Cardboard Construction Kit
Assignment: make a press-fit 3D construction kit
My idea was to make an expandable set of parts based off of a simple circular geometry. I also added more free-form parts as I began designing. In order to make the press-fit dimensions correct without a lot of trial and error, wasted material, and wasted time, I made a jig with several different cutouts along its side.
By cutting out two jigs, I was able to see which size slot worked best. I used dimensions for the slots that started with the thickness of the cardboard when I measured it using calipers and decreased by 0.01" in each slot. I probably should have used a smaller step size, like 0.005". Also, the size needed was less than I expected, by almost 0.2", so I also should have made more small slots. I ended up using 0.14" as the slot size, for cardboard that was almost 0.185" thick. I also marked the size of each slot with an engraving designating its dimensions. Unfortunately the rastered engraving did not show up well. I should have used a slower speed than recommended on the laser guide, but I didn't play around with the settings, since this was only a measuring jig and I didn't need to engrave anything on my final parts.
The construction kit had a variety of parts, shown below.
The press-fit works quite well, and can support its own weight. However, after repeated playing, the press-fit becomes weaker and has trouble staying together. Maybe I should have used a tighter slot size.
All of the parts for this assignment were made on the Universal laser cutter in the MIT Media Lab. My personal user guide can be found here.