Transcript
Phil
Welcome to Board Talk. This is Phil Zarrow and Jim Hall, the Assembly Brothers, also known by day as ITM Consulting. We're here to answer process questions to do with SMT. Today's question comes from a Mr. P.H., in Texas, who writes,
Jim
I have a closed-loop batch wash system used in SMT, running a water-soluble process. An associate wants to clean assemblies that were hand-soldered with a no-clean through our batch wash.
The solder chemistry is the same, 63/37, but the manufacturers are different. Of course, one is no-clean and one is water-soluble. Does this pose potential problems for the assembly or equipment? I prefer not to introduce the no-clean into my SMT environment, since the system is closed-loop.
Phil
Hey, good for you, Mr. P.H. Keep them the heck away from your cleaner with that stuff. What the heck? You don't want him messing that thing up.
Jim
Well, the most important thing, though, is that he's not going to clean his no-clean residues with a straight water cleaner.
Phil
No, he's going to make one hell of a mess, is what he's going to do.
Jim
Well, he might. It really depends on the individual no-clean chemistry. No-clean is not one thing, it is a wide family of many different formulations using many chemicals.
Some can be cleaned with water and a saponifier, others require very special solvents and cleaning processes so you have to match the cleaning processes for no-clean to the specific no-clean flux formulation you're dealing with.
There is no universal solvent, IPA, or anything else that's going to get it all off. It's a common mistake that any people make. But most importantly you're not going to clean it with pure water.
Phil
So that's the bottom line. If you want to allow him to introduce his boards with a no-clean flux that he's planning to wash off he would have to introduce a saponifier to the system.
As far as changing it over from running straight aqueous, he would have to talk to the saponifier companies as to what proportion of saponifier to put in there.
Jim
I suppose that you could say, "I'll run everything with a saponifier," but that's an additional cost and maintenance, and you've got to make sure that your closed-loop system will handle it. There are just a whole lot of issues. So I guess our advice is no, don't try it. It's not going to clean a no-clean, and it could potentially mess up your pure water batch system, even with a closed-loop.
Phil
Yep, and that hopefully answers this question. And on that note, this is Phil Zarrow with Jim Hall, your Assembly Brothers, bidding you farewell, and remember, whatever you do,
Jim
Don't solder like my brother.
Phil
And don't solder like my brother.
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