For this semester’s ENGI 210 midterm project I chose to model Movement 131 from 507 Mechanical Movements.

Vector File

The first step to create a physical mechanical movement was to create an accurate vector file in Adobe Illustrator. Instead of creating a file from scratch, I chose to image trace a picture of my movement. I hoped that by using this method I would be able to quickly and accurately design my chosen movement. I discovered that using the “TEXT” image trace setting would create an accurate drawing of my movement. Nonetheless, this method still created many errors. Most notably, image trace created a double line for every individual line from the original PNG picture of movement 131. In addition, the movement was traced as one continuous path on Adobe Illustrator. However, by using the snipping tool to separate the individual pieces of the movement and manually filling in the gaps left by separating the individual parts of the movement. I believe that by using image trace and correcting any traced errors I was able to replicate my movement much quicker and more accurately than starting from scratch.

Prototype 1

To create my first prototype, I used wood for the rack and pinion but created the base out of cardboard. I decided to use wood for the rack and pinion from the very first cut, because I was very confident in using my image trace method. My confidence was well founded. My rack and pinion meshed perfectly from the very first cut. However, I chose to use a different route to create my movement’s base. I chose to use cardboard instead of wood for the base of my movement. Instead of using the laser cutter to cut out my card board base, I just used a box cutter and a pair of scissors to cut out my base from scrap cardboard in OEDK. This method proved to be much quicker than trying to design and create a wooden base on the laser cutter. Despite, my first prototype’s low fidelity, it worked perfectly.

Prototype 2

For my second prototype, I kept much of my rack pinion design the same but vastly improved my base design. However, I did make some improvements to my rack and pinion design. I replaced the wooden dowel axles with bolt axles and added a 8mm ball bearing to my pinion. These improvements were targeted at reducing friction created by the mechanical my movement. For the base, I created a mantle-clock like design that would fit into a horizontal wooden plate. However, my design had several design errors. The axle for the handle and pinion-rotater still created a lot of friction and the rack did not reach the pinion.

Final Prototype

For my final prototype, I planned to continue to decrease my movement’s friction and incorporate a plasma cut base. Due to bad planning and unforeseen equipment failure, I was unable to create a plasma cut base. I originally planed to have the entire base cut from one piece of metal and then press bent backwards at an angle much like my first prototype. However, I still managed to add two major improvements to address the friction of my device. First, I added a bearing in the base of my design for the pinion-rotater and handle. Second, I added created a multi layer rack to add bearing wheels. Both of these improvements where able to significantly decrease friction. Despite my additions, there were still some problems with my final design. Since the pinion-rotater was press fit onto its axle, during heavy use the pinion-rotater would slip slightly off the axle and rub against the pinion. This created a lot of friction and made the rotating movement of the device difficult. In addition, the rack layers were slightly misaligned when glued. This caused the rack and pinion to occasionally jam during use.

 

To finish the final prototype, I decided to use a three part color scheme. I chose to use a shellac finish on the base and handle, a deep turquoise color for the pinion-rotater, and a dark purple-brown for the pinion. Prior to finishing the device, I lightly sanded each individual part. I believe that this drastically improved the quality of my final finish.

Overall, I thought this project was very difficult. I found that making this simple movement work perfectly 100% of the time to be very difficult. In addition, I was slightly disappointed that my final prototype still had a few mechanical hiccups.