At 10:45 15/04/98 EDT, you wrote:
>Hey you Tech Heads........Help
>
To :
Brian K. Doughty
Numonics Corporation
I am note sure I understand You corectly . It seems to me You are tolking
about two separate problems : pads under cut ( size reduction ) and
dimension stability .
1 ) Pads undercut is completly controlable . Your PCB manufacturer shoul be
able to deal with it like with " normal " rigid PCB .
2 ) Maybe You have a problem of pads size reduction due to uncontrolled flow
of acrylic prepreg used for lamination of coverlay ? Uncontrolled movement
of coverlay ? You have to look on the board and describe more in detals what
You see .
3) Dimensional stability . Acrylic materials have wide range af thermal
expansion coefficients . If You have a problem with " pick and place " , You
have to put on YOUR requirements for final mechanical dimensions of the
panels . Use fiducial points as much You can .
4 ) Flexibles are sensitive to moisture . Pre-bake it .

I do not think it will help You , but at list will give You some idea .
Regards and good lack .

Edward Szpruch
Eltek Ltd - Israel
Tel  972 3 9395050
Fax 972 3 9309581
E-mail :  [log in to unmask]

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