The process

I made use of several resources to complete this project. To start, I used the website en.makercase.com to give the dimensions of my box, and specified that I wanted a 4.5″ x 4.5″ x 4.5″ box with finger joints of size 0.767″, which gave me two tabs on each edge. I also measured the thickness of the wood for this program with calipers, obtaining a 0.2 inch measurement, and used the reported 0.008 inch kerf from the class GroupMe for the program, and so used the same settings for all cuts of 4s, 100p, 10f.

Makercase website settings for box design

When I first exported the box design from the website, I faced some difficulties with how the full layout was presenting on Adobe Illustrator, so instead opted to export each side as a separate object, which could be transferred one at a time into the print file. I cut out a small test square, confirmed that the settings worked,  and then cut out the first side of the box.

Next, I imported the first side of my box, the back panel. I printed it, which went successfully, but observed a good deal of burn marks along the edges. At the advice of Cannon, I learned that placing painting tape over the edges helps prevent these burn marks from forming, so repeated this cut with the tape and observed that this method was effective, although a small amount was not covered with tape so I could see the contrast. I then cut out all the remaining ’empty’ sides, and assembled them so only the top and bottom were open.

Initial burnt box in comparison to after tape was added; top right corner of taped side was not taped and burn marks are visible for contrast

       

I had to do some troubleshooting with the laser engraving for the next part of the box. I still used tape over the piece, but due to the sensitivity of the engraving in comparison to the cutting, my first attempt at cutting these pieces resulted in part of the piece not being engraved, which I attribute to non-uniform tape placement combined with insufficient power to get through the tape. I tried again with a higher power setting, and observed that this was far better, although a thin strip of the Rice logo remained unengraved where two pieces of tape overlapped. Finally, I carefully applied the tape without any overlap and was able to achieve a near-perfect engraving, with a very slight line visible under the bottom owl’s feet, but no other artefacts.

First and second failed attempts at engraving (second attempt worked for written side only)

 

Successful engraved sides:

 

I added the last two sides to the box carefully, and was able to assemble it stably with no tools, indicating proper tolerances for the finger joints based on the provided kerf.

Finally, I cleaned the workspace.

Clean computer benchtop and laser cutter

This project was not technically challenging, but still was a good exercise in troubleshooting for me. Due to my experience troubleshooting the engraving, and other minor problems that were less notable, I feel that I have a fairly strong understanding of what considerations need to be thought through when using the laser cutter and designing for the laser cutter, which will be advantageous for the midterm assignment.

Final box

Cost Model

Materials

• 1/5 inch plywood, 4 ft x 8 ft, Home Depot: $25.78, box uses about 1/20 of area (liberal estimate): $1.29
• Blue masking tape, 60 yd, Home Depot: $7.98, box uses estimated 4 yards (liberal estimate): $0.54

Labor

• Laser cutter operator, ZipRecruiter: $17/hr, estimated 0.5 hours to produce one box: $8.5
• Prototyping Engineer, Indeed.com: $36.5/hr, estimated 1 hour: $36.5

Overhead

• Machine time, TXRX: $50/month, personal use 1 month: $50
• Adobe illustrator license, $22.99/month, 1 month use: $22.99

Design

• Engineering and Development, ZipRecruiter: $90/hr, 1 hour consult: $90

Total: $209.82

This cost model yielded similar results to the crate, likely due to both involving lower material and labor costs and higher overhead and design costs. The material costs are already relatively low, but could be driven down further potentially by finding a suitable wholesale vendor. As a prototyping engineer would not need to work many hours if the design of the box was kept similar but scaling was ramped up, the cost of labor per box produced would therefore go down substantially. Similarly, overhead costs are both given on a monthly basis, so with increased production the cost per box would go down substantially, although if sufficient scale is achieved a pricier machine time option may be warranted. The design costs and therefore consultant fees would be variable depending on the desired outcome of box production, so this expected cost is heavily dependent on what someone would seek to achieve with increased production.