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 Custom built rotary hearth furnace  Selection of crucibles and charge loader. Carbolite can supply crucibles, cuples and loading tools. |
The furnace illustrated opposite is an example of Carbolite's ability to custom design and build units tailored to meet individual specifications. it shows a rotary hearth furnace for the production of wedding rings using the powder metallurgy method. It is used to sinter 'compacts' to provide strength and workability. The compacts are formed from powders which are produced directly from the molten state by passing the material through high pressure water or gas jets. The powder is then packed into a die and pressed to form a ring that has a rectangular cross section, known as a compact. The furnace allows high throughput of compacts which are loaded into trays holding several hundred at a time. After loading, the furnace rotates by 10° to allow another tray to be loaded. The speed of rotation can be adjusted to give sintering times of up to 24 hours. Process temperatures are between 750-800°C under an atmosphere of 95% nitrogen and 5% hydrogen to prevent oxidation. Heating is provided by 27 wire spiral resistance elements supported on ceramic tubes and are separated into three control zones to provide furnace temperature uniformity. |
