Darkly Labs Community

MeArm project 3mm plywood

As part of a project for the local library, I selected the MeArm robotic arm, primarily because it appeared affordable and could be created via laser cut plywood.


I’m not so sure about the affordable part, as the parts will be about US$75 when purchased in quantity but it’s the lowest price robotic project I found that I felt could be handled by teens for the library summer camp.

5mm/sec (300mm/min) at 100% 4W laser resulted in a few cuts not getting all the way through, but easily sliced clear with a razor knife/box cutter. Four hours and three seconds elapsed time. My first real project and it came out as good as I had hoped.

The slight variation is caused by shadows from the garage lights, as the photo was taken without a flash. The plywood was purchased inexpensively from Joanne Fabrics retail store and is uniform surface both sides.

How many passes did you do at 300mm/min? I am having my own issues with clean cuts on 3mm plywood with the 4w laser.

I’m surprised that I left out that piece of information. The project was set to 6 cuts but I’ll likely perform the same thing again next time with 7 to ensure complete fall-through. Some of the gear teeth managed to leave behind pieces when popped out and I’d like to avoid that happening.

I spent about three hours fine tuning the laser to get the absolute smallest focus I could. I used a 50x illuminated magnifier to view the test cuts, having turned the focus adjustment one “knurling-bit” at a time. I marked an index point on the knurling, then ran the tests in a descending sequence. That is to say, perhaps a quarter turn or eighth turn until the tests got wider, then narrowed it to a block of test lines and indexed from there.

With the 50x magnifier, I could see 0.01 mm difference in the laser cuts so I’m confident that I have it as tuned as it can be.