Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
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Dwell: A pause in the application of pressure or temperature to a mold, made just before it is<br />
completely closed, allowing gas to escape from the molding material.<br />
E Glass: A family of calcia-alumina-silicate glasses with a certified chemical composition used<br />
for general purpose and most electrical applications (ASTM D578-90).<br />
Elasticity: A material’s ability to recover its original size and shape after the force deforming it<br />
has been removed.<br />
Ejection (De-molding): Removing a molded part from the mold by hand, mechanical means or<br />
use of compressed air.<br />
Ejection Plate: A metal plate used to operate ejector pins; designed to apply a uniform pressure<br />
to them in the process of ejection.<br />
Elastic Limit: The greatest stress a material can sustain without permanent strain after the stress<br />
has been completely released. A material is said to have passed its elastic limit when the load is<br />
sufficient to initiate plastic, or non-recoverable, deformation.<br />
Elastomer: A material that substantially recovers its original shape and size at room temperature<br />
after a deforming force is removed.<br />
Elongation: As mentioned under tensile modulus, when a bar is pulled it gets longer. The<br />
elongation tells how much longer it gets before it breaks.<br />
Encapsulating: Completely surrounding an object with resin or a fiber resin composite.<br />
Sometimes used specifically in reference to the enclosure of capacitors or circuit board modules.<br />
End: A single bundle of filaments.<br />
End count: An exact number of ends supplied on a ball of roving.<br />
Environment: The aggregate of all conditions (such as contamination, temperature, humidity,<br />
radiation, magnetic and electric fields, shock, and vibration) that externally influence the<br />
performance of an item.<br />
Epoxy: A polymerizable thermoset polymer containing one or more epoxide groups cured by its<br />
reaction with amines, alcohols, phenols, carboxylic acids, acid anhydrides, and mercaptans. It is<br />
an important matrix resin in composites and structural adhesive. Epoxies generally have higher<br />
physical properties than polyester resins. They are also more costly and difficult to process, and<br />
less able to withstand sunlight.<br />
Even Tension: Applying the same amount of tension to each end of roving in a ball.<br />
Exotherm: The liberation or evolution of heat during the curing of a plastic product.