From: Marc Webster [mailto:[EMAIL PROTECTED]]
>
> Hey Pat,
>
> I have been working on a design for a CNC foamcutter for the past few
> months.
...
> have also attemted to eliminate the need for the cutting bow (hope it
> works). Instead as the wire changes length with wing tapor and z height,
> the wire is payed out and retracted as needed. If this does not work, I
> have still made provisions for a bow.
I presume you're calculating the required wire length and driving
a stepper to change the length? Wouldn't it be simpler to maintain
a constant tension in the wire? This could be done by terminating
the wire on a drum driven directly by a DC motor. The motor would
operate stalled most of the time, with it's stall torque (and hence
wire tension) controlled by the applied voltage.
Just a thought.
Ciao - Chris
******
Chris Kaiser
Auckland, NEW ZEALAND
http://rcmodels.co.nz/clubs/asfcnz
RCSE-List facilities provided by Model Airplane News. Send "subscribe" and
"unsubscribe" requests to [EMAIL PROTECTED]
