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12. Molding and casting

Group assignment:

  • Review the safety data sheets for each of your molding and casting materials

  • Make and compare test casts with each of them

To see our group assignment click here

Individual assignment:

  • Design a mold around the stock and tooling that you’ll be using, mill it (rough cut + (at least) three-axis finish cut), and use it to cast parts.

Hello!! for this week, we’ve decided to make a mold from a stl file downloaded from the internet.

The mold

a mold is a tool or device used to give a specific shape to a material such as plastic, glass, metal, etc. In the plastic parts manufacturing industry, the mold is used to inject molten plastic into a particular shape to create a specific part.

Mold example

Counter-Mold design

Step 1 : design your model

use Mirror

Add a touch of color and you get the following

we’ve finished modelling the mould, so move on to the next step

Step 2 : Export in stl format

Files project

Mold file

Toolpath generation in Vcarve

 1 --> Open V carve and create a new file

 2 --> Import the the STL file usi,g the modelind tool on vVcarve

 3 --> Put your piece in center of your space put your part size

 4 --> Import the model

 5 --> Choose your tool and calculate the toolpath

 6 --> Choose the processor and generate the the machine file (rml...)

Set the following parameters as material dimensions

 Width (X) : 150mm

 Height (Y) : 150 mm

 Thickness (Z) : 40 mm

Place your model in the center of the reserved space then click on Position and Import

Mistakes

to tell the truth, getting to this final product was no picnic. First, I made lots of molds, all of which collapsed as soon as I’d modelled them. I soon realized that I needed to make a counter-mold.

After much trial and error, we finally found the ideal mold.

Monofab

At y’ello lab, we have 3 different sizes of machinable wax, as you can see below (this image was taken from the website Karam Khrais).

Here’s the tool we’re going to use 1/8.

the machine is used in the same way as it was in week 4

follow the videos below and you’re sure to make a success of your molds.

Result

Note

Using the monofab can be very difficult, always ask someone with experience for help.

Mold making

We have chosen silicone mould rubber as the product for the mould.SORTA-CLEAR 37.

Be careful when using silicone, as the products are highly hazardous to your health. Above all, read the safety rules carefully. Please consult the following link for the rules to follow. Document. we have selected some of them below

some safety rules

- Keep out of reach of children

- Use in a well-ventilated area (“room-sized” ventilation).

- Wear safety glasses, long sleeves and rubber gloves to minimize the risk of contamination. 

- Wear vinyl gloves only. Latex gloves will prevent the rubber from hardening.

For the use of SORTA-Clear 37 silicone, we have consulted the technical data sheet and extracted the following essential information.

The image below was taken on the KONE Zie Souleymane

by following all the recommendations for mixing and pouring SORTA-CLEAR 37 silicone, we obtain a unique silicone which we use to make the mold.

  • Unfortunately, our degassing machine has broken down, so we’ve gone into the open air to avoid any risk of danger.

  • take the same portion of SORTA-CLEAR 37 part A and part B, then mix the two together

  • deposit the resulting paste into the mold

Here we forgot to wear glasses, so don’t forget to wear glasses before using these products. The mixture tends to burn the eyes

  • put our mould in a place out of reach of children and wait 4H.

  • After the 4H waiting time, we can remove the silicone. Let’s be careful when removing the silicone, as you can see mine is broken.

As you can see, there are enough bubbles in the silicone. When mixing the two products, turn the mixture in one direction only, to avoid getting enough bubbles. If you have a degasser, use it; unfortunately, we didn’t have one at the lab. Remember: if you mix the mixture in all directions, there will be bubbles!

Casting

to make the casting; we used the Smooth-Cast Série 300

read the technical data sheet carefully before using this product.

  • we joined the two counter-moulds we obtained, using adhesive tape to hold them together

  • Take the same dose of Smooth-cast Part A and Part B, then mix them together.

  • Finally, we obtain the following result

Be careful to follow the instructions. The mixing of Smooth-cast Part A and Smooth-cast Part B must not exceed 1 minute, otherwise the mixture will harden and our mold will fail.

hero’s plan

Files

Mold STL

mold file routing

END

Last update: June 23, 2024