Thank you Brian,
I agree with your items mentioned, however it is difficult to convince the
customer of this (you know the drill). We will continue expanding our test
parameters (without heating) and will hopefully come up with an acceptable
mutual resolve soon.
Thanks again,
Steve

Steve Challis
Quality Engineer
Saturn EE, Corp. Offices
Direct: 248-299-1039
Page: 810-769-4249
e-mail: [log in to unmask]
pager e-mail: [log in to unmask]


-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Tuesday, May 01, 2001 2:03 AM
To: [log in to unmask]
Subject: Re: [TN] Ionic Testing


Steve

Theoretically, a heated solution may be better, but it is far less
practical than room-temperature. The disadvantages are:
1) very much greater risk of fire
2) selective evaporation of the IPA requires much more frequent solution
maintenance
3) lower ion exchange efficiency
4) complex (non-linear) temperature compensation required (which
commercial instruments do not offer)
5) reduced equipment life
6) better ventilation required
7) greater leaching of ions from substrate material, giving irrelevantly
high readings.
The one advantage is that the tests are more rapid.

As an ex-manufacturer of such testers, I advise strongly against
heating.

Brian

Steve Challis wrote:
>
> Hello All,
> This question concerns assembled PCBs.
> I (we) have some concerns over the standards surrounding Ionic
> Contamination. Some conversations over heated vs nonheated have been
> brought up, however it is clear to me that heated is the superior test
> method. The temperature for the heated test method is the question. Does
> anyone know exactly what the desired temperature is? If so, what would be
> the source reference document and where do I find it?
> Thanks, in advance.
> Steve
>
>
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