EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: R005T3r on August 09, 2016, 07:00:31 am
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Hi,
I've always wondered what this item from hakko is:
https://www.hakko.com/english/products/hakko_fx780.html (https://www.hakko.com/english/products/hakko_fx780.html)
Then I've discovered this video that explain the difference between N2 soldering and it aslo show the difference:
https://www.youtube.com/watch?v=Sw_AVRLPkec (https://www.youtube.com/watch?v=Sw_AVRLPkec)
Also I've found that this principle applies also to many other industrial welding techniques. In my opinion this principle is very useful for lead-free soldering: basically you can heat up the solder in any temperature you want and there's no oxidizing, what's fascinating is that probably there's no need for fume extraction: if the solder is shielded by nitrogen, the rosin is melt but won't react and no fume will be produced. Is there anyone into this kind of pcb soldering that can explain a little better how it works compared to traditional soldering?
Thanks.
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I wonder what amount shielding gas would be required for a localized soldering job. Those generators are expensive, but you can get nitrogen that's used for plasma cutting in the same tanks that are normally used to store argon for tig-welding.
Even cheaper, get a single-use tank:
https://www.amazon.com/Disposable-Tank-of-Nitrogen-Filled/dp/B013KC9FUK (https://www.amazon.com/Disposable-Tank-of-Nitrogen-Filled/dp/B013KC9FUK)
http://www.actrol.com.au/Products/Refrigerant-Oils--Gases/Nitrogen/Disposable-Nitrogen/ (http://www.actrol.com.au/Products/Refrigerant-Oils--Gases/Nitrogen/Disposable-Nitrogen/)
You'd need a flow meter/regulator as well. Then the challenge is "aiming" the flow to the spot you need it in.
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The amount would be little. For back-purging with TIG-welding you need around 5 l/min. Often you would see the flowmeters are at 15 l/min.
It would be easy to build a little purge-box, and fit it up with regular 4 or 6 mm push-in fittings - after a regulator of course.
I would guess an air exhaust silencer would be fine, if you wanna solder one component at time, and can move it around. Else, take the gas-lense from a TIG torch, and hook it up some way.
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I've found an interesting article about this topic:
http://www.indium.com/blog/dispelling-10-myths-about-nitrogen-reflow-part-i.php (http://www.indium.com/blog/dispelling-10-myths-about-nitrogen-reflow-part-i.php)
For reflow ovens using Nitrogen as a shielding gas
So, following the article, you can certainly use other shielding gas instead of nitrogen for soldering but it will cost more...
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If you are doing it as a hobby or low volume then the disposable tank of gas is cheaper, but if you are in the regime of needing a single N2 cylinder a month or more the cost of the gas and cylinder rental is going to be more expensive than the cost of the oilless compressor, the power to run it and the Nitrogen generator over a year.
You can use a regular compressor, but it has to be at least a 30CFM unit at 10 bar, and you need a cascade of oil coalescers and 0.2 micron air filters before the ultrafilters of the generator to keep the filter and membrane life high.
In an application where I was using it as a purge gas ( FMCG packaging) I simply used the compressor with a 20m air line, and this helped cool the air down enough to allow the coalescing filter stack ( I was using this to feed the machine air as well after a non return valve so the oiler would not contaminate the other circuit) produced cool wet air that then went through another separator and another regulator to provide 6bar air to the generator, with another set of 0.2 micron filters as water and fine particle filters before the N2 generator with it's own ( expensive, the main consumable there) cascaded 0.05 micron filter packs.
Maintenance was to put in the new filter in the second stage, move that to primary and toss the old primary one away as it would be slightly off white. The actual gas generator itself cost as much as 3 months of cylinder rental for the volume of gas it replaced, the compressor and rest of the air handling were already sunk costs. I still have the backup compressor, a regular small spray painting compressor, which has seen a little use while the main one was having the Ingersoll Rand type 30 replaced after it decided to toss a piston.
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what's fascinating is that probably there's no need for fume extraction: if the solder is shielded by nitrogen, the rosin is melt but won't react and no fume will be produced.
This part is probably wrong. Without oxygen, the number of available reactions will surely be reduced. However, organic material such as rosin will still decompose when overheated. And some part of this decomposed material will be in the form of small, volatile pieces (other parts will end up being a charred mess). So, there will still be fumes, but different ones.