TECHNET Archives

September 2014

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
David Hillman <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, David Hillman <[log in to unmask]>
Date:
Mon, 8 Sep 2014 10:34:19 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (924 lines)
Hi Bob - there are adequate tools within the industry to determine if a
flux residue has an unacceptable ionic content - Ion Chromatography, SIR,
specific dielectric functionality testing, etc. so determining if your flux
and process are compatible is simple -lots of work but simple. Many, many
products utilize a "no clean" process using "low residue" flux materials
very successfully so it is not hogwash but just good materials & process
engineering. Of course, if someone does implement a "no clean" process
without doing their due diligence homework and testing, yes, they are not
going to be happy with the result.

Dave

On Mon, Sep 8, 2014 at 10:15 AM, Robert Kondner <[log in to unmask]>
wrote:

> Dave,
>
> Maybe it is "Fundamentally" a bit of hog wash. :-)
>
> The comments that started to thread was your description of why rosin
> based flux was good in the use of wire prep. I your description sounds
> reasonable to me.
>
>  Richard also seemed to find you information interesting.
>
>  But that thread starting point mentioned the use of RMA but never to use
> a "No Clean" flux.  That sounds silly to me. If a manufacturer put that
> same RMA flux in a bottle and called it "No Clean" I guess it would then
> never be used?
>
>  And then I was told to follow the manufacturer's advice! (Maybe that
> means as long as the manufacturers advice is not "No Clean".) (Hmmm is Not
> "No-Clean" = Clean Always?)
>
>  So I am back to the point of:
>
>   1. Read the Label
>
>  2. Follow the recommended processes. (And that included cleaning, if any.)
>
>  3. If you are not cleaning off flux (or you cannot due to entrapment)
> double check everything. Use RMA or No Clean.
>
> But to have  people poo-poo a No Clean as it has not been "Deactivated"
> through proper temperature is not verifiable. And until there is competent
> advice to be found the idea falls into the hogwash category.
>
> Just Say No to Hogwash.
>
> Thanks,
> Bob
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
> Sent: Monday, September 08, 2014 10:43 AM
> To: [log in to unmask]
> Subject: Re: [TN] tinning wires - flux entrapment and long term reliability
>
> Hi Bob - as Richard detailed, you need to get down to the flux supplier
> application engineers for that detail of information. And nope, I don't
> have a clue on why something so fundamental isn't a standard data point on
> the tech data sheet.
>
> Dave
>
> On Mon, Sep 8, 2014 at 9:28 AM, Robert Kondner <[log in to unmask]>
> wrote:
>
> > Dave,
> >
> >  I did look into this issue, several times.  I still sense a bit of
> > "Hog Wash" on this subject. I am trying to separate the hogs here.
> >
> >  Go take a look at the Kester 951 data sheet. No "Deactivation
> > Temperature" spec there.
> >
> >  Go take a look at Kester 2331-ZX,  now this stuff you need to clean.
> > Again no "Deactivation Temperature" specified.
> >
> > So I suggest you get ahold of some flux supplier application folks and
> > ask them for "Minimum Processing Temperature for Flux Deactivation". I
> > don't think you will find such a specification.
> >
> > Thanks,
> > Bob K.
> >
> >
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
> > Sent: Monday, September 08, 2014 10:10 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > reliability
> >
> > Hi Bob - as Richard detailed, if you get ahold of the flux supplier
> > application folks, they have the necessary data for setting up an
> > adequate profile and temperature range, application depenedent. The
> whole "no clean"
> > topic drives me batty - the proper term is "low residue" as I don't
> > have my flux suppliers dictating when I should or should not clean. A
> > case of marketing edging out engineering on the correct use of technical
> terms.
> >
> > Hey Doug - didn't you and Bill Kenyon have a nice synopsis on  the "no
> > clean vs low residue" topic?
> >
> > Dave
> >
> > On Mon, Sep 8, 2014 at 8:57 AM, Robert Kondner
> > <[log in to unmask]>
> > wrote:
> >
> > > Dave,
> > >
> > >  Ok, so if a manufacturer says a flux is categorically "No Clean" we
> > > should believe it, right? :-)
> > >
> > >  Offhand I never recall seeing a Minimum Temperature specification
> > > for the use of any flux. I recall finding usage temperature ranges,
> > > and you find info on how long the flux is active, find statements
> > > about must be cleaned or no clean,  but have you ever seen a flux
> > > with a minimum processing window to be qualified as a "No Clean"?
> > >
> > >  From experience I know that heating profiles of PCB assemblies in
> > > reflow ovens are selected such that all the flux does not completely
> > "Burn Off".
> > > In fact profiles where the flux remains active is what helps make
> > > nice shiny solder joints, everyone loves those.
> > >
> > >  I have not seen one shred of evidence in flux usage information
> > > that suggest leaving flux residue is safe IF it has been heated to
> > > some temperature for some specific length of time. All I see are
> > > fluxes listed as "Must Clean" or "No Clean".
> > >
> > > Do you know of any flux called "You Might Need to Clean"?
> > >
> > > Bob K.
> > >
> > >
> > > -----Original Message-----
> > > From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
> > > Sent: Monday, September 08, 2014 9:23 AM
> > > To: [log in to unmask]
> > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > reliability
> > >
> > > Hi Bob - all fluxes have a temperature range, or at least a minimum
> > > temperature value, that they should be heated to to accomplish two
> tasks:
> > > (1) attack/remove the oxides that inhibit the formation of a good
> > > solder wetting; (2) decompose the activators such that they are
> > > benign in the flux residue. The flux suppliers know their
> > > formulations and can provide temperature recommendations to ensure
> > > we can create adequate reflow profiles in our processes.
> > >
> > > Dave
> > >
> > > On Mon, Sep 8, 2014 at 7:58 AM, Robert Kondner
> > > <[log in to unmask]>
> > > wrote:
> > >
> > > > Richard,
> > > >
> > > >  So, I ask:
> > > >
> > > >   Does a rosin based "No Clean" flux need to be completely heated
> > > > to high temperature to "De-Activate" the flux?
> > > >
> > > > If what Dave say is correct the answer is no. I think?
> > > >
> > > > Bob K
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard
> D.
> > > > Sent: Monday, September 08, 2014 8:29 AM
> > > > To: [log in to unmask]
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > Dave, I never knew that about RMA fluxes. This is valuable
> > > > information, and I thank you for it.
> > > > dean
> > > >
> > > > From: David Hillman [mailto:[log in to unmask]]
> > > > Sent: Friday, September 05, 2014 4:03 PM
> > > > To: TechNet E-Mail Forum; Stadem, Richard D.
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > Hi Richard - I can provide some additional information. The value
> > > > of rosin based fluxes is that when using the proper soldering
> > > > temperatures and dwell times, the resulting flux residues are not
> > > > mobile, ionic species that can participate in corrosion reactions
> > > > (note that there is always an exception to the rule). The rosin
> > > > portion of rosin based fluxes can "bind up" any mobile, ionic
> > > > species if they are not completely consumed in the soldering
> > > > reaction. That is why rosin based fluxes are very robust in
> > > > soldering processes. As George and others detailed, "no clean' is
> > > > a horrible material descriptor as it is a process categorization
> > > > rather than a material categorization. The better term is "low
> > > > residue" and as others detailed, not all low residue materials are
> > > > created equal. Many low residue fluxes are rosin based materials
> > > > so they have applicability for wiring tinning but an engineer has
> > > > to do their homework to make sure there is process compatiblilty.
> > > > And yes, when folks attempt to use water soluble fluxes in the
> > > > same manner as rosin fluxes, bad things happen.  The wire tinning
> > > > process you learned has its credibility in the rosin chemistry
> > > > (the IPA relavence isn't as critical
> > > or necessary as Brian can/has detailed) and is supported by the
> > > products you detailed.
> > > >
> > > > I believe Doug and Bill Kenyon put together a "letter" on this
> > > > topic and I'll see if Doug can find that for posting thru Steve.
> > > >
> > > > Dave Hillman
> > > > Rockwell Collins
> > > > [log in to unmask]<mailto:david.hillman@rockwellcol
> > > > li
> > > > ns
> > > > .com
> > > > >
> > > >
> > > > On Fri, Sep 5, 2014 at 3:00 PM, Stadem, Richard D. <
> > > > [log in to unmask]<mailto:[log in to unmask]>> wrote:
> > > > I started out in life as a small child with a very large pair of
> > > > safety glasses and a leather apron, tinning wires in my father's
> > > business.
> > > > I later re-learned how to do this from two much older engineers,
> > > > who had retired from RCA and Honeywell, and they had been using
> > > > this method since they were little boys in their father's shop.
> > > > I have also taught this method to my three sons, as there still
> > > > seems to be no end of wire tinning requirements even today.
> > > >
> > > > 1. When stripping the wires, leave the tag end of the insulation
> > > > hanging on the end of the wire. This helps prevent the strands
> > > > from fraying during handling.
> > > > 2. When ready, pull off the tag end of the insulation. Dip the
> > > > stripped end of the wire first in IPA up to the end of the
> insulation.
> > > > 2. Then dip the wire in the RMA flux up to about halfway to the
> > > > insulation. Use only RMA flux whenever tinning wires, never OA or
> > > > water soluble flux, and never no-clean flux.
> > > > 3. Then dip the fluxed end into the solder right up to within .010"
> > > > from the insulation and hold for 1 or 2 seconds. This allows the
> > > > solder to wick just under the insulation.
> > > > 4. Pull the wire out of the solder and "swirl" in clean IPA, and
> > > > then lay the wires down flat on a piece of absorbent paper towel.
> > > > 5. If an ultrasonic cleaner can be used, ie, the wires are not
> > > > soldered to any CCA or any electronic components, then instead of
> > > > laying them on the paper towel, drop them into the US cleaner with
> > > > a solution of 90% DI water and 10% IPA. Do not exceed the 10% IPA
> > > > percentage or you will have a new company swimming pool, but also
> > > > you will be minus a few operators and you will gain many new
> > > > friends at OSHA and Davidovich, Davidovich, and Rabinovitch, Atty's
> at Law.
> > > > 6. Once all of the wires have been cleaned for a minimum of 10
> > > > minutes in the US bath, take them out and dry them on a clean
> > > > paper
> > towel.
> > > >
> > > > This is a time-tested method, dating back to the late 1950s.
> > > >
> > > > My understanding (and it may be flawed) is that RMA is used
> > > > because even if small amounts are not dissolved in the IPA,
> > > > whatever residues that do remain are relatively harmless, because
> > > > they are weakened by the IPA already in the wire strands, and
> > > > after tinning, most if not all is removed during the "swirling" in
> > > > IPA. When the wires are laid down on the paper towel, the IPA and
> > > > the flux solids are drawn out, and any remaining residues left
> > > > behind are relatively
> > harmless.
> > > >
> > > > I do know that this method of tinning wires was used in the old
> > > > Apollo program.
> > > > It was also used on the Neartip Mark 5 Torpedo Guidance and
> > > > Control systems.
> > > > It was also used on the older Mark 2 Torpedoes.
> > > > It was also used on the Advanced Lightweight Torpedo.
> > > > It was used on the Apache, C5B, Augusta, F-15, F-16, FA-18
> > > > avionics systems, including the flight control computers, the ring
> > > > laser gyros, the altimeters, the wind speed indicators, the
> > > > flapper controls, the CMRA and HMRA Cruise Missiles, The CH46/CH47
> > > > avionics sets, the Space Shuttle wiring, and about 400-500
> > > > commercial jet plane
> > wiring sets.
> > > >
> > > > I have yet to hear of any wires broken off from corrosion under
> > > > the insulation.
> > > >
> > > > I have heard of many wires corroding away because either water
> > > > soluble flux or no-clean fluxes were used. Water soluble fluxes do
> > > > not wash out or dilute when dipped in alcohol or water (at least
> > > > not very well). Ditto with no-clean fluxes.
> > > >
> > > >
> > > > My only concern is that there are RMA fluxes, and there are RMA
> > > > fluxes, and some may be more aggressive than others.
> > > >
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Nutting, Phil
> > > > Sent: Friday, September 05, 2014 11:56 AM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > Dusting off an old thread here (yes Brian, I listened to your
> > > > request for not changing threads).  I've been thinking about the
> > > > "best" method of wire tinning for some time now and this thread
> > > > makes me think the we should dump our no-clean cored wire solder
> > > > in favor of something that
> > > is more innocuous.
> > > >
> > > > I have an old roll of Kester 63/37 "44" core saved from years ago
> > > > before the switch to lead-free.  Is this acceptable for long term
> > > > soldered wire reliability.  If not, what are the recommendations?
> > > > I guess knowing RA or RMA along with manufacturer and "model"
> > > > would be useful.  Hopefully it is available in 63/37 and lead-free
> alloys.
> > > >
> > > > Thanks in advance for sharing your knowledge and experience,
> > > >
> > > > Phil Nutting
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Carl VanWormer
> > > > Sent: Tuesday, June 10, 2014 11:55 AM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > There sure are a lot of scare stories about flux and reliability.
> > > > I'm now wondering if a solution based on crimping some sort of
> > > > ferrule or machined pin onto the ends of the wires and then
> > > > soldering those metal parts into the PCB holes might be a more
> > > > reliable approach.  Have any of
> > > "you guys"
> > > > seen that type of solution to this problem?
> > > >
> > > > Thanks,
> > > > Carl
> > > >
> > > >
> > > > Carl B. Van Wormer, P.E., AE7GD
> > > > Senior Hardware Engineer
> > > > Cipher Engineering LLC
> > > >     21195 NW Evergreen Pkwy Ste 209
> > > >     Hillsboro, OR  97124-7167
> > > >     503-617-7447x303<tel:503-617-7447x303>
> > > >     [log in to unmask]<mailto:[log in to unmask]>
> > > > http://cipherengineering.com
> > > >
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Karen Tellefsen
> > > > Sent: Tuesday, June 10, 2014 6:00 AM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > I would use Kester 186-18 instead for tinning.  Alpha 615-15 is
> > > > another good choice.
> > > >
> > > > Karen Tellefsen - Electrical Testing Alpha / 109 Corporate Blvd./ S.
> > > > Plainfield, NJ 07080 [log in to unmask]
> > > > <mailto:[log in to unmask]> 908-791-3069<tel:908-791-3069>
> > > >
> > > >
> > > >
> > > >
> > > > From:   Steve Gregory <[log in to unmask]<mailto:[log in to unmask]
> >>
> > > > To:     <[log in to unmask]<mailto:[log in to unmask]>>,
> > > > Date:   06/09/2014 05:43 PM
> > > > Subject:        Re: [TN] tinning wires - flux entrapment and long
> term
> > > > reliability
> > > > Sent by:        TechNet <[log in to unmask]<mailto:[log in to unmask]>>
> > > >
> > > >
> > > >
> > > > Hi Richard,
> > > >
> > > > Good information! But can I ask a question about a particular
> > > > no-clean flux? It's about Kester 951. In their datasheet they say
> > > > that it contains a "corrosion inhibitor" such that no corrosion
> > > > products are formed when bare copper surfaces are exposed to humid
> > > > environments. Do you have any idea what that might be?
> > > >
> > > > We use it as a touch-up flux for our no-clean soldering and do use
> > > > it to tin wires. I know that some of that flux gets somewhere
> > > > where it doesn't get cleaned, and probably didn't get exposed to a
> > > > lot of heat when you're doing point-to-point touch-up and
> > > > soldering with a single
> > > iron.
> > > >
> > > > We haven't had an issue with this flux, at least any that I know of.
> > > > But it doesn't mean that there isn't one. The operators sometimes
> > > > complain when they use it because it evaporates so fast though.
> > > >
> > > > Just curious what the "corrosion inhibiter" might be. The SDS says
> > > > the flux contains ethanol (50-65%), isopropanol (20-25%), n-butyl
> > > > acetate (5-10%), methanol (2.5-5%), and adipic acid (1-2.5%).
> > > > Everything listed is pretty much a solvent except for the adipic
> acid.
> > > >
> > > > Steve
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Stadem, Richard D.
> > > > Sent: Monday, June 9, 2014 2:23 PM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > I agree with George, and also with many others who feel that
> > > > cleaning with IPA is not a very good approach.
> > > > I should have mentioned also that through the years that I have
> > > > seen wires tinned with RMA flux, then soaked in IPA, then that was
> > > > followed by a DI wash.
> > > >
> > > > The old-time engineers back in the 60s and 70s showed me by using
> > > > 3 stages of wires cut open to show what the strands looked like
> > > > under the insulation. Different oldtimers showed me this trick
> > > > more than once, and I have never forgotten it.
> > > >
> > > > First, the operators were trained to insert the wires into the RMA
> > > > flux only halfway up the stripped portion (generally 1/8th inch to
> 1/4"
> > > > striplength).
> > > > Next, the operator was trained to insert the wire only up to just
> > > > below the end of the insulation. Some of the RMA flux would always
> > > > ride up to the insulation, and the solder would actually flow just
> > > > under the insulation, seldom more than .050" past the end of the
> > > > insulation. In other words, if you stop the stranded wire just
> > > > short of the insulation, the solder continues to wick up to a
> > > > point just under
> > > the end of the insulation.
> > > > Then, when the wires were not cleaned with IPA at all, the cutaway
> > > > view would always show a small amount of flux just under the end
> > > > of the insulation.
> > > > When cleaned in the IPA only, but not followed with a water wash,
> > > > when you cut the insulation away you "sometimes" saw a very small
> > > > amount of
> > > flux.
> > > > But when you did all three, any flux residue under the insulation
> > > > (if
> > > > present) could not be seen. It does not mean it wasn't there; it
> > > > just was not visible even at 20X.
> > > >
> > > > And in all cases, the oldtimers were never concerned with RMA flux
> > > > residues being left behind under the insulation; they felt it was
> > > > not a concern even to leave the RMA flux behind, with no cleaning.
> > > >
> > > > But NOT water soluble (OA) and NOT no-clean fluxes. The no-clean
> > > > activators are sometimes even more aggressive than RMA. That is
> > > > still
> > > true.
> > > > So I stand by the statement that when tinning wires, only RMA flux
> > > > should be used, some type of solvent should be used to at least
> > > > suspend the RMA solids, and some type of final rinse or wash
> > > > process should be used. If all of those are done, I do not think
> > > > there is ever a concern for the wires rotting away under the
> insulation.
> > > >
> > > > And one more item: If you are just cleaning tinned wires (no
> > > > connector bodies, sleeving, circuit boards or components,etc.) I
> > > > have found that following the solvent clean with an ultrasonic
> > > > cleaning process where the entire wire or wire assembly is
> > > > immersed in hot DI water with a 6% saponifier will get all of the
> > > > flux out from under the end of the insulation.
> > > >
> > > > I am talking about the end of the insulation, not 1/2" up the
> > > > insulation or anything like that.
> > > >
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Wenger, George M.
> > > > [Contractor]
> > > > Sent: Monday, June 09, 2014 1:21 PM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > As someone who sent 33 years working in the "Bell System" were
> > > > solder assembly quality/reliability was the primary concern,  I'll
> > > > throw my two cents into this discussion.  I've never like the name
> > "No-Clean".
> > > > Any flux used for soldering that doesn't go through a cleaning
> > > > process would be a "No-Clean" if the meaning is it wasn't cleaned
> > > > off.  The old BellCore (now
> > > > Telcordia) GR-78 gives criteria for determining if a soldering
> > > > flux residue needs to be cleaned off for reliability reasons.
> > > > If you make a solder joint with a flux and don't clean it off and
> > > > it passes the BellCore reliability testing then we would consider
> > > > that flux a reliable "Leave-Behind" flux meaning if the flux
> > > > residue wasn't cleaned off there were no reliability risks.  In
> > > > general most of the old fluxes classified as R & RMA passed the
> "leave-Behind"
> > > > requirement.  In fact, our experience was that especially for RMA
> > > > fluxes the reliability was much better if you did leave them
> > > > behind rather than tried to clean them.  If you take an RMA flux
> > > > and try cleaning it with alcohol (which isn't a very good solvent)
> > > > what you wind up doing is dissolving and removing most of the
> > > > rosin in the flux residue, which is what was encapsulating the
> > > > ionic activators, which in turn allowed any ionic activators to be
> > > > mobile and the first time the humidity increased you had the worse
> > > > case for corrosion (moisture,
> > > activators, and electrical potential).
> > > >
> > > > I can see that with a low-solids type "No-Clean" flux that the
> > > > flux would wick up the braided wires and yes when a soldering iron
> > > > was placed on where you wanted to make the solder joint the flux
> > > > activators would be heated and reduce oxides and allow a good
> > > > solder joint to form but the flux that wicked up the wires may not
> > > > have gotten to a high enough temperature to de-activate the
> > > > activators and then the humidity goes up in use you could have a
> > > > problem.  If I were pre-tinning braided wires I would only us an
> > > > RMA flux qualified
> > > according to BellCore GR-78 to be a "Leave-Behind".
> > > >
> > > > Regards,
> > > > George
> > > > George M. Wenger
> > > > Failure Signature & Characterization Lab LLC
> > > > 609 Cokesbury Road, High Bridge, NJ 08829
> > > > (908) 638-8771<tel:%28908%29%20638-8771> Home  (732)
> > > > 309-8964<tel:%28732%29%20309-8964>
> > > > Mobile E-mail
> > > > [log in to unmask]<mailto:[log in to unmask]>
> > > > [log in to unmask]<mailto:[log in to unmask]>
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Carl VanWormer
> > > > Sent: Monday, June 09, 2014 12:59 PM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > I've heard stories of no-clean and hand soldering causing problems.
> > > > In an IR-reflow oven, all of the no-clean flux achieves the
> > > > passivation temperature, becoming inert.  With hand soldering, the
> > > > flux melts, runs away from the heat source, and penetrates any
> > > > tiny
> > > crevice it can find.
> > > > There is an area at the perimeter of the heated area that is hot
> > > > enough to cause the flux to flow, but not hot enough to cause it
> > > > to
> > > become active.
> > > > If this is true, than this is the problem I'm worried about.
> > > > Comments, please?
> > > >
> > > > Thanks,
> > > > Carl
> > > >
> > > >
> > > >
> > > > Carl B. Van Wormer, P.E., AE7GD
> > > > Senior Hardware Engineer
> > > > Cipher Engineering LLC
> > > >     21195 NW Evergreen Pkwy Ste 209
> > > >     Hillsboro, OR  97124-7167
> > > >     503-617-7447x303<tel:503-617-7447x303>
> > > >     [log in to unmask]<mailto:[log in to unmask]>
> > > > http://cipherengineering.com
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Steve Gregory
> > > > Sent: Monday, June 09, 2014 9:49 AM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > It's been some years back, but we were building a cabinet along
> > > > with all the boards and cables. The cables had silver plated
> > > > braided shielding over them and we would have to solder the shield
> > > > wires to either a lug or contact. We were using manufacture XXX
> no-clean flux.
> > > > It had been a rainy spring that year, and rained about every other
> > > > day for at least a month, so you know the humidity was high.
> > > >
> > > > One of the supervisors came to me after that month and said;
> > > > "Steve, we got a problem, all the cables in the cabinets are turning
> green..."
> > > > so I went and looked at them. Sure enough the shield wires were
> > > > turning green, and it was down close to the end sections of the
> > > > cables where they had been
> > > > soldered:
> > > >
> > > > http://stevezeva.homestead.com/files/Green_Junk_1.jpg
> > > >
> > > > http://stevezeva.homestead.com/files/Green_Junk_2.jpg
> > > >
> > > > http://stevezeva.homestead.com/files/Green_Junk_3.jpg
> > > >
> > > > http://stevezeva.homestead.com/files/Green_Junk_Close.jpg
> > > >
> > > > I had a hard time figuring out how this was happening, because
> > > > right at the ends where the soldered connection it was fine. The
> > > > connections were soldered and cleaned with alcohol. Best I could
> > > > figure was that the operators had flux on their fingers when they
> > > > handled the cables and got the flux up on the cable where it
> > > > wasn't reacted with heat, and wasn't cleaned, and with the high
> > > > humidity that we had that month turned the shield wire green.
> > > >
> > > > We switched the no-clean flux to manufacture XXX and the problem
> > > > went
> > > away.
> > > >
> > > > Steve
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Nutting, Phil
> > > > Sent: Monday, June 9, 2014 8:25 AM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > So for many years I have followed the discussion about flux
> > > > cleaning and alcohol always get mentioned as a great way of
> > > > dissolving the flux and depositing it on a much wider area.  There
> > > > has to be a better way to "clean" the wire entrapped flux if it
> > > > really must be cleaned.  I agree that OA flux is not a good
> > > > solution.  My current choice is to use
> > > "no-clean"
> > > > flux cored solder when tinning wires and then leave it alone.
> > > > Soldering the wire into the board can then be done with "no-clean"
> > > > or other flux cored solder.  Where we do not make anything that is
> > > > designed as mission critical this process seems to work for us.
> > > >
> > > > Phil Nutting
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Stadem, Richard D.
> > > > Sent: Monday, June 09, 2014 9:30 AM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: Re: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > You do not tell us what flux you are using.
> > > > But as a general rule, one must never tin insulated wires using OA
> > flux.
> > > > Only RMA or no-clean should be used, and that followed by dipping
> > > > the tinned ends in alcohol.
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> > > > Behalf Of Carl VanWormer
> > > > Sent: Friday, June 06, 2014 8:20 AM
> > > > To: [log in to unmask]<mailto:[log in to unmask]>
> > > > Subject: [TN] tinning wires - flux entrapment and long term
> > > > reliability
> > > >
> > > > My understanding:
> > > > While tinning wires with conventional soldering methods, the wire
> > > > is heated and the flux-cored solder is applied to the wire.  As
> > > > the flux is melted, it wicks up between the wires and the solder
> > > > flows in, wetting the wires.  The liquefied flux flows up the
> > > > wires farther than the solder, and some of the un-passivated flux
> > > > is trapped inside the insulation, around the Copper strands where
> > > > the
> > solder stopped flowing.
> > > >
> > > > My experience:
> > > > One of our control modules had failed in an automotive "road splash"
> > > > environment.  Our connector terminals had been soldered to the
> > > > wires that came out of the "waterproof" strain-relief assembly.
> > > > Troubleshooting let me to cable harness with an open circuit
> > > > between a wired connector pin and the other end of the wire.  The
> > > > wire and pin looked good, but a gentle tug on the pin popped the
> > > > 5mm length of soldered wire out of the wire's insulation,
> > > > revealing a discoloration at the end of the solder-flow where the
> > > > Copper wire had been
> > > "disappeared".
> > > > A few mm inside the wire insulation, there was another discolored
> > > > blob at the end of the wire's total length of good Copper wire.
> > > > Our conclusions of "not quite waterproof" and "chemistry
> > > > experiment" led me to be concerned about the problem.
> > > >
> > > > Current worry:
> > > > We have a product with a "requirement" that some 16-gauge stranded
> > > > Copper wires be soldered to our PC board.  The plan is to have the
> > > > cable assembly arrive with pre-tinned wires, and then the wires
> > > > will be soldered to the board with "no-clean" flux.  The product
> > > > is not expected to be in the water, but may be "near" a wet
> > > > environment, maybe mounted in a pouch on some motorcycle gear.
> > > > I'm worried about the tinning process forcing un-passivated flux
> > > > up, inside the
> > > insulation, to wait for a "humid"
> > > > condition to start another "chemistry experiment."
> > > >
> > > > Questions:
> > > >
> > > > 1.       Assuming we must solder wires to my PC board, is there any
> > > > guidance on how to keep "chemistry experiments" from happening on
> > > > my product?
> > > >
> > > > 2.       Are there any other "very small" connection methods for 15
> Amp
> > > > wires that I should consider that I might be able to fit on my
> > > > tiny PC board that would eliminate my worry?
> > > >
> > > > 3.       Am I just being overly paranoid?
> > > >
> > > > Thanks,
> > > > Carl
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Carl B. Van Wormer, P.E., AE7GD
> > > > Senior Hardware Engineer
> > > > Cipher Engineering LLC
> > > >     21195 NW Evergreen Pkwy Ste 209
> > > >     Hillsboro, OR  97124-7167
> > > >     503-617-7447x303
> > > >     [log in to unmask]<mailto:[log in to unmask]
> > > ><mailto:
> > > > [log in to unmask]<mailto:[log in to unmask]>>
> > > > http://cipherengineering.com<http://cipherengineering.com/>
> > > >
> > > > This message may contain confidential and/or proprietary
> > > > information, and is intended for the person/entity to whom it was
> > > > originally addressed. Any use by others is strictly prohibited.
> > > > If I sent this to you by mistake, please be nice and delete it,
> > > > and then tell me of my mistake so I can send it to the right person.
> > > >
> > > >
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > >
> > > >
> > > >
> > > > ***** Please note that my E-Mail address has changed *****
> > > >
> > > > __________________________________________________________________
> > > > __ This email has been scanned by the Symantec Email
> > > > Security.cloud
> > service.
> > > > For more information please visit http://www.symanteccloud.com
> > > > __________________________________________________________________
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask] <mailto:[log in to unmask]>
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask]
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > > > __________________________________________________________________
> > > > __ __ This email has been scanned by the Symantec Email
> > > > Security.cloud service.
> > > > For more information please contact helpdesk at x2960 or
> > > > [log in to unmask]
> > > > __________________________________________________________________
> > > > __
> > > > __
> > > >
> > >
> > >
> > > ____________________________________________________________________
> > > __ This email has been scanned by the Symantec Email Security.cloud
> > > service.
> > > For more information please contact helpdesk at x2960 or
> > > [log in to unmask]
> > > ____________________________________________________________________
> > > __
> > >
> > >
> >
> >
> > ______________________________________________________________________
> > This email has been scanned by the Symantec Email Security.cloud service.
> > For more information please contact helpdesk at x2960 or
> > [log in to unmask]
> > ______________________________________________________________________
> >
> >
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>
>


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

ATOM RSS1 RSS2