Laser Engraving on a Curved Surface

[thiggins (Tom)]

I’m interested in laser engraving on barrel stave and I’m wondering if Lightburn has the ability to use the Z-axis? I’m a novice at Lightburn, but I have run into a snag with the 3-D shape element.
Here is an example of what I was thinking:

2020 Bourbon Stave Laser Engraving

Does Lightburn offer a solution to this (z-axis, focal length change, etc.)? If not, is there an alternative that I should use instead? I’m running a 7W JTech Laser on a Onefinity CNC.

Thanks in advance.

[thiggins (Tom)]

Also, here is an example of a finished product:
https://www.etsy.com/listing/1190029584/full-length-stave-coordinates-on-barrel

[ednisley]

@thiggins

if Lightburn has the ability to use the Z-axis

LightBurn is resolutely 2.5 D, without any notion of dynamically controlling the Z axis during a cut. It can set specific Z axis positions for a layer, but there’s no way to vary the Z axis across / along an engraved design like those staves.

@thiggins

focal length change

That’s the trick: for slightly curved surfaces, a lens with a sufficiently long focal length will have enough depth of field to cover the whole design from a single Z axis position.

Some previous discussions may provide a starting point:

https://forum.lightburnsoftware.com/search?q=barrel%20stave

[LSS (Samuli Samuelsson)]

Hi.

Weclcome to the LB forum @thiggins .

That will be tricky to pull off with hobby equipment.
Not to mention with a 2.5D controlling software.

If Your One Finity CNC supports 3D engraving, IMO the easiest way to tackle this task would be to use some other software when engraving/marking curved objects.
Lightburn is truly a great software with a great team behind it, but there are lots of things it’s not capable of doing…yet .

In addition to those search hits @ednisley posted:

Not individual staves, but marking whole barrels was discussed in this:

Big logo's on a barrel

Someone I know from a company that makes wooden barrels asked me what kind of laser unit they would need to buy for making big logo’s like on the picture on the barrels. I’ve seen a few youtube videos on that but what would you guys recommend? They don’t want to outsource this but buy a laser unit so they can do it themselves. Any suggestions? The logo’s they want to make are about 75-100 cm (92-39") EDIT: I see I forgot to add the picture… [Scherm­afbeelding 2023-08-21 om 15.23.07]

thread.
As can be expected, that thread was derailed more than once, but there might be some nuggets of information that could be useful in Your case.

Regards,
Sam

[MikeyH (Mike Hembrey)]

@thiggins, one possibility is to fabricate a custom roller mechanism to pass the barrel stave back and forth. With proper design, it could shuttle the stave back and forth while keeping the burn area at a fixed height. A NEMA 24 motor plugged into the Yaxis should have enough torque to move it. Then you could use Lightburn.

[soniclab (Jeremy Hutchinson)]

No, you would need to use an auto focus. That is dependent on if your machine supports that. That is controlled by the laser and not LightBurn.

[thiggins (Tom)]

Thanks for all the great advice. I found an alternative solution by steam bending the barrel staves to be more flat. Since it is just g-code, I would have thought there might be a workaround using another piece of software to account for the changes in the z-axis.