How to translate Focus test to z axis settings

[Marjan (Marjan Stolte)]

Hi all,
I just got a two trees TS2 and I’m having a fight with the auto focus.
If I use the settings provided it is not focuses correctly.

I’m just trying to cut some 3mm plywood and keep getting a flame alarm, and really shallow burned area rather then a cut.

I did the focus test and at 6.7 it gives me a beautiful fine line that lets light trough (cutting al the way through) at 300mm/m and max 80% power

How do I translate this to the programmed macro’s
It came with the following macro’s:
Engraving:
$HZ
G91
G1 Z0

3mm cut:
$HZ
G91
G1 Z-1.5 F300

I know absolutely nothing about coding but my idea of logic thinking made me think that if I would put in
$HZ
G91
G1 Z6.7 F300

It would set the z axis to 6.7 and make the same line as the focus test. It does not.

my next step was to set it to the engraving
$HZ
G91
G1 Z0
and check in the move tap. What value light burn gave for the z axis. is was 2

So I changed my Cut 3mm to:
$HZ
G91
G1 Z4.7 F300
and checked in the move tap. I now stated z as 6.7
But this also did not create the same effect as the focus test. It just give me shallow burns that set of the flame alert and not cut through the material.

Clearly my laser can make those lines. But I can’t seem to get it set up to do so. Can anyone help me with setting this up?

[berainlb (PY)]

@Marjan

I did the focus test and at 6.7 it gives me a beautiful fine line

Focus test was likely done with absolute position. So 6.7 is likely 6.7 mm position for how your controller sees it.

@Marjan

$HZ
G91
G1 Z0

G91 indicates relative moves, not absolute position. So any position changes are indicated relative to current position. This is likely why you’re not getting the same results as the focus test.

You have a few options:

1. focus is often done manually. Just adjust your Z to a fixed height above the material using a calibration tool that is the same height as the focal distance that you want. I believe you want to set “Relative Z moves only” in Edit->Device Settings in this case.
2. Adjust your macro to something like:

$HZ
G90
G0 Z6.7

Note the change to G90 instead of G91. Also, you’d typically use G0 instead of G1 for these types of moves. Not absolutely certain that will work but give a shot.
3. I’m not familiar with the specifics but there are ways of setting material height and Z offsets to manage focus.