Champaign-Urbana Community Fab Lab
Champaign-Urbana Community Fab Lab

Iteration Project – GearBox

This week’s assignment was iteration — redoing something we’ve done before with a new approach and a combination of tools/methods. I chose to reiterate the name tag cutting project. The picture below is my laser cut name tag from the laser cutting week. The reason why I decided to reiterate the project was because I really like the laser cutting machine — I like how precise it is. I thought the name tags we created were really simple so I wanted to see if I could do a project that was more complicated with the laser cutting machine.


I’m not sure exactly where I got the inspiration from – but I thought it would be cool to do something with gears. I looked up a simple design on the internet. Some people in my lab session were also talking about shadowboxes and press fit boxes so I planned for the gears to be in the press fit box. It is meant to be an aesthetic piece. I also thought it would be pretty neat if the gears turned by themselves with a servo motor (powered by Arduino).

The first thing I did was plan out the gears. I found a super useful website – creategear.com – that helped me create the gears I needed. After editing the design of the gears on Inkscape, I laser cut them out. Only two of four gears were cut out correctly on my first attempt. It was a pretty frustrating process because the machine was super busy and I was starting to realize this was a bit of a complicated project because the gears needed to be in precise positions to work. After messing around with the other two gears, I finally got them to cut out properly. The next step was cutting out the press fit box which didn’t turn out as messy or unpredictable as the gears. At this point, I wasn’t sure whether or not I should laser cut holes through the press fit box (to hold up the gears) or drill through the back of the box. I asked James for advice and he told me to use the drill press. After some guesstimates on where the gears should go, I used the drill press. These initial guesses were wrong because the gears overlapped (see picture 2), but I just used the drill press again and this time, they were more or less correct. I feel like I should’ve taken more of a scientific procedure (ie. precise measurements) to ensure that I was drilling into the right place, but it worked out in the end.

             

After I got all the gears into the holes, I immediately ran into my next problem. While the gears turned when I twisted the nut of a bolt in the back, the nut would screw into the bolt and started tightening/pressing against the back of the box. I showed my handy-dandy roommate my gearbox and told him about my problem, and he had a fix for it! He works a lot with bikes which is why he knows a bit about certain mechanical mechanisms. He told me that I just needed to double nut the bolts from the back so that the bolts are tightened against each other and won’t move towards the back of the box. THAT WAS A SUPER HELPFUL TIP! I really wouldn’t have figured that one out by myself.


At this point, I have my gears in my pressfit box and they’re spinning fine. The next obstacle I had was that I wasn’t sure how I was going to attach a servo motor to the bolt/nuts. They’re quite small. Duncan told me to talk to the in-house electronics consultant, Brandon. He looked at my project and recommended that I 3-d print a worm drive and attach it to a motor (super smart!). He told me how it could bet set up on my box and helped me 3-d print a worm drive. I didn’t think the threads would be able to print that well, but it came out looking a lot better than I thought it would.

(3d printed worm drive)

I hot glued the bottom part of the worm drive to one of the bolts, but I wasn’t sure how to set up the other part of the worm drive. Also, I wasn’t sure if the top component of the worm drive was turning the bottom part, so I dropped the idea of completing the worm drive. In the end, I also decided not to attach the servo motor to the 3d printed knob because I knew I wasn’t going to keep/devote an Arduino board onto the gearbox and I didn’t want to rip a servo piece off the 3d printed knob after the project.
This project caused me quite a bit of anxiety because there was a lot of planning and uncertainty, but I’m satisfied with the end result. In the near future, I might ask Brandon how I can get the motor-powered worm drive to the press fit box.