Hello everyone! This post documents my struggles to make a press-fit, laser-cut box. Having issues adjusting vector settings when making our nameplates earlier, this time I found myself struggling to measure the kerf properly on the laser cutters. After three attempts, I finally achieved a snug fit and a successful finished product.

Designing the Box File and Measuring Kerf

Using en.makercase.com, I set the dimensions of my desired box to generate the laser cut file. I set the width, height, and depth to 4″ and the material thickness to 0.18″ as measured by calipers. Next, I chose a finger size of 0.585″.

Before downloading the file, I needed to specify the kerf of the laser cutter to ensure proper fitting of the pieces when cut. From canvas, I downloaded the kerfbox.ai file. I noticed that the file in canvas and the kerfbox in the assignment document were different: the doc’s box had 10 cuts where the canvas file had 11. Upon printing it out, I measured the space with calipers and divided by 11 instead of 10, since the file I downloaded had 11 cuts. I measured the space at 0.16″, so the kerf was calculated to be 0.0145″ on the Epilog M2.

Now, with the files downloaded, I could begin to design the images that would be engraved into the sides of the box. With my name/class/date and college crest required on two sides of the box, I was left with 4 sides to decorate. I decided to add the symbols for the four elements from Avatar the Last Airbender on the remaining sides.

Ensuring the images were rasterized and the box outlines were at 0.001″ line thickness for vector cutting, I was ready to cut the box.

Cutting the Box

Though I initially measured the kerfbox on the M2, the M2 was in use when I was ready to cut the box. A lab assistant told me that the kerf should be the same for both machines and that it wouldn’t make a significant difference if I were to cut the box on the Fusion Pro. I configured the settings as follows:

Engrave:

• Resolution: 1200
• Speed: 70%
• Power: 40%

Vector:

• Speed: 15%
• Power: 100%
• Frequency: 10%

After a quick test cut with the settings looking good, I cut the box out. After it finished, I tried putting the box together, but the finger joints were way too big to press-fit.

Believing it may have been an issue with measuring the kerf on the M2 but cutting the box on the Fusion Pro, I made a new kerfbox on the Pro, where I measured the kerf to be 0.010″. I remade the box file with the new kerf measurement and cut the box on the Pro again using the same settings. Once again, the joints were too big and still didn’t fit together properly.

Final Box

For the third and final attempt at cutting the box, I used a value of 0.0075″ recommended by Marc. This box fit much better where it was a tight fit putting the pieces together without anything breaking and without the pieces being easily able to be taken apart.

I was so excited that the box finally fit perfectly that I assembled the whole box, forgetting that there were a few burn marks that I needed to sand clean. Because of the near-perfect fit, I wasn’t able to remove any of the pieces to sand. This made the sanding much harder, as I wanted to keep the dark edges from the laser cutter on the joints as contrast. Using the finest grit sandpaper, I carefully touched up the edges where burn marks were present.

Conclusions

Overall, this project took me a lot longer than it realistically should have. However, I made a box that fits well and looks nice at the end of it all. Looking back, one of the biggest troubleshooting solutions I looked over was simply cutting out two sides instead of the whole box to test the fit and ensure correct kerf measurements. Doing so would have saved a lot of time and materials. Additionally, sanding before assembling would have been much easier since I wanted to avoid sanding the joint ends. Aside from the nameplates made during the TA tutorial, this was my first time laser cutting by myself. This project provided me with invaluable lessons in troubleshooting, designing, and planning using the laser cutter.

Cost Analysis and Cleaned Workspace

Total Cost Estimate: ~$46.5

• Labor (3 hours @ $10/hr) = $30
• 3/16″x12″x24″ wood (1.5 sheets @ $11/sheet) = $16.5
• Laser Cutter Rental = free at public library

The cost analysis is a rough estimate. The labor time was high as I had to redo the box a couple of times, and the extra material needed to redo increased the cost as well.

Below are images of the cleaned final workstation used.