Design Process

Version 1

In version 1, we tried to limit the amount of plastic used and make the center of gravity as low as possible. You can check out the file (you must have Auto Desk Inventor).  Unfortunately, it used too much plastic, which would make it more expensive.

Version 2

Version 1 had an unnecessary amount of plastic on the base, we removed this since it wasn't significantly lowering the center of gravity. You can check out version 2. Unfortunately, versions 1 and 2 will only work properly if they are oriented correctly.

Version 3

In version 3, we completely revised the design. We designed it to be rotationally symmetrical in that it will work regardless of its orientation. The goal for this design is to utilize the water's surface tension. The water's surface near the unit would curve down, creating a low area near the unit. As a result two units will be drawn two each other as the water between them is lower.  The slanted sides were designed will prevent them from stacking. As a result the units will tend to stick together and self-tessellate, forming a near complete cover for the surface of the reservoir. Check it out here.

Version 4

In version 4, we refined the design from version 3. We filled in the top and bottom which were hollow in the previous version to save plastic, but in the test of version 3 they filled with water. We increased the angle of the sides to make prevent stacking.

Vacuum Forming Blank

For version 4, we started evaluating designs when it comes to their ability to be mass manufactured. We made a blank that would allow us to form two halves of the units from version 4 using a Vacuum Former

Version 5

Version 5 was quite similar to version 4. In version 5, we switched from using a chamfer to using a loft to from the sloping sides. This would allow the units to more easily turn when riding across each other, as seen in the large-scale test of version 4.

Vacuum Forming Blank

A vacuum forming blank was made for version 5.

Version 6

Version 6 was similar to version 5, but instead had ridges along the edges. These ridges were designed to prevent the units from stacking as seen in large-scale test of version 4. 

Vacuum Forming Blank 

A vacuum forming blank was made for version 6.

Biscuit Joint

The loft in versions 5 and 6 were difficult to 3d print. So with Mr. Marx's recommendation, the model was then remade to use a biscuit joint to make 3d printing easier.

PLA and PetG

Version 6 was printed using both PLA and PetG plastics. All previous versions were printed using PLA. PetG is UV stable so it would withstand the conditions of the reservoir.