The Story of How Ellie Learned She Was NOT Advanced | ENGI 210: Prototyping and Fabrication

Hello dearest reader,

Today I share with you my long and arduous journey of laser cutting a box.

My first mistake (of many) was made when I saw the assignment had different levels of difficulty depending on one’s experience with the laser cutter. Having used the machine a handful of times during my freshman year, I balked at the thought of doing the beginner assignment and immediately set my eyes on the intermediate/advanced project.

No, my ~experienced~ self was not going to grab a premade box file off the Internet and laser cut it. I was going to design one myself, and it was going to have internal compartments, and it was going to be absolutely beautiful.

The project started off on a good note. I laser cut a few sample joints with different amounts of material overlap to determine what the kerf was. It turned out to be a good thing that I did these sample cuts, as I had incorrectly assumed the wood was 1/4″ when in reality it was 3/16″. When assembling my sample joints, I observed some protruding material and I quickly realized my mistake.

Test joint assuming 1/4″ thickness (left) vs correct 3/16″ thickness (right)

Wanting to err on the side of caution, I intentionally chose a higher degree of material overlap than was strictly necessary. I would rather sand down the joints a bit or use a rubber mallet than have my connections be too loose and need recutting. And so for my 3″ tall box, my male section was 1.02″ and my female sections were 0.98″. My laser cutter settings were 2% speed, 100% power, and 10 frequency. (Might I mention, the day I cut most of my box, the laser cutter was only functional on its lowest speeds, so the kerf was much greater than normal)

Once I was satisfied with the tight connection of my test joints, I moved on to designing my box on Illustrator. Almost immediately, I realized how inexperienced I truly was. You see, the problem was that despite knowing how to focus the laser and set up the wood for cutting, I had almost no experience with using Adobe Illustrator.

I didn’t know any of the fast ways of drawing shapes with so many protrusions, so I developed my own method using overlapping rectangles and the Shape Building Tool. I also wasn’t sure of how people who were actually well-versed in Illustrator measured distances, but I got by drawing rectangles of the offset distances I wanted, filling them a different color, and using them as a sort of ruler. The Auto-snap tool was my best friend.

Using the Shape Builder Tool to join my little rectangles and create my walls

I designed the internal and external walls in a similar manner, but I decided to add some star cutouts on the outer walls for some extra artistic flair. With all of my walls designed and my laser cutter settings determined, I sent them to print. Easy peasy, or so I thought…

Almost immediately, I realized something was very wrong with the laser cutter. It was behaving very inconsistently: within one print job, it would cut out half the items, but not the rest, despite everything having been given the same stroke size. At first, I thought maybe the painter’s tape I was using to prevent charring was getting in the way, so I tried cutting without that, but saw no improvement.

Laser cutting taped wood to prevent charring

Then I thought maybe it was because the wood wasn’t perfectly flat, so the laser wasn’t in proper focus on some of the sections: I tried to solve that by placing metal weights throughout the wooden board to press it down:

Holding the wood flat with metal weights while cutting

Still no improvement… Not knowing what else to do, I restarted my print jobs. But, when even that didn’t seem to consistently work, I resorted to pushing out some of my half cut pieces, splitting the edges of the wood along the way. I then went and sanded these edges, along with some of the charred bits, during assembly.

Example of pieces that didn’t cut through all the way

Funnily enough, as inconsistently as the laser cutter was behaving, the one thing it would consistently do was not cut my stars. Inspired by learning how to use the vinyl cutter a few days prior, I decided to try to DIY stickers on the laser cutter by taping off the stars and then having them not fully cut. This part actually worked out, as you can see by the blue tape stars on my final product!

Upon trying to assemble my box, I realized some of my pieces didn’t fit together. They fingers and the holes were not aligned, but strangely enough, the were misaligned by the tiniest amounts. As it turns out, the Auto-snap tool was not my best friend. I had accidentally been auto-aligning holes with the midsections of other lines and not with their intended parallels. As such, I had created a box where all of the pieces almost fit, but didn’t.

My other major mistake I hadn’t realized in the Illustrator stage was how I laid out my compartments. Two of my neighboring compartments’ walls were 3/16″ off from parallel from each other. As you can see in the below image, these compartment walls were so close that for the middle piece, instead of having two separate holes for the joint fingers, I instead cut one large hole.

Planning compartments: walls shown in red

It was only when attempting to assemble this part of the box that I realized my mistake. Because I had rounded up my kerf measurements, my box required quite a bit of malleting to fit together; however, hammering two wooden pieces into opposite sides of the same hole proved to be basically impossible, as hammering in one would push out the other, leading to an endless cycle of reclamping and re-malleting. Even when I thought I had finally succeeded, I realized the pieces were each not fully in.

You can see a gap between the connected pieces at the almost 4-way joint : this makes the outer walls impossible to assemble!

So, back to the drawing board: I returned to my Illustrator file and moved some of the internal compartments around to avoid facing that issue again.

New compartment layout: Unfortunately making this change meant having to recut all of my pieces

Rinse and repeat, back to the laser cutter, I reprinted my pieces and went back to the OEDK basement, aka my second home, mallet in hand, to assemble what I had. Upon encountering resistance when trying to mallet in my internal walls, my great judgement led me to believe the best course of action was to mallet more vigorously, and so, as you can imagine, I broke my box.

Ready to mallet!

The very sad result of my malleting

I realized that even though I had rearranged my compartments so two internal wall fingers no longer had to share the same hole, they were still close enough that assembly was going to be a nightmare. And so I decided to scrap the internal wall side fingers altogether. Rereading the assignment, there was no clear rule about needing every piece to be fixed on every side to other pieces, so I considered it within my creative freedom to only connect my internal walls to the base, rather than to every adjacent wall. I initially tried to make this change by manually sawing off the fingers, but eventually realized that redesigning and recutting was probably a lot more efficient.

My original attempt to saw off the protruding sides

Returning to my Illustrator file, I removed my internal side protruding fingers and decreased my intended amount of material overlap for my joints to 1.01″ male and 0.99″ female, as I realized that the amount of malleting my old dimensions had required was somewhat ridiculous. I also finally cut and engraved my base piece (I had held off on doing so until this point because it was the largest piece and I wanted to make sure I had finalized the locations of all of the connecting joints before I cut it).

The new internal wall with no side fingers!

The engraved base

And finally, after a bit of sanding and malleting, my box finally reached completion.

The final product has 4 external walls with side and bottom finger protrusions, 5 internal walls with only bottom finger protrusions, and one engraved base with hole for all 9 of the walls to fit in. Parts of the outside are decorated with the blue laser-cut stickers I referenced earlier. The box is held together entirely by the friction fit of the joints without any adhesive.

The box!

Some final details I thought worth mentioning: when I decided to remove the side finger protrusions, I didn’t bother reprinting the pieces with holes in them that they were meant to connect to since that wouldn’t change the functionality of the box and would just waste more wood. One of my external walls is also loose which I later realized was because the kerf settings I had used in my calculations were not what ended up being my reality, since by the time I cut my last few pieces the machine was only working on its lowest speed. As it turns out, the slower it cuts, the more material it removes, which is why one of my walls pops out a bit. This too I didn’t consider worth reprinting, since I had already realized the cause of the issue, and wasting more wood wasn’t going to teach me anything new.