Hey everyone,

I’m now a proud builder of an MPCNC plasma cutting “table”.

[attachment file=110887]

But i kicked some problems.

First sketch my situation.

I use Ramps 1.4 with arduino Mega and the marlin firmware from V1-engineering

I make drawing (save as .DXF) → Use sheetcam to generate the G-code (i adapted a post-processor myself) → Use repetier to run the G-code.

Straight lines and large arcs/circles are not a problem.

[attachment file=110886]

GCODE:

G92 X0 Y0 Z0

G00 Z10.00

X28.77 Y47.13

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X28.77 Y47.13 Z1.50 F150.0

G03 X29.0 Y49.8 I-1.2 J1.5 F1200.0

X29.0 Y49.8 I-2.6 J-3.2 F800.0

M106 S0

G00 X29.04 Y49.83 Z10.00

X28.13 Y61.35

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X28.13 Y61.35 Z1.50 F150.0

G03 X28.4 Y64.1 I-1.2 J1.5 F1200.0

X28.4 Y64.1 I-2.0 J-2.4 F1200.0

M106 S0

G00 X28.39 Y64.05 Z10.00

X10.56 Y43.58

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X10.56 Y43.58 Z1.50 F150.0

G03 X10.8 Y46.3 I-1.2 J1.5 F1200.0

X10.8 Y46.3 I-2.3 J-2.8 F1200.0

M106 S0

G00 X10.82 Y46.29 Z10.00

X9.41 Y21.68

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X9.41 Y21.68 Z1.50 F150.0

G03 X10.2 Y24.3 I-0.9 J1.7 F1200.0

X10.2 Y24.3 I-1.6 J-2.0 F1200.0

M106 S0

G00 X10.17 Y24.28 Z10.00

X13.62 Y9.63

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X13.62 Y9.63 Z1.50 F150.0

G03 X14.7 Y11.0 I-0.1 J1.2 F1200.0

X14.7 Y11.0 I-1.0 J-1.3 F900.0

M106 S0

G00 X14.70 Y10.99 Z10.00

X30.95 Y27.24

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X30.95 Y27.24 Z1.50 F150.0

G03 X30.8 Y29.9 I-1.5 J1.3 F1200.0

X29.1 Y31.0 I-4.3 J-5.0 F1200.0

X30.8 Y29.9 I-2.6 J-6.1 F2000.0

M106 S0

G00 X30.75 Y29.95 Z10.00

X32.69 Y87.13

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X32.69 Y87.13 Z1.50 F150.0

G03 X32.6 Y89.8 I-1.4 J1.3 F1200.0

X30.9 Y91.0 I-6.1 J-6.7 F1200.0

X32.6 Y89.8 I-4.5 J-7.9 F2000.0

M106 S0

G00 X32.56 Y89.84 Z10.00

X47.29 Y100.72

Z3.80

Z3.80

M106 S255

G04 S0.3

G01 X47.29 Y100.72 Z1.50 F150.0

G03 X47.4 Y98.0 I1.4 J-1.3 F1200.0

G02 X48.7 Y96.5 I-7.4 J-8.0 F1200.0

X50.9 Y90.0 I-8.7 J-6.5 F2000.0

G01 X50.90 Y20.00 Z1.50 F2000.0

G02 X30.0 Y-0.9 I-20.9 J0.0 F2000.0

G01 X0.00 Y-0.90 Z1.50 F2000.0

G02 X-0.9 Y-0.0 I0.0 J0.9 F2000.0

G01 X-0.90 Y95.00 Z1.50 F2000.0

G02 X5.0 Y100.9 I5.9 J0.0 F2000.0

G01 X40.00 Y100.90 Z1.50 F2000.0

G02 X47.4 Y98.0 I0.0 J-10.9 F2000.0

M106 S0

G00 X47.40 Y98.00 Z10.00

X0.00 Y0.00

M106 S0 M30

But when using smaller holes or fillets, the machine is doing strange things.

I tested so many things, but now i found out that when there are two arc commandos (like G3 and G2) after each other, this makes a problem. It does only the first line and the second arc, it ignores and moves on to the next line. So many times it does the lead in arc, but then it refuses to cut the circle. Sometimes it does, sometimes is doesnt.(See picture)

[attachment file=“110888”]

Can somebody explain and try to help finding a solution?

Also why is it slowing down so much in arcs/circles?

Kind regards,

Dieter