ROSE testing with Ionograph and Zero-Ion can be used for statistical
process control of no-clean assembly, just don't expect the ionic values
to mean anything wrt reliability except with regard to process control.
The IPC limit of 10 eq μg NaCl pr square cm2 is useless for no-clean
assembly, and the values measured will generally be higher than that.
Different measurement equipment will give different values. However, in
one assembly plant using one instrument, consistent values will be
obtained. Suppose a circuit is usually reliable and has ionic
contamination values within a statistical process range. If a batch of
circuits were to give values much high than that process range, something
is wrong, maybe over-fluxing,maybe something else. The process needs to be
adjusted.
Of course ionic testing is more useful for cleaned assembly, but it can
still be used for no-clean assembly.
Karen Tellefsen - Electrical Testing
Alpha / 109 Corporate Blvd./ S. Plainfield, NJ 07080
[log in to unmask]
908-791-3069
From: "Stadem, Richard D." <[log in to unmask]>
To: <[log in to unmask]>,
Date: 07/13/2012 10:18 AM
Subject: Re: [TN] [TN] Ionic Contamination Test for Non-clean PCBA,
is it really necessary?
Sent by: TechNet <[log in to unmask]>
Graham,
While I agree with you, we need to realize that what Willis Tam originally
asked was "Does it really make sense to perform Ionograph testing on a CCA
built with no-clean flux residues, but not washed?"
The answer is no.
If the CCAs were cleaned, then it might make a little bit of sense, just
to see how consistent the cleaning process is but not to determine if the
CCAs were actually clean.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Graham Naisbitt
Sent: Friday, July 13, 2012 9:07 AM
To: [log in to unmask]
Subject: Re: [TN] [TN] Ionic Contamination Test for Non-clean PCBA, is it
really necessary?
Fellow Techies,
Ionic Contamination Testing is a fast, accurate and reliable way to
control your assembly process.
ROSE testing ought to be consigned to history. At one time the US DOD
wanted to have a stake in the ground to better define what is acceptable
and unacceptable in terms of "cleanliness" hence the ROSE test was born
and setting a level of acceptance. This has caused more confusion and
argument in our industry than it reasonably deserves.
Tan Geok - in 1995 GEC Hirst Research determined that there are AT LEAST
16 different types of "white powder residues". You are not at all correct
to state that the flux residue will become white and, by inference, that
this is a bad thing. It might simply be cosmetic. How so? Because of a
trapped particle within the board surface that refracts the light in a
different way that "shows it to be white" - this might simply be pure and
inert rosin. Of course it could also be something far more sinister.
If I might be so bold, there will be an SMTA Conference in Chicago in
November on Cleaning and Coating. I shall be presenting a revised test
method that everyone assembling electronic circuits would benefit from, if
it is used correctly. If anyone wants the method, let me know, but I need
a few more weeks to complete the job.
Finally, and for the record, there are many systems in the market place
that are, in many cases, superior in performance and accuracy than either
the OmegaMeter or the Ionograph. There is also the Zero-Ion, the CT100 and
our Contaminometer - ALL of which deserve recognition. Hows that for fair
play?
So, to answer the original question - is it really necessary? If you want
a fast and accurate control of your assembly process - yes.
Graham Naisbitt
Gen3 Systems
On 11 Jul 2012, at 08:40, Tan Geok Ang wrote:
> Ask your customer to pay for the PCBA once it undergoes the Ionic
Contamination Test with Omega tester as the flux residue will become white
residue on the PCBA. Who is your customer who might advice you how to go
about the process.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of WTSJ-Willis Tam
> Sent: Wednesday, 11 July 2012 3:14 PM
> To: [log in to unmask]
> Subject: [TN] 答复: [TN] Ionic Contamination Test for Non-clean PCBA, is
it really necessary?
>
> Bob,
>
> The Omega Test is not yet set up, as I don't have the test result now.
>
> Actually, we don't want to set up such a test.
>
>
> Regards
> Willis Tam
>
>
> -----邮件原件-----
> 发件人: TechNet [mailto:[log in to unmask]] 代表 Robert Kondner
> 发送时间: 2012年7月10日 21:50
> 收件人: [log in to unmask]
> 主题: Re: [TN] Ionic Contamination Test for Non-clean PCBA, is it really
> necessary?
>
> Willis,
>
> I would be curious to hear the test restuls.
>
> Do you have any rework ( :-) ) and do you need to clean that for
> cosmetic appearance? If so soes that cleaning affect the No Clean flux?
>
> Thanks,
> Bob K.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of WTSJ-Willis Tam
> Sent: Tuesday, July 10, 2012 12:13 AM
> To: [log in to unmask]
> Subject: [TN] Ionic Contamination Test for Non-clean PCBA, is it
> really necessary?
>
> Hi Technet,
>
> We have implemented non-clean SMT and wave soldering processes for
> more than
> 10 years and there's no any issue, but recently one of our new
> customer required us to buy the Omega tester and set up the Ionic
Contamination test
> for the non-clean PCBA, according to IPC-TM-650. 2.3.25.
>
> We feel the Ionic Contamination test might not be an appropriate test
> for the non-clean PCBA, but is there any technical paper or industry
> standard for this topic? We need some supporting documents for further
> discussion with our customer.
>
> Any suggestion/feedback would be appreciated.
>
> Regards
> Willis Tam
>
>
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