Week 14 Molding and Casting
Summary
This week I made a tealight candle holder out of Zhermack ZA22 mould silicone that in turn could be used to cast tealights from leftover candlewax to use in this and other holders.
Assignments
Group assignment
Review the safety data sheets for each of your molding and casting materials then make and compare test casts with each of them and compare mold making processes. See documentation for the group page here
Individual assignment:
Design a mold around the process you'll be using, produce it with a smooth surface finish that does not show the production process toolpath, and use it to cast parts
For the individual assignment I want to make a silicone tealight candle holder that could be used that way and also to cast tealights using wax to replenish it.
I drew up a simple design in Fusion 360 and then followed the instructions in this youtube video to create molds around the design.
Here is the image of the design and the molds that I then created around it.
To create a double sided mold you extract a square shape around the part and then use the combine function in Fusion to create a cut in the mold. I then added two holes in the bottom of the mold to be able to add the silicone and then to vent it. Because of the way the candle holder is shaped I had to cut it somewhat assymetrically so that I would not go through the cut out that will hold the candle and/or allow me to cast a tealight.
Then I moved on to the manufacture tab in Fusion to setup the toolpath to make the mold. There we discovered that we needed to change the release angle in the mold or the silicone would most likely get stuck so we added a 5 degree taper on both sides of the mold so that it would be possible to release it.
Then I went through the setup process to select the settings for the milling and I essentially copied the settings of my instructor Svavar's page. I also measured the 1/8 inch end mill and added the measurements required into the setup. I also had to go back to design and create stock pieces identical to what I will be using on the ShopBot so that I could run the simulation. After a couple of iterations the simulations look good. It will most likely not finish the holes in the bottom completely but we may be able to fix that with a drill.
We then started the Shopbot to mill the first half of the mold, the machining time was over an hour and unfortunately I was not able to start the milling for the second half and will need to complete this assignment after the deadline.
