Laseoko Pro Build Thread

I found this little nugget of info that nearly looks identical to the cuts in the pics I posted earlier, found at 2 minutes 48 seconds: However that doesn’t explain the source of why the Pro might have backlash in it and how to solve it without a software bandaid.

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This is really cool. I know that LightBurn is held in wide regard (and have played with it a little) but didn’t realize it was this advanced. Thanks for sharing!

Given the low backlash nature of timing belts and pulleys, and assuming you have good tension all around, have you checked your grub screws for good seating and tightness?

That was the first thing we did on unboxing the Shapeoko Pro was tighten the pulley grub screws. Glad we did since they were loose! :slight_smile:

Should you be able to pinch the belt below the pulley above the bearing idlers in any way, shape or form? What is a good amount or none at all?

Unrelated, but here is an interesting (not in a good way) feedback loop of the height sensing in action. Note that isn’t caused by air going through the nozzle or any outside forces. I stopped the loop by holding the plate down. I initiated it by lifting the plate up and dropping it!

How are you doing height sensing and how tightly does it have to be controlled? Sheet metal is such a pain for flatness, at least on the plasma the arc voltage sensing gives a pretty nice control loop. I’ve only really seen vision and lidar based autofocus for hobby grade lasers.

The industry uses these RF amplified capacitive sensing via a ceramic insert in the end of the fiber head. In earlier pics you can see the amplifier mounted midway on the left side of the head with a coaxial cable going to the business end.

I actually have it on the least sensitive setting and I wish it could go even lower.

You can also jog to the plate manually with height sense disabled and use a feeler gauge to get the nozzle gap right. I made a cut that way to see if it would work. I’m not sure if it would work though going across the entire working envelope of the slats due to any cumulative tolerance issues. For the 20x20mm cut though it was nice to not see the head ‘hunting’ for the plate.

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I stumbled on this old post on CNCZone that confirms my thoughts:

Going to give this a try today.

https://www.cnczone.com/forums/diy-cnc-router-table-machines/322998-cnc-post1967716.html#post1967716

Works fine, as long as the belt pulleys screws are tightened with both motors “on” to make sure they are stepping in sync. Belt does not need to be super tight since it will not influence the accuracy.

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That’s is almost certainly backlash. My first 3D printer made circles like that. It had a very similar layout to the Shapeoko. X had two steppers. One on either side. The GT2 pulley on one of the X steppers did not have the grub screw properly tightened. It would wiggle from one side of the flat on the stepper’s D shaft to the other. This meant that that side would lag behind the other. This is why one of the flats on you circle is higher than the other.

Unfortunately one of the pulleys is totally seized to to the motor trying to remove it, so now we will need at least one new pulley and one new motor.

Is there an emergency overnight way to get parts @WillAdams ? I’d prefer a shaft clamping pulley instead of set screws but they probably don’t even exist in this size.

Let us know at support@carbide3d.com and we’ll do our best to work through this with you.

Done :slight_smile: cc’d sales as well.

So, I tested the X axis for backlash after tightening the belt even more, and here is a video. Jogged 100mm of movement each time.

No idea what’s going on. :frowning:

Seems to have lost -0.321 mm on the first pass and the passes after that are not consistent in returning to where it previously was, but at least no huge losses after the first pass?

Any ideas? Thank you :slight_smile:

Have you calibrated the steps for each motor? It appears you have it zeroed then when you return to the “zero” position, it is reading around -0.3mm. This could be due to the stepper motors not being calibrated and moving the distance specified in your command. Anything beyond that tenth of a mm measurement, I have a hard time trusting, unless your digital dial is accurate and precise to the hundredth, or thousandth of a mm.

Should belts be tightened from both ends to ensure equal tension in both belt segments underneath the bearing idlers, or just push the gantry to the end opposite of the tensioner and only tension one side?

If you slide the gantry all the way to one side and tighten the belt with the steppers powered down you will be fine and do not need to adjust both ends. Just make sure both Y axis belts have the same tension but be careful not to over tighten the belts as you can damage the stepper shafts with the larger belts. You will possibly snap or bend one.

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There is enough slop in the Y carriages to cause a slight racking angle of the gantry if the steppers are powered off and not clamped at the rear of the machine before tightening the belts.

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I have a standard SO3 that was not an issue for me when I adjusted the belts at the same time 1/4 turn at a time with the same tooth count through the clip. I don’t remember if we clamped the gantry in place though.

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So, the new motor arrived today and carefully made sure all the pulleys were set correctly and loctited and tightened the belts, and things seem better, however circle shapes are still terrible. The way the X axis motor pulley comes from the factory doesn’t have the set screws clamping on the D shaft profile of the motor, so that was resolved by turning the pulley around.

Measuring square shapes seems accurate according to the drawing. Really lost on this but definitely needs solved asap. Circles are the last piece of the puzzle.

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What happens if you create a close to circle polygon?
Could it be the software?

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How many sides do you suggest? 8?