> We're currently working on a design which entails a leap into the unknown
> for us. I'd like to know if anyone's been here before and what they found.
>
> I've got a very small Flex which needs folded up in order to fit it into a
> tube, Once the flex is inside the tube everything is potted and so the
> flex never moves again. In order to get it into the smallest diameter tube
> we need to put a sharp, permanent bend into the flex. Has anyone done this
> before and did it cause cracking in the tracks - the bend will always be
> perpendicular to the tracks.
>
> The spec fo the flex is:
>
> double sided
> 1/2 oz copper
> 0.002" pyrolux (polyimide) substrate
> 0.25mm inner bend radius.
> Epoxy coverlay top and bottom.
>
>
>
>
> Eric Christison
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################ To
> subscribe/unsubscribe, send a message to [log in to unmask] with following
> text in the body: To subscribe:   SUBSCRIBE TechNet <your full name> To
> unsubscribe:   SIGNOFF TechNet
> ################################################################ Please
> visit IPC's web site (http://www.ipc.org) "On-Line Services" section for
> additional information. For technical support contact Hugo Scaramuzza at
> [log in to unmask] or 847-509-9700 ext.312
> ################################################################

As a general rule the minimum bend radius your flex circuit should
undergo would be 8 to 15 X the total thickness of the flex or in your
case .0592 to .111. If you can roll this circuit around a mandrill of
this size to try and pre-form the flex you may have better results.
Also keep any electrodeposited copper off of the circuits in the
bend areas. This copper will crack first, then propagate through the
rolled copper causing failures.



Robert P. McGarry jr
Technical Sales Analyst
Proto Circuit Inc.
2035 Midway Dr.
Twinsburg, OH. 44087
330-425-4939 fx. 330-425-9704
[log in to unmask]
http://www.protocircuit.com

"QUALITY MANUFACTURED PRINTED CIRCUIT BOARDS"

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################