Setting up a Rotary Chuck or Roller

I now have both a Chuck and a Roller rotary unit. I have done some testing in an effort to make some sense of the needed settings. The Chuck rotary is an xTool RA2 Pro and the Roller rotary is an Atezr KR. Both machines used are the Sculpfun S30 Pro and the SF-A9 (GRBL controllers). Because most rotary units use the same size stepper motor, this information may be relevant to nearly all setups. But no warranty.

I will not get into all the stuff you have to switch when attaching the rotary here. Nor will I get into positioning the rotary or workspace objects.

Perform the steps in the order listed. This will be easy because the input boxes are listed in the correct order. Do not move to the next box until the one you are currently setting is complete.

Yaxis as a Rotary: In reality, you are wrapping the flat Yaxis into a rolled up cylinder, like Christmas wrapping paper. You will be using Current Position, and be aware you will be at one end of that paper roll when you power up. I normally Jog the rotary some rotations so I will not be on one edge of my Yaxis.

In the Rotary Setup window, you select Roller.
You enter the approximate mm per rotation value. This will typically be 40 or 80mm, but you will have to Test to make sure you get 1 exact rotation of the roller and return. You should not get something like 42.75 for a setting. If you do, start over.
Next is the Roller Diameter. Here, expect the actual setting to not be the exact roller diameter. I measured 16mm, but my final value was 15mm. To get this value correct, you need to do four things.

  1. Obtain a cylinder object like a straight side tumbler or soft drink can. Measure the diameter or circumference, and enter that value in one of the lower two input boxes. Be exact as you possibly can.
  2. On that cylinder object, put lines or tape strips 50mm apart and parallel. Put the object on the rollers. This will be your measuring tool.
  3. In Lightburn, make a box 50mm wide (Y axis) and a reasonable length. You should travel 50mm across the cylinder and back when Framing. Feel free to reposition the cylinder so that the start point of the Frame is in a line of tape edge.
  4. Now, you test by Framing and adjust the Roller Diameter value to get the laser to travel exactly between your reference marks or tapes. Repeat until you get an exact result. The more exact you are here, the less error you will have when you scale your work up or down.

This one is much easier.
Select the Chuck button.
Mark the rotary chuck and frame with a line or tape for alignment.

  1. Click the Test button and the Chuck will rotate one revolution and return.
  2. For a starting entry in the mm per rotation box, you might try using the circumference of the chuck or belt pulley (mine were the same).
  3. Repeat until you get the best stop points that are the same in both directions. This is your only Rotary setting.
  4. Measure your test cylinder object and enter that in the Object Diameter box, or use circumference instead.
  5. Make a 50mm box and use it to frame your test cylinder. You did put marks on it, right?

The part diameter or circumference will change, but your Rotary settings will not. Record those in case you want to switch back and forth between the two types. I also discovered that setting the Chuck on one laser and the Roller on the other will save the rotary settings for each machine.

This dialog is the experience of one person with the equipment stated above. Feel free to copy, modify, or quote as you see fit. Just no cursing please!


Just adding the Atezr manual cause I believe not everyone have it.
Atezr_Roller.pdf.txt (2.8 MB)

That manual is for an older roller version. The KR manual is only 2 pages, and not much help at all.

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