I have found that the nitrogen helps open up the process window of the wave
solder process, particularly with the use of no-clean flux. Reference my
previous reply to another message concerning my feelings and the benfits of
nitrogen. Another reply stated that if solderability of the boards and
components was good, and you used the proper flux, that nitrogen was not
needed, in theory I agree, and at my facility the shelf life of my
components and boards is very short. In theory, if everything is
solderable, you do not need flux. But this is the real world, and we need
to be able to accomodate that reel of components that sat somewhere for 6
months, and may have solderability problems. Plus, when you are attempting
to reach six sigma levels of quality (I know, not possible with the wave
operation, but I am at 4 sigma now!), you want to take advantage of
everything you can. What is the cost of quality? Thus, I continue to use
nitrogen to enhance my process. Anyway, the nitrogen helps with the
soldering, changing the way solder flows, etc. What it did, was get rid of
the random defects, so any wave solder defects that occured were easily
identifiable as design defects. Nitrogen also fixed some solder defects
that occured due to questionable pad designs.
How much solder will you save with nitrogen? Cannot give a hard and fast
answer, depends on amount of time in production and a few other factors.
When I did my cost analysis, I was conservative. I knew how much solder
we bought per year and how much dross we created per year. I decided the
difference was how much solder was used in production (stayed on the
board). I made a one to one correlation then between the dross and
remaining solder purchesed. Reduce the dross and we would have to buy less
solder. Presently, we were de-drossing once per day. I decided that with
the nitrogen system, the solder pot would have to be de-drossed once per
week. I extrapolated and decided that one days worth of dross with my
existing machine would equal one weeks worth of dross with my nitrogen
machine. This was backed up by info from SEHO, Electrovert, and existing
users. Eliminate 4/5 of the dross and you eliminate 4/5 of the solder
purchased that generated the dross. The math can be done from there.
Don't forget you are now buying less solder, have less dross to
reclaim(hazardous waste) and to include the cost savings due to reduced
maintenance time. Before I am attacked by others for my assumptions, I had
very little data to work with, luckily I was conservative in my numbers and
the actual cost savings were greater than expected. I too would be
interested in what others have found. While it is not a direct
correlation, I found that the savings due to dross reduction pay for the
nitrogen used in the system. Thus your cost savings is due to improved
quality, reduced maint. time, and a more robust process.
Consumption of nitrogen can be determined by the machine. Each vendor will
tell you how much N2 the system will use, measured in cubic feet per minute
(or its metric equivalent)
Other cost savings have been addressed in other responses. if you have any
questions, please call
Ed Holton
Hella Electronics
734-414-0944
[log in to unmask] on 06/25/98 04:04:04 PM
Please respond to [log in to unmask]; Please respond to [log in to unmask]
To: [log in to unmask]
cc: (bcc: Ed Holton/Hella North America Inc.)
Subject: Re: [TN] Nitrogen in the wavesolderingproces
Hi all,
I have a few questions like to get the answer from the expertises:
1. Nitrogen being used on the wave process, what kind of process
improvement do we achieve? I heard people said that they have better
joint, better reflow.....
2. If it helps to reduce drossing of solder, how much solder do we save
monthly? How much dross produce/reduce each month? (Use % for
calculation).
3. How much nitrogen consumption in a month? (Let's say the machine runs
2 shifts in 22 days/month).
How can I measure/justify of using nitrogen in the process in terms of
quality and savings?
Your answer would be a great help for me.
Thanks
Simon Shin
> ----------
> From: superflx[SMTP:[log in to unmask]]
> Sent: Thursday, June 25, 1998 1:19 PM
> To: [log in to unmask]
> Subject: Re: [TN] Nitrogen in the wavesolderingproces
>
> If you use a No-Clean flux with clean, fresh components and new HAL or
> OSP boards, the nitrogen will add, marginally, to the process.? If you
> use a water-soluble flux, the nitrogen does not add anything as the
> flux will overcome any oxidation problems.
> Our experiuence has been that Nitrogen doesn't necessarily add
> anything to the soldering process, but helps reduce drossing of
> solder.? If reducing dross can help save money relative to the cost of
> nitrogen, then its a worthwhile investment.
> Phil
> Jesper Kj?rnulf Konge wrote:
> ?? 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 KongeDanica Supply A/SDenmark?Mail
> : [log in to unmask] <mailto:[log in to unmask]>
>
>
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