In a message dated 03/01/2000 12:55:19 PM US Eastern Standard Time,
[log in to unmask] writes:

>
>  I think the expression is something like sassenfrassenrassen.........

Hmmm.  Must be an English expression that never made it over the
pond............

>
>  Thank-you all for your inputs, they were very much appreciated. Now, maybe
> you could help us again. Does anyone out there have access to about 10 or
12
> IPC-B25A coupons on ceramic and or polyimide.

Sorry.  I have the B25As in copper and HASL finish, but only on FR-4.  As
these boards are used primarily for solder mask and coating qualifications,
and the specs say FR-4, I seldom see anyone ask for anything other than FR-4.
 I could have some made out of polyimide, if you can wait about 4-5 weeks.
However, considering the shipping and other factors, it might be better if I
e-mailed the B25A Gerber files to you and have your substrates made locally.

>
>  The reason for this type of substrate is that we are developing a new
water
> based coating that we suspect will run continuously at 200 deg C - Yup!
200!!
> (That's 392 F!) This is beyond the Tg of FR4 and we are not too well clued
up
> on laminates - can anyone help? BTW, it has crossed our minds that water
> based coatings being applied to polyimide is not the ideal marriage......
> hence the testing. Anyone suggest another laminate that is designed for
>180
> degC (356 F) operations?
>
>  And I am curious, I understand that the automotive guys out there, have
> under-hood applications where > 180 C is a requirement. What type of
laminate
> do they specify?

I think you are looking at polyimide.  I had a client who does geothermal
exploration (drilling).  The electronics in the drill head have to withstand
200C.  They use polyimide laminate.  I don't recall the brand.

Doug Pauls
CSL

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