Knocking sound in the Y axis when engraving

Hi All,

I am running a Ten-High laser machine with a cohesion3d laser board with lightburn. I have noticed that when I am running off a full board sheet I am experiencing some issues.

I am engraving text at the bottom and top of a circle and cutting it out on a full sheet A3 Board (so I am getting as many as I can from one a3 sheet). I am noticing that I cannot execute a full sheet of engravings and cut outs. When engraving the text and the bottom finishes there is a KNOCKING sound when the machine move up the Y axis to the top of the circle. This knocking sound is the indicator to me that something has gone wrong. Instead of moving to the top of the circle the top engraving is now executing at the middle of the circle - completely the wrong place.

  • I can set the cut out only on a full sheet and the machine will happily cut all the circles out in the correct positions but strange as it seems to struggle to engrave and cut in the correct places.

  • I can execute individual jobs one at a time…
    1.Engrave the bottom

  1. engrave the top
  2. cut out the circle

all this happens perfectly fine; but as soon I ask it to do a job lot I have ZERO faith that it is capable of doing this.

If I am engraving a full sheet of circles only, set to each component is done at a time rather than having the laser head move through the white space; again it seems to miss print the engraving.

My laser machine cannot handle:

  • Engraving text in more than one locations and cutting more than one components in one job
  • Engraving and cutting multiple components in one job

My laser machine can handle:

  • Engraving in one location and cutting a single component

I daily clean my lenses and mirrors and run a cw5200 chiller.

I cannot understand what seems to be happening and why? I know its nothing to do with a dirty lens or or smoke build up on the mirrors.

Your stepper motors are losing steps. That’s the clunking sound you hear.

First, make sure your stepper motor currents are correct and if that doesn’t solve it try reducing the acceleration values for the X and Y axes, then that probably will. Do a search on the forum, I’ve written up how to do this a bunch of times.

Thanks Loather!
How do I know what my stepper motor values need to be? is this something I need from the manufacturer~?

Yes, jot down the model numbers of the stepper motors and do an internet search for them.Either the manufacturer or a reseller will likely have the values on a website you can steal. If you can’t find them they’re obscure motors (china does this from time to time) and you’ll have to determine the values on the fly, which is time consuming, but doable.

I’ve touched on the process here:

and here:

My Stepper Motor is but not sure what brand it is or who manufacturered them.

Stepping Motor
TYPE 17HA801Y-22P2
FH200102 Smooth

They’re made by the Chinese company Smooth, and I can’t find the data card for it with a couple quick google searches. I have Smooth motors in my machine too and recall a similar level of difficulty finding datasheets for them at the time. I had to use the iterative process to find a current value that worked.

I’ve posted a couple links to posts where I’ve gone over that process before and there’s a configuration guide in the documentation section of the C3D website:

It will probably be around 1.0-1.2A - play around with the config file until you get better results. The motor acceleration will probably need some tweaking as well.

It seems I have managed to resolve the issues:

Previous Stepper Motor Current
alpha_current 0.4 # X stepper motor current
beta_current 0.6 # Y stepper motor current
gamma_current 0.6 # Z stepper motor current
delta_current 0.6 # Z stepper motor current

New Stepper Motor Current
alpha_current 0.6 # X stepper motor current
beta_current 0.8 # Y stepper motor current
gamma_current 0.8 # Z stepper motor current
delta_current 0.8 # Z stepper motor current

Now able to Cut and Engrave multiple shapes in one job! Thanks!
No knocking sound!

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