18. Wildcard week¶

This week I experimented with vacuum forming as a part of wildcard week.

Vacuum Forming¶

What is Vacuum forming? The Method in which we use Vacuum to shape a sheet of plastic around an object. How is it done? We first use heat to soften the plastic sheet, the sheet can be any plastic sheet that can be formed and machined, tough, low cost rigid thermoplastic with high impact strength, recyclable, which is ideal for moulding, turning, drilling, milling, sawing, die-cutting, shearing. For our purpose we can use either PolyCarbonate or H.I.P(High Impact Polystyrene).

we used Polycarbonate sheet.

After the plastic sheet is softened we use high pressure vacuum to suck out all the air and the sheet will mould around the piece or job you placed on the surface.

What are the applications? There are quite a few applications for vacuum forming but the major application is the Packaging industry. Other than that we can use it to make moulds.

Now, I used Vacuum forming to make chocolate moulds The Process is quite simple, and these are the steps.

Make(Mill,3D Print, etc.) or find the pieces of which you want to make the mould.
Preheat the heater.
Place the Polycarbonate sheet on the heater.

Every machine has its own method of heating the plastic sheet Read the Instructions of your machine on how to do that.
when the sheet softens and droops push it on to the vacuum surface to form the mould.
let the vacuum run for a few seconds to cool of the sheet.

Using the moulds I first tempered my chocolate by microwaving chocolate for every 30 seconds till it is pourable. In the meantime I put the mould in the fridge to cool it, when the chocolate is tempered bring the mould out and wipe it with a paper towel to remove any condensation.

Water is an enemy of chocolate.

There should not be even a single drop of water when you are pouring the chocolate in the mould.

Vacuum Forming Machine¶

The Lab has a vacuum forming Machine made by the company Mayku. It is easy to operate and has very simple instructions.

It can be used to cast multiple materials like Chocolate, Plater, cement, soap, resin, etc. It can also be used as a packaging machine.

It does not have an inbuilt vacuum system but we plug in our vacuum cleaner instead of buying a suction system. The company provides an adapter for the vacuum cleaner.

The process for usingthe machine is as follows:

Make(Mill,3D Print, etc.) or find the pieces of which you want to make the mould.
Preheat the heater.
Place the Polycarbonate sheet on the heater.

Every machine has its own method of heating the plastic sheet Read the Instructions of your machine on how to do that.
when the sheet softens and droops push it on to the vacuum surface to form the mould.
let the vacuum run for a few seconds to cool of the sheet.

Loading the Sheet

Making the mould

Experimentation with casting¶

I experimented with chocolate and charcoal.

Chocolate¶

My plan was to make the pokemon Staryu because it was easy to design. I 3D Printed the parts individually so that I can join them after casting. I tested both White and dark Chocolate both require quite some time to cool down and harden. The tricky thing about chocolate is no matter how cold the chocolate is if we touch itt with our bare hands it will start to mel immediately. The only solution is to wear gloves and it was a big challenge for me as I have huge hands.

Charcoal¶

This was more experimental than the chocolate as I had to experiment with various ratios to make charcoal briquettes.
To make the briquettes we must first grind the coal into a fine powder

Out of experience I am suggesting; Please wear facemask, gloves and safety goggles. After the whole thing was done I looked like a coal miner in the 20’s.

I then had to mix the coal powder with a binding agent in this case I used flour to bind the coal I tried out various ratios though I am yet to figure it out the most successful batchestill now are the ratios 5:1:1 and 6:1:1 where
5- Coal powder
1- Binding Agent(Flour)
1- Water

Precautions¶

While designing the moulds see that there arre no undercuts in your design because if there are undercuts the it will be impossible to remove the casts after they moulded.
Make sure that the designs are sturdy
Wear safetywear while dealing while working with coal powder.

Problems faced¶

This Week was simple but a little more reasech would have yeilded much better results.

Coming to the problems, in the chocolate moulds I should have made the prints a bit bigger in terms of height.

The machine we used creates grooves from the grill on the suction base which will be a bit problematic if you are not careful while pouring he chocolate in the moulds.