Jeff,

   From a regulatory standpoint UL94V0 is the most stringent
flammability rating that you can get. The construction of a flex circuit
is much different than a PCB since the material is different. For your
application you will need to go to the design engineer and find out what
flammability rating the UL inspector will accept for the product they
are designing. IT, Medical, Audio visual, toys have different criteria.
Once you know the demands for the marketplace, then you can go to the
fabrication house and find out their capabilities and recommendations
from a cost and manufacturability standpoint. Once you have this
information you will be able to specify the correct callout to
manufacture a safe cost effective solution. Other will have to chime in
on what they have designed to in the past but this would be a good place
to start.

Regards,
 
Jeffrey A. Traw  |  Electronic Engineer  |  Polyvision  |  o:
503-523-2018  |  c: 503-781-8311  |  f: 503-523-2020  |  polyvision.com
 
Meet eno. One whiteboard... infinite possibilities
http://www.youtube.com/watch?v=SSLKGQEeags&fmt=18

 

-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of
[Jeffrey] [Jenkins]
Sent: Monday, July 20, 2009 9:36 AM
To: [log in to unmask]
Subject: [DC] Flex circuit and UL94V-0 requirement

Good Morning,

I have a question that was presented by one of our engineers in regards
to requiring UL94V-0 rating on flex circuits that I hope somebody with
experience doing flex circuits may be able to better answer as I have
only done Rigid boards.

Their question stems from a vendor response to Rigid-flex board design
which was done by an out of house designer, who added a requirement for
UL94V-0.  The vendor responded that they don't get UL94V-0 ratings on
Flex circuits because the cost of obtaining the certification was too
substantial.

I typically always call it out on Rigid boards, but as I said, I haven't
done Rigid-flex and my only recourse thus far has been to comb through
other peoples flex board designs, and none have stated the UL
requirement.  But that isn't to say it may not be buried in one of the
spec's called out.

Does anyone out there typically call out UL94V-0 ratings on their flex
circuits?  Along with this, are there any facilities or courses in
design for flex circuits?

Thanks in Advance!!

-Jeffrey

________________________________


JEFFREY A. JENKINS
SR. PCB/CAD Designer CID+
L-3 COMMUNICATIONS LINKABIT DIVSION
3033 Science Park Rd. 
San Diego, CA 92121
Tel:  (858) 552-9832
Fax:  (858) 552-9487
[log in to unmask]

 

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