HOw to set machine origin to centre?

LightBurn Software Questions
1

Hi there.

So I am using my custom built IDEX 3d printer (DUET3d 2 based) to run my laser, I have managed to get the laser working, but I am having an issue with the origin.

Lightburn only allows me to have a machine home/origin at any corner but my duet is set to the centre, mainly due to the IDEX 3d printing nature (2 tool heads)

I really dont want to re code all my machine and change its origin as I like the way it works.

Is there any way at all to allow lightburn to have a centre origin?

The odd thing is, no matter what lightburn won’t spit out “negative” axis movements , I tried to put my object outside of the workspace into a negative area and looked at the Gcode and it just doesn’t like it.

2

I think Lightburn only works with positive values.

Most cnc machines for lasers work in a single quadrant, usually based on where it homes.

Good luck

:smile_cat:

3

Thanks, that totally screws my project :sweat_smile: means from my 400x400 bed I can only use 200x200

4

If you use “Current position” for Start From it may generate negative coordinates.

But overall, LightBurn is inherently a positive workspace system. Trying to work in a negative or mixed workspace setup is fighting the tide.

5

I did try your approach to no avail.

I hope they can add this feature so I’m not left with a £2000 paper weight :sweat_smile::sweat_smile:

6

Perhaps you could gimmick a G-Code header with a G10 L2 P2 offset to drop the G55 coordinate system origin dead center on the platform, then select G55 before your G-Code starts. A corresponding footer would select G54 to restore the default coordinate system so everything else works the way it does now.

The gotcha would be interrupting the job, which would leave G55 active and confuse everything. Enabling Soft Limits will save your bacon.

Source: Did something like that for tool length probing on my Sherline mill.

7

My 3d printer homes to the rear/right and the object is placed where ever it is on the slicer work area. I use Lightburn on this machine…

Maybe if you explain how your machine boots and determines where is is.

If it has home switches, they are usually in one corner, not in the center of the machine.

Relax, have a cup of something, we’ll probably figure out something, but you might have to meet us somewhere in the middle…

Let us know how it ‘homes’ or how you set it to home.

:smile_cat:

8

I’m still somewhat getting used to gcode (despite closing the machine myself) I can’t find anythong in the duet forum or manuals that allows soft limits or zeroing an axis?

9

Thanks.

So the machine homes on its limit switches, the bed comes to the top and hopes the x and u axis homes at their end points (left and right respectively) and the Y homes to the rear, the machine then comes to the middle as its home point, middle is 0,0,0.

If I send a home command it’ll always come to the middle of the bed.

The main reason is becasue it has 2 tools on the x axis (x and u) if I had the home to the far right or left it would cause tool head crashes

10

Normally LightBurn uses G54 for GRBL machines. Looks like nothing is used for Marlin so you could use anything. What @ednisley suggests using G55 would be fine.

Try running this in Console:

G10 L2 P2 X-200 Y-200
G55

That should put your 0,0 position at front-left.

You may want to put G55 in your Start g-code found in Device Settings->G-code tab. @ednisley has indicated G54 as your default but I had thought this was G53 for Marlin so one of those in End g-code.

You can eliminate the offset by:

G10 L2 P2 X0 Y0
11

Thank you, I’m making repairs on my machine (awaiting parts) when they arrive I’ll give it a try. Thank you

12

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