Molding and casting

 

WEEK ASSIGNMENT:

-Design a 3D mold, machine it, and cast parts from it

 

For my assignment i decided to do a small keychain of a key from the game Hearthstone

 

I made my mold design using Rhino i decided to do the negative form and make a direct pour on to a wax mold

Fab Academy 2016 • Oliver Ochoa Garcia • Fab Lab Puebla • Mexico • oliver8agar@gmail.com

Next i used the roland milling machine to machine the wax for my mold

Next I used a polyester crystalline resin for my casting into my mold with a k-200 catalyzer. As it was a 3 mm cast i was worried of not being able to pull out my piece, so i used a little of demolding wax.

In the next picture you can see my final product, as i used crystal clear resin its a bit hard to see. Also as the final piece is really thin the finish  cut given to the piece wasn't enough to remove some of the roughness however, this isnt the correct way to do it and I realized it too late. It's supposed to be hard-soft-hard. So i did it again.

In the next picture you can see my final product, as i used crystal clear resin its a bit hard to see. Also as the final piece is really thin the finish  cut given to the piece wasn't enough to remove some of the roughness however, this isnt the correct way to do it and I realized it too late. It's supposed to be hard-soft-hard. So i did it again.

 

This time I decided to do a guitar, something a bit easier to cut. After doing the STL in Catia, I loaded it into the fab modules. In the program i converted this stl, into PNG and got the face i wanted to work in this case Z.

Then the PNG is converted into a path. The tool i used was 1.65mm in diameter, with an overlap of 25%

I also did a silicon mold for some pieces I had to reproduce in mass for a project inside the university.

 

Steps to follow:

1. Fix the part to be molded with a little play dough on the wooden base. This in order to prevent the workpiece from moving when using the silicone.

2. form with the clay wall around the piece to be molded, in order to create a kind of container / barrier to empty the silicone.

3. In a mixing bowl, pour the silicone and solvent and mix regularly until the two substances are combined.

4. Add the catalyst and stir quickly. Immediately pour the silicone in part, within the look created earlier.

5. Wait for the silicone to dry (about 8 hours) and then the piece can be removed to obtain the desired mold.

To remove the piece more easily, it is recommended to apply a little Vaseline on it and the walls created, to serve as anti-adhesive element.

 

Measures to use:

it is recommended that the proportions of the materials are 100% silicone rubber by 50% solvent. to dissolve the silicone.

To catalyze is recommended catalyst 50 drops per 100 grams of silicone.

To practice 50g of silicone and 60 drops of catalyst were used. This with the purpose of accelerating the drying process due to the time with which it had to practice. This will make the silicone dry in less than an hour.

 

 

Silicone rubber boat P-48 Polisil bought "Poliformas".

Rubber mixed with the solvent in an exclusive container for this use.

I poured the mixture

And then I unmolded it.

And a picture of my mold with my cast

As an extra I also dabbled into metal casting. My instructor Huber Giron was getting married so I offered to make him his wedding rings as well as one personal one. I made the rings in Rhino and send them to be printed in the wax printer.

To make the mold I joined the printed rings to a wax tube. and then mount it on a cap. Then that mount is put on a tube which is then filled with, dental plaster. Once it dries we remove the cap leaving the wax. This plaster mold is then heated up to harden and evaporate the wax from the mold. Finally using a centrifuge we smelt the metal, in this case silver and and thanks to the centrifugal forces the melted silver is forced into the mold

The final result of the wedding bands