No-Clean or water

Jake,

The No-cleans on the market, to me, still aren't as good as OA and water wash. But they have gotten better. The type of No-Clean flux and paste to use really depends on each individual assembly, the machines used, settings, and the environment used in. That said, however, there are a couple of good No-cleans that have a nice wide processing window to work with. We use only two types of no-cleans at my company after trying many. We use either Kester's R256 or Aim's 293+ pastes. As for wave solder, we use either Kester 951 flux or Kester 971 flux as a foam and Kester 110 for the thinner. Check out manufacture's web-sites for specific information on these and other pastes and fluxes.

Don't forget to get prior customer-approval before switching paste and flux to build their boards....

Spanky

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Hi, This is Katrina speaking from ShenZhen,P.R.China. Hi, Jack Our company SELP(a member of CIPC) is a representative of some leading manufacturers in US and EUC,such as SEHO GmbH and Heraues.There are some typical No Clean/Non-halid paste from Heraeus such as F813,F817,K180 and LPL926 in which LPL926 is largely adopted in HongKong and some other regions in China.

If you are interested in it,please do not hesitate to contact ship@public.szptt.net.cn Tel No:++86 0755 6490050 Fax: ++86 0755 6070403

This message was posted the Electronics Forum @

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No-clean solder paste is definately a trend for tomorrow. However, there are several points you need to consider before you shift from WS to no-clean:

1. Component quality - No-clean solder paste generally (not essentially) get a lower avtivity than WS. You may need to perform a feasible study to see if all your components are suitable to use No-clean paste.

2. Solder Joint Color- I suppose most of No-clean solder pastes will give you bright solder joint now. The most important is the color of flux residue.

3. Reliability - Although a solder joint "looks" good, it does not mean it is reliable. Halide content and SIR value may give you a better evidences for a good solder joint.

Best Regards

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Hi Jacob, NC vs WS, what a story! No-clean paste means no-clean for your products but what a mess it makes in your reflow systems. If you are a contract maunufacturer of high volume production, then No-Clean is they way to go. This helps keep your costs down, since you do not need cleaning. One thing to consider is if your customers require you to clean the boards. Some customers (especialy) government products, still require cleaning even when no-clean paste is used. This wastes money since no-clean paste is more costly. If you are producing boards for yourself or are low volume, I would suggest staying with what works for you now. It wont be long before Lead-Free may become the way of the future. Why change to no-clean now when you may be changing to a lead-free paste in a short while.

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Others make good points.

Consider "TP-1115 - Selection & Implementation Strategy for A Low-Residue No-Clean Process" as a starting point.

Remember that in-bound components and boards can be loaded with unNC res that can turn the best implemented NC program on its head. Undercured soldermask will sop flux res like a sponge and then let you have it back over time. Ummm.

Finally, do not underestimate the effect of the change on your ability to control a narrower process window. For example, all the people whining about solder balls on SMTnet are not running a washer. Trust me!!!

Then again, a very good water washer can clean BGA ... uBGA fugedaboudit!!!

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