Manufacturing Processes - Pressure Die Casting Process

Pressure Die Casting Manufacturing Processes

Pressure Die Casting Equipment

Photograph taken by Swoolverton July 2008 and used here under the Creative Commons license ref: http://creativecommons.org/licenses/by-sa/2.0/deed.en
Photograph taken by Swoolverton July 2008 and used here under the Creative Commons license ref: http://creativecommons.org/licenses/by-sa/2.0/deed.en

Pressure Die Casting

Pressure die casting is a process that fits under the general category of casting as a manufacturing process. It utilises a permanent mould where molten metal is forced into the die cavity through a system of runners and sprues. The metal solidifies quickly due to the use of hardened steel dies and typically a water cooling system.

By utilising pressure, thin section complex 3D shapes can be produced. Although any coring used will need to be relatively simple and retractable.

There are 2 methods for pressure die casting:

  • Cold Chamber die casting
  • Hot Chamber die casting

For cold chamber high pressure die casting the molten metal is poured into a cold chamber and a plunger is used to force the metal into the die cavity. Solidification is for all intents and purposes instantaneous. This process is used for aluminium alloys or zinc alloys with a large composition of aluminium, magnesium and copper. In other words alloys with higher melting points or that may become contaminated by the steel chamber in a hot chamber arrangement.

The hot chamber high pressure die casting is more automated and uses a gooseneck arrangement, submerged in molten metal pool to provide charges of molten metal. A plunger is inserted and retracted to push the molten metal into the die cavity and the gooseneck is replenished from the molten pool when the piston is retracted. This process is only suited to the lower melting point alloys such as magnesium, tin, lead etc.

Pros

  1. Fast solidification times typically less than 1 second
  2. Good surface texture
  3. Porosity can be controlled using an oxygen cavity fill
  4. Thin sections can be cast
  5. Relatively low amount of waste material which can be recycled

Cons

  1. Equipment costs are high
  2. Not really suited for high melting point alloys
  3. Separate furnace required for cold chamber pressure die casting
  4. Requires relatively high volume production to justify equipment costs

This process is ideally suited for small complex shapes with thin sections required in relatively high production quantities.

Automated Pressure Die Casting

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Pressure Die Casting - Your Comments 1 comment

romper20 profile image

romper20 6 years ago from California

Great, sounds fun!

Great hub :)

Romper20

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