Last weekend I spent most of a Saturday at the Idea Studio working on Mark II’s front panel.
A few weeks earlier I earned my laser cutting badge, so I knew the basics of operating the laser but I’ve never actually used one on a project before. So the first step was learning the workflow and doing some experiments to dial-in the settings for the material I’m working with.
I picked-up some 3mm acrylic sheet (transparent and black) to cut the panel from. Based on my research, this seemed thick enough to do the job but thin enough that the 40 watt laser should be able to cut it. Turns out the laser has no problem cutting this. I probably could have gone even thicker but even this thickness caused other problems I’ll describe below.
Based on these tests I settled on the following settings:
- Cutting: vector cut mode, power 100%, speed 25%, 10 passes
- Engraving: raster engrave mode, power 100%, speed 100%, 1 pass
Once I had the settings for cutting and engraving figured out, I set the laser loose on a front panel design I made awhile back. While it was busy cutting that, I re-worked the panel based on the results of some fitting tests (I’ll leave the details of that to future post). This ability to literally multitask (doing two things simultaneously) is one of my favorite things about working with robots.
The test panel came out pretty good. I learned that my drawing had some errors in it which resulted in doubling the number of passes when cutting-out the LED holes. I also noticed that the laser was liquefying the “plugs” left after cutting the holes. On top of that, because I left the film on the back of the sheet, these liquid plugs were being suspended (instead of falling out the bottom) and getting stuck to the inside of the holes. Not great.
I fixed these errors in the updated drawing and set the laser loose on the uncut portion of the acrylic sheet.
This time the results were better, but even with the drawing corrected, 10 passes was still overkill (especially with the protective film removed). I also noticed that the plastic around the hole was getting soft, either due to excess cutting passes or maybe because I still had the protective sheet on the back and it was conducting heat. Either way, I’ll remove all the film next time.
Just for fun I populated the panel to see how it looks (these parts will actually be mounted to the 3d printed compute modules). I’m pretty happy with how it’s turning out, even Jamie thought it looked good.
However, this revealed that the thickness of the panel creates a few problems. First is that the mounting screws that came with the case are too short. This is easily addressed with longer screws, but the bigger problem is that the combined thickness of the compute module faces and panel is too thick for the controls to work properly. For this reason (and a number of others) I’m going to have to make some more adjustments to the printed parts.
Once I’ve got the printed parts dialed-in I’ll plan another trip to the Idea Studio to cut an updated version of the panel. Minimally there will be changes to accommodate mounting hardware for the modules and I’d also like to try some new aesthetic techniques for engraving the legends.
I also need to design and cut a back panel…
I had a great time working with the laser. This is definitely a tool I’d eventually like to add to my lab, but for now I’m very fortunate to have access to one thanks to the Idea Studio. If you are in the region I highly recommend you take advantage of it.