With all due respect, you may be confusing the original questioner. YOU
may have a need to clean, but that does not answer the question of does
HE need to, does it? I have been in India several times and have seen
products made in ITI factories. Some of them DO need cleaning, many of
them DON'T (but even these ARE often cleaned, for a number of supposed
reasons). This is why I asked the question. Now I also know that in much
of south, south-east and east Asia, one of the most frequent excuses why
a "no-clean" process is not used is because few local makers manufacture
a satisfactory flux/paste, which means importing a foreign product,
often with swingeing import duties. The fact that paying these duties
would still be cheaper than cleaning appears to be irrelevant.
Recommending a foreign cleaning product also could entail heavy duties,
so I know this person is probably wanting a generic cleaner, rather than
a US brand name. If IPA worked and was safe to use (which it isn't on
both counts), it would be ideal, as it is available everywhere.
I therefore rest my case until I learn WHY he needs to clean.
Incidentally, I'm very surprised that you think that IPA would ever come
near to meeting YOUR requirements.
Another incidentally is that many companies in Malaysia have gone
"no-clean" with excellent results, so I do know it's possible in Asia.
Brian
Kasprzak, Bill (sys) USX wrote:
> Brian,
>
> You have certainly opened the forum for the larger question of the "need" of
> cleaning.
>
> Our surface mount reflow and wave soldering operations use water soluble
> fluxes and obviously there is a definite need to clean when using these
> aggressive fluxes.
>
> However, for secondary operations (Hand soldering, soldering stranded wire,
> etc.) we use Rosin cored solder and RMA fluxes for these operations. Most
> programs that we work with require ionic contamination testing so, cleaning
> is necessary. In addition, it is good practice to have clean assemblies when
> conformal coating needs to be applied.
>
> Since Freon and similar products have been banned, IPA has become the
> solvent of choice for these applications even though the IPA only "smears"
> the material around. It does allow us to "get by".
>
> I have used Flux-off CZ in limited applications. It removes flux residues
> nicely but its drawback is the high cost.
>
> So, there is a definite need for cleaning. Use of no-cleans requires
> pristine parts, boards and has a tight process window. For me it's not a
> practical choice. It can't be used everywhere just as water solubles can't
> be used everywhere. So IPA has become a popular choice only because there is
> nothing else when dealing with rosin fluxes even though it's marginally
> effective.
>
> Any suggestions for an alternative would be welcomed.
>
> Bill Kasprzak
> Moog Inc., Systems Group, Process Engineer
>
>
>
>
>
> -----Original Message-----
> From: Brian Ellis [mailto:[log in to unmask]]
> Sent: Friday, July 02, 2004 6:40 AM
> To: [log in to unmask]
> Subject: Re: [TN] cleaning solvent
>
>
> Despite popular belief, IPA and other light alcohols are not good
> solvents for removing flux residues. However, I cannot answer your
> question without knowing a lot more about your products and the
> flux/paste used, quantities, equipment etc. However, my first question
> is: Are you sure you **need** to clean? Would not a "no-clean" process
> be more suitable for your products? Please give your technically
> justified reasons for cleaning.
>
> Brian
>
> Murulidhara wrote:
>
>>Dear Technetters,
>>
>>I want to know what are the better solvents to clean PCB assemblies better
>
> than IPA.
>
>>Also give the sources.
>>
>>Thanks in advence.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
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