Week 02 · September 16 · Computer-controlled cutting

Computer-controlled cutting

Assignment

For the individual assignment, I used the laser cutter to make a small finger-jointed cube. I then tried running engraving and cutting in the same job.

Finger-jointed cube

I started by making a cube from laser-cut plywood. The six faces use finger joints along their edges. I used the kerf results from our group tests when sizing the tabs and slots, so the pieces would still fit after the laser removed material.

After cutting, I pressed the sides together by hand. The joints held the box together, and the top can be removed.

Small laser-cut plywood cube with finger joints and its removable top — The assembled cube and removable top.

Group assignment

My teammates ran the experiments and gathered the data for focus, power, speed, and kerf. I used their results for my cut.

The power and speed tests showed how the cardboard and acrylic changed across a range of settings. The kerf test compared offsets from 0.0 mm to 0.7 mm. The focus test compared eight focus positions.

Group laser tests for focus, kerf, cardboard, and acrylic — Overview of the test pieces made by my teammates.

Cardboard kerf test labeled from 0.0 to 0.7 millimeters — Kerf test from 0.0 mm to 0.7 mm.

Laser focus test cut into cardboard — Focus test with eight positions.

Cardboard laser power and speed test grid — Cardboard power and speed test.

Orange acrylic engraving power and speed test grid — Acrylic engraving power and speed test.

Engraving and cutting in one job

Next, I tried putting engraving and cutting into the same job. I made one layer for the engraved circles and numbers, and a second layer for the outlines that should be cut all the way through. Keeping the operations separate let me give each one different settings.

Engraving layout with numbered circles — The engraving layer.

Cut layout with finger-jointed panel outlines — The cutting layer.

Finished finger-jointed cube with engraved circles on its faces — The final cube after engraving, cutting, and assembly.

Failed triangle version

I also tried a version with a triangle-shaped piece. The parts cut, but this version did not turn into a usable box. I stopped this attempt and went back to the square cube design.

Failed laser-cut triangle version still sitting in the plywood sheet — The triangle attempt and the other cut panels.

What I learned

Kerf matters even on a small box. Without the offset, the tabs and slots would not match the dimensions in the drawing. I also learned to keep engraving and cutting as separate operations, and to engrave before cutting so the parts do not move.