Molding and Casting

Design

The purpose of the week is design a 3D mold, machine it, and cast parts from it.

In Annecy the trashes for recycled items are locked, you need a triangular key to open them. so I decided to create a mold for this triangular key. The 2 parts were created under Rhino and export as STL file:

The first part of the mold is used to cast the mold of the symetric part of the piece.

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The second part of the mold is used to cast the mold of the triangular part of the piece.

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Machining the molds

The Modela is in used so I decided to mill the mold using the Shopbot in order to practice PathWorks3D

I will use a block of parafine which was recycled, so the Top surface is not really regular and has some bubbles. I will use pathWorks(2D) to clean this surface by creating a 'poche' which cover the whole surface:

Then under PartWorks 3D for each stl file you have basically 4 step:

1: set a correct Size and Position of your STL in order to mill it from the top.

2: set a correct Size and Position of parafine block, and the position of the job into it

3: define path / tool /speed for the Rough Milling.

4: define path / tool /speed for the Finishing.

unfortunatly when the block of parafine was recycled, lots of bubbles were stuck near the top surface and some are still here after the machining. but I am lucky because it s not the important part of the mold.

Casting the Molds

I used the Smooth-On Mold Star 16 FAST to cast the mold. First I filled the molds with water and I put the water in a glass just to evaluate the quantity of product necessary.With this product the propotion is 1A for 1B.Then I cast the mix into the molds and put them under Vaccum air system to get ride of the small bubbles

Then I have to cast a second time the symetric part.

Casting the final object

1: Prepare molds with "Universal Mold Release

2: Putting all molds together

3: I used "SmoothCast325" which is liquid plasic, perfect for pouring into rubber molds .

4: Then Put it under the Vaccum air system to get ride of the small bubbles.

3: After 15 Min release the item and remove extra plastic with a cutter.

all the shortcoming are due recycled block of parafine,not from the casting.