How to create an artificial muscle in silicone

Tutorial

Tutorial for the creation of a linear artificial muscle in silicone by injection in moulds

Dates
  • Creation: 02/20/2020
  • Update: 03/09/2020
artificial-musclealex_dru

Moulds 3D Conception:

You can use any 3D modelling software to make the moulds, you just need to make sure of the followings.

You will inject the silicone from the bottom to the top. Thus, you will design your moulds with an entry for the syringe an exit for the air to come out. While designing your moulds, you need to think about the air that could stay trapped in certain areas.


Choosing the right silicone:

There are a lot of different types of silicones with different properties: pot time, cure time, Elongation at break, etc. The choice is up to you!


Injection process:

Here is an example of injection with the “dragon skin” silicone.

First step, check if you have all tools required:

-         A syringe, a piece of clay, your silicone (part A and B), a vacuum chamber, mould lubricant (in our tutorial we use this one -> “smooth on: universal mold release”), some clamps, a flexible cup and a spatula to mix in it, a timer and of course your moulds.




-         Security: it is recommended to wear a mask, glasses and disposable gloves.




Second step, setting up the moulds:

-         Spread the mould lubricant all over the mould parts that will be in contact with the silicone.




-         Lock the moulds with the clamps. Tip: you will have to position them smartly to avoid the mould from falling or moving during the cure time.




Third step, silicone set up:

-         Put part A of the silicone inside a cup (be careful on the quantity, you’ll have to put the same amount of part B - the proportions depend of the silicone you chose earlier).

-         Put part B inside the cup and start your timer!!! (for dragon skin we now have 8 minutes to proceed).




-         Mix actively the two parts for about a minute and a half.




-         Put the cup inside the vacuum chamber for 3 to 4 minutes (all air bubbles must disappear).




-         Put a small piece of clay on the tip of the syringe and transfer the silicone in it.


-         The second to last process before casting is explained in the following video:


VIDEO



-         Inject slowly the silicone inside your mould until some silicone spills out from the exit. Then remove quickly your syringe and put a piece of clay to fill the injection hole.





Cure Time:

Put your mould on a good spot so it won’t be disturbed and wait the appropriate cure time. (tips: there is still silicone inside your cup. You can use it as an indicator to know when the cure time is over).



Releasing the inside mould:


VIDEO TIME LAPSE