Plasma cut small circles only produce short arcs

[ronateah]

This is an odd issue that I have seen a few years ago but i can not figure out how i had fixed or where it came from. I recently upgraded sheetcam but other than that i don't know where this is coming from. I am looking for a 0.3 inch whole instead I am getting a portion of the circle cut. This seems to be related to circles under a certain size 2 inch perhaps. Attached is a dxf file. The paths look fine in sheet cam but once the gcode is in mach 3 it does not look right and does not work. Attached also is the gcode. I am using one one of the THC 1000 posts.

Any thoughts would be greatly appreciated


Here is the code

N0000 (Filename: TestMountingBracket1.tap)
N0010 (Post processor: MP1000-THC Delay -Fan on -piercecount - clearance PARK Ron.scpost)
N0020 (Date: 11/06/2011)
N0030 G20 (Units: Inches)
N0040 M8
N0050 G53 G90 G40
N0060 F1
N0070 (Part: TestMountingBracket1)
N0080 G00 Z3.0000
N0090 M06 T20 F120 (16 Ga Mild Steel)
N0100 G00 X0.1903 Y3.6342 Z3.0000
N0110 G28.1 Z0.12
N0120 G92 Z0.0
N0130 G00 Z0.1000
N0140 G92 Z0.0
N0150 G00 Z0.1000
N0160 M03
N0170 G04 P0.21
N0180 G01 Z0.0650 F80
N0190 G02 X0.1103 Y3.7142 I-0.0000 J0.0800 F120.0
N0200 G01 F120
N0210 G02 X0.1903 Y3.7942 I0.0800 J-0.0000 F120.0
N0220 M05
N0230 G04 P1
N0240 G00 Z3.0000
N0250 X1.6143 Y1.9589
N0260 G28.1 Z0.12
N0270 G92 Z0.0
N0280 G00 Z0.1000
N0290 G92 Z0.0
N0300 G00 Z0.1000
N0310 M03
N0320 G04 P0.2
N0330 G01 Z0.0650 F80
N0340 G02 X1.5394 Y2.0437 I0.0050 J0.0798 F120.0
N0350 G01 F120
N0360 G02 X1.6243 Y2.1186 I0.0798 J-0.0050 F120.0
N0370 M05
N0380 G04 P1
N0390 G00 Z3.0000
N0400 X0.1738 Y0.2196
N0410 G28.1 Z0.12
N0420 G92 Z0.0
N0430 G00 Z0.1000
N0440 G92 Z0.0
N0450 G00 Z0.1000
N0460 M03
N0470 G04 P0.2
N0480 G01 Z0.0650 F80
N0490 G02 X0.1136 Y0.3154 I0.0178 J0.0780 F120.0
N0500 G01 F120
N0510 G02 X0.2094 Y0.3756 I0.0780 J-0.0178 F120.0
N0520 M05
N0530 G04 P1
N0540 G00 Z3.0000
N0550 X3.7036 Y0.1888
N0560 G28.1 Z0.12
N0570 G92 Z0.0
N0580 G00 Z0.1000
N0590 G92 Z0.0
N0600 G00 Z0.1000
N0610 M03
N0620 G04 P0.2
N0630 G01 Z0.0650 F80
N0640 G02 X3.6236 Y0.2688 I-0.0000 J0.0800 F120.0
N0650 G01 F120
N0660 G02 X3.7036 Y0.3488 I0.0800 J-0.0000 F120.0
N0670 M05
N0680 G04 P1
N0690 G00 Z3.0000
N0700 X3.6362 Y3.6311
N0710 G28.1 Z0.12
N0720 G92 Z0.0
N0730 G00 Z0.1000
N0740 G92 Z0.0
N0750 G00 Z0.1000
N0760 M03
N0770 G04 P0.2
N0780 G01 Z0.0650 F80
N0790 G02 X3.5760 Y3.7269 I0.0178 J0.0780 F120.0
N0800 X3.7047 Y3.8303 I0.1297 J-0.0296
N0810 G01 X3.7364 Y3.8267 F120
N0820 G02 X3.5760 Y3.7269 I-0.0306 J-0.1295 F120.0
N0830 X3.6718 Y3.7870 I0.0780 J-0.0178
N0840 M05
N0850 G04 P1
N0860 G00 Z3.0000
N0870 X4.0997 Y-0.0997
N0880 G28.1 Z0.12
N0890 G92 Z0.0
N0900 G00 Z0.1000
N0910 G92 Z0.0
N0920 G00 Z0.1000
N0930 M03
N0940 G04 P0.2
N0950 G01 Z0.0650 F80
N0960 G02 X4.0197 Y-0.0197 I0.0000 J0.0800 F120.0
N0970 G01 Y0.0000 F120
N0980 Y4.0000
N0990 G03 X4.0000 Y4.0197 I-0.0197 J0.0000 F120.0
N1000 G01 X0.0000 F120
N1010 G03 X-0.0197 Y4.0000 I0.0000 J-0.0197 F120.0
N1020 G01 Y0.0000 F120
N1030 G03 X0.0000 Y-0.0197 I0.0197 J0.0000 F120.0
N1040 G01 X4.0000 F120
N1050 X4.0197
N1060 G02 X4.0997 Y-0.0997 I0.0000 J-0.0800 F120.0
N1070 M05
N1080 G04 P1
N1090 G00 Z3.0000
N1100 M9
N1110 M05 M30

[neilw20]

I bet it doesn't work as you expected.
Looks a bit strange in NCPlot also.
Something not right with CAM settings or post processor.
Make sure helical cuts are not ticked.
Tray to use absolute (IMHO). Probably a mixture of incremental and absolute by the look of the rubbish output.
Not a MAch3 problem. That code is peculiar, to say the least.

[ronateah]

Got from Terry Parker

Here is the FIX,

sheetcam.com :: View topic - Stable version.010 bug

(;-) TP