Missing steps/misaligned

Machine: Redsail m900 - 900*600cm

Board: Laserboard

Firmware: Smoothie

Steppers: MOONS 24HC3301-05 (with pully’s and belts, so not direct driven)
Drivers: MOONS 3SR8H

I’m sorry to start a new topic on my issue but the old one is locked and i finally have time to tweak my machine. Old topic: Missing steps?

I have a first real job with my laser, making menu’s for a restaurant. The issue i have is that the text becomes misaligned after a few minutes.

It first burns the lightblue text and then the black. Losing position in moving allover the object.

Her is the config file. I did all the recommondations of the larger laser install topic.

What else do i need tweak

config.txt (28.4 KB)

This is probably acceleration and/or currents to your stepper drivers. Look up the motor model numbers and set the dip switches on the drives to match the stated motor currents, first and foremost. If the currents are correct, start lowering the acceleration values per axis (alpha_acceleration, beta_acceleration in the config file - they’re set to 2500mm/sec^2 now, i’d try somewhere around the 1000 range for a larger machine like this).

I checked the motor’s datasheet and the current is 5.8A and the drivers where set to a lower current. Changed it now.
I also activated smoothie clustering.

Also did change the acceleration to 1000 as you advised. Still having exact the same misalignment during the laser task.

Any other options?

This is the driver

I checked the externalstepper topic and think i stopped reading after the wiring part… Set the microstepping to 3200 (copieed that from the photo in the ext.stepper topic) and discovered that dipswitch 4 was on (half current…) flipped that to 90% --> Okay now i found out this is only the idle current… never mind this setting

Now i’m gonna check again

Update 2:

After recalibrating the steps/mm in the config file by making a square. An changing the steps/mm to the new value. I started the same task (the menu) and i still have the same misalignment. Exact in on the same spots only the space is bigger.



Update 3:

If i rotate the design 90degrees the problem stays at the X-axis. So now the words are aligned to the left and the spacing between the sentences differ.

Update 4:

Swapping the stepperdrivers does’nt swap the problem

Thanks for helping




If it follows the one axis, here are a few things you can try:

  • lowering the acceleration value on that axis further, say, 500.
  • lowering the max rates the axes can move (they are set to 24000, try e.g. 18000)
  • lowering the default_seek_rate parameter.

If the gantry can’t physically move as fast as it’s commanded it will cause the machine to lose steps during a fast-move. It seems like that might be what’s happening here.

Hi Loather,

Thanks for your answer. After lowering the speeds you said it still having the same issues.

Could it be a hardware issue, like the motor failing?

Did not have a lot of time last days to experiment more.


It could be a hardware issue, yeah. Try lubricating all the bearings, greasing the gantry and shuttle rails, and making sure all the belts and such are tight, but not overtightened. It’s unlikely that a motor would be failing - usually when steppers go they lose one or both poles and just wiggle back and forth one step or stop moving completely. That said, motors are pretty cheap so it may be a good idea to just order up another one and give that a shot in the event the motor has some gunk in its (sealed!) bearings or some crap that’s causing it to bind or something internally.

I’m so done with it that i will change the motors. Did the check on the belts and linear rails already, everything is smooth.

Should i go for Nema23? Cause there are not much nema24 motor’s available overhere.


The NEMA23 motor is 2.3 inch vs. the NEMA24 at 2.4 inch frame size. Your mount may or may not fit it, so measure first. In the axis that’s giving you trouble, try and get a motor that has higher torque than the one you currently have. That will hopefully help as well.

Ordered new motor’s and drivers. Keep you updated when they’r installed