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Best Alpha Lead Free WS paste??

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#53130

Best Alpha Lead Free WS paste?? | 10 January, 2008

Looking for some opinions on what the best, readily available, Alpha lead free water sol paste is out there. Only thing I can see on their website is the WS-819. Anyone with experience with this? We currently are using the OM-338 NC which works great but I have a couple of difficult boards that I really want to try to maximize wetting on.

Thanks JD

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#53136

Best Alpha Lead Free WS paste?? | 10 January, 2008

Hi JD,

We use the OM-310 NC for most of our lead free work and see some wetting issues.

We also have a lead free produst that requires cleaning so we use the WS-819. It does seem to wet better although I have never tried the WS-819 on the same boards as the OM-310. The WS-819 may foam alot on you during cleaning depending on the amount of solder paste applied.

Jerry

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#53137

Best Alpha Lead Free WS paste?? | 10 January, 2008

Thanks for the reply.. May foam eh? We actually clean some of our no clean boards anyways so I have Zestron in the wash sump. That should mitigate any foaming that would occur in straight DI I would think...?

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#53140

Best Alpha Lead Free WS paste?? | 10 January, 2008

You may want to ask Zestron to be sure. We have a batch cleaner with pure DI water. The first time we cleaned some of these boards in it we had a bit of a mess around the cleaner.

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#53141

Best Alpha Lead Free WS paste?? | 10 January, 2008

Yes thats always an awful site isnt it? It used to happen to use because an operator was opening the door during the cycle to check if it was done. I smartened up and fired the operator (for other stuff also) and put the washer on a pallet in a big yellow basin. At least if it overflows again it will be contained until we can get the shop vac in there.

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Pete B

#53197

Best Alpha Lead Free WS paste?? | 15 January, 2008

We too are trialling WS819 with SAC305 alloy. The foaming in cleaning causes us a headache but all other attributes seem much improved over earlier types. Previously we were using WS619 - no foaming issues but MUCH shorter stencil life (less than 4 hours), poorer fine pitch printing performance etc..

Just as an aside - does anyone out there use WS819 in a Vapour Phase process?

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#53244

Best Alpha Lead Free WS paste?? | 17 January, 2008

Stay far away from the WS619 paste. It is a nightmare to get a decent solder joint out of it. And dont get me started on voiding issues with this paste. We eventually started to use Indium 3.2 lead free "water wash" paste and this drastically reduced voiding and improved all solder joints.

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Reflow Oven

Used PCB Equipment - AdoptSMT