The refractive index can be misleading if you wash boards that have water
soluble temporary
solder mask on them. These types of spot mask lend a large contibution to
the solutions
refractive index and indicate high enough concentrations of Aquanox when
there isn't.

The rinse water has to be monitored for organics by refractive index and by
electrical conductivity for ionically  conducting contaminates.

-----Original Message-----
From: Hinners Hans Civ WRALC/LYPME [mailto:[log in to unmask]]
Sent: Wednesday, February 09, 2000 11:00 AM
To: [log in to unmask]
Subject: Re: [TN] Saponifier concentration measurement


Hi Lou and All,

<de-cloaking>

We're using a Leica refractometer to measure Kyzen's Aquanox XJN
concentration in our in-line cleaner.

Automatic controllers are great and if you run enough product (or chemistry)
they can sure pay for themselves in a hurry.

The biggest hurdles I've had to overcome with using the refractometer had
more to do with training the operators than the chemistry.

My question, why the change?  Are boards or assemblies failing after
cleaning or is this part of a general process review?

As Alain pointed out, there are several methods of achieving the same result
(to varying degrees) - knowing when to dump the sump or knowing how much to
add.  It depends on your specific needs - greater precision & control vs.
cost (several models) vs. ease/speed of use.

It's like Rudy said, the titration may come out as a false positive (bath
okay) but if the boards aren't clean it doesn't really help.

Hans

~~~~~~~~
Hans M. Hinners
Materials (& Process!) Engineer
Warner Robins - Air Logistics Center/Avionics Production Division
Manufacturing Branch (LYPME)
380 Second Street, Suite 104    (Building 640)
Robins AFB, GA  31098-1638
912-926-1970 (Voice) 468 - 1970 (DSN)  912-926-7164 (Fax)
mailto:[log in to unmask]


> -----Original Message-----
> From: Lou Hart [SMTP:[log in to unmask]]
> Sent: Monday, February 07, 2000 11:39
> To:   [log in to unmask]
> Subject:      [TN] Saponifier concentration measurement
>
> Technetters, how do you measure saponifier concentration in a board
> assembly cleaning machine?  We've been using a refractometer to measure
> degrees Brix, but this is appears to be a "legacy" method.  I've been
> hearing titration would be the way to do it.  Please comment.  Lou Hart QA
> manager, Compunetix 412-858-6184
>

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