This past week I used the laser cutter for my first time ever to create a 4″x4″x4″ snap-fit box. I started with the makercase website to input the dimensions of my box, as well as the desired width of the snap joints. For the plywood sheet, I measured the width of it with digital calipers and got a value of 0.214″, which I subtracted from 4 and used the value of 3.786″ for my length, width, and height calculations for the box. I selected that these were the external dimensions for the box, when they were actually the internal dimensions. This resulted in a mistake which was not obvious until the box was assembled, so I will come back to that later. I then input the width of the plywood sheet, 0.214″, and chose a width of 0.708 for the tab width which I chose using the slider on the website and an assumption of which width would limit the cut time needed but still hold the box securely. After all information was input, I downloaded it as an SVG after choosing a kerf value of 0.005 in, which I decided on using information from my classmates who gave us a suggested range of 0.0045-0.0065 in for the kerf. I was more concerned about the box being too large to fit, so I chose a value in the lower end of that range.

Website used to generate the box file

After the file was generated, I uploaded it to illustrator and then deleted the insides of the boxes which labeled the position of each side piece. I then grouped the individual side pieces and changed the pt value to 0.001 in to signal for a vector cut. Once that was complete, the next step was to input the text and my college crest (Jones). I placed the text box in the center of the first side piece, and then placed a jpg of the Jones crest onto a piece of the exact same shape to ensure that the text and the crest would go on opposite sides of the box. Now, the box was ready to be cut. I prepped the wood by placing masking tape over the area that would be cut, and then placed the sheet in the top left corner of the laser cutter. I set my origin at the corner of the wood, where I was sure there was enough room on the wood to cut the full file. The height of the laser cut bed was already correct, as the user before us had focused it and we tested it with the CO2 metal piece and it was just barely touching the wood. Now, the machine was set, and I was ready to choose my print settings. Using the guide for 1/4″ wood on the information sheets in the laser cutting room, I chose to use a power of 100% and a speed of 6% for the vector cut, and a speed of 100% and power 40% with the Jarvis setting. I sent the job to the machine which took about 9 minutes to finish. I removed it from the wood and the vector cut went through cleanly, but the etching did not go through the masking tape as I had hoped, so I had the sides of the box cut out with no etching.

Etching with the tape over top

I checked the tabs to ensure they fit together, and they did fit with after using some significant force to get them together. The next step was to etch without the tape to have the text and crest on my box. I positioned the text and the crest on the side pieces in the top left corner in illustrator, and then made them share an edge and set the top left corner of the side piece at (0,0). I removed the side piece outlines on the illustrator file so that it would only etch, and then I placed the side pieces I wanted etched right next to each other on the machine and ran the etch again.

Etched Pieces

The result was satisfactory, so the final step was to put the box together. After a significant amount of elbow grease, I was able to snap the parts together and they stayed securely attached to each other. The tabs look like there is no issues with the fit, but when I ran my fingers over it I could feel that there was a bit of overhang. To fix this, next time I would use multiple measurements with the digital calipers and take the average to ensure that I get the width measurement of the plywood as accurate as possible.

The completed box

Going back to the mistake I mentioned in the beginning of this blog, The box is only 3.8″x3.8″x3.8″, as opposed to 4″x4″x4″, which is because I chose that the dimensions I input were external rather than input, even though I removed the width of the box from the side dimensions. Next time, I will remember to choose internal if the width is not included, and external if the width is included in the dimensions for length, width, and height.

Reflection:

The laser cutter was easier to use than anticipated as the OEDK includes easy guides to follow for the laser cutter and the project was enjoyable to complete, but there are small aspects of design that I feel like will take a couple of attempts to get down including choosing correct dimensions and the correct kerf values. Here is what I would change in my next project that involves the laser cutter:

• Etch on wood that has no tape over it to ensure the results turn out as anticipated
• Ensure input dimensions for any files used reflect the size of the actual device I want
• If I had more time, I would test the kerf values using the file given to us in the assignment

After completing this assignment, I feel confident using the laser cutter and understand the fundamentals to how it works, and am comfortable using it going forward.

Cost Estimate:

Plywood 1/4″x 48″x48″ sheet x 1: $5.75 at Home Depot

Labor Cost: 2.5 hours at $15 = $37.50 (professional is about $25-$80, so with my skill $15 is an estimate for cost)

Overhead Estimate (Electricity, Internet, OEDK resources) = $15

Total Cost = $58.25