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Author Topic: z axis gaining height with vcarve toolpath's only  (Read 7575 times)

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z axis gaining height with vcarve toolpath's only
« on: November 22, 2013, 04:53:41 PM »
 I am using mach3 control, probotix monster mill kit and vectric vcarve pro 7.0. My x and y axis use 1/2-10 precision acme lead screw with 280 oz-in stepper motors. My z has 3/8-12 two start acme precision lead screw with 400 oz-in stepper motor. Only when using the vcarve/engraving toolpath the z will gain height and cut above the wood. I have no other problems when using other toolpaths. I have already checked coupling slip and that is not happening. It seems to be losing its postion and I do not know why. Just wondering if anyone has seen this before and what to do to correct the situation. I know the electronics and kit that I have are capable of cutting 2.5d and 3d toolpaths but something gets out of sorts when using the vcarve/engrave toolpath.

Offline Hood

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Re: z axis gaining height with vcarve toolpath's only
« Reply #1 on: November 22, 2013, 04:57:19 PM »
Could it be the V Carve toolpath is plunging the Z into the material faster than you normally do on other work and thus causing your stepper to be overloaded and its stalling a bit? Try reducing the feeds in the code to see if it helps.

Hood
Re: z axis gaining height with vcarve toolpath's only
« Reply #2 on: November 22, 2013, 05:17:53 PM »
I will try that. I am about to do a test on cutting an arc with the x and z moving simultaneous just to verify correct movements then I will try the reduced feeds test on the vcarve toolpaths. I am like everyone else. My time is limited and I have to  do testing spaced out over several days. Thanks for the advice though.

Offline ger21

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Re: z axis gaining height with vcarve toolpath's only
« Reply #3 on: November 22, 2013, 05:46:59 PM »
Cut the Z axis acceleration in half. my machine acted similar when doing 3D carving, but ran fine doing 2D work. After reducing the Z accel, it's been perfect ever since.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: z axis gaining height with vcarve toolpath's only
« Reply #4 on: December 28, 2013, 04:14:35 PM »
I  reduced the z axis feed rate on the v-carve tool setup page and then ran a test. Now the z axis cuts deeper instead of gaining height. It progressively cuts deeper as the program continues to run. I checked the  tool path in Mach 3 and the place it was cutting to deep definitely should not have been that deep. I  was v-carving an image  of the 40th anv. Mustang emblem and the program started with the a  and was working around to the  rest of the letters and I noticed  it was cutting deeper with each letter. I let it go  for a few minutes  and finally had to stop it because it was too deep to continue. Any advice or suggestions?

Offline Hood

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Re: z axis gaining height with vcarve toolpath's only
« Reply #5 on: December 28, 2013, 05:05:19 PM »
Have you tried reducing the Velocity and Accel in Motor Tuning? Sounds like you may be losing steps on rapid Z + moves.
Hood

Offline ger21

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Re: z axis gaining height with vcarve toolpath's only
« Reply #6 on: December 28, 2013, 05:05:40 PM »
You need to reduce the acceleration in Motor tuning, not just the feedrate. Reduce the acceleration settings by 50%.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: z axis gaining height with vcarve toolpath's only
« Reply #7 on: December 28, 2013, 05:51:21 PM »
Ok thanks.I will  adjust the velocity and acceleration in Mach 3. I think I might have tried this with my x and y axes but I have not adjusted the z axis  while testing a vcarve toolpath. Thanks for the information. I will post the results.
Re: z axis gaining height with vcarve toolpath's only
« Reply #8 on: December 29, 2013, 09:27:28 PM »
I adjusted the accel. and velocity in the motor tuning and I still had the problem of the z cutting too deep. I then put all settings back to where they were originally and ran another test and then it goes back to cutting above the wood. I said ok I will meet in the middle on the settings(accelerate and velocity and the feed and plunge in the tool setup) to see if I can find a combonation that will work. So far nothing has worked. It either cuts deeper and deeper or it cuts above the wood. I am not sure what to do next. Everything works great except when the v-carve toolpath is used. I will not give up until I get the v-carve toolpaths working because that is why I bought it. When I get this solved I will share what the problem and solution is. Thank you very much for taking the time to offer you advice and suggestions.

Offline ger21

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Re: z axis gaining height with vcarve toolpath's only
« Reply #9 on: December 29, 2013, 09:32:01 PM »
What are your Z axis acceleration and velocity settings?
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html