Rotary Turntable seems to be running faster along the Rotary Axis

I have a little different DIY laser engraver that works horizontally or vertically. In order to use a rotary axis, I designed a self centering turntable to hold the object centered & place the engraver in vertical position using the cantilever arm as the X-axis. That is usually my Y-axis, but lightburn does not seem to have an option for changing the linear movement axis.

Anyway, my problem with the rotary axis seems to be that it moves faster in the rotary axis than in the X-axis. I have set the rotary axis as the Y, but will probably change that to Z later. You can see this problem in the 1st part of the linked video below when it is drawing a rectangle around the object.

In the rotary section of Lightburn, I have 32 mm per rotation (DRV8825 drivers) and Chuck rotary type set. Any help would be appreciated.
Thank you.

Below are the GRBL settings I am currently using in this configuration.
Grbl 1.1h [’$’ for help]
$0=10 ;Step pulse time, microseconds
$1=255 ;Step idle delay, milliseconds
$2=0 ;Step pulse invert, mask
$3=3 ;Step direction invert, mask (invert x & y)
$4=0 ;Invert step enable pin, boolean
$5=0 ;Invert limit pins, boolean
$6=0 ;Invert probe pin, boolean
$10=1 ;Status report options, mask
$11=0.010 ;Junction deviation, millimeters
$12=0.002 ;Arc tolerance, millimeters
$13=0 ;Report in inches, boolean
$20=0 ;Soft limits enable, boolean
$21=0 ;Hard limits enable, boolean
$22=0 ;Homing cycle enable, boolean
$23=0 ;Homing direction invert, mask
$24=25.000 ;Homing locate feed rate, mm/min
$25=500.000 ;Homing search seek rate, mm/min
$26=250 ;Homing switch debounce delay, milliseconds
$27=1.000 ;Homing switch pull-off distance, millimeters
$30=1000 ;Maximum spindle speed, RPM
$31=0 ;Minimum spindle speed, RPM
$32=1 ;Laser-mode enable, boolean
$100=160.000 ;X-axis steps per millimeter
$101=200.000 ;Y-axis steps per millimeter (200 * 32 = 6,400 rotates 1 revolution with 1.8 nema17)
$102=200.000 ;Z-axis steps per millimeter
$110=500.000 ;X-axis maximum rate, mm/min
$111=500.000 ;Y-axis maximum rate, mm/min
$112=500.000 ;Z-axis maximum rate, mm/min
$120=100.000 ;X-axis acceleration, mm/sec^2
$121=100.000 ;Y-axis acceleration, mm/sec^2
$122=10.000 ;Z-axis acceleration, mm/sec^2
$130=435.000 ;X-axis maximum travel, millimeters
$131=435.000 ;Y-axis maximum travel, millimeters
$132=0.000 ;Z-axis maximum travel, millimeters

I withdrew my post because I realized I had set up a Chuck type rotator on a SmoothieWare system with an ‘A’ axis so sufficiently different from yours to be pretty much worthless. I believe the test button only rotates 90 degrees. To test a full circle you need a pattern that exactly matches the circumference of your cylinder.

In my case it was easy because the ‘A’ axis operates in degrees so I could type in G0A360 on the command line.

Sorry for the misdirection…

This test does 5 - 45mm diameter flower of life designs & they measure 45mm in both axis, so I think the steps are correct. I will have to find a better test object that burns evenly. Maybe it is not a problem.

I just checked the video time between running the 45mm vertical & the 258.4mm around the circumference. It took 5.14seconds for the 45mm vertical line & 4.045 seconds for the 258m.4 length. Using a spreadsheet, that distance around circumference is 5.742 times further. If I went vertical for the same distance with current setup, it would take 29.515 seconds. I think it is going 7.296 times faster around the circumference. Does that make sense? I had the speed for the burns set to 600mm/min. Maybe I have $110 & $111 set to low. I use to have those set to 3000, but lowered them when the rotary was turning too fast. I will have to run these at 500mm/min tomorrow & see if that changes anything.

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After some trial and error, I have the settings correct for using the Z-axis with this rotary turntable.
$102=27
243 mm per rotation.
Here is a video of it burning a 3/8" birch dowel. I have the power set a little too high, but worked quite well for first test with this small material.

I went a little smaller & engraved a toothpick.

Personalized toothpicks! What a great idea! :grinning: