molding & casting

this week's focus was on molding and casting. i used fusion 360, the cnc mill, machineable wax, silicone and clear epoxy to start working on a button for my final project.

designing the button

i used fusion 360 to create the design of a button i'll be using for my final project. the button consisted of three objects:

• a cylinder with a height of 15mm and a width of 50mm
• a cylinder with a height of 5mm and a width of 60mm
• a negative extrusion of the word "DAO" into the first cylinder

creating the wax mold

i then exported the final body as a .stl file and started the milling process. fortunately for me, and everyone else in the class, there is a very detailed guide on how to take the .stl file, a block of machineable wax and turn it into a wax mold here

to summarize:

1. secure the wax block onton a piece of wood using hot glue
2. drill the wood onto the shopbot's sacrificial layer
3. load the .stl file on partworks3d
4. orient the size of the model
5. set the material size and margins
6. set the roughing toolpath
7. set the finishing toolpath
8. PREVIEW THE TOOL PATHS (i didn't and didn't notice the word "DAO" wouldn't mill)
9. save the roughing toolpath
10. save the finishing toolpath
11. open shopbot3
12. insert the mill bit
13. zero the shopbot
14. load the roughing toolpath file
15. start the mill
    
16. load the finishing toolpath file
17. start the mill
18. vacuum wax
19. remove wood and wax block from the shopbot's sacrificial layer
20. separate the wax block from the wood
    

creating the silicone mold

after i finished milling, i noticed that the top of the button was flush with the top of the walls. before i could start mixing the silicone, i first used masking tape to increase the wall height so that i could pour over the button.

after applying the masking tape wall, i put on my gloves and gathered:

• two plastic cups
• a popsicle stick
• a scale
• oomoo 25 silicone mold rubber mix
  

to create the silcone mold with the 1:1 part a to part b silicone mix:

1. place a cup on the sacle and tare it
2. pour 2 grams of part a and remove the cup from the scale
3. place the second empty cup on the scale and tare it
4. pour 2 grams of part b and remove the cup from the scale
5. pour the contents of the second cup into the first cup
6. mix the two vigorously until it is mixed well
7. pour the mix into the wax mold
8. place the mold into the vacuum to remove internal bubbles
9. per the package instructions, let set for 15 minutes
   
10. after 15 minutes, remove the silicone mold from the wax mold
    

creating the epoxy button

with the silicone mold finished, i put on some gloves and gathered:

• two plastic cups
• a popsicle stick
• a scale
• tarbender clear epoxy encapsulant
  

to create the final epoxy button with the 2:1 part a to part b epoxy mix:

1. place a cup on the sacle and tare it
2. pour 2 grams of part a and remove the cup from the scale
3. place the second empty cup on the scale and tare it
4. pour 1 gram of part b and remove the cup from the scale
5. pour the contents of the second cup into the first cup
6. mix the two vigorously until it is mixed well
7. pour the mix into the silicone mold
8. place the mold into the vacuum to remove internal bubbles
   
9. per the package instructions, let set for 16 hours
   
   i had more epoxy mix than the button needed, so i took the turtle mold and poured the rest in there
   
10. after 16 hours, remove the epoxy button from the silicone mold
    

future work

for my final project, i'd like to add some coloring to the epoxy so that i can have color-coded buttons.

i also need to make sure to make the words i use large enough for the mill bit to cut into the wax mold.