I have installed five SEHO full tunnel wave solder machines in the past
three years, four of these systems replaced older (at least 10 years) open
air Electrovert machines. Both systems are dual wave. I have found that
the dross savings basically pay for the cost of the nitrogen.
Approximately 2/3 of the solder purchased (by wt) was sent out as dross (by
wt) and we used the Alpha Hi-Flo solder. (Please note, the use of company
names on equipment or solder is not an endorsement, names are mentioned
only ensure that all details are understood).
One of the cost savings you will realize are reduced maintenance time.
With the open air machine, you have to de-dross every day. With the Seho
machines, depending on use, you have to de-dross much less, i.e. once per
week to twice per month, plus, the amount of dross generated is less, you
do not get the thick layer of dross in the N2 machine that you do in the
open air machine. Before I bought the first SEHO machine, I spoke to a
user who had yet to fill a 5 gal pail with dross, and they were running 1.5
shifts over a 1 year time frame. An intangible cost, but a factor to
consider, is the less you have to work on the machine, i.e. take apart
nozzles, lower the solder pot, etc, the less opportunity for variables to
change, thus a more repeatable process.
Other benefits of the nitrogen: Nitrogen opens up the process window,
especially in a no-clean process! Defect rates dropped when we switched to
nitrogen (but then again, there was also a ten year leap in machine
models). Wetting appears to be better, less flux is needed. For example,
the spray fluxer was turned off accidentally and single sided boards were
built all morning before someone noticed the fluxer was off. The soldering
on these boards looked great!
Nitrogen may also permit you to use a different grade of solder. With open
air systems, I have always used the Alpha Hi-Flo to reduce the dross as
much as possible. With my latest full tunnel machine, I have switched to
Alpha Vaculloy, a significant cost reduction in solder price, and have
noticed no significant increases in dross between the Hi-Flo and Vaculloy
when used in the full tunnel system, however, I only have 6 months of
comparison thus far. ( Only use pure solder, watch out for those bargain
brands!!!)
The air flow in the closed tunnel machines is less than the older models I
replaced. I am now able to vent the wave solder systems in the plant, thru
a filtration unit. This is also possible with newer models of other
vendors. By venting inside the factory, you now have significant cost
reductions in the factory air, less make up air required, less air to
"condition" to maintain at temp. and humidity. I have also noticed that
during the winter, the operators find the air coming from the fume
extractor exhaust is a dandy hand warmer!!!
So, from a cost analysis view (in my opinion and research):
The reduced dross pays for the nitrogen(1:1 swap)
Improved quality of process
Less maintenance time
Process repeatability improved because of fewer changes to the machine
during the process
Reduced amount of flux used
Lower solder cost by using a different grade of solder
As an added note: I now have a pallet style wave solder machine in place,
the previous four were all finger conveyors with an adjustable rail. To
clean the solder pot/solder nozzles of the finger conveyor machines, you
have to lower the solder pot. With the pallet conveyor system, I can
remove the nozzles from inside the machine, I do not need to lower the
solder pot. One less variable to consider, adjusting the wave height
because the solder pot did not go back to its original height! The
maintenance time on these systems is much less than I have experienced on
other wave solder machines in the past.
ADDITIONAL INFORMATION!!!
Matte finish solder mask vs gloss finish solder mask and solder balls!
I use a no clean process, nitrogen and gloss finish solder mask and had
solder balls (very small) I could not get rid of the solder balls, despite
varying the amount of flux, preheat etc. I even had solder balls with
no-flux! When we switched to a matte finish solder mask, the solder balls
disappeared. Both styles of boards were run thru, side by side, in the
same pallet, and the difference in solder balls was amazing. No solder
balls at all with the matte finish!
Ed Holton
Manufacturing Engineer
Hella Electronics
734-414-0944
[log in to unmask] on 06/25/98 06:45:16 AM
Please respond to [log in to unmask]; Please respond to
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To: [log in to unmask]
cc: (bcc: Ed Holton/Hella North America Inc.)
Subject: [TN] Nitrogen in the wavesolderingproces
At our factory we are going to have a new waesolderingmachine with
nitrogensupport. But our director dosen't think that we need the nitrogen
because it has no effect compared to the price that we have to pay. But
in me department we dosen't aggree.
I would like to hear about your experience with nitrogen so that we can
tell our director that it isn't just us that thinks that nitrogen
soldering is good. And if anyone has a meaning about the Seho MWS-8200
PWR i would like to hear that too.
With Regards
Jesper Konge
Danica Supply A/S
Denmark
Mail : [log in to unmask]
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<DIV><FONT face=Arial size=2> At our factory we are going to have a
new waesolderingmachine with nitrogensupport. But our director dosen't
think that we need the nitrogen because it has no effect compared to the
price that we have to
pay. But in me department we dosen't aggree.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> I would like to hear about your
experience with nitrogen so that we can tell our director that it isn't
just us that thinks that nitrogen soldering is good. And if anyone has a
meaning about the <EM><STRONG>Seho MWS-8200 PWR</STRONG></EM> i would like
to hear that
too.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>With Regards </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT><FONT color=#000000 face=Arial
size=2>Jesper
Konge</FONT></DIV>
<DIV><FONT color=#000000 face=Arial size=2></FONT><FONT face=Arial
size=2>Danica
Supply A/S</FONT></DIV>
<DIV><FONT face=Arial size=2>Denmark</FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Mail : <A
href="mailto:[log in to unmask]
">[log in to unmask]</A></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV></BODY></HTML>
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