Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

wave pallets

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wave pallets | 20 February, 2009

Hi all, I have a question regarding some wave pallets having metallic traces of Titanium. The solder mask is blistering in some locations on the PCB and I am wondering if this Titaniumn may have an influence by incresing locally the temp. Also we are using a kester 979 flux and recently it was changed to IF 2009M. The results are the same! thank you

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wave pallets | 22 February, 2009

On a wave solder pallet, we'd expect the metal parts that go through the pallet to be warmer than the pallet material, but we don't expect them to be warmer than the solder. We don't expect a well made board to blister at soldering temperature. So, if your board blisters when run across the solder pot, we'd expect it to blister at the places it touches titanium on a solder pallet.

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wave pallets | 23 February, 2009


PWB Blistering/De-lamination may not be due for Titanium finished threads / holders which is typically being used to draw high Shelf Life of Pallets and even flow across Auto Wave Soldering rails. There is also nothing to suspect on Liquid Flux being used. Check for below causes. 1. Poor masking & the Lamination Temperatures used during PCB fabrication. 2. Inappropriate Solder Mask selection 3. Temperatures & Time set at Pre Heat & Soldering Phases in Reflow / Auto Wave Soldering. 4. Moisture acquisition which shall away by Thermal Baking Process 5. Mechanical stress during Assembly Process such as Press Fit connector Assemblies & etc.

Tnx, David.

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wave pallets | 23 February, 2009

thk you very much for your fast answers. And yes, I am suspecting the same things also. The problem is to convince the PCB supplier that is his fault. A big fight all the time. SO, i will double check everything you said, and I willl come back with results. Thank you once again. Nico

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wave pallets | 24 February, 2009

It is probably due to the solder mask being undercured and is porous alowing the flux to be absorbed which boils when it hits the solder wave that kills the adhesion. You should be seeing this only over copper traces/tracks. Reduce flux volume and increase preheat to volatise the flux carriers off quickly and problem should improve. Solvent wipe resist and should get the discolouration off,if its very undercured then just IPA will fetch it off but best with Stencil Solvent Hope it helps Cheers Greg

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wave pallets | 6 March, 2009

Hi We have anew material that is very cost effective for solder pallets called Electro-Lock. You may find out more at Kind regards dee claybrook

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wave pallets | 12 March, 2009

Thank you for support. As i promised you, I am coming back with the results. The SM used was Probimer 77 with Kester 979 flux. The supplier says that there is an incompatibility and we have changed the flux with IF2009M. Same problem! They have changed the SM with PSR4000. The the same. So...the problem came in my lab for analyses. I didn`t know this beautifull story untill now. SO...I have checked the Cu surface under the blister, and surprise! traces of flux and Al plus Si. Components from the pumice used at scrubbing. The structure of the SM looks like a sponge almost. I will attach a photo. No wonder that any flux from the world is not compatible with their SM. Plus, the thinckenss over the knee is 8um. Which i think is too less for an Enig process. SO, thank you very much for your help, and good luck from now on. Nicoleta


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wave pallets | 12 March, 2009

Thanks Nicoleta

It is nice to hear the problem is solved and this is a massive problem in the industry especially for Lead Free. It is easy for a supplier who doesn't understand to blame incompatibility just a quick way out but doesn't fix anything as you proven. The Si is also very common ingredient of under cured resist as well. If only they had temperature probed the board when curing they would see the PCB was not hot enough. Thanks again for feedback Cheers Greg

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