reforming

• reforming metals

  • sand casting - bonding agent ( usually clay) is mixed with sand and the mixture is moistened by water to develop strength
  • sand is contained in a system of frames or mould boxes called flask
  • feeds and risers
  • 2 metal boxes used top is called cope and bottom is drag
  • contains channels called risers and sprues which allow molten metal to flow through
  • trapped air escapes through risers
• reforming metals -

  • die casting - molten metal is forced under high pressure into a mould cavity
  • mould cavity created using 2 hardened steel dies which have been machined into shape
  • most made from non-ferrous metals: zinc, copper, aluminium, magnesium
  • depending on metal used a hot or cold chamber machine is used
  • different methods
• reforming metals

  die casting - GRAVITY DIE CASTING

  • uses gravity to force the molten metal into the mould

  
• reforming metals -

  • pressure die casting - uses a ram to force the molten metal into the former using either a hot or cold chamber
  • additional pressure ensures greater accuracy

  
• reforming metals

  • industrial die casting - use of multi side die casting for complex 3d shapes

  
• reforming metals -

  • lost was casting - a metal object is cast from an original wax sculpture. intricate works can be achieved

  
• reforming metals -

  extrusion - used to create objects of a fixed cross section profile.

  • Material is pushed or drawn through a die.

  
• reforming polymers

  • injection moulding - material fed into a heated barrel then forced into a mould cavity.
  • used for small components or body panels of cars

  
• reforming polymers

  • rotational moulding - heated hollow mould is filled up with a charge or set weight of material.
  • slowly rotated causing softened material to disperse and stick to mould walls.
  • mould rotates at all times to ensure it remains thick
  • slow process
  • causes shapes to be hollow but have thick walls
  • e.g. kayak

  
• reforming polymers

  • extrusion - similar to injection moulding but its pushed through a die

  
• reforming polymers -

  • compression moulding - produces products using thermosetting polymers such as urea formaldehyde.
  • high volume, high pressure method
  • low cost and wastes little material
  • e.g. plug socket

  
• reforming polymers

  • resin and grp moulding - resin is left to cure and set hard, with GRP its also combined with fine strips of glass to reinforce the resin
• reforming polymers

  • 3d printing - additive process
• redistribution - the movement of material in oreder to shape it