Definitions /Dictionary/Glossary - nptel

Flame Retardents: It is a certain chemicals that are used to reduce or eliminate a resins
tendency to burn.
Flame Retardent Resin: It is a resin which is compounded with certain chemicals to reduce or
eliminate its tendency to burn.
Flammability: A measure of how fast a material will burn under controlled conditions. ASTM
D-635/UL E-84 tests.
Flange: An extension around the perimeter of a mold or part for the purpose of demolding,
stiffening or connecting two components.
Flash: Excess material which forms at the parting line of a mold or die, or which is extruded
from a closed mold.
Flashover: This term is used when the arc produced by a gap breakdown passes over or close to
a dielectric surface without puncture.
Former Plate: A die attached to a braiding machine which helps to locate the fell.
Flash Point: The lowest temperature at which a substance gives off enough vapors to form a
flammable or ignitable mixture with air near the surface of the substance being tested.
Flexural Modulus: This is a number associated with the stiffness of materials. It is used to
calculate how far a bar will bend when a bending load is applied to it. Units are normally
millions of pounds per square inch. (106 psi) - Giga Pascals (gPa). Higher numbers for materials
mean that they are more resistant to deflection when equal thickness are being compared.
Flexural Strength: The resistance of a material to being broken by bending stresses; the strength
of a material in bending, expressed as the tensile stress of the outermost fibers of a bent test
sample at the instant of failure. (With plastics, this value is usually higher than the straight tensile
strength.)
Flow: The movement of resin under pressure, allowing it to fill all parts of a mold; flow or creep
- the gradual but continuous distortion of a material under continued load, usually at high
temperature.
Flow Line: A mark on a molded piece made by the meeting of two flow fronts during molding.
Also see, 'striae', or 'weld-mark,' or 'weld-line.')
Flow Meter: An instrument designed to measure the flow of a liquid. Normally used with
catalyst injection equipment.
Foam: A lightweight, cellular plastic material containing gas-filled voids. Typical foams
include urethane, PVC and polyester.