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Hot Plate for Soldering

J

James Morrison

Jan 1, 1970
0
Hello all,

I'm looking for a hot plate to help with both soldering small runs of
PCB's or rework of the same. I've seen these devices, I've even used
them at previous jobs. But I can't find any info on the web. There are
lots of hot plates for chemical lab use but I can't find anything like
what I expect to see.

Does anyone know who manufacturers these types of units? Something in
North America is preferred as they are pretty heavy so I imagine
shipping would be costly. But I"m open to any and all ideas here.

Here are the things I think I require. These are soft requirements:
1) a way to set the temperature (labelled in degrees rather than cold
to hot would be better)
2) heating area approximately 6"x10", larger would be better
3) 110VAC 60Hz
4) a cover that can be placed over the hot surface for safety

If anyone had something like this sitting around in their lab collecting
dust I may be interested in taking it off your hands.

Thanks a lot.

James.
 
James said:
Hello all,

I'm looking for a hot plate to help with both soldering small runs of
PCB's or rework of the same. I've seen these devices, I've even used
them at previous jobs. But I can't find any info on the web. There are
lots of hot plates for chemical lab use but I can't find anything like
what I expect to see.

Does anyone know who manufacturers these types of units? Something in
North America is preferred as they are pretty heavy so I imagine
shipping would be costly. But I"m open to any and all ideas here.

Here are the things I think I require. These are soft requirements:
1) a way to set the temperature (labelled in degrees rather than cold
to hot would be better)
2) heating area approximately 6"x10", larger would be better
3) 110VAC 60Hz
4) a cover that can be placed over the hot surface for safety

If anyone had something like this sitting around in their lab collecting
dust I may be interested in taking it off your hands.

Under the "I'm open to any and all ideas" category...a $30 hotplate
from Target!

http://www.sparkfun.com/tutorial/ReflowToaster/reflow-hotplate.htm

Cheers,
James Arthur
 
R

Roy L. Fuchs

Jan 1, 1970
0
Under the "I'm open to any and all ideas" category...a $30 hotplate
from Target!

http://www.sparkfun.com/tutorial/ReflowToaster/reflow-hotplate.htm

Surface mount repair using a hot plate for the reflow segment of the
process is very bad if the PCB assembly has parts on both sides of the
board.

Also, the board should be pre-heated in a chamber (read toaster oven)
before placing it on the "reflow bench" (read hot plate) for the
repair.

Reflow benches, as they are called are old school and can be very
bad for many parts. Ceramic capacitors, in particular, can lose the
layer connections to the end "caps" (platings actually).

This is why a modern reflow oven ramps up the temp, reflows the
assembly, and gets the product out the other end in a very timely
fashion, and is also why hand soldering is detrimental, because a
would be assembler or repair "technician" invariably turns up their
irons far far too high for such tasks.

550 F is good... maybe 600F, but NOT 800F, which I see all the time
at workstations. It takes a well trained tech with knowledge of how
components are made to really appreciate the processes in the
industry, as opposed to merely stating "I know how to solder".

It reminds me of the argument I had with the girl that insisted on
attaching resistors and caps to the board with two irons, even going
so far as to pick the part up with the two irons.

Me? Tweezers, and one side at a time, and that is Solder it fast
(less than 2 seconds), and NO big blobs on the pad. Just a tiny drop
of solder on the tip of the iron, and lots of flux present is all that
is required for hand operations. Less IS more!

The word for today is "FILLET".

When I assemble, it looks like it came from a machine. In fact, one
cannot tell the difference.

The crap I see others build is so blobby that a rocket launch would
rip the pads and parts right off the board, they are so big.

Sad that we cannot educate our kids so well these days.

Anyway, hand assembly of short runs by skilled soldering personnel is
far far better for the life of your product than a hot plate or
toaster oven reflow process could ever be. I mean you aren't talking
about 12" x 18" digital HDTV processing CCAs (I have done them).

If you are stenciling paste onto the PCB, you have six hours to get
the parts placed and get it reflowed, before the paste begins to
express major performance issues like tombstoning and flux popping
parts clean off the board.

I am Solder Man (Black Sabbath inflection).

NASA certification is the best, most comprehensive soldering cert.
followed by mil 2000, then IPC 610-A.

DON'T OVERHEAT YOUR PARTS AND ASSEMBLIES!
MTBF goes right out the window.
 
R

Roy L. Fuchs

Jan 1, 1970
0
For lead free ?

No. It would be a higher temperature. Sad, that.

The whole RoHS thing is utter crap.

Metallic form lead does not pose an environmental threat.

It was certain European nations' way of boosting the eurodollar and
that's about it.

Now an entire industry in the US has to switch gears. The flux
makers, and the PCB makers, etc. etc. all get screwed to play into
some lame pissy country's baby bullshit directives.

I am only glad that military product makers got an exemption.

If it were such a big problem, lead would have been showing up in the
water tables near dumps decades ago, and it never did. Nor was there
an increase in cancer rates near such water tables.
 
P

Pooh Bear

Jan 1, 1970
0
Roy L. Fuchs said:
No. It would be a higher temperature. Sad, that.

The whole RoHS thing is utter crap.

Metallic form lead does not pose an environmental threat.

It was certain European nations' way of boosting the eurodollar and
that's about it.

Now an entire industry in the US has to switch gears. The flux
makers, and the PCB makers, etc. etc. all get screwed to play into
some lame pissy country's baby bullshit directives.

I am only glad that military product makers got an exemption.

If it were such a big problem, lead would have been showing up in the
water tables near dumps decades ago, and it never did. Nor was there
an increase in cancer rates near such water tables.

I totally agree. Furthermore, WEEE is supposed to stop electronics being
dumped anyway.

Graham
 
Roy said:
Surface mount repair using a hot plate for the reflow segment of the
process is very bad if the PCB assembly has parts on both sides of the
board.

Also, the board should be pre-heated in a chamber (read toaster oven)
before placing it on the "reflow bench" (read hot plate) for the
repair.

Reflow benches, as they are called are old school and can be very
bad for many parts. Ceramic capacitors, in particular, can lose the
layer connections to the end "caps" (platings actually).

This is why a modern reflow oven ramps up the temp, reflows the
assembly, and gets the product out the other end in a very timely
fashion, and is also why hand soldering is detrimental, because a
would be assembler or repair "technician" invariably turns up their
irons far far too high for such tasks.

550 F is good... maybe 600F, but NOT 800F, which I see all the time
at workstations. It takes a well trained tech with knowledge of how
components are made to really appreciate the processes in the
industry, as opposed to merely stating "I know how to solder".

It reminds me of the argument I had with the girl that insisted on
attaching resistors and caps to the board with two irons, even going
so far as to pick the part up with the two irons.

Me? Tweezers, and one side at a time, and that is Solder it fast
(less than 2 seconds), and NO big blobs on the pad. Just a tiny drop
of solder on the tip of the iron, and lots of flux present is all that
is required for hand operations. Less IS more!

The word for today is "FILLET".

When I assemble, it looks like it came from a machine. In fact, one
cannot tell the difference.

The crap I see others build is so blobby that a rocket launch would
rip the pads and parts right off the board, they are so big.

Sad that we cannot educate our kids so well these days.

Anyway, hand assembly of short runs by skilled soldering personnel is
far far better for the life of your product than a hot plate or
toaster oven reflow process could ever be. I mean you aren't talking
about 12" x 18" digital HDTV processing CCAs (I have done them).

If you are stenciling paste onto the PCB, you have six hours to get
the parts placed and get it reflowed, before the paste begins to
express major performance issues like tombstoning and flux popping
parts clean off the board.

I am Solder Man (Black Sabbath inflection).

NASA certification is the best, most comprehensive soldering cert.
followed by mil 2000, then IPC 610-A.

DON'T OVERHEAT YOUR PARTS AND ASSEMBLIES!
MTBF goes right out the window.

Solderman,
Thou art forsooth Solderman, and all thy points hard and true, and I
acknowledge all except perhaps the bit about hand-soldering caps one
side at a time seems inconsistent with your earlier admonitions.

Although this is exactly how I solder caps, doesn't it throw all that
careful ramping / thermal profile stuff right out the window and apply
maximum thermal and mechanical shock to an brittle, inflexible part?
And yet, carefully done, these connections seem very secure and
reliable.

Of course I'm just doing small stuff for fun this way, not launching
anything into space, but perhaps there's a little more lattitude in the
soldering process than is otherwise acknowledged, yes?

For single-sided soldering, I'd think one could do a really good job
on a skillet, as you can ramp the temperature up to suit, and ramp it
back down the instant you see the solder flow. That should be very
gentle on the components, exposing them to the minimum temperature
needed, and for the shortest time.

Soldering double-sided boards on an electric skillet would of course
be a good way to roast the parts riding on the skillet surface, as well
as preventing proper heat flow through the printed circuit board
substrate. Ergo, double-sided needs a double-sided, controlled heat
source...a toaster !

From SED's own Robert Lacoste, a toaster oven controller:
http://www.circuitcellar.com/renesas/winners/3323.htm

The Seattle Robotics Society has a manually operated scheme:
http://www.seattlerobotics.org/encoder/200006/oven_art.htm

If you're too busy, here's a pre-built toaster oven controller for
sale:
https://www.articulationllc.com/

And the Sparkfun guys are at it too:
http://www.sparkfun.com/tutorial/ReflowToaster/reflow-toaster.htm

If you read through their discussion of the merits,
(http://www.sparkfun.com/cgi-bin/php...&start=0&sid=3e6fd6a2da8390b7ea12d83f29a3e31b)
they prefer their hot plate to their commercial, bought reflow oven, as
the latter melts connectors. That failing of the commercial product,
in fact, was what spurred them to roll their own soldering setup.
Ultimately it seems they liked the skillet so much that they aborted
their toaster project.

All in good fun!
James Arthur
 
James said:
Hello all,

I'm looking for a hot plate to help with both soldering small runs of
PCB's or rework of the same. I've seen these devices, I've even used
them at previous jobs. But I can't find any info on the web. There are
lots of hot plates for chemical lab use but I can't find anything like
what I expect to see.

Does anyone know who manufacturers these types of units? Something in
North America is preferred as they are pretty heavy so I imagine
shipping would be costly. But I"m open to any and all ideas here.

Here are the things I think I require. These are soft requirements:
1) a way to set the temperature (labelled in degrees rather than cold
to hot would be better)
2) heating area approximately 6"x10", larger would be better
3) 110VAC 60Hz
4) a cover that can be placed over the hot surface for safety

If anyone had something like this sitting around in their lab collecting
dust I may be interested in taking it off your hands.

Thanks a lot.

James.

---------------------------------------------

James,

Here are a few possibly-related discussions that I found interesting
(mainly was looking for through-hole whole-board-at-once soldering
ideas, at the time):

http://groups.google.com/groups?hl=...ing&hl=en&lr=&ie=UTF-8&safe=off&start=10&sa=N

http://groups.google.com/[email protected]&rnum=7

http://groups.google.com/groups?hl=...ing&hl=en&lr=&ie=UTF-8&safe=off&start=60&sa=N

Regards,

Tom Gootee

http://www.fullnet.com/u/tomg

---------------------------------------------
 
D

DJ Delorie

Jan 1, 1970
0
Although this is exactly how I solder caps, doesn't it throw all that
careful ramping / thermal profile stuff right out the window and apply
maximum thermal and mechanical shock to an brittle, inflexible part?

FYI the matcal talon recommends picking up tiny parts with the tips
*cold*, holding them in place, then turning the iron on. That gives
you a 10-15 sec ramp-up and you can let go as soon as the solder
melts.
 
DJ said:
FYI the matcal talon recommends picking up tiny parts with the tips
*cold*, holding them in place, then turning the iron on. That gives
you a 10-15 sec ramp-up and you can let go as soon as the solder
melts.

That sounds kind to the parts (but the thermal cycling will be rough
on
that lovely Metcal).

There was a rather contentious thread discussing this topic on s.e.d.
a few eons ago... ah, here we go: Soldering surface mount components,
8-Jun-2004,
http://groups.google.com/group/sci....&q="soldering+surface+mount"#43c28b4659605278

Therein Clarence reported reliably hand-soldering caps in hi-rel
(space) hardware, while others gave a dimmer view. All in the
technique, perhaps?

Best,
James Arthur
 
R

Roy L. Fuchs

Jan 1, 1970
0
Thou art forsooth Solderman, and all thy points hard and true, and I
acknowledge all except perhaps the bit about hand-soldering caps one
side at a time seems inconsistent with your earlier admonitions.

Hold on pads with tweezers, solder one pad, then the other in
succession. Both together is where to part is held by two irons in
tweezer like fashion, soaking far too much heat into them for far too
long. Very, very bad. Quite consistent.
 
R

Roy L. Fuchs

Jan 1, 1970
0
Although this is exactly how I solder caps, doesn't it throw all that
careful ramping / thermal profile stuff right out the window and apply
maximum thermal and mechanical shock to an brittle, inflexible part?
And yet, carefully done, these connections seem very secure and
reliable.

The single iron ramps it up faster, and it doesn't ramp back down
between the two sub second operations. Absolutely proper. Iron temp
should only be a few tens of degrees over the 495F 63/37 typical melt
point. Minimal attack on the part. Circuit boards are a lot hardier
these days, but the parts are susceptible. It becomes very apparent
when working with high voltage ceramic SMDs. If done right,
everything works fine. DOne wrong, and the thing won't make voltage,
and sinks a lot of power. Testing the cap doesn't show anything as
the problem only exhibits itself at working voltages.

It is cheaper at that point to replace all six caps in a three stage
multiplier with fresh, than it is too attempt to determine which cap
is leaking. Ceramic terminations are actually contacting a huge number
of "plate ends". Such attachments are weak at best. Far weaker than
say a plated through hole's integrity is. Heat damage is one of the
only ways to damage a ceramic that has never been overvoltaged.

Back to the heat issue...

The two iron approach, however has the full iron temp on the part,
on both terminations with nowhere for the heat to go until you lace it
on the board. Very, very bad.
 
R

Roy L. Fuchs

Jan 1, 1970
0
For single-sided soldering, I'd think one could do a really good job
on a skillet, as you can ramp the temperature up to suit, and ramp it
back down the instant you see the solder flow.

There has to be a lot of flux present, a fume hood, and unless you are
using a paste, you may as well hand solder the entire assembly. Also,
one should remove the board immediately after reflow, not even attempt
waiting for a huge thermal mass like an iron skillet face to cool
down. Bad move. It will hold its temp a while. It also sports a very
high emissivity, which is a factor in this case. A teflon coated
griddle would be best as even the REAL reflow benches are teflon
coated. They also pass the PCB OFF the plate area. There is a ramp
up heat plate, and a reflow plate, and the boards are slid across in
continuous fashion. With skillets or griddles, one would be about
480F (just below reflow temp), and the other should be at about 525F.
That is a high temp and an electric stove would have a hard time
creating a uniform temp over the surface (evenly). Flame is much
better at this in this case. The board would go one the ramp griddle
for about 15 secs, then over to the reflow griddle until a few secs
after one sees reflowing taking place as they do not all flow together
when getting their heat through the bottom.
That should be very
gentle on the components, exposing them to the minimum temperature
needed, and for the shortest time.

Gentle? The solder process is by far the most damaging event in the
life of an assembly. That discounts circuit/part failures and shorts
etc.. I am talking about proper operation.

The water or solvent wash after soldering should be followed by a
60C dry chamber (often "aired out") bake out for about 30-45 min.
This especially important if EL caps with rubber mount faces, or any
transformers, inductor, etc. are on the board. Hell, even the SMD
versions. Baking is important step. The PCB itself is hygroscopic.
A vacuum step, then bake is ideal
 
R

Roy L. Fuchs

Jan 1, 1970
0
FYI the matcal talon recommends picking up tiny parts with the tips
*cold*, holding them in place, then turning the iron on. That gives
you a 10-15 sec ramp-up and you can let go as soon as the solder
melts.

Metcals are famous for coming up to temp in 5 seconds flat.
 
R

Roy L. Fuchs

Jan 1, 1970
0
That sounds kind to the parts (but the thermal cycling will be rough
on
that lovely Metcal).

They are meant to be turned of after each and every use. The life of
your $45 plus tip depends on only using it when needed. The supply
they hit it with is designed to handle it, and meant to be used just
that way.
 
Roy said:
They are meant to be turned of after each and every use. The life of
your $45 plus tip depends on only using it when needed. The supply
they hit it with is designed to handle it, and meant to be used just
that way.

Nice units, those Metcals.

Cheers,
James Arthur
 
Roy said:
There has to be a lot of flux present, a fume hood, and unless you are
using a paste, you may as well hand solder the entire assembly. Also,
one should remove the board immediately after reflow, not even attempt
waiting for a huge thermal mass like an iron skillet face to cool
down. Bad move. It will hold its temp a while. It also sports a very
high emissivity, which is a factor in this case. A teflon coated
griddle would be best as even the REAL reflow benches are teflon
coated. They also pass the PCB OFF the plate area. There is a ramp
up heat plate, and a reflow plate, and the boards are slid across in
continuous fashion. With skillets or griddles, one would be about
480F (just below reflow temp), and the other should be at about 525F.
That is a high temp and an electric stove would have a hard time
creating a uniform temp over the surface (evenly). Flame is much
better at this in this case. The board would go one the ramp griddle
for about 15 secs, then over to the reflow griddle until a few secs
after one sees reflowing taking place as they do not all flow together
when getting their heat through the bottom.

I don't have any data to judge the thermal time constant of an
electric skillet. It seems to me a very lossy device, but if it cools
too slowly, one might simply add a cooling fan blowing underneath, or a
2nd adjacent skillet at a lower temperature, as you suggested. But
then, I'm talking about hobby / fun / proto stuff, and you're talking
industrial.

Gentle? The solder process is by far the most damaging event in the
life of an assembly. That discounts circuit/part failures and shorts
etc.. I am talking about proper operation.


Certainly being awash in molten metal isn't gentle in the ordinary
sense. I meant 'gentle' in that the skillet produces less thermal
shock (dT/dt) to the components than being suddenly contacted by a blob
of molten solder sitting on a soldering iron.

Such a thermal shock--and more particularly, the resulting thermal
gradient across the part, and resultant mechanical strain--could
shatter a component with sufficient thermal mass, such as a large
ceramic capacitor.

The water or solvent wash after soldering should be followed by a
60C dry chamber (often "aired out") bake out for about 30-45 min.
This especially important if EL caps with rubber mount faces, or any
transformers, inductor, etc. are on the board. Hell, even the SMD
versions. Baking is important step. The PCB itself is hygroscopic.
A vacuum step, then bake is ideal

Cheers,
James Arthur
 
R

Roy L. Fuchs

Jan 1, 1970
0
I don't have any data to judge the thermal time constant of an
electric skillet. It seems to me a very lossy device, but if it cools
too slowly, one might simply add a cooling fan blowing underneath, or a
2nd adjacent skillet at a lower temperature, as you suggested. But
then, I'm talking about hobby / fun / proto stuff, and you're talking
industrial.

Still, simply removing the PCB to another surface IS what you WANT
to do.

Actually time at reflow stage should be minimal required to perform
full reflow. After that, the ramp down has traditionally always been
faster than the ramp up. The ramp up passes through four or more step
in a big reflow oven, then the last stage IS reflow temp area, then it
passes out the end into a room temp environment, seconds after it
actually got soldered.

Id say it matters.

I'd also still say that hand soldering the first article, if not the
entire run, by a skilled soldering personage is the best route.
Especially for short runs.
 
J

James Morrison

Jan 1, 1970
0
Hello all,

I'm looking for a hot plate to help with both soldering small runs of
PCB's or rework of the same. I've seen these devices, I've even used
them at previous jobs. But I can't find any info on the web. There are
lots of hot plates for chemical lab use but I can't find anything like
what I expect to see.

Thank you one and all for all of your input. It was a bit more than I
originally asked but its all good.

Cheers,

James.
 
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