Definitions /Dictionary/Glossary - nptel

Bushing Tip: It is a small tapered protrusion on the bottom of bushings, each containing an
orifice through which molten glass flows and from which continuous filaments are drawn.
Cabled Yarn: The yarn that is plied more than once or made by plying two or more previously
plied yarns.
Carbon: Element that provides the backbone for all organic polymers. Graphite is a more
ordered form of carbon. Diamond is the densest crystalline form of carbon.
Carbon-Carbon: Composite material consisting of carbon or graphite fibers in a carbon or
graphite matrix.
Carbon Fiber: Fiber produced by the pyrolysis of organic precursor fibers, such as rayon,
polyacrylonitrile (PAN), and pitch, in an inert environment.
Carding: It the process of untangling and partially straightening fibers by passing them between
two closely spaced surfaces which are moving at different speeds of which one or more is
covered with sharp points, thus converting a tangled mass of fibers into a filmy web.
Casting: Process of pouring resin, fillers and/or fibers into a mold vs. building up layers through
lamination. Casting results in physical properties that are different than those resulting from
lamination.
Catalyst (Hardener): A substance that markedly speeds up the cure of a compound by
decomposing in the presence of a promoter to release active oxygen radical. Catalyst content can
vary from 0.2% to 2.0% with higher catalyst levels giving faster gel times. Examples are methyl
ethyl ketone peroxide, benzoyl peroxide.
Catastrophic Failures: Totally unpredictable failures of a mechanical, thermal, or electrical
nature.
Catenary: A consolidated group of individual strands which, when checked between two fixed
points of length, exhibit strands of different lengths. The resulting curve between fixed points of
the inextensionable material is defined as catenary. The amount of catenary is measured by the
distance between the topmost and lowermost strands when stretched between two fixed points.
Caul Plates: Smooth metal plates free of surface defects with the same size and shape as a
composite lay-up that contacts the lay-up during curing. Caul plates transmit normal pressure and
temperature to the finished laminate while providing it with a smooth surface.
Cavity: Space inside a mold in which a resin or molding compound is poured or injected. It is
the female portion of the mold. That portion of the mold that encloses the molded article (often
referred to as the die). Depending on the number of such depressions, molds are designated as a
single cavity or multiple cavities.