Ceramic and Pottery Defects 4: Defects Generated During Drying Operations

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