Rough Motion on Circular Toolpaths

[Salted_Pork]

Hi friends.

Acorn Board on a CNC Router. Been Struggling with rough motion on circular toolpaths. Machine sort of shakes, causing bad surface finish.

I have smoothing turned off

Here is the GCode on one of the rough toolpaths:

N135 G17 G2 Y-1.625 I0. J-1.625
N140 Y1.625 I0. J1.625

The rough movement is while X axis is slow and Y axis is fast (affecting two sides of the circle). Circles moving Couter Clockwise aren't as bad.

Machine acts like its getting bogged down in code, but this is a super simple code/movement.

Anyone else struggled with this? What setting am I missing?

[suntravel]

Looks like a mechanical problem, backlash or something else not tight.

Uwe

[tblough]

Is the code a G2/3 arc move or a bunch of G1linear moves?

[Salted_Pork]

Is the code a G2/3 arc move or a bunch of G1linear moves?

Its a G2 move

[cnckeith]

need much more info to help you, this is machine related, either mechanical or motor resolution (electronic or mechanical or both)
please read the tech support request posting guidelines.

need photos of the machine, lots of them.

and a fresh report.zip

otherwise we are all just guessing.

[spikee]

Happen to be running servos? I have had issues before when using a gantry and servos that when you have a machine which is not very stiff, thus servos cant be really tuned to be very dynamic. Then when you do quick circles, it does not go as smooth as you would have hoped.

But all aims at mechanics. Usually you can test it by tuning feed much lower and see it it improves.

[Salted_Pork]

Here is my Report:

report_54453804251C-0118247882_2024-05-16_16-07-42.zip

(1017.36 KiB) Downloaded 5 times

Link to more Photos:
https://photos.app.goo.gl/qw5bZLduJaSR4R8n8

Thanks!

[Salted_Pork]

Happen to be running servos? I have had issues before when using a gantry and servos that when you have a machine which is not very stiff, thus servos cant be really tuned to be very dynamic. Then when you do quick circles, it does not go as smooth as you would have hoped.

But all aims at mechanics. Usually you can test it by tuning feed much lower and see it it improves.

Yes I have servos (Chinese kind). I tried running a slower feedrate, but same problem :/

[cnckeith]

post a copy of the g code you are using in the photos/video

[Salted_Pork]

%
(1001)
(T7 D=0.125 ZMIN=-0.01 - flat end mill - 1/8)
N10 G90 G94 G17
N15 G20
(2D Contour9 (6))
N20 G28 G91 Z0.
N25 G90
N30 T7 M6
N35 S20000 M3
N40 G4 P10.
N45 G54
N55 G0 X-5.8625 Y3.925
N60 G43 Z0.696 H7
N65 M8
N70 Z0.296
N75 G1 Z0.121 F60.
N80 Z0.09
N85 G19 G3 Y4.025 Z-0.01 J0.1 K0.
N90 G1 Y4.125
N95 G17 G2 X-2.3875 I1.7375 J0.
N100 X-5.8625 I-1.7375 J0.
N105 G1 Y4.225
N110 G19 G3 Y4.325 Z0.09 J0. K0.1
N115 G0 Z0.696
N120 G17