The journey to a fully assembled 4×4″ box was not a short or easy one, but we were able to complete it within a couple hours which felt like a win!
Adobe art
Prior to the session, I worked on Adobe to size out my etched sides of the box. One Univ. of Iowa crest, one Rice crest, and the last with my name/date/class info. These would be moved into the file to laser cut once all the dimensions were determined.
Fallen test piece. RIP.
Kaira, Jeff, and I started our session aiming to get the perfect fit between a single joint. This happened after cutting a test piece (0.25″ x 0.25″) of course to get the settings right. Sadly it fell through the grates… but at least we knew the cut went all the way through the board!
Our mini fit once we had the dimensions right!
We found the right fit by printing rectangular holes of different sizes and a piece with varying depths and widths to fit into the holes. We went this route after hearing of the failed kerf calculations of our friends in earlier sessions, and ended up getting the right fit. Our first determination was that the pieces needed a height of 4mm to fit the depth of the wood piece it was fitting in to. We had close estimates for the other measurements, so we printed a couple more boxes with incremental differences until we got the right fit on all sides. We looked at the maker box designs to figure out where the specific lengths needed to be since the box sides fit in together differently (aka, they aren’t 6 of the exact same piece). These extension bits were 5.004mm x 10mm and the slots were 4.904mm x 9.5mm. The vector cut settings we used were 4 speed, 100 power, 10 frequency. We had the speed so low because the laser wasn’t getting all the way through the board when we went to fit two full pieces together. We then chose etch settings and did Kaira’s Dartmouth crest as our practice. The etch/raster settings were 100 speed, 40 power.
My thin Iowa etch midway through a re-etch 🙁
We next taped the entire board, then had to remove the tape when we realized the etch needed to come first haha. We portioned off all 16 pieces (6×3 -2 already cut) on Adobe Illustrator and started the etching. My Iowa etching was a little thin for the given settings, and we had to run that specific etch a couple of times, which we later discovered was due to the warped wood making the laser too far away from the wood. We next taped the board again to begin the cuts. Unfortunately, the wood was not our friend and the cut didn’t make it all the way through. We ran the laser cutter again (twice), with failed results. Our wood was now crispy black on the edge and still not cut all the way through on all the pieces. We realized that in trying to do all the pieces at once, we weren’t able to secure the warped board, so our focus height wasn’t exact in all places. BOOOOOOO. We reset it all with a new piece of wood and were able to get Jeff’s sides cut.
Look at those perfect edges!
After a failed cut the next time around, Douglas took a look at the glass and noticed it was pretty dirty/smudged, which likely was the cause of some error in the pieces. He was able to clean it and we reset the settings to their normal (speed 5) and did a SUCCESSFUL test cut! After this it was smooth sailing for the last couple pieces. It was a little tough to push all the pieces into each other since the edges were meant to be perfectly tight, but it came together in the end! Ta-da.
Looks at her pt.1
Look at her pt.2
Look at her pt.3
Total Cost for a single box: $29.67
Materials- 5mm x 4′ x 8′ plywood = $27.48 @ ~155in^2 -> 155in^2/4608in^2 = 0.0336 * $27.48 = $0.92 for box + test square
Overhead for building and machine use- $5/hr @ 2 hrs = $10
Labor: $7.5/hr @ 2.5 hrs (additional 0.5 for design and assembly not done in building) = $18.75
