Molding and Casting
For this week, our group had to review safety data sheets and compare molding and casting materials. The individual project was to design and mill a mold, and then cast it!
Group Assignment
For our group assignment this week, we started by using a mold of the Wheaton logo that we already had and casted it with FlexFoam. This had a 35 second pot life and a 25 minute handling time, so we had to work fast! After mixing the two elements, we poured them into the mold. Because the FlexFoam expands so much, we had to put a piece of acrylic with a hole in it on top of the mold. This allowed our w to keep its shape.![](photos/week12/group.gif)
While it definitely expanded, our w wasn't as successful as it could've been, and it was a mess to get out because a bunch of it stuck to the acrylic we had put on top.
![](photos/week12/foamw.gif)
Individual Assignment
When I was introduced to this week's assignment, I knew I wanted to do something with jewelry. I decided to make a heart charm for a necklace. I started by creating a heart in Fusion, before working to make it dimensional over 3 axises. After adding a rounded top and a hole for the charm, I added a box around it, which would function as the edges of my mold.![](photos/week12/heartwithbox.gif)
Once this design was done, I went into the manufacturing tab to get the correct bits and files for actually milling out my piece. The first end mill I was going to use was 6mm, which would take material away for the rough cuts much quicker. For the finer details of my design, I was going to use a 1.2 mm bit.
![](photos/week12/bit.gif)
To make the correct milling files, I started with a pocket mill, which took the majority of the excess part of my stock out for my design. This is what the toolpath for that looked like.
![](photos/week12/firstmill.gif)
I then had a second file that bore down into the hole of the heart. Because the first toolpath made my mold design a bit choppy, I then added another milling file with the smaller bit which would round our the layers of my design a bit more. You can see that here.
![](photos/week12/detailedmill.gif)
After all of my files were finished, I exported them to a usb to be used at the ccomputer with the Roland. I took my machinable wax and put a piece of double sided tape to the bottom, before sticking it to the bed of the mill. The 6mm bit was already in the machine, so all I had to do was move it to the corner of my wax and set the x, y, and z origins.
![](photos/week12/origin.gif)
I opened my first cut file and ran it without a hitch!
![](photos/week12/cut.gif)
I went ahead and did the boring file as well, as you can see in the following picture.
![](photos/week12/twofilesdone.gif)
Since my next file was for a smaller bit, I had to not only change the bit out of the Roland, but the collett as well. This was done by putting a wrench on the bottom and top parts and twisting. You can see the collett I took off here.
![](photos/week12/collett.gif)
I put the correct bit in, and did my final mill job. This worked out perfectly, and it turned out great!
![](photos/week12/finishedmold.gif)
Now that that step was done, I could mix up my molding material to put in the wax! For this I used the Moldstar 30 silicone rubber. This had a 1:1 ratio by volume, so I added equal parts of material A and B, and mixed it together. This mixture has a potlife of 45 minutes, so I didn't have to worry too much on getting everything together in time.
![](photos/week12/moldstar.gif)
I them poured my mixture into the mold.
![](photos/week12/filled.gif)
Once that was done, I put it in the vacuum chamber to bring any bubbles to the top.
![](photos/week12/bubbles.gif)
I let that set overnight, and came back the next day to take it out! After shimmying a popsicle stick around the edges of the silicone to loosen it, my mold popped out, and it looked great!
![](photos/week12/mold.gif)
My next step was to add resin to it for my jewelry charm! I measured the two resin parts by weight and mixed them together before splitting what I had into separate cups and adding dyes to get them to the colors I wanted for my heart. I also put some metallic powder in the mold first, to add a shiny outer layer!
![](photos/week12/resin.gif)
The colors I ended up using were blue, green, red, and clear. I poured a bit of each of these in at a time to create a sort of marbling effect.
![](photos/week12/filledmold.gif)
You think that would be the end of it, but no!! When I went to clean up and put my resin away, one of the containers was sticky on the bottom and stuck to the paper towel that I had put down on the table. I didn't realize this, and when I went to pick it up, it dragged the paper towel with it, upending my mold and spilling my resin all over the table.
![](photos/week12/spill.gif)
I cleaned that up, and made another batch of resin to fill my mold back up! Easy fix! I let it set overnight, and my charm was done! It came out great!
![](photos/week12/rounddone.gif)
![](photos/week12/backdone.gif)