Hello Guest it is September 21, 2019, 10:37:39 AM

Author Topic: machine not cutting as simulation.  (Read 5352 times)

0 Members and 1 Guest are viewing this topic.

machine not cutting as simulation.
« on: October 06, 2015, 11:41:24 PM »
Hi. All. Been out of action for a while and just getting back in to my CNC. I'm having a problem with the cut in Mach3. V cutting works fine with no problems but, in either Profile or Pocketing operations even though the simulation when saving the job in my drawing software shows perfectly square corners, when I cut the job it starts in a corner and cuts the other three corners with a radius, so the only square corner is the one it started at. Same thing happens when pocketing. From what I am able to find out the problem is at the Mach3 CNC end. The Art program is working perfectly. Does anybody know how to fix this??? Is it a parameter not set in Mach3??? The machine came with the program, but with very basic setup instructions. Regards to all ...Ron. ???
Re: machine not cutting as simulation.
« Reply #1 on: October 07, 2015, 12:36:49 AM »
Hi. All. Between my last post, I found part of the answer to my problem.Saw an article Quick CNC. As in their page, changing the mode from Constant Velocity to Exact Stop fixed the problem. Only thing is now when cutting my little model window the machine cuts the straight lines in a smooth action , but the small curves it cuts in a small steps at a time speed. Should I change my motor and velocity settings to improve this??? In the quick article the settings they have are a fair bit faster than mine are set at. Mine is at 2000 for the X and Y. They are suggesting 4800 and 9600 for the X. Will this cause any problems??? I have noticed that the X speed is painfully slow, the way it is set now. Regards ...Ron.

Offline RICH

*
  • *
  •  7,361 7,361
    • View Profile
Re: machine not cutting as simulation.
« Reply #2 on: October 07, 2015, 06:38:14 AM »
Look at your gcode for any curved object, and you will probably see that instead of arcs the curve is represented / broken down to small combination
axis moves.

You set your max velocity and acceleration based testing such that axis movement will repeatable and without fault.
Also note that the feedrate in a program is user defined.

RICH
 
Re: machine not cutting as simulation.
« Reply #3 on: October 07, 2015, 07:07:26 AM »
Thanks Rich. How do I change the curve to arcs you mention? I guess with the speed I can just experiment using the suggested ones Quick CNC have on their sheet.

Offline RICH

*
  • *
  •  7,361 7,361
    • View Profile
Re: machine not cutting as simulation.
« Reply #4 on: October 07, 2015, 07:21:09 AM »
Quote
How do I change the curve to arcs you mention

Don't know what CAD/CAM you are using, so it's done CAD first and CAM may recognizes the curve as an arc.

Quote
guess with the speed I can just experiment using the suggested ones Quick CNC


There are programs, charts, lot's of info on selecting the correct feedrate based on the material / tool / etc.
May want to learn how to rather than using some speed that may be meaningless for your setup.

RICH
Re: machine not cutting as simulation.
« Reply #5 on: October 07, 2015, 09:42:29 AM »
When requesting assistance with a specific problem it's always helpful to give full details of any hardware and software involved.
That way you're not forcing those reading your post to help to make guesses or assumptions, with the added advantage that anyone with specific experience of your kit may recognize the issue and comment, rather than just assume they can't help and move on,
Regards,
Nick

Offline ger21

*
  • *
  •  6,288 6,288
    • View Profile
    • The CNC Woodworker
Re: machine not cutting as simulation.
« Reply #6 on: October 07, 2015, 09:49:24 AM »
Go to general config, and check "Stop CV on Angles>", and set it to 89. Then turn Constant Velocity mode back on.
Gerry

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

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: machine not cutting as simulation.
« Reply #7 on: October 07, 2015, 08:37:58 PM »
Hi. All. Thank you all for your help. Gerry? You're a genius.! Your suggestion solved the problem. Basically my setup works well. I'm very happy with my Chinese machine. Only other minor issue I have and don't understand is, whatever I design in Artcam comes out half the size. I always have to double the scale in Mach3 for it to be the size I've drawn. Also I usually have to anything up to 4 times scale to get the depth of cut in the Z axis. Don't know if others have this issue. I've learned to live with it. Would be nice to know why it happens though. Thank you all for your help... Regards.. Ron.

Offline ger21

*
  • *
  •  6,288 6,288
    • View Profile
    • The CNC Woodworker
Re: machine not cutting as simulation.
« Reply #8 on: October 07, 2015, 08:46:46 PM »
You need to make sure your native units are correct, and y our steps/unit are set correctly.
One or the other, or both are wrong.
Gerry

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

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: machine not cutting as simulation.
« Reply #9 on: October 07, 2015, 10:51:44 PM »
Hi. Gerry. Not sure what you mean. Native units are inch. Don't understand the rest. I just set it per instructions from Chinese, which is apparently pretty basic just to get it working.