First, we measured the thickness of the plywood using a digital caliper. We then took our measurements and used the MakerCase website to make our box design, with outer dimensions of 4x4x4 inches and a tab size of 0.591 inches. Initially, we used a kerf of 0.013 inches, according to the given range in the guidelines of the instructions, but later on this kerf value proved to be the biggest struggle for us during this project.
To proceed with our first trial, we set up the laser cutter machine, jogging the laser pointer and adjusting the height of the bed using the paper test that we learned during the tutorial training session. We first used initial settings of 5s, 95p, and 10f, and made a small square test cut to evaluate these parameters.
We found that there was some excess charring occurring, so we kept adjusting our settings to find a better set of values that still successfully cuts through the wood, finally arriving at the settings of 8s, 95p, and 10f.
In order to test for kerf, to ensure that our pieces could fit together and had a pressure-fit (but also not too tight), we cut up the pieces in Adobe Illustrator, using only the sides of two pieces in order to save wood and time. One memorable moment was when Tori estimated exactly the placement of cutting our test pieces in order to save wood, depicted below. Our first kerf value, 0.013 inches, was too tight and the pieces would not fit together. We then experimented with three other kerf values, 0.011 in, 0.010 in, and 0.009 in. We found that the 0.009 inches finally fit together! (initially ……..)
We then continued to cut our box design out, with the engraving settings for the text set to 20s, 20p, and 50f. We ran into an unexpected problem however…. the pieces would not fit together for some reason, even though our test pieces for 0.009 inch kerf fit together. Another issue was that for some reason, the laser cutter had successfully engraved the text at the start, but then after finishing all of the vector cuts, it went back over the engraving and cut through.
After testing out a couple more kerf values, 0.006 and 0.005 inches, we finally decided on using 0.005 in as our kerf value (keeping speed, power, and frequency settings constant). The 0.006 in kerf was a little too tight, although the pieces fit together after putting a lot of pressure. The 0.005 was a nice press-fit but also didn’t require too much force to put pieces together!
We finally cut out our box pieces (which actually fit nicely!) and engraved our text and college crest on two of the pieces. We had done the engraving with the masking tape on, and found out that the college crest details were not engraved very clearly. The text showed up clearly though. We had used the settings of 40s and 20p. In order to fix the engraving on the crests, we kept the placement of all the wood the same, peeled off the tape, put some weights down on the cut out piece just in case, and ran the laser cutter one more time to engrave just the crests, using 30s and 20p this time.
And finally our boxes were finished!
I really like how the engraving turned out, because I personally like the light, clean style of the text engraving, and the college crest came out really clear and not too dark as well.
Cost Analysis:
Raw materials:
- plywood ~ $2.75
- tape ~ $1.00
Labor, machine, overhead:
- laser cutter: ~ 2 hr ($20/hr) = $40
- labor: ~ 3 hr ($7.25/hr) = $21.75
Total: $65
