Hello again! I’m back this week with the most complex project yet, creating a press-fit laser cut box with six seperate compartments. Before this, I had used ‘make a box’ programs in the past, but I had always used a glue of some sort to hold the pieces together, so I knew creating something that would have the perfect tolerances would be very difficult.
Getting into the actual process of making this box, I began by designing the layout. We were given general dimensions of the six compartments needed, however these areas did not immediately fit together in a simple way. After getting the go ahead from Wettergreen, I slightly adjusted the margins of some of the containers (by no more than half an inch on each side) and was able to form a single rectangular box. This layout is shown in Figure 1.
Figure 1: The rectangular layout of my box!
After this point I began to create the Adobe Illustrator file of the box pieces. I began by thinking about the dimensions. I knew what the internal dimensions of each compartment needed to be, but the overall dimensions were a bit different as I had to account for the thickness of the wooden dividers in the overall internal dimensions. Once I figured this out, I was ready to design my box.
I used a “make a box” program for multiple steps in this process, but before I could use it to a great extent, I needed to test the tolerances of the pieces I would be cutting to check that they could be press fit. After talking with my partner for the project, Saad, he recommended I try tolerances of 0.01” as that is what worked for him. I used this tolerance in a small corner design to test, and found that 0.01” worked perfectly. The test corner can be seen in Figure 2 and 3.
Figure 2: The pieces of my tolerance test
Figure 3: My tolerance test put together
After I confirmed the tolerance size, I began using illustrator to make my design. I began by creating a basic outer box using the software, and added slots and adjustments to that. To determine the size of the slots that the internal pieces would fit into, I either used the tab lengths and spacing already generated by the first file, and I created new files with the dimension of the inner compartments to use those tab lengths and spacings. One difficulty of this process was making sure I accounted for the right tolerances in the areas that I would design, rather than the software I used. Despite this, I successfully created a final box design, which you can see in Figure 4.
Figure 4: The Final Box Design
I proceeded to get some laser cut table wood from the OEDK and used painters tape to tape both sides of the wood to prevent any smoke or burn marks as much as possible. Once this was done, I used the laser cutter to cut the piece. After the first run, I noticed that the etching I had didn’t appear to actually etch the wood, but had just etched the tape. To account for this, I left the wooden pieces in their location in the laser cutting beg and peeled the tape off of the wooded base, and re-ran just the etched sections. This led to a successful etching, the process of which you can see in Figures 5 and 6.
Figure 5: Successful tape etching, but not so successful wood etching
Figure 6: The peeled back wooden base along with all of the other laser cut pieces
Next cane my biggest difficulty in this assignment. When removing the wood from the laser cutting bed, I saw that the pieces appeared to be fully cut but we sticking to each other. I attributed this to the tape on the back side of the wood and removed the entire piece to separate at a different table. The issue was that while the pieces were mostly cut out, some of them were not entirely cut out. This can be seen in Figure 7.
Figure 7: An unfortunately incomplete cut
To mitigate this issue, I used a utility knife to carefully cut the areas that hadn’t gone all the way through. This method was successful, and through using it I was able to separate all of he pieces without having to recut any of them. At this point, I put all of the pieces together, took a mallet to each of the outside surfaces to make sure the pieces were as tight a fit as possible, and I lightly sanded all surfaces. This left me with the completed box, which you can see in Figure 8 and 9!
Figure 8: The Final Box!
Figure 9: Laser etchings on the final box
Finally I will complete a quick cost analysis. Labor costs include 6 hours of work at $20/hr, for a total of $120. Material costs include laser cut table plywood, which you can purchase for $13.73 for a 4’x4’ square from Lowes. This gives the box a total cost of $133.73.
