This week I continued progress on my final project of building a pinball machine by creating the mold for one of my parts. Oringinally, I wanted to create a mold for the playfield. Specifically, I wanted to create the post for the kickers which would involved a hollowed out cylinder with the addition of sharp angles and curve which would complicate the molding process and may difficult with the shopbot we have. Instead, I decided to create the flippers for my pinball machine instead. I modeled the following flipper below after the standard flippers off of pinball machines. However, I lost some of the curvature of the flippers as I went through the molding process. I no longer have the holes in the flippers for connecting to the mechanics because I couldn't get the holes and indentation of the curvature that I needed. Similarly, I couldn't maintain the hollowed bottom and the indent in the side curves which will be better seen from the plaster molding.

From here, I split the flipper into a 2 molding pieces. The bottom, hollowed structure, and the completed top one. I used vcarve to set the offset asnd toolpaths to end up with the mold featured below. From there, I created the silicone mold of the two parts that looked like the following:

From there I punched two holes into the side of one half of the mold for a vent and space to pour my plaster into. However, the first holes I punched were actually too small for the visosity of the plaster and to allow proper air flow. I had to increate the hole sizes three time and thin out the plaster to properly fill my mold. In the end, the diffuclties with filling it actually showed in the creation of the flipper. I think the time it took me to actually fill my mold was too long that cause the plaster to set and cause a gap in it as following. Alternatively, there could have just been a large air bubble within the mold to cause this shape. In the future, I plan to cast these flippers out of a plastic or a metal for durability but will do that as I get closer to the final project.

The files from this week can be found here:
this is the CAD file for the flippers
the crv ishere and here
the sbp files are hereand here