To Infinity and Beyond | ENGI 210: Prototyping and Fabrication

For my midterm project I decided I wanted to utilize a simple linear motion and apply a space theme. After browsing through the 507 motions site, I chose movement 113 for my project.

I decided that I wanted to use this motion to lift a rocket. I decided that I would put my rack and pinion against a backboard and have a box like structure to secure the rack. In my initial Illustrator design, I created a rack and pinion with rectangular gears, as well as the backboard, base, and box.

Original rack and pinion design

Base and box structure

Backboard and rocket to be lifted up

After creating my initial low-fidelity cardboard prototype, I ran into a few issues. The rack and pinion motion was not at all smooth, so I redid my gear using an online gear generator. I also realized I did not think about how my backboard would stay upright when attached to my base, and had to use dowels to secure it in place.

First low-fidelity prototype

Thus, I updated my Illustrator files with the new gear (I used a gear generator) and added two triangular pieces with tabs that would attach to the base to hold the backboard in place.

I then created my second low-fidelity prototype, as I wanted to make sure that the new gear shape worked well before moving to the medium/high-fidelity prototype. This gear worked a lot better than the more square gear, and the triangular pieces helped to hold the backboard in place.

While the gear worked well, I decided to make a few more changes before creating my final prototype. Adulfo suggested adding tabs (to the backboard and box structure) to help align the pieces and keep the structure more secure, which seemed important when working with a more rigid material (aka wood). Additionally, I made the bottom section of the box structure longer as well as added a tab that extended outward from the rack that would stop the rack from moving up too high, as the rack was not very stable when moving and would fly out of the bottom part of the box. Having not made my own tabs during the laser-cut box project (I used an online box generator), I struggled a lot both in creating the tabs so that everything would fit in place perfectly as well as accounting for kerf. My final illustrator files ended up looking like this (although I also added a hole in the gear as well as made two circles to secure it in place):

Before I started to print everything out, I needed to find a kerf that worked well for me (I used the older laser cutter). After a lot of trial and error , I found that a kerf of 0.016 inches was good for the joints I was using.

Using this kerf, I was able to successfully fit the joints into place.

After I had printed out pieces that all fit into place well, I sanded (with 220 grit) and stained all of the wood pieces with Mahogany stain. In the meantime, I decided cut my rocket using the waterjet cutter. Initially in my low-fidelity prototypes, I just had a two dimensional rocket shape (from the nounproject.com), but found that this was not very stable (I used LOTS of hot glue to hold it upright), so I decided to create two interlocking pieces to create a 3D shape, taking inspiration from some rockets others had created online. My initial design had circular holes in it for decoration, but the waterjet cutter did NOT like the holes at all and made little lines coming out from each hole that were not in the original file. Additionally, there was one line in the file where the pieces interlocked that the waterjet cutter decided it didn’t want to cut, so when I removed the piece from the metal sheet it had a little nub that made the interlocking uneven.

Thus, I decided to get rid of the holes and have a plain rocket, which I then wire-brushed, sandblasted, and then powder coated in black. After all of my stained pieces were dry, I assembled everything together, using wood glue for the larger surfaces, super glue for smaller surfaces, and epoxy to attach the rocket to a circular platform below it. Additionally, I noticed that the rack’s movement had a lot of friction (since it is wood on wood), so I used Vaseline reduce the friction and make the movement smoother. I also added some black vinyl-cut decals to decorate the piece, as well as nameplate to the back between the triangular supports. I originally wanted to add some sort of handle to the gear to make user-interaction easier, but the way I set up my gear, there was not really a good spot to put a handle, so I decided to leave it off.

Here is the final form of the project: