Find the center

LightBurn Software Questions
1

When I try using the command [Move Laser To Selection Center] nothing happens and I get an Error 5 code saying that homing isn’t enabled.

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After searching thru the documentation I discovered this and followed the instructions.

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Now the laser moved to the center, so far so good?

Nope!

Sadly, the center point that the laser moved to is now considered the bottom left corner of the item to be engraved. Obviously that won’t work if I’m tiring to center an image to a product.

I tried all three modes [Current Position], [Absolute Coords] and [User Origin] to no avail except the joyful sound of the laser banging on the side of the frame.

Any thoughts?

2

Are you leaving out anything, like Set Origin or something? I tried both ABS and CurPos, and they both moved the laser to the middle of my square.

I am not duplicating anything like you describe.

3

You have job origin set to center?

4

I have the job origin set to bottom left corner. I also moved the square to the bottom left as well, but that didn’t work.

5

The Center Finder doc tells how to line it up:

If you’re using Current Position, then make sure you have the Job Origin set to the center:

LightBurn - Job Origin - center
LightBurn - Job Origin - center318×223 36.4 KB

My process:

  • Machine homes at startup
  • Set Start from: Absolute Coordinates
  • Find the circle center point
  • Hit the finder’s Jog to Circle Center button
  • Select the thing to engrave / cut
  • Set the Nine-Dot Control to the center point
  • Hit the Move to Laser Position button
  • Fire The Laser

After you’ve manually homed the machine to the correct corner, see if that process gets you closer to the goal.

1 Like
6

My problem is my laser doesn’t have limit switches so I can’t home at startup. I tried installing the switches and had a problem. Longer sent me a firmware update which didn’t work either so I removed them. (all the firmware did was change the codes $20, $21, $22, and $27)

In the past I’ve tried using LB’s [Center Finder] without success. I’ll try again using the command G92 X0 Y0 in the console and see if that helps.

What I’ve been doing to get work completed is to setup the art in LB with all the layers set in the order and the way I need them. Save as Gcode then open the file in LaserGBRL. Then I click on [Move to Center of the Frame] and start firing. This works well, but I’d like to get centering this simple in LB

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Everything, including overscanning and cutting order is saved the the .nc file. LGBRL just doesn’t show layer colors. Luckily it does work correctly.

FWIW. the code for centering in LGBRL is G0 X[left+width/2] Y[bottom+height/2]
I haven’t tried inputting that into LB’s console, not sure if I should.

7

To run without limit switches:

Then you must do one of these two things:

You must also have the origins set properly, but I assume that’s working because you haven’t mentioned things being mirrored. :grin:

Because GRBL accepts only numeric values, those variable get processed by the program creating the G-Code. LightBurn’s Custom G-Code has a different syntax:

It is not clear (to me) whether arithmetic operations are permitted.

1 Like
8

In my first post you’ll see that I posted the info on lasers without limit switches

Yes, thank you, I already have that set.

[quote=“ednisley, post:7, topic:188367”]

  • Disable GRBL’s homing cycle: $22=0
  • Disable LightBurn’s Auto Home At Startup option
  • Never touch LightBurn’s Home button

Also my device doesn’t have a custom gcode tab. Is it my machine or is there a way to incorporate that into that window?

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9

I found how to get the custom gcode tab,

I also found this saying the Origin should be bottom left, not center as you suggested. Which is right?

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10

There are several “Origins” in play, which the doc does a poor job of defining.

The machine controller has an origin which is always located in a corner of the platform, because the home switches are at the ends of the axes. When the controller homes the machine, each switch sets the place where the axis coordinate is 0.0.

CNC machines can apply offsets to the home position to put the (0,0) origin anywhere on the platform, but in general diode lasers running GRBL do not use any of those offsets and leave the origin in one corner. Because GRBL started in the CNC world, it can process the commands setting those offsets, which causes untold confusion in the laser world.

LightBurn must know which corner the machine homes at, which is the Device Origin you defined when you set up the device or tweaked in the Device Settings. If those two do not match, then the display won’t match reality.

Having the machine properly homed ensures the controller knows where the laser head is in relation to the physical limits of the axes. If it’s not properly homed, then the controller cannot prevent the laser head from smashing into the limits, because it does not know where the head is.

After homing, the LightBurn workspace will exactly map to the machine platform in Absolute Coordinates mode: where you put the design in the workspace is where it will appear on the platform.

In the other modes (which I rarely use), the Job Origin dots in the Laser window define where the design lies in relation to the User Origin or Current Position, both of which are defined with respect to the overall coordinate system origin set by the home position.

The doc describes how those modes work:

So if you want the design centered on the User Origin, you’d select the center dot. Then it’s your responsibility to place the the User Origin so the design doesn’t extend beyond the machine limits.

11

Thanks for the info.

Center Finder didn’t work. I get this error message. Yes I did try all three “Origins”.

This is the error message I get

Screenshot 2026-03-14 122416
Screenshot 2026-03-14 122416472×307 14.9 KB

But I did find a way to center in LB after some futzing around.

12

Per the doc:

LightBurn can’t calculate center, or it would be outside your laser’s work area.
This typically happens on machines without homing switches that were not manually homed properly.

So the basic problem seems to be you must manually home the machine using the process linked earlier.

Some quick checks:

  • Is the laser head fully into the homing corner when you turn the controller on? (take a photo)
  • Does the LightBurn Device Origin dot match that corner? (take a screenshot)
  • What coordinates does LightBurn report at that position when you hit Get Position? (another screenshot)
  • Do the LightBurn jog arrows move the laser head in the correct directions?

Show us what’s happening and we can likely get it working properly.

13

Firstly, I would like to thank you for your offer.

My laser is installed in my pottery studio and uses the same exhaust system as my kilns. I’ll be firing my kilns for the next 2-3 weeks in preparation for an upcoming show.

Because of the laser’s close proximity to the kilns I had to move the laser to an area of the building that does not have power to run.

I would really to take you up on your offer if you don’t mind waiting until I can reinstall my laser.

A couple of notes which I will verify with images at a later date:

  1. The laser head was set to the bottom left corner when I turned on the laser.
  2. [Start From] was set to [Absolute Coords]
  3. In the [Console] I entered [G92 X0 Y0] then pressed [Enter], going forward, I created a macro to do this.
  4. I set the image to bottom left corner
  5. The coordinates in LightBurn showed [X: 0.00 Y: 0.00] when I pressed [Get Position]
  6. Yes, LightBurn’s jog arrows does move the laser head in the correct directions.

Lastly, I did all this before reading your post about “Origins” and look forward to experiment with the information you supplied.

Again, I thank you.

14

If it is now working, be careful making changes.

Most of us are not on the timeclock, so we will wait.

15

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