Hello,
Can anyone share what trick they use to get the right Laser focus “especially on wood & acrylic”
I have seen some people have used pens, or a stick to put it under the laser during calibration before the engraving process has began.
Is there a simpler way to get this right everytime.
I have been engraving on wood for sometime now, and i have been getting some different results every now and then, sometimes i get it right, sometimes it gets deeper, sometimes it gets very shallow, and sometimes it doesn’t do anything at all (Mostly because of wet wood, i guess 
)
Any ideas or walkthroughs would be appreciated.
Buy some digital calipers. If you don’t have them already, you really should - useful for all 3 functions. Then it’s easy to use the auto-focus (assuming you’ve calibrated your focus height properly) and just set your material thickness and know it will always be the same.
There’s always going to be a variability on different wood. Just the nature (no pun intended) of using natural materials. But if you make sure focus is consistent that will eliminate one variable.
-S
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@andyfaby since the Snapmaker is also a 3D Printer, you can print a block or cylinder of the exact height that you need, and use that for quick adjustments. Cura, PrusaSlicer, and SuperSlicer all have the ability to place simple objects on the build plate for slicing w/o requiring a drawing. 
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Can you share the link of the digital calipers you are refering to?
Can they be printed in any way?
-S
I’ll give you a ‘hack’ for the XY calibration. The new 10W laser seems to forget the work zero you set right after the job instead of keeping it. Even if you use a corner crowd there’s no guarantee you’re pushing every piece in good and tight as you lock it down each time (within the width of the laser beam). So if you ever do incompletely cut the wood and need to repeat the pattern another time, here’s how I got away with it.
- Fix your part down appropriately, use either manual or auto thickness test (doesn’t seem to matter), then set work zero and test with run boundary. ONLY USE FULL 10 or 1mm minimum movements setting your zero, and remember how many you used!! (e.g. X offset was 66mm, Y offset 40mm)
- Cut once whatever program (in my case it was 100% about 110mm/min on roughly 1/4 inch stock for this test. Hopefully your ‘blank’ is not sized much bigger than the actual boundary as you want to be able to see the smoke ejecting out of the platform grooves during the cut (or final pass if doing multiple). That’s your indicator of ‘was it enough’.
- If you’re not sure, you can re-run the program, BEFORE picking up the piece, and inevitably never getting it back into the right spot. You will have to reset the work zero but can reproduce it. And you can crank up the workspeed for the repeat possibly so as to not spend a huge amount of power burning paint off the platform…
I’ve tried fiducial engrave marks out at corners but never been able to put something back down not only with the right zero but also perfectly aligned just yet. Need a fence or actual hold-down parts. I suppose with the right clamp parts you could leave 2 sides in place and remove the workpiece, to check, then restore to position, but I haven’t been that successful yet…
I’m considering researching if anyone makes small T-slotted material sheets one could use to come up with an upgrade laser table that would actually accept captive workpiece mounting hardware…far more economically viable to just test with scraps and get it right I guess.