Investment casting


LOST WAX CASTING

Metal Injection Moulding phases are:
  • Mould construction to mould green parts
  • Moulding of green body parts (metal powder and plastic compound)
  • Catalytic thermal debinding to erase plastic compound
  • Final sintering

  • Advantages
  • Investment casting (lost wax process)
    or MIM tech is often the best choice and solution when: Complex shape needed
  • Welding process are to be avoided
  • Shapes, geometries and dimensional reproducibility
  • Surface accuracy (Ra: 3,2 max)
  • Wide range of steel alloys
  • High alloys waste are to be avoided a are required

The other method commonly used is called "investment" casting. The pattern is set up in much the same way as for ceramic shell, except that more venting is necessary due to the decreased porosity of the mold material, which is made using gypsum plaster (plaster of Paris) as a binder for sand, silica flour, or another refractory aggregate. There are many proprietary investment mixtures available, or one may choose to mix one's own. The dry ingredients are mixed with water and poured into a container or "flask" surrounding the gated model, which is either waxed down to a board or attached to a commercially available rubber device which holds the pattern and flask. Jewelry flasks are generally placed in a vacuum chamber while this mixure is still fluid, where they are boiled at room temperature to remove air-bubbles clinging to the models. It is helpful to de-air the investment mixture before pouring it over the wax models, in order to reduce boiling-over when vacuuming.

Home page - History of investment casting. PDF - Investment Casting - Microfusion MIM - Investment Casting Metal injection Moulding MIM - More information about Lost wax Casting | investment-casting.pdf

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