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Need help with Constant Velocity
« on: July 06, 2014, 02:56:42 PM »
Hi guys,

I converted a chinese router from NCstudio and steppers to DMM servos and Mach3.  It all works perfectly except that I can't get constant velocity to work.  There is a pause between every line of Gcode, not a long pause, but enough to make it jerky. It is driving my nutty...

XYZ all are set to the same acceleration (400mm) and speed.
Constant Velocity is on, and G64 appears in the first line of my Gcode.

My machine: DMM servos with DYN2 drivers, Mach 3 with Ethernet Smoothstepper.

I use Mastercam with the mach3 pp, but the Gcode does not seem to be the problem.  Even basic test code pauses on all the lines.

Anyone have any ideas?

Offline ger21

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Re: Need help with Constant Velocity
« Reply #1 on: July 06, 2014, 04:17:28 PM »
Turn of CV Distance and CV Feedrate on the Settings page, and all other CV options in General Config. The only option you want is "Stop CV on angles", and set it to 89.

2010 Screenset

JointCAM Dovetail and Box Joint software
Re: Need help with Constant Velocity
« Reply #2 on: July 06, 2014, 04:38:40 PM »
Ya, I already had all the options turned off.  I enabled "Stop CV on angles" but it didn't make a difference.  I am pretty new to this so maybe I'm making a dumb mistake, but it seems like everything is correct.  I attached the Gcode that I am using to test it.  It is a combination of arcs and line segments to cut an irregular shaped pocket.  No matter what I try, it always stutters from line to line in the gcode.


O0000 (CHASSIS V2)

N100 G00 G17 G21 G40 G49 G80 G64 G90
N110 T1 M06 (  3. STRAIGHT BIT)
N120 (MAX - Z5.)
N130 (MIN - Z-4.)
N140 G00 Z5.
N150 G00 X92.302 Y44.044 S2000 M03
N160 Z2.
N170 G01 Z-.5 F2000.
N180 G03 X99.844 Y46.766 I-5.752 J27.748 F5000.
N190 G01 X99.889 Y46.79
N200 X99.935 Y46.811
N210 G02 X99.844 Y46.855 I.613 J1.369
N220 G03 X92.302 Y49.577 I-13.294 J-25.026
N230 G01 X82.218 Y51.436
N240 G03 X78.722 Y51.744 I-3.375 J-18.313
N250 G01 X69.605 Y51.825
N260 G03 X60.938 Y46.811 I.055 J-10.093
N270 X69.605 Y41.797 I8.722 J5.079
N280 G01 X78.722 Y41.878
N290 G03 X82.217 Y42.186 I.121 J18.62
N300 G01 X92.302 Y44.044
N1010 G00 Z5.
N1220 M05
N1230 G90
N1240 M30