Drying operations relate to plastic forming operations and casting operations. Forced drying in controlled driers expedites production and guarantees continual controlled production flow.
Driers are usually built into automatic casting machines and roll forming machines. The drier is often designed to accommodate the different stages of drying. Airflow is adjustable throughout the drier.
When a piece of ceramic ware is first formed, the particles are separated by a water layer which can be easily and safely removed. For that reason, excessive heat can be supplied at this stage of drying.
Once the particles touch, the process becomes diffusion controlled and the water molecules must move slowly through the body matrix.
Finally, the last tightly held water must be removed.
These last two steps require careful heat and humidity control in the drier. Airflow must be controlled locally. See Ceramics: Industrial Processing and Testing by John T. Jones and M. F. Berard.
For automatic plastic forming operations incorporating built-in driers, the slip must be controlled as to particle size, specific gravity, and viscosity. The slip must be in the flocculated state during filter pressing and subsequent operations. If not controlled, the ware may not dry properly after forming and the operations can be drastically slowed down. Drier losses due to cracking or distortion can be dramatic. Airflow control by adjustable jets can eliminate losses.
Drying of cast ware is less critical except for automatic casting machines. Slip control is again the most important function to prevent loss.
See the reference for more information on the drying process, slip control, and industrial driers.
John T. Jones, Ph.D. (tjbooks@hotmail.com, a retired VP of R&D for Lenox China, is author of detective & western novels, nonfiction (business, scientific, engineering, humor), poetry, etc. Former editor of Ceramic Industry Magazine, Jones is Executive Representative of International Wealth Success. He calls himself "Taylor Jones, the hack writer."
More info: http://www.tjbooks.com
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