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Flux splatter issues

Views: 3637

#75308

Flux splatter issues | 3 February, 2016

Hi, New to this forum. I am an engineer assigned to resolve a quality issue on our production line. It seems that we have been getting small droplets of flux on our boards after the reflow process.

Occasionally, they land on a board to board connector and that can cause an open under certain conditions, even months or years later in the field.

I ran a test with bare boards to verify that the problem was not a "global" problem. i.e. resident flux circulating in the oven itself.

The splatter only occurs locally on the board. I read that the profile used for the ovens determines the amount of flux splatter that can occur. So we change that once to see what happens, but not much difference. However there is more work we can do there. We also noticed that this occurs on several of our lines, but the residue doesn't affect most of our products.

Some say to put kapton tape on the connectors and remove it afterwards. However I can't see how you do this on a manufacturing line affectively. I have yet to find anyone that does this.

Any thoughts or war stories would be appreciated. Thanks, Greg

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#75310

Flux splatter issues | 3 February, 2016

Have you ever done QC type thinking on your problem or are you aware o fthe methodology?

Do you run your plant in a clean room environment?

Do you clean after reflow? If not Why?

What sort of products are you running?

What sort of oven are we talking about?

The answers to these and more questions will determine the correct solution to your problem GrassHopper.

regards sarason

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#75315

Flux splatter issues | 3 February, 2016

Our company being an automotive supplier is all about quality control, not a clean room requiremen, This is a no clean process, all surface mount boards and Solitec ovens. Hopefully this answers your questions. Greg

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#75316

Flux splatter issues | 3 February, 2016

> Our company being an automotive supplier is all > about quality control, not a clean room > requiremen, This is a no clean process, all > surface mount boards and Solitec ovens. > Hopefully this answers your questions. Greg

Hi Greg,

Are you certain that the splatter is occurring in the oven and not during placement? I’ve seen part heights entered that were to thin causing paste to splatter. I’ve also seen too large of a nozzle used on a part and the blow off during placement was causing paste splatter. If you are certain that the issue is happening in the oven I would look for moisture in your board or parts.

Good luck, Mac

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#75317

Flux splatter issues | 4 February, 2016

I have never considered that before. I don't think so, but I will look at it closer. The reason I don't is that most of the micro spots are nearly all resin but I will look at this.

I will try to attach a photo that shows the contamination

Attachments:

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#75319

Flux splatter issues | 4 February, 2016

Have you re-visited your paste manufacturers profile requirements? Start there, adjust accordingly to critical components on the boards (ie LED's, moisture sensitive, etc..).

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#75321

Flux splatter issues | 4 February, 2016

Yes, working with both the solder reps and the oven manufacture. It seems everything is in spec.

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#75329

Flux splatter issues | 5 February, 2016

HI Greg, you may want to consider trying a paste especially developed to minimise splattering. I work for Almit and we offer a paste called SPM ( SPlatter Minimiser)...it is widely used for applications where no splattering is required. Take a look at our website http://almit.co.jp/eng/product/sold_past.html about half way down the page you can download the SPM info. If you are in the USA and want to look at a sample please email nishiyama@almit.co.jp He is repsonsible for support for USA market. Thanks Graham

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#75330

Flux splatter issues | 5 February, 2016

Hello Greg,

there are several things to be considered:

I will start this investigation in the oven. Look in your cooling zones. Many ovens build up a lot of flux there(especially the ones with water cooling) and should be cleaned every so often. I have seen flux dripping randomly over boards just like the pictures you show here. Good luck

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#75332

Flux splatter issues | 5 February, 2016

Thanks for that, I will look into it. Unfortunately the plant is in Sweden, however maybe I can get a sample from someone local there. Do you have any contacts?

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#75333

Flux splatter issues | 5 February, 2016

I thought it might be the oven too, except it seems the splatter is too small for drips from the oven, secondly, when I ran a couple of bare boards among the populated boards we saw no splatter or flux contamination.

So it seems it comes from the board itself.

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#75334

Flux splatter issues | 5 February, 2016

Your most likely ramping temp to fast and boiling the flux, or do have moisture in the fabs. BTW every solder paste rep has the solution until their product doesn.t work then they have excuses.

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#75335

Flux splatter issues | 5 February, 2016

Thats funny, maybe so. Anyway, changing the ramp rates will probably be the first thing we will try next week in Sweden.

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#75339

Flux splatter issues | 8 February, 2016

Hi, Can you let me know how I can talk to you about this product? I need to talk to the company pretty quick Thanks, Greg

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#75342

Flux splatter issues | 8 February, 2016

talk to who, and what product?

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#75343

Flux splatter issues | 8 February, 2016

Sorry, I guess I don't know how to address an individual on this thread directly. The fella who represents the anti-flux solder paste - Graham Cooper.

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