Yes, but....
Alpha is not alone in doing this. Many users require the repair material to
be the exact same FLUX as the original solderpaste. Others are happy to use
a Tacflux which is the same generic type.
--
Regards
Mike
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, December 16, 2015 12:42 PM
To: [log in to unmask]
Subject: Re: [TN] IPC 7095 and Liquid Fluxes for Rework
Also, Alpha uses the same material "name" for their flux crèmes (sticky or
tacky fluxes) as they do for their solder pastes, which is a constant source
of confusion.
I don't think they realize just how much confusion and angst this leads to.
There have been several occasions that I am aware of where the operator was
told to use a crème or tacky flux and because they were familiar with the
solder paste by the same name, they used that instead, which led to
disaster.
So give your crème flux a different Company Part Number and identify the
material by that and the term "Crème Flux", or "tacky flux", or whatever you
want to call it, and teach (train) them to know the difference between that
and the different Company Part Number and description for the solder paste.
I am not saying anything good or bad about any of the products I mention
here, I just need to cite some examples so everybody hopefully understands
what we are talking about.
There is both a WS-609 crème flux and a WS-609 solder paste, for example.
So please don't be confused by that.
Bad dog, Alpha! Noooo doughnut.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, December 16, 2015 6:11 AM
To: [log in to unmask]
Subject: Re: [TN] IPC 7095 and Liquid Fluxes for Rework
Not sure what you mean, Tan, but I am talking about liquid fluxes such as
Kester 2331ZX, for example, and tacky flux (also called paste flux or flux
crème) such as Alpha WS-809.
NOT solder paste.
Hope this helps.
dean
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Tan Geok Ang
Sent: Tuesday, December 15, 2015 7:32 PM
To: [log in to unmask]
Subject: Re: [TN] IPC 7095 and Liquid Fluxes for Rework
Paste flux not liquid flux....
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Wednesday, 16 December 2015 3:32 AM
To: [log in to unmask]
Subject: Re: [TN] IPC 7095 and Liquid Fluxes for Rework
I'm going to come right out and make this statement. You can laugh all you
want, but the data proves that liquid fluxes are terrible!
Not only for BGA rework, but pretty much any type of rework! They form
particulates in the solder joints, they run all over, and they like to
penetrate and boil. Many people do not realize that is one of the main
causes of lifted pads.
Let the screaming and moaning and hysterical laughing begin. I really don't
care.
I have been training operators in the companies I work for years and years
to use only tacky fluxes for touchup, for simple rework, and for hot air or
hot gas rework, as well as for molten solder fountain rework. I have
qualified the use of tacky fluxes to replace liquid many, many times. The
cleanliness results of both water soluble and cleaned RMA tacky fluxes are
several times better than for liquid fluxes. The tacky fluxes seem to
promote wetting much better than any liquid flux I have ever used, and I
think I have used them all.
Because the tacky fluxes are developed for worst-case conditions (hot gas
and solder fountain rework) they actually work much better than any liquid
flux I have ever tried.
And they typically are much easier to confine to just the solder joint(s)
you are trying to touchup or solder.
And they don't evaporate or burn off before you even reach liquidus.
And for about 10,000 other reasons, but one of the biggest is that once the
operators try using tacky flux for all rework and touchup, they never go
back.
If the REACH folks decreed that there would be no more liquid flux allowed,
beginning yesterday, it would not mean a thing to me. I would say, "Good
riddance".
Most liquid fluxes on the market today were developed for wave solder or
selective solder use; they were never intended to be used as a benchtop
flux. People adapted them for compatibility reasons.
My feeling is that they should be limited to wave or selective solder
processes.
Use a good tacky flux of the same chemistry for everything else. Those from
one particular solder company have always worked best for me. God is the
____ and the Omega.
But always qualify, qualify, qualify.
dean
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Wettermann
Sent: Tuesday, December 15, 2015 10:40 AM
To: [log in to unmask]
Subject: [TN] IPC 7095 and Liquid Fluxes for Rework
Dear Technetters:
In reviewing the IPC 7095 BGA guidelines I noticed a mention of liquid based
fluxes for BGA rework. Has anyone heard of liquid fluxes being robust enough
for Sn63 or lead-free rework processes?
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Thanks
Bob Wettermann/BEST
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