Moulding and Casting

Week 12: Assignment

This week's assignment is to design a 3D mold, machine it, and cast parts from it.

My Approach

I've decided to design a simple mould for casting because this was the first time, I am doing anything of such kind. To understand the workflow, I had detailed discussions with my local instructor next day, after the class. After discussion, I decided to follow the following steps:

  1. Create a 3D model, using Onshape tool.
  2. Export STL file and generate toolpath using fabmodules.
  3. Mill it using the SRM 20 Modella out of the wooden block. Ideally milling should be done on a machinable wax, but since we were not having machinable wax in our lab inventory. So, we proceeded with wooden block.
    • Make a rough cut on the MDF block and then finishing cut.
  4. Create a silicone mould.
  5. Cast a piece using the silicon mould.

Step 1

Make a account on onshape server.

Step 2

Think of an object, create it and make mould for it. In my case I created a gear, as shown below.



Onshape 3D Model

Step 3

Export the created design as STL file.

Download STL file for the designed mould.

Step 4

I used MODELA Player 4 for creating tools path which is discussed as follow:

  1. Open MODELA Player 4 software and import .stl file.



  2. Go to set > Model and do the required settings, as mentioned below.







  3. Go to set > New Process and do the required settings, as mentioned below.













  4. After doing all the settings, as discussed above tool path is set for roughing.





  5. In the similar fashion as discussed above, tool path is set for Finishing also.






Step 5

After the rough and finishing cut on the MDF block, the final block looks as follow. Also, the surface of the mould was cleaned with lubricating oil, so that the casted piece can be removed properly.

Step 6

Mixture of Part A (Silicon Resin) and Part B (Binder) is made in the ratio of 1:0.05, 148.26 gms of Part A is taken and then 5% of 148.26 gms i.e. 7.413 gms of binder is added to the Part A and then mixed thoroughly. Afterwards the mixture is poured into the mould.



Step 7

After creating mould, to create the final casted piece, it is being filled with Epoxy resin (Part A) and binder (Part B) in the ratio of 1:0.5, i.e. 37.30 gms of Epoxy is taken and 18.65 gms of binder. The mixture is mixed properly and poured into the mould, theirafter it is left for drying for 1 day.



Step 8

Final part developed is as follow: