I have a Sainsmart 3018 Pro that I have converted to a dedicated rotary laser.
It has worked fine with the Gemitsu Laser Rotary Roller, but I’m having a problem using the Creality Rotary Roller Pro (chuck style).
The “mm per rotation” is set to 4.00, which results in one full rotation of the chuck. (4.00 mm per rotation is also used for the Gemitsu Roller, which results in one full rotation of the rollers.)
When using “Fill” at 0 degrees, there is banding. When I use “Fill” at 90 degrees, there is nothing burned. I suspect a speed issue on the Y-axis, but I haven’t found a way to change it that solves the issue.
Something is not right. That number should be basically the circumference of the chuck or pulley driving it. Closer to 120, not 4. For the roller, it is typically 40 or 80.
I think you need to redo your rotary setup to see if you get different results. You should not have to be messing with GRBL parameters. $131 is Yaxis max travel, and has no bearing on a rotary because it can make lots of revolutions. [I hope you made a backup of the parameters before changing them.]
Here is a Posting I did a while back. The value for the setting on my chuck is 130mm, and the roller is 40.
Chuck = xTool RA2
Roller = Atezr KR
And another set of instructions that is very good.
Thanks for the reply. I also thought 4mm per revolution was odd, since the manual for the chuck rotary suggested starting with 40mm. But, that resulted in the rotary making 10 revolutions.
I dug back into my backups and found the original settings for the 3018. I restored those settings and now the mm per rotation is set to 80mm for one revolution. And the speed is more in line with what I expected.
I did the 50mm box test and tweaked the $101 parameter to 42 to get lines spaced exactly 50mm apart.
It appeared I was on the right track, so I did the fill test again with both a 0 degree scan angle and a 90 degree scan angle. Since the y-axis speed has slowed, the 90 degree scan angle is now burning.
However…
The banding is still there (on both scan angles). Changing the line interval of the fill has no effect.
Good, now on to the banding issue. Try rotating the square in the Lightburn design space, still 0 rotation in the settings, and tell us what happens. What do you see in the Preview window?
To save tumblers, tape some paper to the tumbler and adjust the power so it just clearly marks the paper.
Whoah! I think we are getting somewhere. My guess is it is a belts issue.
Your 3018 is a screw drive machine, right? If the screws are properly lubricated and the couplings are tight, that leaves the belt drive in the rotary.
The chuck on the Creality roller is attached directly to the stepper motor shaft with grub screws. So, no belts. I double-checked and there is no slippage of the chuck and shaft.
Also, the Creality chuck roller requires a cable that crosses over the middle two pins.
Since the banding is consistent on every test, it looks like the chuck’s stepper motor is somehow missing steps, even though the rotation appears smooth when making a full rotation.
The control board on the 3018 is a factory replacement, but I still have he original control board (with a bad stepper motor driver). I have ordered new drivers and will try replacing the current control board with the original when they arrive.
But, that still doesn’t explain why the Sainsmart roller rotary functions correctly.
That zig-zag square is on a flat surface, right? Can you do this test:
Make a circle about 4" in diameter. Crank up the power and speed so that you get a dark line, but not cut through the material. I am looking to see if you might have a backlash problem. Just saying no backlash won’t do, we need a snapshot of the output.
I think we are attacking the wrong axis. Unless you got your X and Y wrong, that stuttering is in the Xaxis, not Y. You have an issue with your trolley, not the rotary (Y is gantry). My first guess is that the belt is too loose and the laser power is not high enough to burn when it jerks forward suddenly.
So, I’ve spent the better part of the morning trying to figure this out. It’s not a problem with the x-axis belt, since it uses a lead screw. I did double check the coupling nut and it was tight.
Since the roller rotary is working as expected, I think my best plan now is to return the Creality Chuck Rotary. Even though it’s advertised as compatible with 95% of machines, mine must be in that 5%.
If you do get another chuck, get one with the tilt head. I wish I had. My chuck, which worked without a hassle, is an xTool and Sculpfun has a tilt head one now.
Just jumping in with a thought. Since you stated the manufacturer recommended 40mm per rotation and that gives you 10 rotations you probably need to mutlitply your steps on your rotary axis by 10. I think that’s why it’s jumping. Can’t hurt to try. Just be sure you know your origina;l setting to go back to flat work.
Also, make sure your object diameter is correct. This is critical for chuck rotaries. It doesn’t matter so much for rollers, since they drive along the surface.
In the initial post you showed mm per rotation set at 4. Later you said the manufacturer recommended 40. How did you get to 80? Not saying that is the wrong answer, just curious how you jumped from 4 to 80.
You $101 is 40 for flat work, is that correct? What happens currently with the rotary set to 80 and $101 set to 40? How many rotations do you get?
Try leaving the rotary at 80 and changing $101 to 400. How many rotations do you get now?
It is going to be a balancing act, trial and error, finding the right combination.
