Moving towards mass-production

We are overall happy with our final prototype, although there is still room for progress to be made before moving to mass production. We faced some limits with the 2.008 manufacturing equipment, and other limits in the part time effort during one semester.

The largest limit we see with using the 2.008 manufacturing equipment was the predefined mold blanks. We received aluminum blocks with a set sprue location that we had to work around. These were a problem for two reasons. First, aluminum molds are prototype molds and would likely be switched to a more durable metal for mass production. Second, the sprue caused us to flow plastic in from one side of the yoyo to the other, rather than feeding the plastic in from the center. Due to this location, the flow of plastic forms a pressure gradient from one side of the outer diameter to the other, resulting in a density gradient. The final yoyo has an eccentric mass that causes it to wobble. This could be solved by placing the gate at the center point of the yoyo parts.

Another limit was in the ejector pin machinery. We had a list of radially spaced pin locations to choose from, but in the case of the alien, this was a problem. We changed the location and number of the aliens in the mold to accommodate this, as seen in the above mold configurations.

In addition, the thermoforming setup was a limit towards mass production. We had plastic blanks that only allowed for one dome to be formed at a time. In mass production, we would likely build much larger tooling to work on a larger thermoforming machine, or even one that allowed for a constant automated line, in order to build more parts in the same amount of time.