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. >>>> ________________________________ >>>> This message and any attachments are solely for the use of the >>>> addressee >>>> and may contain L-3 proprietary information that may also be defined as >>>> USG export controlled technical data. 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