For this assignment, we were tasked with using the laser cutter to create a finger-joint box – a box that can be assembled with interlocking pieces and does not require glue/fasteners. In starting this assignment, I initially attempted to design my own compartmental box. I sketched out the dimensions of each compartment, modifying the individual box dimensions slightly so all of the smaller compartments could fit within one rectangular shape. I then went to Adobe Illustrator to attempt to create my own finger joint box template. This involved planning and visualizing where the various sides and compartments of the box would be located, where the pieces would interlock, and accounting for the thickness of the wood that would be laser cut. Below is an example of the initial design in Illustrator.

I then attempted to cut this initial design. I performed a couple of test cuts and ultimately decided on 2% speed and 100% power to cut through the ~0.2in thick wood piece. After laser cutting this piece, I then went to assemble, where I noticed a couple of issues with this first iteration. The first issue was that some of the pieces did not cut all the way through and resulted in some splintering along the wood when trying to take the pieces out. After a bit of deduction, I hypothesized that this was because when performing the test cut, the wood was flipped on its other side, and that the settings may have needed to be different depending on the side of the wood that was facing up. I decided that moving forward, I would make sure to always perform the test cut on the same side of the wood as the actual cut. In addition the the splintering, I realized that I had forgotten to account for the kerf, and so some of the pieces did not fit together well in a “press-fit” fashion. Finally, I realized also that there were still some adjustments to be made to the design, as the alignment in some of the compartmental pieces was slightly off.

Therefore, I modified the design to account for the kerf, attempted to fix the misaligned areas, and then attempted to re-cut the design with the second version. I also made sure again that the test cut was on the same side of the wood as the final cut.

While some of the pieces fit together well after this second cut, there was additional misalignment in some of the cross-sectional pieces that seemed to have occurred when adjusting for the kerf. Because a large percentage of pieces now had some level of misalignment, I concluded that it would likely require several additional iterations to achieve a successful press-fit box. Therefore, I decided to pivot toward the simpler box design due to time constraints with the impending end-of-semester. However, I still learned quite a bit from this process and came to appreciate the value of the box-maker software. I learned how important it is to account for the kerf when trying to achieve a press-fit that requires no glue or fasteners. I also learned how difficult it can be to design your own press-fit, since high-level precision is required to ensure that all of the finger joints line up properly. For example, it would be easier to design a finger joint box with glue in which tolerances could be given to some of the finger joints, but it is much more difficult when you cannot incorporate these tolerances to ensure the “press-fit.”

To make the non-compartmental box, I used the Make a Box website, as this was one of the websites I found that allowed for the input of the kerf. I input internal box dimensions of 3.6in, to account for the 0.2in wood thickness on either side and result in a 4x4x4in outer dimensioned box. I decreased the tab width until I came across a width that looked representative of previous box examples. Finally, I input the kerf that I had previously measured. I downloaded the file, imported it into Illustrator, and ensured the dimensions matched the desired dimensions of the end box. I also added in the text file and Rice logo that I had previously created/imported for the compartmental box. I then positioned these to align in the appropriate locations so that they would appear on either side of the box.

I moved onto laser cutting, in which I performed a test cut with the same 2% speed and 100% power settings. I then estimated the engraving settings as 45% speed, 100% power, and 600 DPI based on the recommendations for wood. I then proceeded to cut and engrave the wooden box using the “combined” feature. It was helpful to use the combined feature to prevent having to re-align the wooden pieces and ensure central placement of the logo/text box. The wood cut through cleanly with these settings and the engraving appeared quite legible.

Finally, to post-process I spray-painted the box with a matte clear coat.

Cost Analysis

• Materials cost: x1 32″x24″ Birch plywood – $5 (From OEDK website)
• Machine use cost: $12 (0.1 hr active machine time @ $120/hr)
• Labor cost: $15 (1.5 hrs @ $10/hr)

Combining the materials cost, machine use cost, and labor cost, the total cost for the creation of the box is $32. If a cost analysis were conducted on the compartmental box,  I would expect the labor cost to be significantly higher in comparison to the standard box, with a labor time of closer to 10 hours rather than 1.5 hours. In summary, it is very helpful to use the automated box software, as this significantly reduces labor time and also increases the quality of the finished product. In the future, it could be helpful to develop a compartmental make-a-box software, as I could not find an existing platform for this application from preliminary searching.