Upgraded to 40W laser and curves seem to be a bit off


Atomstack S10 upgraded from LaserTree 20W to 40W


The gantry is square, and the belt is tight. I recently cleaned all the bearings, and the machine ran smoothly with the 20W until I swapped it for the 40W. Following the manual for the 40W, I set the Y-offset to -21mm.

Ever so slightly, the curves seem to struggle where they won’t connect from beginning to end. Straight lines do not struggle, as I tested with square and rectangle shapes. It’s only the curves.

I cut 36 pieces of 3.5"x2" business cards measured precisely the same dimension, but the second circle, where the line starts slightly above, is off. So, the distance between the two long edges has the same 2" & 3.5" spacing throughout. Most pieces end up having these extra rounded edges.

I tried cutting curved lines, and it seemed off when cutting the tight radius.

I also tested using a JPG file created in Photoshop with a similar radius but got similar results.

I’m just learning, so I’m not overly concerned. I figured it was a configuration with the x and y axes, but I do want to get this fixed.


You probably more than doubled the mass of the laser module. Did you slow the acceleration to compensate? More mass with the same Accel puts a LOT more physical stress on the entire system. Belt stretch/bounce, frame flex, step skipping, etc.

Very good question as I did notice the 40W module is hefty and has a slight lean.

I was running this at 650mm/min at one pass. I’ll try to slow it down if not I’m assuming the horizontal rail that’s 2020 should be upgraded to 2040? I’ve been looking at upgrading this platform either way as I originally extended the length to 36" and do see a little bit of flex here and there.

But the chonky new laser head can be loose or, more likely, slinging all that mass around puts more stress on a slightly loose bit of hardware.

As other folks have pointed out, lowering the acceleration can help, but the real solution will be finding where that backlash comes from and fixing it.

Go through the whole machine looking for loose screws and couplings, because it’s got at least one of them somewhere inside!

1 Like

Will do! Luckily, I’m still doing this as a hobby so I have time but if all else, I may need to upgrade the whole gantry to better suit this chonker for sure :sweat_smile:

At high speeds and accelerations my tiny 5W machine walks itself off the table. If this happens (machine walking) and the bed/material isn’t fixed to the frame somehow, all kinds of odd things can happen. Just one more avenue of investigation.

1 Like

Not good, but not a disaster. A sudden change in direction, or stop, of the Yaxis can give a substantial shift in beam location. I added a manual Zaxis adjuster and had to add a piece of dampening foam between the head and adjuster.

1 Like

I’ll have to look into this. Thanks!

Part of me wants to rebuild this whole thing using 2040 extruded aluminum throughout, as it’s already extended to 30", but seeing some flex here and there. I might as well make it into a 48" bed, but there will be more parts to add :thinking:

Did you do this?

I saw no reference to you changing the acceleration values, only speed…