Focus height for thin kerf

Hi everyone, Something I found when experimenting with inlay work with 1.5mm ply.
My normal settings were 2 passes at 100% power and 4 mm /sec speed. The the parts would drop out cleanily. I found that on my setup with a .8mm thick protective sheet of cardboard on the bed of the machine plus the 10mm silicone mats that the focus height was 11 mm. Using this setting and adding half the thickness of the workpiece and reducing the speed to 3 mm /sec i could cut the work cleanily in one pass.
To me its suggests that setting the focus height and half the thickness of the material you could get a very thin kerf and reduce the number of passes.
Anybody found this as well
John

Hi John,

Yes! We often recommend using a Z-Offset equal to half the material thickness for single pass cuts.

This means the thinnest point of the beam is in the center of the material, which minimises the beam taper and ensures the laser power is as focused as possible - meaning thinner and quicker cuts.

Do you have any examples of your inlay work? I’m intrigued…

Lliam, sorry to have not got back to you sooner. I seems I have dug myself into a hole and need to go back and try again. Not the thin kerf but with the grapgics and timber selection. The only sample I had was not good enough to display (Colour bleed). I will post when I have a suitable example.
John

Lliam, I finally got a set of examples to show, and I attached a pdf for people to download if they are interested in this subject.
Whilst a thin ferf is desirable when cutting out shapes it issometimes necessary that a thicker line be burnt. So after some experimentation with thin kerfs and trying to add colour to the engraving , I settled on the method shown in the PDF. I have tried to produce a fine detailed engraving similar to line drawings.
Maybe some other people have had similar ideas and it would be great to see some examples of their work.
Bird3
Here is the PDF for download
line engraving.pdf (429.4 KB)

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