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Author Topic: help with tangential knife please  (Read 3228 times)

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help with tangential knife please
« on: March 20, 2006, 05:08:25 PM »
Hi All, Newbie here ???

I am currently trying Mach 3 with a view to using it on my plotter/cutter.

I am assured by art that G2 / G3 moves now incorporate tangential control..they do but mine does not work correctly

for example.....I have drawn a circle inside a square using autocad....I import dxf using Mach 3...Fine, no probs here but:-

when i run the g code, the tangential control works correctly for the square but the direction of knife rotation is opposite to the move for the circle???

if i convert the dxf to hpgl and then import hpgl file using Mach 3, run the g code it all works OK, if a little jerky

what have I done wrong??  or is there a bug in the prog?

I would like to confirm it will work for me before i purchase full version....and another box of blades!!!!lol.

kind regards

Ian d. :-[
Re: help with tangential knife please
« Reply #1 on: March 20, 2006, 07:08:00 PM »
I don't have a machine that will run this... I am in hopes that I will have a test machine in up and running in the next few months.

sorry about that

Fixing problems one post at a time ;)

Re: help with tangential knife please
« Reply #2 on: March 21, 2006, 12:23:01 PM »
Hi Brian,

Thankyou for your swift response,

I  came to the conclusion that something was amiss by setting up a stepper axis next to my PC, I made a mark on the pulley as an imaginary knife blade, and then by watching the toolpath display on the screen and looking at the stepper axis.....I realised there was an anomaly between the two cuts

If it is not too much  bother, perhaps this would suffice for testing purposes?

in fact it is not necessary to attach a motor at all, just setup the a axis as angular and turn on tangential control

I have attached the TAP file i used as a test

In fact if you run the file the "square" toolpath is counter clockwise the a axis increments from -0.500 to -0.250 to 0.00 and +0.250,, positive movement

and the "circle" toolpath is clockwise but the a axis still increments in a positive fashion!....I am sure, because the cut directions are opposite so should be the a axis motion

kind regards

I hope it is not just me got it wrong!

Ian d.