I tried to do a 3" OD groove 0.400" deep.
The first piece machine perfectly fine.

When I tried to do the second part.  1/2 way thru the bed (X&Y) stop moving.  It physically sat there for ~ 7 seconds (while DRO changes) then continue on "a different" circular path.

The path in blue is the correct path while the new green path is the bad one that developed after the pause.


PC: IBM ThinkPad T20 / only run Mach3 no viruscan or anything else
Machine: Syil SX3
Material: Cast iron

Could someone help explain my problem and how to potentially resolve it.

Many thanx,
Jonathan

Do the steppers scream when the problem occurs?
Hood

No not at all.  During this time all axis just sit there w/o any noise.
My feed rate is reasonable (I think) @ < 5 IPM

It stopped couple times around line #141.  I then centerfind the part and resume from line #137.  But shortly after it would failed again @ #146.  The weird thing is the first part cuts perfectly fine.  Actually it was "perfect" nice round hole @ 3.000" ID


Here's my g-code JIC.

(FM1 6-24-2007)
G90 G64
 M6  T1 (TOOL CHANGE endmill0500:reg) (MSG, LOAD TOOL # 1)
G0 G54 X1.25 Y0.
M03 S767
M01
G43 H1 Z1.0
 Z0.1
G1 Z0.01 F2.1
G2 X1.1699 Y-0.4403 Z-0.017 R1.25
X1.1513 Y-0.4868 Z-0.02 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.029 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.032 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.035 R1.25 F1.7
X1.234 Y-0.1991 Z-0.038 R1.25 F1.5
X1.241 Y-0.1496 Z-0.041 R1.25 F1.4
X1.246 Y-0.0999 Z-0.044 R1.25 F1.3
X1.249 Y-0.05 Z-0.047 R1.25
X1.25 Y0. Z-0.05 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z0.05
G1 Z-0.04 F2.1
G2 X1.1699 Y-0.4403 Z-0.067 R1.25
X1.1513 Y-0.4868 Z-0.07 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.079 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.082 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.085 R1.25 F1.7
X1.234 Y-0.1991 Z-0.088 R1.25 F1.5
X1.241 Y-0.1496 Z-0.091 R1.25 F1.4
X1.246 Y-0.0999 Z-0.094 R1.25 F1.3
X1.249 Y-0.05 Z-0.097 R1.25
X1.25 Y0. Z-0.1 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z1.0
 Z1.0
 G54    M08
 Z0.
G1 Z-0.09 F2.1
G2 X1.1699 Y-0.4403 Z-0.117 R1.25
X1.1513 Y-0.4868 Z-0.12 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.129 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.132 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.135 R1.25 F1.7
X1.234 Y-0.1991 Z-0.138 R1.25 F1.5
X1.241 Y-0.1496 Z-0.141 R1.25 F1.4
X1.246 Y-0.0999 Z-0.144 R1.25 F1.3
X1.249 Y-0.05 Z-0.147 R1.25
X1.25 Y0. Z-0.15 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z-0.05
G1 Z-0.14 F2.1
G2 X1.1699 Y-0.4403 Z-0.167 R1.25
X1.1513 Y-0.4868 Z-0.17 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.179 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.182 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.185 R1.25 F1.7
X1.234 Y-0.1991 Z-0.188 R1.25 F1.5
X1.241 Y-0.1496 Z-0.191 R1.25 F1.4
X1.246 Y-0.0999 Z-0.194 R1.25 F1.3
X1.249 Y-0.05 Z-0.197 R1.25
X1.25 Y0. Z-0.2 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z-0.1
G1 Z-0.19 F2.1
G2 X1.1699 Y-0.4403 Z-0.217 R1.25
X1.1513 Y-0.4868 Z-0.22 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.229 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.232 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.235 R1.25 F1.7
X1.234 Y-0.1991 Z-0.238 R1.25 F1.5
X1.241 Y-0.1496 Z-0.241 R1.25 F1.4
X1.246 Y-0.0999 Z-0.244 R1.25 F1.3
X1.249 Y-0.05 Z-0.247 R1.25
X1.25 Y0. Z-0.25 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z-0.15
G1 Z-0.24 F2.1
G2 X1.1699 Y-0.4403 Z-0.267 R1.25
X1.1513 Y-0.4868 Z-0.27 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.279 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.282 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.285 R1.25 F1.7
X1.234 Y-0.1991 Z-0.288 R1.25 F1.5
X1.241 Y-0.1496 Z-0.291 R1.25 F1.4
X1.246 Y-0.0999 Z-0.294 R1.25 F1.3
X1.249 Y-0.05 Z-0.297 R1.25
X1.25 Y0. Z-0.3 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z-0.2
G1 Z-0.29 F2.1
G2 X1.1699 Y-0.4403 Z-0.317 R1.25
X1.1513 Y-0.4868 Z-0.32 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.329 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.332 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.335 R1.25 F1.7
X1.234 Y-0.1991 Z-0.338 R1.25 F1.5
X1.241 Y-0.1496 Z-0.341 R1.25 F1.4
X1.246 Y-0.0999 Z-0.344 R1.25 F1.3
X1.249 Y-0.05 Z-0.347 R1.25
X1.25 Y0. Z-0.35 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z-0.25
G1 Z-0.34 F2.1
G2 X1.1699 Y-0.4403 Z-0.367 R1.25
X1.1513 Y-0.4868 Z-0.37 R1.25 F2.0
G3 X1.2013 Y-0.3454 Z-0.379 R1.25 F2.1
X1.2142 Y-0.2971 Z-0.382 R1.25 F1.9
X1.2251 Y-0.2483 Z-0.385 R1.25 F1.7
X1.234 Y-0.1991 Z-0.388 R1.25 F1.5
X1.241 Y-0.1496 Z-0.391 R1.25 F1.4
X1.246 Y-0.0999 Z-0.394 R1.25 F1.3
X1.249 Y-0.05 Z-0.397 R1.25
X1.25 Y0. Z-0.4 R1.25 F1.2
G2 X1.2013 Y-0.3456  R1.25 F4.1
X1.1865 Y-0.3934  R1.25 F3.9
X1.1698 Y-0.4406  R1.25 F3.4
X1.1512 Y-0.487  R1.25 F3.0
X0. Y-1.25  R1.25 F2.1
X-1.25 Y0.  R1.25
X0. Y1.25  R1.25
X1.1512 Y0.487  R1.25
X1.1698 Y0.4406  R1.25
X1.1865 Y0.3934  R1.25 F3.3
X1.25 Y0.  R1.25 F4.1
G0 Z1.0
M05 M09
G53 G00 Z-.100
M30

Hi Jonathan,

that's a lot of code to mill a 3" groove, try this version and see if the same happens.

(FM1 6-24-2007 VERSION 2)
G90 G64
 M6  T1 (TOOL CHANGE endmill0500:reg) (MSG, LOAD TOOL # 1)
G0 G54 X1.25 Y0
M3 S767
M1
G43 H1 Z1.
Z.1
G1 Z0 F2.1
G3 I-1.25 Z-.05 F1.5
G3 I-1.25 Z-.1
G3 I-1.25 Z-.15
G3 I-1.25 Z-.2
G3 I-1.25 Z-.25
G3 I-1.25 Z-.3
G3 I-1.25 Z-.35
G3 I-1.25 Z-.4
G3 I-1.25
G0 Z1.0
M5 M9
G53 Z-.1
M30

Graham.

I ran both Graham's code and my original code (from FeatureCAM).  Perfect circle in both case.
What ticked me off was that it failed during real time run when I was boring out my friend's brakes assemblies

any suggestions as to where to look & how to prevent this problem?

Johnny,
    If it ran fine while you were cutting air and didn't while cutting material, you can take lighter cuts, slow down your feed and speed, or you may need to tune your motors down a little so they can handle the tool load.

Brett

Run the Driver test and post a screen shot of what you get please. I think you are having trouble with your compter and Mach3.

Thanks
Brian