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CENTRIFUGAL CASTING
The investment mould for centrifugal casting is often much smaller and compact when compared to a vacuum cast mould; in fact most centrifugal moulds contain just a single wax pattern impression. The mould flask for this process is removed from the burnout kiln using tongs, then placed directly into a clamping mechanism at one extreme of a rotating centrifuge arm (the arm may be fixed either to a vertical, horizontal or inclined axis of rotation). A carefully measured out charge is then melted in a crucible adjacent to the placed mould. Melting can be done with the aid of a directed OXY-GAS flame for the heat source, this being sufficient to melt the small quantities of precious alloy normally used to fill this type of mould.
Once the charge has been melted, the crucible outlet is aligned with the BUTTON inlet on the investment mould, and the safety covers on the centrifuge secured. Simple centrifuges are spring-loaded, and after PRIMING the wound mechanism can be released to revolve the arm at speed to force metal into the furthest reaches of the investment cavity. Alternative centrifuge mechanisms can be hand or motor operated, and some advanced versions may also include an integrated furnace.
The sophistication and expense of acquiring all these special casting processes can vary considerably – inevitably the level of financial investment by the foundry in purchasing tooling and quality materials is ultimately reflected in the cost charged per cast.
KILN & CASTING SUMMARY >
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