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Wave soldering defects

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#76784

Wave soldering defects | 26 December, 2016

Hi all,

I'm having some troubles while trying to set up a wave soldering machine that was working just fine until a few weeks ago.

The wave soldering machine is quite basic chinese made. It's 2 meters long, has spray fluxing and a short preheating zone. It has dual waves.

I'm using SnPb and NR300-A2 low solids water based flux.

The solder pot temperature is set to 250ºC and preheat to 130ºC. Speed is set to about 1 meter per second.

The boards come out full of shorts and icicles. Attached there are 2 pictures.

Any help is most welcome.

Thnaks, Luciano.

Attachments:

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#76792

Wave soldering defects | 27 December, 2016

Dear Pro,

Pls, increase temperature up to 255ºC and considering solder's profile.

Good luck

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#76793

Wave soldering defects | 27 December, 2016

Thanks for your advice.

I've tried setting the temperature up and even measuring the temperature at the wave itself but had no luck at all.

I've also tried using temperatures going from 245 ºC up to 260 ºC. The amount of flux was adjusted as well as the preheat and conveyor speed. The parameters were changed in relative small steps (5 ºC for the temperature and 0.1 m/s for the speed) and in varous set ups.

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#76796

Wave soldering defects | 27 December, 2016

Dear Pro,

I want to confirm with you about conveyor speed. is 1m/s?

We are using wave soldering but it is 1.2m/min, min not second. Pls, check it agian.

The flux is not relative this error. It is relative no sodering, bridge. The solder bar is the most important,You must follow the solder's profile for choosing the best temperature for your setting.Besides, you also consider the pallet design if you use and the angle of conveyor.

Good luck.

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#76797

Wave soldering defects | 27 December, 2016

Hello,

Sorry for the mistake. The speed is 1m/min.

We are using Alpha Vaculoy solder and a conveyor angle about 7º. We are not using pallets since the fingers hold the boards directly.

Thanks!

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#76800

Wave soldering defects | 27 December, 2016

Dear pro,

Could you show the solder's profile.

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#76803

Wave soldering defects | 28 December, 2016

Dear Anshang38,

I actually don't have a profiler in order to get a new profile. I adjusted the machine once a coulpe years ago and did all regular maintenance and cleaning and it kept working fine until some weeks ago.

I've changed all the flux and cleaned up the system, pipes and spray. I've removed the dross and cleaned the pumps removing residues. I've also checked the temperatures with external devices just to be sure the readings from the machine are correct.

The one thing I didn't do is changing the solder bath.

Thanks!

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#76804

Wave soldering defects | 28 December, 2016

Dear Pro,

Pls, try to get solder's profile from solder supplier.

That is the most important in wave soldering process... if not you will be difficult for improvement.

Good luck.

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#76806

Wave soldering defects | 29 December, 2016

I would cut a piece of cardboard to the same dimensions as your circuit card. Run that through the fluxer of your machine and pull it out before the pre-heater. Take a look at the cardboard and verify that flux has been sprayed on it. That board looks like you either didn’t spray flux on it, sprayed something on it that was not flux, or are using a flux not designed for your solder.

Beg/borrow/steal a profiler. The reflow curve is crucial. If your flux test was good, then I would suspect the temps (or conveyor speed) is way off. That flux has a temperature that it activates at. If you aren’t activating your flux (or you have no flux) you will get results like you are seeing.

Also, wash your cards! Those cards are some of the dirtiest ones I have seen. Did they look that bad before going in? Solder will not flow right on a contaminated pad.

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#76808

Wave soldering defects | 29 December, 2016

Luciano,

It looks you have no flux there. Please flux one board by hand and send it through the wave. That will eliminate a lot of the possibilities.

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#76810

Wave soldering defects | 29 December, 2016

Thanks Anshang38 I'll try and get a profiler.

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#76811

Wave soldering defects | 29 December, 2016

Thanks Evtimov,

The flux is brand new and the amount of flux is enough and consistent across the surface of the boards.

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#76812

Wave soldering defects | 29 December, 2016

Thanks SuMoTe,

I've already tried fluxing various boards (new clean ones and older ones) without turning the waves on and with different temperature setups (within the suggested params from Alpha) in the preheat zone. The results were in many cases just fine and adecuate.

I'll try and get a profiler.

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#76824

Wave soldering defects | 30 December, 2016

First profilers are expensive and you can use temperature dots for setting up a wave. You stick them to the top side of the board and they change color based on temp. Top side temp should be around 250f or 125c when it hits the fountain.

If you sprayed the board by hand with new flux and didn't flash it off with extreme pre heat then it's not the flux.

Is this happening on all your boards? If it's on an isolated assembly it could be uncured or contaminated solder mask.

you said you cleaned the pot. The pictures show solder dross all over the board. It looks like you pumping dross. Did you empty the pot and pull the pumps and clean them?

Last your solder could be contaminated. Send a sample off to your solder supplier for analysis.

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