Hi Dee,
Thermount has low X and Y CTE. However the Z axis CTE is higher than FR4.
When I used this material, couple of years ago, it used to have low copper
peel strength (repair was very difficult), poor machinability and high
moisture absorption. Arlon claims that these issues have been already dealt
with and that the new improved Thermount does not have these drawbacks.
You should also select a PCB manufacturer that has experience with this
substrate.
Sherif Refaat, Eng.
Technology Roadmap Consultants Inc.
E-mail: [log in to unmask]
Tel. (514) 624 9842
Fax (514) 624 0091
----- Original Message -----
From: "Crepeau, Phil" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, August 15, 2002 6:00 PM
Subject: Re: [TN] Dimensional stable material
hi,
although not inexpensive (which is a relative term) thermount (for example)
from arlon (for example) has a low cte.
since you seem to be a non-profit sort of business, you might try appealing
to the charitable nature of your supplier for freebies. i mean, who can
turn down a request for heavily discounted materials coming from the
'national optical astronomy observatory'. i mean, we don't have to pay to
see all those great images at the 'astronomy picture of the day' web site do
we (other than our income taxes). the vendor could claim that their
material is 'space age'.
bon chance,
phil
-----Original Message-----
From: Dee Stover [mailto:[log in to unmask]]
Sent: Thursday, August 15, 2002 12:33 PM
To: [log in to unmask]
Subject: [TN] Dimensional stable material
I have a board that needs to be built with material that has a very low
rate of thermal expansion.
I believe polyimide material is what I need; however, I would be interested
in hearing other possibilities that are still reasonably priced.
I would like to get the specifications to see if it does indeed meet our
requirements and would also like some guidance on how to properly specify
this material and prepreg it in a fabrication drawing to ensure I get what
I want.
You input is appreciated.
Dee Stover [log in to unmask]
Associate Technician Design
National Optical Astronomy Observatory
950 N Cherry Ave
Tucson, AZ 85719
www.noao.edu
520-318-8489
FAX 520-318-8303
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