CCD-world: Help on Flexible PC suppliers?

[Tom Droege]

The following was posted to CCD-world:

OK, it was a struggle but I found them.

At Fermilab we bought some pretty strange PC boards.  Things like 4' x 10'
printed circuit boards for Liquid Argon Calorimeters.  Sheldahl was often
the only supplier that would bid on such things.  They were rarely the low
bidder unless they were the only bidder.  You will find someone there who
understands your problem if you find it anywhere in the industry.  

Sheldahl, Inc.
1150 Sheldahl Rd.
Northfield MN 55057
Tel  507 663 8000
Fax 507 663 8545
www.sheldahl.com

I have no connection with Sheldahl etc..  

Tom Droege

At 04:46 PM 1/21/00 +1100, you wrote:
>The following was posted to CCD-world:
>
>
>Dear CCD-World gurus,
>
>we have recently found at the AAO that our 
>instruments are moving into areas where our
>current flexible PCB suppliers can no longer
>be relied on.
>
>Can we get some recomendations on people's
>preferred flexible PCB suppliers? A
>detailed specification of our requirements is
>attached, however to summarise.
>
>* Flexible PCB - only millimetre motions at most
>  after installation.
>* Use in vacuum and temps at least 77K
>* Polyimide and teflon have been OK in past
>*** Low capacitance!!
>* Sizes from 80mm x 150mm up to 60mm x 400mm
>
>Thanks in advance,
>
>Chris T.
>
>> 
>> 
>> Dear Sir/Madam,
>>
>> 		for my current project I require approximately
>> 18 different flexible printed circuits, possibly panelised 
>> into 4 or 6 groups depending on your available panel sizes.
>> 
>> 	These flex circuit will be used to replace wiring within
>> a cryogenic camera, the boards have no components on them 
>> except for a connector at each end, where stiffeners are 
>> required. The circuit will not be flexed continuously just 
>> shaped initially then only a few millimetres movement will 
>> be required infrequently. The flex material must be 
>> suitable for use in a vacuum and at low temperature (we 
>> have tested polyimide and teflon material at our operating 
>> temperature and found both acceptable).
>> 
>> 	The most important of our requirements is low capacitance.
>> Therefore the base material we prefer is 0.005" teflon with 
>> a dielectric constant (Dk) < 2.5, however other 0.005" base 
>> materials may be suitable such as Kapton KN (R/Flex2001) 
>> with a Dk = 3.2 or polyester (Dk = 3.1) although we have 
>> not verified polyester at our operating temperature.
>> 
>> The sizes of each flex range from 80mm x 150mm up to 60mm x
>> 400mm. 
>> 
>> General specifications for the flex circuits:
>> 
>> 1.  Double sided copper with plated through holes.
>>     1oz finished copper weight.
>> 
>> 2.  Track width 0.006", spacing >0.010".
>>     Solid or 45 deg. cross hatched ground plane on one side.
>> 
>> 3.  Hole sizes >0.020", annulus >0.010".
>>     Aprox. 50 holes per board.
>> 
>> 4.  Insulating layer or solder resist both sides.
>> 
>> 5.  0.005" stiffener over the ends (1 side) approx. 15mm 
>> long.
>> 
>> 6.  No silkscreen.
>> 
>> 7.  Silver (preferred) or solder finish on pads.
>> 
>> 8.  Protel CAD files or Gerber files available for 
>> manufacturing.
>> 
>> 9.  Quantity will be 2 or 3 each of the 4 or 6 panels (18 
>> types) initially.
>> 
>> 	I believe these designs are not unusual and should 
>> not present any manufacturing problems apart from the 
>> selection of base material. Please let me know what 
>> suitable low Dk base materials you have available and 
>> rough idea of pricing for the production of these flex 
>> circuits. I also need your panel sizes and manufacturing 
>> time.
>> 
>> ----------------------
>> Lewis Waller
>> Anglo-Australian Observatory               Email: lgw at aaoepp.aao.gov.au
>> PO Box 296, Epping. NSW 2121               Tel:   61 2 93724831
>> 167 Vimiera Road, Eastwood. NSW 2122       Fax:   61 2 93724880
>> Australia
>> 
>> 
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