09.   Molding and casting
Design a 3D mold, machine it, and cast parts from it

I decided to focus this assignment more on the casting process rather than the molding. Therefore, in determining what to design, the final form needed to be small, allowing it to dry fast and making it easier to duplicate casts in different materials. For that reason, I decided to design fridge magnets.

The design of the fridge magnet is the arabic word 'زفت'. It's literal meaning is asphalt, but it is used to display discontent.I designed the lettering in Rhino by using the font option to write the text and then exploding the font to generate the outline. To make the font 3D, I found the mean curve of the outlines and used sweep rail to generate the surfaces. The negative was designed with a 5mm offset bordering on all edges. For the roughing, the 1/8 toolbit was selected and the finished was milled with a 1/32 end mill bit.

Once the wax was milled, it was cast using the PMC 121/30 to make the soft mold. After waiting 12 hours for the soft mold to dry, a 1:1 ratio of Smooth Cast 300 liquid pastic was cast in place and dried completely in less than 20 minutes. The pieces were removed from the mold and then spray painted. Once dried, 4-5 coats of magnetic paint were applied to the back to attract onto any magnetic surface.

Download the corresponding files here.