Hello Guest it is January 28, 2020, 03:12:35 AM

Author Topic: non consistent speed during arcs  (Read 2370 times)

0 Members and 1 Guest are viewing this topic.

non consistent speed during arcs
« on: February 21, 2015, 02:58:26 AM »
Hi all. We have made ourselves a cutter plotter that uses rhino for the cad and rhinocam for the cam. For long time now we have been unable to make mach3 run a consitent speed around arcs it always seems to stall at some placejust for a moment. We have a job next week to cut over 1000 shoe sole profiles and we are looking to solve this once and for all.
To explain the issue, the knife runs tangetial. And will make its way through a few compound curves well and then stops for a moment recommences the curve and stops again for a moment and finally comletes.the shape.
We are looking ahead 100 lines. The shape is a closed curve of 27points or nodes we have cv on and the g code looks clean. Im not sure what else may be the issue.
I would appreciate any suggestions and am happy to share code xml fikes or photos or video !

Offline TPS

*
  •  1,452 1,452
    • View Profile
Re: non consistent speed during arcs
« Reply #1 on: February 21, 2015, 06:53:39 AM »
hi,

have you had a look for the CPU usage during a cut.
just thinking that something else makes this stops.

Thomas
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: non consistent speed during arcs
« Reply #2 on: February 21, 2015, 06:57:15 PM »
Yeah.ok will lookat that. I know that if tje usb cable is too long the smoothstepper has issues maybe the flow if g code is not consistent for a similar reason?
Re: non consistent speed during arcs
« Reply #3 on: February 23, 2015, 05:48:46 AM »
No didnt seem to be the computer. What we noticed was the gcode had go2 and go3 moves breaking up the line into clockwise and anticlockwise direction.during this change in direction the knife has accelarate and decelerrate so as the line is broken up the acceleration differences appear as a momentary pause. Correctly or not we disposed of the motor accelation and decelleration to in effect make a consistent transition between line segements.... we are now working on lead in and out speeds to initiate the cut without freaking out the steppers....comments?