Duck and Bunny’s First Play Date! | ENGI 210: Prototyping and Fabrication

Planning:

Originally, we brainstormed many ideas for our mechanical model and decided that we wanted to build a mini roller coaster model. We wanted the model to include an elevator-like mechanism that would bring a figurine up to the top of the ride in a basket, a movement that rolls the basket down the roller coaster, and finally a mechanism that rotates the figurine back to the bottom of the start of the roller coaster.

Our Idea!

However, after realizing that our idea would not be feasible due to the complexity of the design, which involves too many rotating gears connected to each other, we shifted our design to a simple slide instead. The slide design would still include the mechanisms of an elevator and rotation that brings it back to its starting place. Now, instead of having gears move the figurine down a roller coaster track, we would simply let it slide down with the help of gravity.

The design that we ended up moving forward with for low fidelity prototyping used a modified version of the Mechanism 85 for the elevator part of the model, and Mechanism 35 for the rotating track at the bottom. The change really helped simplify our design a lot, but little did we know that our idea would be much more complex in prototyping than we expected.

Low Fidelity:

With our idea in place, we decided to construct the mechanisms of our intended product with the low fidelity materials found in the low fidelity cart found in the OEDK. To do this, we utilized a weaker cardboard material along with super glue and popsicle sticks to imitate mechanical movement 85 for the elevator motion and mechanical movement 35 for the track to bring the object back to its original spot. As shown in the images, it seems like both of the mechanisms should move smoothly for the functions we expected them to be able to demonstrate, but we were wrong when we started our medium fidelity prototyping.

The track;)

The elevator;)

Medium Fidelity:

For our medium fidelity prototype, we decided to cut our ideas into reality with cardboard! However, after some fiddling around with our low fidelity elevator, Emily had the idea to incorporate mechanical movement 113 as our star gear for the vertical transportation in our model since the long prongs of the movement 85 we were desiring seemed as if they can get stuck or would not extend the elevator as smoothly as we believed gears would. We first cut out the cardboard with the settings of speed 10, power 100, and frequency 10 to gain a test cut. After realizing that it came out so easily, we decided to modify the settings to speed 15, power 100, and frequency 10 for less burning. As shown in the pictures, we cut out models of our elevator and track to show a more sophisticated look than our low fidelity attempt.

Our settings

Our cardboard plan in motion;)

The more stable track!

Look at this beauty:)

After this, we wanted to complete a couple of wood cuts to try out our designs since cardboard is not known for its ability to rotate well. Therefore, we measured and calculated all our gears and necessary helpers with a speed 7, power 95, and frequency 10 to gain a smooth, clean(ish) cut. After seeing our two mechanical components, we decided to start composing a good idea of how we were going to lay everything out into a confined space. Therefore, the idea of the model having two layers was formed! We desired for it to have more stability and structure in order to have a rotational component on the bottom that would not hinder the elevator in any way. The only problem was that now we did not want the crank that would have risen right above the track to be under the slide we were going to laser cut at the end. After looking through the 507 Mechanical Movements website given to us, we established that it may be a better decision to incorporate a mixture between movements 35 (the smaller gear spinning around the larger gear) and 92 (the slider crank motion). Our next version of the medium fidelity prototype displayed this “genius” idea we had and contained a length that was rivaling the predetermined enclosure we were thinking for this project. On the third check in, after talking to Rafe, Tori had a sudden idea on how to simplify the track portion by a lot (and it seems logical now, but it was eye opening at the time)…to get rid of the gear in general and keep the sliding crank motion to somewhat imitate a steam engine wheel. And to ensure that the basket we wanted our figurine to rest on after it goes down the slide reverses instead of continuing in its rotational motion, we decided that the crank will not reach the very tip of the circle, not allowing it to gain enough space to make that full rotation. Watch the video inserted below to get a better grasp of the motion:) (and watch Tori really struggle…)

The 2 layer design:)

A more sophisticated version!

The new gear design with the slider crank

New mechanism idea! -> video of Tori!

During the transition between using cardboard and wood, we also changed the elevator gears from 3 to just 2 to further simplify it and make the rotation smoother.

High Fidelity:

Our high fidelity prototyping was a RIDE. With our many adjustments and learning curves, it was interesting to see it all come together! However, that does not mean we did not have a few bumps along the way. We would laser cut our pieces and then sand with many different types of grits, including 60, 80, 120, 150, 320, and 400) to gain a smooth finish as we wanted there to be no sharp edges and have an easier time staining/more post processing whenever we choose to do so.

Prior to cutting the two layer platform structure of our model, we made countless calculations in order to orient and fit the elevator part and rotating track onto the circular platforms. Through these calculations we were able to use AI to simulate the movement of the rotating track and make sure that the position of the basket when it catches the figurine off the slide and the position where it reaches the start of the elevator were precise. We had to plan this orientation specifically in order for the basket not to run into any other parts that will be protruding from the top layer. After making these calculations and preparing files, we finally began cutting the platforms and fitting the parts all together. However, even after meticulous calculations, there were some parts that we inevitably missed, which we realized after cutting and piecing the parts together.

The challenge that we ran into was that there were multiple times where we cut out our pieces and after putting them together, we would realize there were some factors that we forgot to consider in calculation and designing the files. We realized that it is a lot harder to try and visualize all of our parts coming together without a physical model to work with, which most likely created our issues. For example, we had to recut the top platform of our two layer structure that supports the slide and the mechanisms multiple times until it was able to exactly fit all the pieces of the elevator and rotating track. Through trial and error, we were able to recut this platform and some of our other parts and finally reach a functional model. A trick that we used was to keep our plywood and reposition the piece exactly in the same position and make any additional cuts to that piece in order to adjust our design.

Another challenge (for Tori) was to remember to always save the after making a modification, especially when one is one the computer connected to the laser cutter. There was a time in which Tori needed to utilize a “wacky” method of positioning the circular bottom with the correct cutouts for the supporting pieces up to the computer screen to gain the correct position for the top layer (crazy that it worked).

After hours of sanding, gluing, and making trips back and forth from the laser cutter to the computer lab and downstairs, we finally assembled most of our parts and began staining our model. We used linseed oil for a more natural and consistent look. Finally, after completing the slide and its mechanisms, we made small duck and bunny figurines to ride the slide, and our mechanical model was done!

Here comes our burst of pictures:)