Week 2: Computer Controlled Cutting21 Sep 2016 · 3 min read
I used the laser cutter to build a press fit construction kit.
I’ve only used a laser cutter once before, and I didn’t really know what I was doing back then, so in my design, I ended up with loose joints because I didn’t understand what a laser kerf was. Back then, I compensated with epoxy glue, so I didn’t end up with a nice friction fit design. This time, I wanted to make sure I got it right, using a parametric modeling tool and making sure it was really easy to tune the parameters until everything fit perfectly.
I took the “press fit construction kit” part literally — I designed a part that was designed to fit together with other copies of the same part, forming a construction kit that could be used to make all sorts of (mostly very boxy) shapes.
I used Fusion 360 to parametrically model a square shape with 3 cutouts on each side for slotting into other copies of the same shape. Parameters included things like piece size, slot spacing, and most importantly, material thickness and laser kerf width.
I was cutting this on a Universal PLS 6.75. When cutting, I had to experiment with laser settings to get good results. Initially, I was using the materials database, setting the material to balsa wood (it was actually cardboard), 0.160” thickness, with a +50% modifier for vector cutting.
That didn’t make clean cuts through the material, so I switched over to manual control. I tried using 70% power, 8% speed, 300 ppi, and setting the thickness to 0.160”. That worked a little bit better, but it wasn’t quite perfect — I still didn’t get clean edges on some of the pieces I was printing. I tried boosting the power to 75%, and I consistently started getting nice pieces.
After getting the laser cutter parameters tuned, I did my first real cut:
After playing around with the physical pieces, I felt that the notches were too close together, so I tweaked the design and cut some new pieces. I was happy with the new results, so I cut 60 copies:
The pieces looked quite nice when neatly laid out on the laser cutter bed:
After printing, I ended up playing with the pieces for some time, and I ended up with this art:
Bonus: Laser Cut Laptop Stand
After getting some experience with the laser cutter, I was interested in making something useful for myself using the tool. I decided to make myself a laptop stand, designed parametrically in Fusion 360: