The last ride of ENGI 210

This project was completed in a team consisting of me (Margo) and Lidvin Calderon.  We decided to make Fat Yoshi chess pieces after finding a file of the meme image on Thingiverse.  We learned a lot about mold making and the CNC machine, especially about how to seal a silicone mold.

It begins

After a test 3D print to show that the guy had a file that would work for both the CNC machine and the 3D printer, we separated the file into the halves that would be made on both of those machines.  We had to adjust the base files a couple of times, both to center Yoshi and to make sure there was enough space on either side of him for the mold.

 

3d Printing

The 3D printing went pretty smooth, but was redone after edits to the width of the base, to make sure that the base had enough surface area to cover Yoshi.

CNC-Ing

The CNC-ing part of the project was very time consuming, and took multiple attempts.  The drill was too small to do a rough cut at the lower levels of our piece, and the maximum height of the drill was exceeded by our piece.  This caused the drill bit to hit the top of the wood several times during the CNC process, so we changed the height of the CNC part from 1.5 to 1.2, and lowered the drill bit slightly.  Three attempts later, Yoshi’s other half was cut.  After sanding, we were ready to mold.

Mold Making

The Mold Making process was easy.  After measuring the volume of our piece, we poured the silicone and let it sit.  The next day, we de-molded the negative parts for our molding process.  For the 3D part, we used a water displacement measurement for the volume.  For the CNCed part, we blocked off the open sides with wood and measured the amount of water it took to fill the mold, and added a little extra to that in our silicone pouring.

 

Shapemaking

The process of pouring the mold took a few tries to get right, but was very gratifying when it was figured out.  We ended up using about 2 oz of part A and about 1.6 oz of part B to make our pieces, adding color to the bottom of the mixture, and demolding after about 15 minutes each time.  After adding color to the mixture, the dye began to collect at the bottom of the silicone beaker we were using, slightly changing the overall color of our later molded Yoshis.  There were air bubbles that collected in the bottoms of the Yoshi’s shoes, and we did our best to sand those out.  Tapping the molds reduced the size of the bubbles, but did not remove them completely.

conclusion

This project was really fun, and benefitted from being spread out over a month.  Once a process and measurement was established for each step of the process, it became very fun to move through.  We’ll be sad to say goodbye to this class, but we are proud of what we have learned here and (Margo, at least) will keep on coming back to the OEDK next semester to tinker hand have fun, thanks to the processes she learned in this class.

Cost Breakdown

Cost Breakdown
Category	Item	Cost	Source	Quantity	Total ($)
Materials	Wood (roughly 4x4in/planklet)	$15.72/16×48 in piece (768in)	Amazon	7 planklets (112 in)	$2.29
	PLA Filament	$11.13/cannister	Amazon	1 cannister	$11.13
	Silicone	$380 for 1 set	PolyTek	1 set	$380
	Liquid Plastic	$150 for 1 set	PolyTek	1 set	$150
	Cups	$55.09/100 cups	Amazon	3 cups	$1.65
	Silicone Beakers	$21.79	Amazon	2 beakers	$10.90
Labor	CNC Machinist	$19.64	Indeed	6 hours	$117.84
	Molder	$27.39/hr	Talent.com	4 hours	$109.56
				TOTAL	$783.37