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July 2012

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Subject:
From:
Paul Edwards <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Paul Edwards <[log in to unmask]>
Date:
Fri, 13 Jul 2012 08:29:09 -0700
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I agree with Richard...There really isn't a point to it...

A ROSE test is going to determine "ionic contamination level" of a finished PCA after everyone and thing has touched it

The "ionics" are in and on the PCB, the components, the "flux residue" and material from the soldering iron tip if there is any hand touchup...

A better measure might be to pour all the components in a bag, including the PCB and run that through a ROSE test. 

I once built some leaded medical power supply PCAs in a W/S process and ran them through a ROSE for certification...

They all failed...Root cause... The long exposure to IPA solution attacked the adhesive material holding the ferrite bobbins together and to the PCB...
The bobbins feel off the PCA when handled after the ROSE test...
 
Also Dirty Inductors will read dirty PCAs...

My 2 cents...

Paul

Paul Edwards
Process/Quality Engineering
Surface Art Engineering

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Friday, July 13, 2012 8:00 AM
To: [log in to unmask]
Subject: Re: [TN] [TN] Ionic Contamination Test for Non-clean PCBA, is it really necessary?

Yes. That is correct. I don't see any point in it.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Glidden, Kevin
Sent: Friday, July 13, 2012 9:52 AM
To: [log in to unmask]
Subject: Re: [TN] [TN] Ionic Contamination Test for Non-clean PCBA, is it really necessary?

I agree it COULD be used as a process monitoring system for the ionic levels from the "no-clean" process.  But I wouldn't go putting production boards through that - I would use a test coupon.    As I stated before, it is my understanding at least, that much of the premise of "no clean" is that the "bad stuff" is bound in the "neutral stuff" (at least for the no cleans that leave residues).  If some of that "neutral stuff" washes away in the tester, you've done more harm than good.


-----Original Message-----
From: Karen Tellefsen [mailto:[log in to unmask]]
Sent: Friday, July 13, 2012 10:42 AM
To: [log in to unmask]
Subject: Re: [TN] [TN] Ionic Contamination Test for Non-clean PCBA, is it really necessary?

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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