as they are seems acceptable for cleaning

2.       The boards we are supplying have some type of residue on them 
regardless of the results of the zero-ion testing.



Bob













-----Original Message-----
From: Mike Fenner [mailto:[log in to unmask]]
Sent: Thursday, February 20, 2014 12:56 PM
To: 'TechNet E-Mail Forum'; Robert DeQuattro
Subject: RE: [TN] Acetone as a cleaning agent for PCBA's



Hmm

I think I would like to know what their wiping procedure is and what they 
are hoping to achieve by doing it before making any firm comment.

Naturally nothing has changed in your place or theirs, but something has 
if this has just started to appear.

I would start from the premise that the boards can be no cleaner than the 
last thing that touched them.

Unless the acetone is being allowed to flush off the board the probability 
is that they are making the boards dirtier. If there is anything in the 
acetone or on the board and it dries in place then the board will be no 
cleaner than it was before (the soil might be redistributed slightly) and 
anything in the acetone or on operators gloves will be left on board. If 
they are applying the acetone to the wipe by holding it against the bottle 
then anything in the wipes will gradually accumulate in the bottle.

Quite likely they are just seeing a surface effect as you would get on any 
shiny surface wiped over like this. Think of cleaning a mirror. So it 
could be technique or the acetone is dissolving something from the wipe or 
softening the resist slightly. OR your boards are contaminated from 
packaging say and they are seeing partial removal. In this respect the 
boards could be ionically clean as measured by zero ion tester, but 
theoretically could have non ionic contamination.

So a lot of what ifs and maybes at this point.





Regards



Mike

-----Original Message-----

From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert DeQuattro

Sent: Thursday, February 20, 2014 5:00 PM

To: [log in to unmask]<mailto:[log in to unmask]>

Subject: [TN] Acetone as a cleaning agent for PCBA's



I have a customer that uses acetone to wipe down their PCBA's upon 
receipt.

The assemblies we make for them are cleaned using a closed loop aqueous 
board washer then sampled for cleanliness with our zero-ion tester per 
J-std-001E guidelines.

Recently this customer commented that boards appeared dirty upon cleaning 
with the acetone.  Does anyone have any thoughts on this acetone cleaning 
process.

Thanks,



Bob



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