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Old Aug 19, 2006, 10:25 AM
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GMFC problem on tapered wing

I'm getting this error in GMFC:

Speed above step motor limit on X left axis : 0.78 mm/s, Move to block start d1

What the heck does it mean? I'm trying to cut a P51 wing with a 190mm root and a 90mm tip. The Tip is centered in the root.. but for some reason no matter what I do I cant get rid of this message.

I've read through the manual (help guide), and it mentions syncing the wire at root and tip, is this what I need to do.. the guide does not mentio how to do it..

anybody have experience here?

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Old Aug 19, 2006, 10:50 AM
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I think I know why. Interestingly, my version of GMFC does not show the cut speed option "Measured" for Poly expanse. Only "Maximum" and "User choice" show up.
I think what is happening is that you have chosen "Maximum" cut speed, so now it is trying to cut the root rib with the maximum speed that you specified for your table configuration. Since it is a tapered wing, the left wiresupport will have to move at a greater speed to achieve this, which is then above your specified maximum, hence the warning. Try "User choice" with a cut speed lower than max.

Max.
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Old Aug 19, 2006, 11:04 AM
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well.. it kinda worked.. if I set the cut to manual and 0.2mm/s it will work, but it now will take 45 minutes.. is this way too long? There must be a better way
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Old Aug 19, 2006, 11:09 AM
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Have you checked your table configuration to see what max. cut speed is set at? Does it reflect the actual mechanical limitation of your drive?
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Old Aug 19, 2006, 11:33 AM
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yep.. that was it.. 400 steps and 2.54mm rod did the trick.. thanks man I overlooked it
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Old Aug 19, 2006, 11:37 AM
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Old Aug 20, 2006, 12:40 AM
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another solution... in foam configuration, slow down the max/min cutting speeds.. you will also have to reduce the heat to keep the kerf the same.

GMFC produces this error because it's trying to keep the wire above min speed (usually calced for the smaller tip chord). On tapered wings, the longer root chord needs to be cut faster, sometimes exceeding the machines velocity settings.
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Old Aug 20, 2006, 05:35 AM
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Quote:
Originally Posted by OzDragonFlyer
GMFC produces this error because it's trying to keep the wire above min speed (usually calced for the smaller tip chord). On tapered wings, the longer root chord needs to be cut faster, sometimes exceeding the machines velocity settings.
OzDragonFlyer,
I had always thought that the min. and max. speeds specified under Foam Management were just for kerf compensation calcs, and the only restricting speed value is the max. cut speed under Table Configuration. Are you sure?
I have just tried to specify a ridiculous max. speed way beyond the table max. and the software happily accepts it. (I have not tried cutting since my machine is stored away right now).

Max.
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