lecture Notes

Assignement

design a 3D mold, machine it, and cast parts from it

What i am going to do

I want to make a casted wrist band using rubber .

sand Casting

Courtesy : http://www.technologystudent.com/equip1/poly2.htm

Mould

I had done sand casting in my college days Courtesy : http://www.custompartnet.com/wu/SandCasting : sand Casting ,now i am going to make a real mould in wax,We are using Machinable Wax for it .

Why Using Machinable Wax?

Machinable Wax is a very hard Wax having High Melting Point specially designed for Machining Applications .

Mould Designing in Rhino

I designed a Negative Mould in Rhino for my Wrist Band, What is Negative Mould ? You Can easily understand by looking the following picture.

Negative Mould

A)Positive Mould b)Negative Mould

Source :http://www.fibre-reinforced-plastic.com/2011_12_01_archive.html

Rhino Designing Screenshots

: Rhino Fab Academy Moulding
Rhino Fab Academy Moulding 2
Rhino Fab Academy Moulding 3

Yaa, I created a mould design in Rhino , Now it is ready to Export to .STL format for Milling in Modella or ShopBot . Download Rhino File

Milling Mould in Modella

Modella supports STL file thats a new information to me also have an option to convert .STL to .PNG , I used 1/8” Bits for both Rough Cut and Finishing Cut .

Rough Cut and Finishing Cut

This 2 level cuting method saves energy and time also gives a good finishing , Yaa rough cut removes major portion of the unwanted wax by milling and same time finishing cuts makes smooth and accurate.

Rough Cut Pic with Bit  : Finishing Cut  with Bit

Yaa, Mould is Ready . Next step is Casting.

Casting Process

This is the process of filling mould by which material we want to use ie, Rubber, Silicone,Plastic,Metal etc…

Now i am going to use Silicone Rubber(SORTA Clear 37)

SORTA Clear 37

It is a Water white translucent silicone rubbers which cure at room temperature with negligible shrinkage and feature high tensile and tear strength.

SORTA Clear Part A and Part B: SORTA CLear Part A

List of Materials needs for Casting

1.Mould
2.Sorta Clear 37 :Part A
3.Sorta Clear 37 :Part B
4.Water
5.Plastic Cup
6.Wooden Stick
7.Aluminium Foil
8.Patience :) :) Your Patience will indicate in your final Result .

Casting Materials

Process

1.First fill your Mould with water and pour that water into a Vaccant Glass (It is for measuring the volume of mould)
2.Take Part A and Part B in Glasses (Equal to 1/2 Volume of Mould)
3:Mix It(1:1 Ratio)
4:Add 1 drop of Coloring Agent(If you need color)
5.Pour the mixed material carefully to Mould (Be careful to air bubbles that makes holes in final product)
6.Remove Unwanted Material from Mould
7.Wait 4 Hours then Open the Mould

Casting Process

Casting Process

Wait 4 Hours to set .

Finished Product

: Silicone Rubber Wrist Band DIY shot 1
Silicone Rubber Wrist Band DIY shot 2

Problem Faced : I designed this bracelet to my hand but after casting shrinkage happen

Solution :

Need to add some shrinkage allowance in mould design.