Casting Flashcards
What does Casting involve?
Pouring heated and moulded metal into a mould
Any waste material can be re-melted and used again
What is Sand Casting?
Used to shape metals eg. cast iron, aluminium, brass
What is the process of Sand Casting?
Pattern made in two halves and attached to a board
Pattern sandwiched between open boxes (cope and drag)
Special, oiled sand used to fill each box
One of boxes used to contains 2 tapered wooden pegs (sprues) which form the pouring spout and riser to let air out
Pattern is removed and space left filled with molten metal
What is the process of Lost Pattern Casting?
Used to form metals eg. aluminium into complete forms that would not be possible without split pattern casting
What is the process of Lost Pattern Casting?
Pattern made from polystyrene foam
Foam is buried into sand and runner and riser added
Molten metal poured into mould and burns away polystyrene foam
Space left is filled with hot metal that’s been poured into a cavity
What bad thing is produced in Lost Pattern Casting?
Toxic fumes that must be extraced
What is Lost Wax Casting?
A more sophisticated form of lost pattern casting using wax, which is melted before silver or gold is cast
Used by jewellers
What is Die Casting used to manufacture?
Large quantities of metal products
What Metals can be used for Die Casting?
Alloys with a low melting point eg. pewter, aluminium, zinc
How is the Mould created for Die Casting?
Created by a spark eroding the form required into two blocks of steel
The mould is water cooled in order to control temperature
What is the method of Die Casting?
Metal heated in crucible until molten
Hydraulic Ram pushes a quantity of molten metal into mould
Pressure is maintained until metal has cooled enough for mould to be opened and component removed
How do you Die Cast in Schools?
Use low melting point pewter melted with electric paint stripper gun/blowlamp
Pour pewter into holes in easilt worked materials eg. MDF, acrylic
Mould can be hand cut or by CNC router
