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From: David on 11 Jan 2010 19:01
In article <jdKdnQrYYecIFtbWnZ2dnUVZ_txi4p2d(a)earthlink.com>,
"Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote:

> David wrote:
> >
> > In article <afbik51666ll913td721atop30jggrcb9s(a)4ax.com>,
> > mm <NOPSAMmm2005(a)bigfoot.com> wrote:
> >
> > >
> > > (When I was a summer employee of the US Naval Avionics facility in
> > > Indianapolis in 1965, they were working on a way to solder all the
> > > connections on a circuit board at one time. They had a couple
> > > "machines" each with river of solder a foot wide that they would
> > > barely dip the whole circuit board into. They'd been working on this
> > > for months or more, plus the three months I was there. I walked by
> > > every day but didn't work in that department. I think my boss said it
> > > was hard to keep the surface of river flat.
> > >
> > > Who did figure out how to do this, and do any of you know when it
> > > happened?
> > >
> > > Do any of you know what the process is called?
> >
> > This is how Kriesler Australia soldered components to PCBs for their
> > transister radios around 1960 - 64.
> >
> > The PCBs were on a sort of travelling frame which first took the board
> > over a rosin spray then into the solder bath - the height was such that
> > only the lower (etched) side of the board dipped into the molten solder.
> >
> > After the solder bath the board went to a production line where first it
> > was checked for dry joints, then aligned and tested for function.
> >
> > It was a proven process with thousand of sets made this way
> >
> > If only the Navy had thought to ask any of the radio set mfgs they could
> > have saved themselves a lot of work, as I presume it wasn't only
> > Kriesler that used this method.
>
>
> Were any of those 'radio set mfgs' certified for 'mil spec'
> soldering? It's one thing to splash solder on a cheap paper based,
> consumer grade PC board and quite another to have it pass inspection for
> military applications.

No as far as I know they were only for commercial distribution - eg for
people who wanted a quality transistor radio.

But it wasn't about 'splashing..' it was dipping and then the board was
run by inspectors who then hand soldered any joints that even looked
suspect.

My job at the time was final testing and faulty part replacement of the
completed boards before they were mounted into their case. Though for a
few days I was one of the dry joint inspectors.

As far as I can remember there were very few faults due to dry joints by
the time the sets came to me.

But I know nothing about military specs etc so... But on a TV show last
night they mentioned that the rockets with the space program would have
up to 60,000 faults in a rocket I guess their specs were either not up
to military standard or the military needs to do some quality control ed.

David

David
From: Michael A. Terrell on 11 Jan 2010 20:33

David wrote:
>
> In article <jdKdnQrYYecIFtbWnZ2dnUVZ_txi4p2d(a)earthlink.com>,
> "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote:
>
> > David wrote:
> > >
> > > In article <afbik51666ll913td721atop30jggrcb9s(a)4ax.com>,
> > > mm <NOPSAMmm2005(a)bigfoot.com> wrote:
> > >
> > > >
> > > > (When I was a summer employee of the US Naval Avionics facility in
> > > > Indianapolis in 1965, they were working on a way to solder all the
> > > > connections on a circuit board at one time. They had a couple
> > > > "machines" each with river of solder a foot wide that they would
> > > > barely dip the whole circuit board into. They'd been working on this
> > > > for months or more, plus the three months I was there. I walked by
> > > > every day but didn't work in that department. I think my boss said it
> > > > was hard to keep the surface of river flat.
> > > >
> > > > Who did figure out how to do this, and do any of you know when it
> > > > happened?
> > > >
> > > > Do any of you know what the process is called?
> > >
> > > This is how Kriesler Australia soldered components to PCBs for their
> > > transister radios around 1960 - 64.
> > >
> > > The PCBs were on a sort of travelling frame which first took the board
> > > over a rosin spray then into the solder bath - the height was such that
> > > only the lower (etched) side of the board dipped into the molten solder.
> > >
> > > After the solder bath the board went to a production line where first it
> > > was checked for dry joints, then aligned and tested for function.
> > >
> > > It was a proven process with thousand of sets made this way
> > >
> > > If only the Navy had thought to ask any of the radio set mfgs they could
> > > have saved themselves a lot of work, as I presume it wasn't only
> > > Kriesler that used this method.
> >
> >
> > Were any of those 'radio set mfgs' certified for 'mil spec'
> > soldering? It's one thing to splash solder on a cheap paper based,
> > consumer grade PC board and quite another to have it pass inspection for
> > military applications.
>
> No as far as I know they were only for commercial distribution - eg for
> people who wanted a quality transistor radio.
>
> But it wasn't about 'splashing..' it was dipping and then the board was
> run by inspectors who then hand soldered any joints that even looked
> suspect.



That is float soldering, not wave soldering. A much older method, and
prone to quality problems. regency built two way radios that way at one
time, and they rarely survived the warranty period withoutout time on
the bench to clean up and resolder large areas of the board.


> My job at the time was final testing and faulty part replacement of the
> completed boards before they were mounted into their case. Though for a
> few days I was one of the dry joint inspectors.
>
> As far as I can remember there were very few faults due to dry joints by
> the time the sets came to me.
>
> But I know nothing about military specs etc so... But on a TV show last
> night they mentioned that the rockets with the space program would have
> up to 60,000 faults in a rocket I guess their specs were either not up
> to military standard or the military needs to do some quality control ed.


That's why they don't use lead free solder. Yhe US military and NASA
have their own standards that take weeks to learn at an approved
school. There is no way any US missle is going to leave the factory
with those kinds of problems. I have built electronics for NASA and the
ESA. You don't ship cold solder joints in $20,000 to $80,000 radios. I
have no clue about those built down under. :)


--
Greed is the root of all eBay.
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