Barry Gallegos,

Concerning using nitrogen, there are several reasons why one should use
nitrogen:

1. It opens up the process window. If your boards and /  or components are
oxidized and won't wet to solder, soldering them in an inert atmosphere may
help.

2. There will be less residues on the assemblies after soldering. So
cleaning will not be as difficult.

3. Your solder joints will be brighter than if soldered in air.

4. There is less chance for oxidation of materials through the process.

5. On the wave solder, there would be less dross associated with the
process.

As far as using organic water soluble fluxes, I believe these general ground
rules would apply. I consider them ground rules for soldering with Lead-Free
solders. Some solder paste / solder flux manufacturers require you to use
nitrogen. I will also state that some solder paste / solder flux
manufacturers will tell you that its not needed, but when you run your
hardware with their material the hardware comes out better in nitrogen than
in air.

As far as the economics go, obviously, if you can get away with not using
nitrogen, that would be great. However, if you are spending more time
reworking hardware before and after soldering, using nitrogen may improve
the quality of your hardware. As far as retrofitting your equipment, you
should consult your equipment manufacturer. There are some companies, like
Air Liquide, which could modify your hardware at a "nominal price".
Recommend you use liquid nitrogen instead of bottled nitrogen to support
your equipment. From experience, I drained a C - size tank (approximately 5
feet tall) in less than 1 hour when I attempted to inert a reflow oven (My
only excuse: I was a rookie at that time and I learned quick).

I found some papers with respect to using nitrogen. I'll be sending them
over to you (and anyone else who is interested).

Good Luck and Happy Holidays.

Lee Whiteman
Senior Manufacturing Engineer
ACI / EMPF
Telephone: (610) 362-1200; Ext. 208
FAX: (610) 362-1290
E-Mail: [log in to unmask]

  -----Original Message-----
  From: TechNet [mailto:[log in to unmask]]On Behalf Of Barry Gallegos
  Sent: Friday, December 15, 2000 5:13 PM
  To: [log in to unmask]
  Subject: [TN] Nitrogen and its uses. (help)


  Hey all,

  I am looking for a snapshot consensus on the use of nitrogen in the
assembly process for reflow as well as in wave solder where the flux vehicle
is organic water soluble flux.

  what does it buy me. for the cost. I have no equipment in place for
nitrogen and my ovens are not even retrofit able. the wave is upgradeable
but is a Vitronics delta wave that has reduced drossing process on it that
is using organic water soluble flux.

  I am just asking for some industry experts opinions on this process.

  I would like to say thank you for any help in advance.

  Barry Gallegos, PE
  Western Electronics, LLC
  110 E. 43rd st. Boise, ID. 83714
  P-208-377-1557
  F-208-377-9836