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Centrifugal casting article icon

Science, Maths & Technology 

Centrifugal casting

Typically used to cast hollow cylinders or pipes. The casting process is not by gravity or applied pressure, but by centrifugal forces. Molten metal is poured directly into a mould, which is rotated at high speed. Centrifugal force projects the metal outwards from the rotational axis and onto the walls of the mould.

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Full mould casting (evaporative pattern) article icon

Science, Maths & Technology 

Full mould casting (evaporative pattern)

A pattern is made from fused polystyrene beads heated in an aluminium die. Once cooled, the pattern is coated with a refractory compound, before being placed in a flask and surrounded by sand. A vacuum is applied to the flask and molten metal is poured into the pattern. Molten metal vaporises the polystyrene material as it flows into the mould cavity. Once cooled the casting is removed.

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Melt casting article icon

Science, Maths & Technology 

Melt casting

Molten polymer is extruded, via a sprue, into the closed mould cavity formed from two parts bolted together. The mould is vented, and once polymer leaks from the vent, extrusion stops and the material is left in the mould to solidify. Bolts are removed and the component is extracted.

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Monomer casting article icon

Science, Maths & Technology 

Monomer casting

A non-pressurised casting process using a controlled chemical reaction of polymer materials. The monomer is mixed with an initiator (catalyst), before pouring into the mould. Whilst the mixture is curing inside the mould, polymerisation takes place. Once cooled, the component is removed from the mould.

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Reaction injection moulding (RIM) and Reinforced reaction injection moulding (RRIM) article icon

Science, Maths & Technology 

Reaction injection moulding (RIM) and Reinforced reaction injection moulding (RRIM)

In reaction injection moulding, two types of monomers are mixed together before being injected into a mould, where they polymerise to form the plastic component. In reinforced reaction injection molding, reinforcing agents are added to the monomer mixture.

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Transfer moulding article icon

Science, Maths & Technology 

Transfer moulding

Similar to compression moulding, however, the polymer material is not placed directly into the die, but is often pre-heated before being loaded into a separate heated pot chamber situated above the die. A hydraulic plunger (ram) forces the polymer into the die cavity via a sprue. When cured, the moulded component is released using ejector pins.

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Rotational moulding (Rotational or rotary casting) article icon

Science, Maths & Technology 

Rotational moulding (Rotational or rotary casting)

A low pressure and high-temperature process for moulding hollow plastic components. Three separately rotating ‘arms’, with moulds connected to each, revolve bi-directionally around their axes. One arm is for loading and unloading of moulds, another arm is rotating within an oven, and the third arm holds a cooling chamber. The mould is opened to remove the component.

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Compression moulding article icon

Science, Maths & Technology 

Compression moulding

A preheated pellet of thermoset plastic is placed into the bottom half of a heated die. The top half of the die (punch) compresses the molten plastic into the shape of the die. After curing under heat and pressure, the moulded component is ejected.

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Squeeze casting and squeeze forming article icon

Science, Maths & Technology 

Squeeze casting and squeeze forming

Molten metal is poured into the bottom half of a pre-heated die cavity. As the metal starts to solidify, the top half of the die (punch) is pressed into the bottom half and held in position until the casting has solidified. The cast component is then ejected.

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Hyperforge process article icon

Science, Maths & Technology 

Hyperforge process

A process which combines casting and forging to give components with mechanical properties comparable with forged materials. Uses retained heat from casting process.

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Pore-free die casting (active atmosphere casting) article icon

Science, Maths & Technology 

Pore-free die casting (active atmosphere casting)

Porosity is almost eliminated by the injection of an ‘active gas’ into the die cavity, prior to molten metal being piston forced into the cavity at high pressure. The gas combines chemically with the metal to form a finely dispersed solid casting.

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Acurad process article icon

Science, Maths & Technology 

Acurad process

Similar to high pressure die casting, but has wider gate to reduce turbulence, and a secondary plunger fitted inside the primary plunger. Pressure is applied to the molten metal forcing it through the gate and into the die cavity. The inner plunger operates, seconds after the primary plunger, ensuring any pores are filled, hence reducing shrinkage of the casting.

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