Our midterm is meant to be a culmination of our skills used thus far for our other projects: Prototyping, laser cutting, plasma cutting, sanding, painting, staining, drawing, attaching, and new skills like water-jet cutting. We needed to choose a mechanical movement from 507 movements and implement it in a drawing, some form of rapid prototyping, and a final prototype. The rapid prototype doesn’t have to be functional, but the final prototype does ideally.

For my movement, I chose the same movement as in my Project 2, Movement 68, which would allow me to control smaller portions of movement from a single revolution. I decided to center my movement around a Ferris wheel and have each rotation bring a new Ferris wheel car to the bottom. I would combine my movement with a 10:6 gear train to simplify the drawing in illustrator. This would allow me to make the proper movements without having to modify the original design in illustrator. I just copied the image trace I used in Project 2 and added a gear train along with some other goodies such as:

• A large wheel to represent the actually spinning Ferris wheel
• Some rectangular pillars to hold up the gear train + movement
• Some upside down V shaped pillars to add some style to the Ferris wheel
• A smaller wheel to use as a lever to spin the whole mechanism

That was all I drew up for the rapid prototype. I simply laser cut everything in cardboard, found some fat base made up of cardboard, and decided to wing the actually construction. I essentially used hot glue to hold everything together since it dries really quickly and doesn’t require much preparation to use. The gears were held up by some straws found in the prototyping cart at the OEDK and were convenient because they were fairly strong while being easily cut and modified. I measured out the diameter of the straws to be used as axles and the circles in each of the laser cut pieces ever so slightly larger so that it could spin fairly easily but still securely.

As it turns out, cardboard is really bad for gear based movements because the innards of cardboard consists of a bunch of empty space and some folded up paper. This means there is a lot of extra gaps that can result in the gears not making contact with each other, undermining the whole mechanism. I tried to counteract it with some hot glue on each of the gears contact points with some success. Another con to using cardboard for prototyping would be how flexible it can be when you don’t want it to. I used single pieces of cardboard to hold up each of the straws that connected pairs of gears, but it usually bent under the stress of the movement. It was pretty unreliable to say the least, but I at least got a feel for how I want to fit together physically rather than in a drawing or in my head.

One more note, I found out with my cardboard prototype that the current design for the single toothed-gear was perfectly circular, causing bits of it to scrape against the other gear of the mechanism. I quickly remedied this in inventor so I wouldn’t have issues later on with this.

Next, I decided on making my Ferris wheel actually look like a Ferris wheel in inventor. I started by editing the large wheel to make it have 6 spokes, one for each car. Then I copied it to add some depth to the wheel. Dowels will go where each spoke touches the outside circle and will each hold a laser cut car.

Each car fits inside of 1″ x 1″ square and were especially fun to make because I individualized them. I’ve got a family sitting in one, a couple on a date in another, some guys looking out of the car, and a couple others. Each one is a different color just for some added spice.

I decorated the entirety of the Ferris wheel and V-pillars with spray paint except for a single purple car, while I stained the gears and rectangular pillars. I attempted to make the larger circle with spokes look like it was made from steel in order to recreate a Ferris wheel more faithfully. I sandblasted the single metal gear to make it look more uniform and kept everything else its usual color.

Besides that, I also decided to make most everything out of wood for laser cutting, from the base to the pillars to the dowels. The only pieces that aren’t wooden are the Movement 68 pieces, some metal washers, a person in front of the Ferris wheel, and a disc that will act as the lever for spinning the whole mechanism. The lever disc was plasma cut from a thin sheet of aluminum, as was the person. The single tooth gear was made from acrylic and the other gear was made from metal, cut by the water-jet cutter.

I assembled most of the wooden pieces with super glue which typically wouldn’t be used for wood, but I found the gel to be fast acting, strong, and fine for the porous material. It didn’t work as well for the metal materials, so I turned to epoxy for bonding metal to wood. It was kind of a problem for the metal disc lever to bond to the dowel with epoxy since it takes quite a bit of torque to turn the mechanism. I decided to make a wooden copy that I would replace the metal iteration with in case it failed.

I used washers to space stuff out and to add a little stop to the dowel holding the Ferris wheel. For the other dowels, I used the gears themselves as stops and basically added a glue covering to prevent the dowel from slipping or moving around.

The base is a 7″ x 7″ square with some extra base pieces used to hold the pillars in place a bit more securely. I quickly CAD-ed those by measuring the width and length of each of the pillars with a caliper and adding about .1″ to each dimension. It took me a few attempts to get right, especially the piece holding the V-pillars together. The first time, I didn’t take into account the V-pillars slant inwards and it made the whole thing not fit. The second time, I didn’t remember the cars and they ended up hitting the floor and making the whole thing get stuck. Otherwise, the base pieces were fairly straightforward.

I ended up adding a metal person with an afro towards the end of the project, mostly because I needed a plasma cut piece in case my metal disc fails to provide the torque needed for the project and I end up replacing it with wood. I thought it looked amusing.

My final project ended up being nice and compact, fitting in an 7″x7″x8″ cube. This was a fun project, but I wish I had planned things out better because there were some instances where my poor planning came back to bite me:

• The base for the Ferris wheel took multiple trials
• The dowels used in the Ferris wheel weren’t as precise as I would have liked them to be
• I should have made larger unified pillars that hold multiple axles together so I didn’t have to eyeball the positioning (made the gears a pain)
• Staining my wooden gears somewhat carelessly, which caused some extra friction between the teeth

• Not being more conscientious as to what pieces were made from. I arbitrarily decided which pieces would be wood, metal, or acrylic, despite each one having its own pros and cons.
  • I used wood to make the Ferris wheel and then spray painted it metallic, when I could have made it from metal to begin with
  • I used wood for the gears when the acrylic may have been a better choice to reduce the friction between them. This could have caused problems with slipping, but getting stuck every now and then because of friction isn’t great either. I used some vaseline to try and combat this, but I’m not sure which would have been better.
  • I used metal as a stop for my dowels (metal disc lever) when wood should have been the immediate choice. Glue would have much more easily bonded to wood and would have made torque less of an issue I think. I liked the aesthetic of the metal disc which is why I went for it anyway, but wood would have been so much simpler.
  • I didn’t use a 3d modelling software to make more precise measurements and placements of pieces. Granted, we were never taught how to use these in class, but seeing other students use them to fit everything together made them seem invaluable to streamline the process of piece placement.

That’s that. I could have remedied most of these with some more intermediary prototypes before my final prototype, but I think my current result is good.