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10. Molding and casting

This project was totally new for me. I had never had any experience doing molding and casting. Since it is time for practice I decided to build something interesting for my puppy.

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. Plese take a look at the Group assignment of Silvia Lugo web page.

Individual assignment

The activity consist of:

  • Design a 3D mold around the stock and tooling that you’ll be using.
  • Machine it, and use it to cast parts.

On this opportunity I had made the design at Fusion by Autodesk.

I feel really comfortable working on it. Extrusion are edition are simpler than other programing CAD languages. My design consist of :

I would like to built a tin collar label for my puppy, if possible later on to grab its name on it.

Molding

Once the STL file is complete I had use the Shopbot Software for defining the routes, material to be remove, the proper tool to use. You may have a lot of tutorials at Shotbot.

However, I need to recognize the available bits for cutting and removal the empty material. Then, one of the most important task is to set the zero point. Also, at the tutorial of Shopbot you may have a good recipe how to do it.

Some tests

My first test was with FlexWax, unfortunately as you may see at the pictures, it was not so easy to work on it. Unfortunately, the wax melt. Later on I had noticed it was possible to change the speed of the bit at PW3D design.

For the second test I had decided to change the flex wax for a Blue wax. The decision was correct, because its material is harder. I used the default values of PW3D. As you may see the results are much better.

You have to be very careful at fixing the material, otherwise you may have some broken bits. Please take a look of a video taken during the carving process.

Please see the results of the process:

Casting

I had chosen a resin able to support a tin metal fusion. The silicon is from Silicon Peru. In order to change the silicon state to solid, there is the need of a catalyst. The relation is of 2% of the total of the silicon weight.

I had to done the procedure twice, the first time I did not mix it properly, so the silicon did not solidify. The second try was better, now I am ready to do the melting process.

You may download the files here