Homework 6: 3D Rings, Laser-Cut Nametags, and Low-Fi Vehicle

Part 1: 3D Modeling and Printing

Design and 3D model a ring to be worn on one of your fingers, must be sized to fit you.

This part was a light introduction on how to use 3D modeling software and 3D printers.

Process

First of, I spent a while toying with different CAD programs. While in the Invention Lab or the Jacobs makerspace, AirBears2 wasn't fast enough: 123D Design, a 338 MB program, was estimated to take 8 hours to download. As a result, I tried to use AutoCAD to make my ring. That didn't go far, given advice from a fellow hacker (Ian) that AutoCAD wasn't the greatest program for 3D CAD. Stressing out for a bit, I left the Invention Lab, went to Soda, and downloaded 123D Design in 2 minutes, along with Autodesk Fusion 360.

I had greater plans for the ring: it was going to include a 3D printed abstraction of a laurel (inspired by something I saw while Googling "3D printed rings"). In the end, the ring was simple: 24 mm x 24 mm x 10 mm, with a chamfer of 1.5 mm on each outer edge of the ring. I made three of them, with hole diameters of 18 mm, 19 mm, and 20 mm respectively (my finger's girth was measured to be roughly 18 mm). I got the basics of 3D CAD with 123D Design, but ended up making the same models more rapidly and precisely with Fusion 360.

Results

The results were good: the rings had nice quality, but alas, only the 20 mm diameter ring actually fit my finger comfortably. Given I had made the chamfer 1.5 mm on both outer edges, it would appear the rings got deformed in the printing process. I suspect the filament's own weight squashed itself on the upper level, resulting in the difference in shape. 

Conclusion

Turns out, 3D printing isn't as daunting as I thought it would be. I found myself browsing for 3D printers and imagining what I could do with 3D printing. Besides that, a 2 mm extra margin of space sounds like a healthy choice for tight-fitting things like a ring.

Part 2: Laser Cut Nametags

Laser cut two name tags to use for critiques, Include the class name and semester. Must be readable and have a design sense to them.

This part was an open-ended assignment to make a nametag for project critiquing.

Process

The first thing I thought of was bent plastic nametags, so I aimed to master the arcylic bender for this part. My first design was a simple plastic sign saying "Eric" in Lovelo font. I intended for the nametag to stand on its own by bending it to a 60 degree angle, like an inverted "V". However, that would have required a block of wood with a 30 degree bend on it to mold the heated acrylic when the time came, which I wasn't willing to machine for this sole purpose. After watching a tutorial on how to use an acrylic bender, I came up with an alternative, a "U" shape sign, with two right angle bends. My first attempt came out really well, and after the first bend, I felt the sign was good enough as is, eschewing the second bend.

I was so happy, only to realize the fine print of the assignment.

Include the class name and semester.

Of which I didn't have. I had two nametags cut, but only bent one at this point, so I quickly added the text into the .ai file and went to Jacobs to cut a new one while etching the remaining piece I had. Unfortunately, I mis-calibrated the laser cutter in Jacobs, causing the engraving to be off-centered for the existing piece. Eventually I bent both (and painted the engraving, which was new for me), like so:

but I was bothered by the the off-centered text of the sign I was likely going to use for myself (since I ought to turn in the nicer copy), and as for the nicer copy, I managed to get glue that was on the workbench stuck on to the heated sign, resulting in this huge, nasty, sticky spot on my sign. I was dissatisfied with either sign, so I made another pair.

Only, none of these signs had my surname. 

Hoping to not use a whole other sheet of acrylic, I crafted smaller signs out of the remaining acrylic I had. I thought that cutting out the word "Eric Chen" at that smaller scale could be prone to fusing, so I made four signs, with two of them engraved instead. I was proven right.

Results

I like the result. However, the later signs I made never came close to the quality of the first one in the bend. The rest all had the corners stick up and would wobble a bit (this was less so in the last few signs I made). The paint job went well.

Conclusion

The acrylic bender and painting were new to me, but both went pretty well, and I can see myself using it more often. Of the things I learned, 1: read the assignment, 2: let the acrylic paint sit for a bit for better results, and 3: wait for the faintly darker strip that runs all-across to appear in the acrylic before bending.

Part 3: Label the Arduino Shield

Put your name on your hand made Arduino shield (3 LEDs and connector for servo motor) ...

See my last Hackster project.

Part 4: Low-Fi RC Vehicle

Low fidelity prototype of three chassis designs using lasercut cardboard, 3d printed parts, bamboo skewers, straws etc...

This part was to make early prototypes for our second major project, an RC vehicle.

Process

When brainstorming on how to get this vehicle to move, I looked to nature for inspiration. The main solutions I could think of were walking and sidewinding. But then another thought came to mind: we made wheeled vehicles first because they're easier and simpler to make.

Thus I went back to wheels.

But then, the question is how many wheels: my three models have two motorized wheels and one motorized wheel respectively. My more fleshed out design has two motorized wheels in the front, where the rest of the circuitry and battery cells would be held, with a tail in the back, which also houses another wheel to keep it stable. It kind of looks like a sting ray in my sketches, so that's how I think of it now.

I made my three chassis out of cardboard with cardboard wheels (thanks Matt!), tape, zip ties, and the lollipop sticks.

Model 1:

Model 2:

Model 3:

Results

For some reason, Model 1 and 2 seem to veneer to the right whenever I let them roll. I'm not sure what that's about, but it'll be fixed by the final model. I was excited to see Model 3 go, but it doesn't really work, which is disappointing.

Conclusion

I probably won't continue with unicycle models again, but at least I got some practice with the "rover-like" wheel build.