Yes: better to be on the plaque; then part of the plague.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
Sent: Wednesday, February 19, 2014 9:28 AM
To: [log in to unmask]
Subject: Re: [TN] Cleanliness testing at component level
Focus Grasshopper Focus.............
Doug Pauls
From: jrusseau.precisionanalysts.com <[log in to unmask]>
To: <[log in to unmask]>
Date: 02/19/2014 10:25 AM
Subject: Re: [TN] Cleanliness testing at component level
Sent by: TechNet <[log in to unmask]>
Hi Brian,
Thank you for the reply. I know that some discussion has occurred within the meetings at IPC about solvents. I believe Graham has alluded to the solvent you speak of, but for obvious reasons hasn't divulged the blend. I
guess that I don't expect that of him or you. The man has to eat and so I
understand the need to protect a potential revenue stream. It sounds
like
you developed quite the sensitivity in your system, which is a plus considering the standard ROSE systems are not that sensitive. For me, and I won't go into great detail, part of the equation to evaluating cleanliness
isn't just the sensitivity, it is also selectivity. With modern fluxes, you have a huge menu of different activator packages. The wide range of different organic acids that can be used for no cleans still need to be studied. I see folks using no cleans that clean afterwards. That presents a different set of challenges and issues to boot. That all said, I am of the mindset that if the residue can't be brought into solution, then you can't accurately measure it.
Many have argued that that makes no difference with a no clean because it is designed to be left on the board. In most cases that might be a valid argument. However, I have seen some materials, classified as no cleans, that have led to field issues due to leakage. When this happens clients want to understand why. That said, I think that multiple solvents might be required to cover the wide array of flux materials that are used in industry. The days of the one-size-fits-all are nearly gone. Too, I think the Hansen solubility parameters might provide some insight into a direction for solvents. Though any development might take a bit of time. One has to factor in effects to other board materials, like solder mask. Anyway, I could discuss this for quite some time, but I will stop here. I look forward to any thoughts that you can share short of placing yourself into any unnecessary conflicts of interest.
My apologies for the random thoughts. Working on multiple tasks as I type
this.
Best Regards,
Joe Russeau
----- Original Message -----
From: "Brian Ellis" <[log in to unmask]>
To: "jrusseau.precisionanalysts.com" <[log in to unmask]>; "TechNet E-Mail Forum" <[log in to unmask]>
Sent: Wednesday, February 19, 2014 10:48 AM
Subject: Re: [TN] Cleanliness testing at component level
> Joe,
>
> Thanks for your interesting message. It may interest you to know that,
> when I developed the Microcontaminometer, I came across a severe
problem.
> With just a few cubic centimetre of solution in the measuring circuit,
how
> could I calibrate it? The lowest standard NIST solution is 1
> microsiemens-centimetre. If I used this, I would have to measure
> accurately quantities in the order of picolitres, which would be an
almost
> impossible task. It is not possible to use water as the standard
solution
> solvent below 1 microsiemens-centimetre because the conductivity of
> the salt (potassium chloride) would be lost in the conductivity of the
water.
> I therefore had to develop a standard solution with a much lower
> conductivity and which was stable. I succeeded with this, down to
> 0.001 microsiemens centimetre and I researched the characteristics,
> such as stability, temperature coefficient, linearity and so on fairly
thoroughly.
> One major difference is that I used sodium chloride as the salt,
> because
> this was the equivalent used for ionic contamination testing. As you
> can
> imagine, I used an organic solvent as the major solute.
>
> A few years later, one of my interlocutors informed me that they could
no
> longer do ionic contamination testing because, following a fire, the
> company boss men decreed that no flammable solution could be used or
> stored in a plastic container; only metallic containers and pipework
were
> permitted. This got me thinking and I did a number of experiments,
> based
> on the same solvent as I used in the test solution. This revealed
itself,
> in a 50% mix with water, as being nonflammable, non-toxic and
> compatible
> with the constructional materials of our instruments with a
> sensitivity pretty similar to that of conventional IPA/water mix.
> Because of its low
> volatility, it had less odour than IPA and was consequently more
> stable,
> requiring practically no maintenance of the proportions of the solution.
>
> The big question was whether this solution dissolved flux residues in
> a similar way to the conventional IPA/water solution. My tests, which
> were
> rather perfunctory, indicated that it did so for both water-soluble
> and rosin-based fluxes. At that time, no-clean fluxes and pastes, as
> we know
> them today, did not exist, so I have no idea as to whether this
> solution
> would be better than, equal to or worse than the conventional solution
for
> these residues.
>
> This work was done on a mandate by the company that originally
> acquired the rights for the Contaminometer, with whom I had a
> nondisclosure agreement. As a matter of legal precaution, I don't feel
> that I can disclose, at this stage, the composition of the solution. I
> have no idea
> whether the NDA has been passed to Graham Naisbitt and company but I
> am not taking the risk or, if it has, is it still valid, as I have
> signed nothing with him and the original agreement was dated 1991? Big
> question
> marks!
>
> I have vaguely discussed this with Graham on a couple of occasions,
> assuming that they may be interested in exploiting it and he is the
> only
> one, other than myself, to know the composition of the solution.
However,
> he seems reluctant to go ahead with it; I won't discuss this in detail
but
> it may be a question that the solution costs more than the
> conventional one. It has one minor additional disadvantage but several
> advantages
which
> I think some may consider more important.
>
> I feel that this subject should be discussed in detail with Graham and
> that the work that I did should be in the public domain.
>
> Best regards,
>
> Brian
>
>
>
>
>
> On 19.02.2014 15:37, jrusseau.precisionanalysts.com wrote:
>> Hello Brian,
>>
>> I would certainly be glad to have your valuable input on developing
>> cleanliness methods. Currently, we are considering adapting the
>> existing IPC ion chromatography method for printed boards to include
>> components. We are also considering a completely different method
>> for components. As you are well aware, the no clean fluxes pose some
unique
>> challenges in that the old solvent mixture of 75% IPA and 25% DI
>> water really have little ability to bring many of those materials
>> into solution. I have been after our group to look at studying other
>> solvents that might prove better, but many of my colleagues hesitate
>> to abandon the staple mix. They simply want to modify the concentrations.
>> Alas, I won't bore you with the dilemma's of IPC meetings /
discussions,
>> but would relish the opportunity to gain some additional insights
>> that
I
>> may be lacking personally and to help drive industry methods into a
more
>> modern era.
>>
>> Peace,
>>
>> Joe Russeau
>>
>>
>>
>> ----- Original Message ----- From: "Brian Ellis" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Wednesday, February 19, 2014 3:32 AM
>> Subject: Re: [TN] Cleanliness testing at component level
>>
>>
>>> In 1983, my now defunct company introduced the Microcontaminometer
>>> MCM-1 which what I claimed was the most sensitive conductivity meter
>>> in the world. The smallest tank was 26 x 26 x 5 mm, to take 1"
>>> wafers, DILs, SOILs, passive components (remember we were still
>>> mostly in the through-hole components era then, except for hybrids).
>>> It could measure a single diode, down to the most sensitive range of
>>> 0-1 µg/cm² eq. NaCl. A better description is on pp 317-9, if you
>>> happen to have my book. An improved MCM-2 with better software on a
>>> PC was launched in 1989. I guess I must have been ahead of my time
>>> by some 30 years or so because measuring component contamination has
>>> been a very silent subject up to now; I can't remember how many MCMs
>>> were sold but you could count the number on two hands, at least
>>> until I ceded the Contaminometer range to a third party in 1991 and
>>> I think they dropped the MCM range. I have no idea if Graham
>>> Naisbitt's company, which now has the rights to the know-how, is exploiting this niche market.
>>>
>>> Guess Doug has inherited my titles of King of Kaka and Prince of Poo
>>> (actually, I know in Germany I was nicknamed the Reinigung Papst -
>>> Cleaning Pope, slightly more complimentary!). For the anecdote, a
>>> guy in the UK Ministry of Defence called our APL-5 aqueous cleaning
>>> machine the best solderability tester in the world; you just had to
>>> look at the components in the sump to see which ones weren't
solderable!
>>>
>>> As for discussing the subject within the IPC, I'm obviously far too
>>> old to participate actively in a committee and I am really well out
>>> of touch with modern components (I retired in 1997), but would be
>>> honoured to be able to help in the editing of any proposals. Modern
>>> technology would make this easy with e-mails and possibly Skype.
>>>
>>> Brian
>>>
>>> On 18.02.2014 22:53, Douglas Pauls wrote:
>>>> That's me, the Emperor of Effluvium, Duke of Dirt, Sultan of
>>>> Schmutz, the Marquis of Mud ...........
>>>>
>>>> As Joe indicated, cleanliness at the component level, or at least
very
>>>> small sub-assembly is being examined. Once IPC as an organization
gets
>>>> its hands around how do you determine cleanliness at that level and
>>>> give some guidelines on what is desirable, then it can go into
>>>> larger specifications like J-STD-001.
>>>>
>>>> Doug Pauls
>>>>
>>>>
>>>>
>>>> From: "Stadem, Richard D." <[log in to unmask]>
>>>> To: <[log in to unmask]>
>>>> Date: 02/18/2014 02:34 PM
>>>> Subject: Re: [TN] Cleanliness testing at component level
>>>> Sent by: TechNet <[log in to unmask]>
>>>>
>>>>
>>>>
>>>> Yes, the lack of component cleanliness requirements in IPC
>>>> documents
is
>>>> lacking. Are they covered in JEDEC standards? If so, I think there
>>>> should be a reference within the IPC documents, especially those
>>>> standards dealing with cleanliness and contamination issues to the
>>>> next level (contagion). And no, I am not going to be a part of that
>>>> committee,
as
>>>> I
>>>> am suffering sufficient filth unto today to keep me busy thereof.
Maybe
>>>> Doug Pauls and Terry Munson? Those guys know dirt like nobody else.
>>>>
>>>> -----Original Message-----
>>>> From: [log in to unmask] [mailto:[log in to unmask]]
>>>> Sent: Tuesday, February 18, 2014 1:56 PM
>>>> To: Stadem, Richard D.; [log in to unmask]
>>>> Subject: RE: Cleanliness testing at component level
>>>>
>>>> Dean,
>>>>
>>>> No, I agree with you completely. I just don't see the specification
>>>> addressing component level. I would like to see the words
"component
>>>> level" added so that everyone sees it the way we do.
>>>>
>>>> In my case, the pre-tinned component may be shipped back to me and
>>>> sit in stock for a year before it is assembled onto a PWA which is
>>>> subsequently tested for cleanliness.
>>>>
>>>> Phil
>>>>
>>>> -----Original Message-----
>>>> From: Stadem, Richard D. [mailto:[log in to unmask]]
>>>> Sent: Tuesday, February 18, 2014 9:00 AM
>>>> To: TechNet E-Mail Forum; Bavaro, Phillip @ MWG - TW
>>>> Subject: RE: Cleanliness testing at component level
>>>>
>>>> For me, the difference between components and assemblies is
>>>> becoming
so
>>>> blurred that it is very difficult to determine where the spec
>>>> applies and where it doesn't.
>>>> Can you tell me that a PoP component consisting of 4 stacked
miniature
>>>> pwbs that is soldered together using a special flux and laser as
>>>> well
>>>> as
>>>> standard solder and flux and touched up and cleaned in an in-line
>>>> cleaner does not require the same treatment by the specification as
>>>> the 36"
>>>> by 24"
>>>> supercomputer CCA that has 24 layers, 36 miles of copper traces,
>>>> weighs 45 lbs when populated with just 24 sockets?
>>>> Why?
>>>>
>>>> -----Original Message-----
>>>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Bavaro
>>>> Sent: Tuesday, February 18, 2014 10:31 AM
>>>> To: [log in to unmask]
>>>> Subject: [TN] Cleanliness testing at component level
>>>>
>>>> I have reviewed the J-STD-001 several times but still have a
>>>> question regarding a subcontractor who performs component level
>>>> soldering operations for Class 3 hardware.
>>>>
>>>>
>>>> If the subcontractor is performing a soldering operation, then
>>>> cleaning is required to remove flux residues (this is not a no
>>>> clean flux situation).
>>>>
>>>> If the subcontractor is cleaning, then cleanliness testing is
required.
>>>>
>>>> The J-STD-001 does not really address the component level when it
>>>> comes to the Post Soldering Cleanliness Designator (PSCD).
>>>>
>>>> If a component is having its leads pre-tinned or a BGA being
re-balled,
>>>> then is it defaulted to a C-22 PSCD?
>>>>
>>>> My position is yes but I can see where there might be arguments
against
>>>> this since the designator codes seem to speak to the assembly level
and
>>>> not the component level.
>>>>
>>>> My concern is that there is considerable time lag between when
>>>> component soldering operations are performed relative to the actual
>>>> PWA process which does get checked for cleanliness.
>>>>
>>>> Any input is appreciated.
>>>> ________________________________
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