Hello Guest it is October 19, 2019, 04:43:05 AM

Author Topic: Tangential Cutting Table and Feedrate  (Read 3335 times)

0 Members and 1 Guest are viewing this topic.

Tangential Cutting Table and Feedrate
« on: December 27, 2007, 08:19:25 PM »
Thank you for the previous assistance with my tangential control.

I have since cut some shapes out with the table and things are looking up.

My current problem is I wish to up the feed rate to +10000 mm/min in Tangential mode.  With tangential off my machine moves very smooth with 10000 mm/min feedrates on curved objects. The moment I switch tangential on all hell breaks loose with it stop/starting jerking like in Exact stop mode. I have added the g64 to my code

I have adjusted the look ahead units to 500, adjusted accel setting in motor tuning, but with such feedrates of 5000-10000mm/min in tangent control mode my machine shakes it seft to bit's.

Any thoughts??

Jason
Re: Tangential Cutting Table and Feedrate
« Reply #1 on: December 29, 2007, 12:04:33 AM »
Is it possible that with Tangential Control selected the Mode reverts to exact stop mode.???

I have spent all day on this machine and in Tangential mode there does not seem to any CV blending with the A axis, meaning the X and Y axis pause fot the A axis to rotate.  I think with the high feed rate of 12000 mm/min and accell at 1250 this is where the jerky ness starts.  My X gantry weights about 30kg so lots of inertia.

I have also saved drawings in iges, dwg and dxf to see if this helps with no change really

Offline Hood

*
  •  25,855 25,855
  • Carnoustie, Scotland
    • View Profile
Re: Tangential Cutting Table and Feedrate
« Reply #2 on: December 29, 2007, 03:29:53 AM »
You should be able to tell if CV is in use or not by looking at the CV LED on the screen.
Hood
Re: Tangential Cutting Table and Feedrate
« Reply #3 on: December 29, 2007, 05:33:11 AM »
Thanks Hood,

CV is on, however if I add the tangential the machine seems to run exact stop just on the A axis moves.

Jason
Re: Tangential Cutting Table and Feedrate
« Reply #4 on: December 29, 2007, 06:05:28 AM »
OK,

I have been reading some old Yahoo post and this came up

Hi Stuart:

It may simple be the fact the table must stop at the line temrination
points to do the correction of the tangental axis. There is no way to smooth
it out except to use G2/G3 arcs to follow gently on a given path..

Thanks,
Art
www.artofcnc.ca


OK now I have to find out how to draw patterns so that when post processed Gcodes ends up with G2/G3 interpolation
Re: Tangential Cutting Table and Feedrate
« Reply #5 on: December 29, 2007, 06:57:52 AM »
OK,

I have read every Yahoo post back to 2004 with regards to Tangental Control.

I have figured out Mach 3 needs G1 codes to calculate the Tangent angle

I have also realised the square wave limitations of Mach3 with regards to CV and acceleration values.

It looks like that a test of Quantum is of the order.

I need a little reasurance that I'm heading in the right direction

Offline Hood

*
  •  25,855 25,855
  • Carnoustie, Scotland
    • View Profile
Re: Tangential Cutting Table and Feedrate
« Reply #6 on: December 29, 2007, 10:24:43 AM »
Quantum is at its very early  stages. It seems to work well for a quite a few that are using it, I tried it right at the beginning and it worked well but I have not tried it since. I think if you try it just keep a hand over the estop until you have confidence that its working on your system.
You can still keep Mach3 setup on the same computer so its not a case of if you try Quantum and find its not right that you have to go through all the hassles of reverting to Mach 3 and starting from scratch.

Hood