ASSIGNMENT
Design a 3D mold, machine it, and cast parts from it.
WHAT I DID
- I designed my 3D model in Rhino.
- I prepared the wax block for the milling.
- I milled the 3D object with the Rolonad Modela MDX-20.
- I created the negative polyurethane mold.
- I casted with different materials.
3D MODEL
My first plan was to design a flower, I ended with the model of only one petal and I also wanted to insert a led inside the petal so I tried to create the space for that inside the petal.
WAX
It's not so complicated, I took the proper pot, warmed it and filled the pot with wax surplus of old molds. When it was complitly melted I filled in the box to make the wax block.
I tried different container: a food plastic box upholster by owen paper and mdf-tape box. The second one gave a workable result after I cutted with a circular saw the upper part. The next time I will use arcylic.
Using the owen paper- plastic box:
Using the mdf box:
3D MILLING
I had two jobs, the petal-top and the inner part.I fixed the wax block with double side tape and used MODEL player 4 software to set-up the milling job.
The petal-top has been done with 1/8 mill bit and the software already had the right set-up to work on wax. I runned two processes: the rough and the finishing.
Rough process:
Finishing process:
The inner petal has been done with 1/16 mill bit.
The rough process:
The finishing:
MOLD
Using polyurethane two components I created my negative mold. I used 1:1 components proportion and left it dring for about 16 hours. I learned that:
It's important to work in a safty environment, dress transpiration mask and gloves.
When you mix the two component, move the stick in a way to not absorb air and don't forget to scratch the sides of your container.
When you fill in the mold start from the lower side and leave the two-components flow around the mold, it's recommended to pour the two-components over two-components and not directy on the mold surface.
If your mold is too low you can use mdf plates to make your mold high enough. Once the mold is ready you can remove the over-step with a cutter.
CAST
The casting process is very similar to the molding job. I used tape to close the mold and I used Smooth-on Vytaflex-60 (urethane rubber compound), pot life 60min - cure time 16h (it was over-date 2010).
I learned:
To understand how much material I needed I filled in the mold with water and measure the volume with a graduated glass.
To stir the two components separetly and then mix them together.
PETAL
After one rest night I could remove the petal from the mold.
Comment: I made a mistake in my 3D model design. I made an empty where it was supposed to be full. So I filled the error with wooden cude and sticks.
MATERIAL TEST
I really liked the process so I wanted to test more material also for my final project and here are my test:
Smooth-on Vytaflex-60 (urethane rubber compound), pot life 60min - cure time 16h (it was over-date 2010).
[It use supposed to be white.....I like the soft touch and the flexibility]
Smooth-Cast 310 (xxx), pot life 10min - cure time 4h.
[the surface is not shiny, it's hard and can't be bended]
Smooth-Cast 326 (xxx), pot life 7min - cure time 1h.
[like with the 310 the surface is not shiny, like it should be, in the picture you can see the left material that got hard inside the cap I used to mix, it's trasparent and shiny, why??????]
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