Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
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Bi-directional: Reinforcing fibers arranged in two directions, usually at right angles.<br />
Bi-directional Laminate (Cross Laminate): A reinforced plastic laminate whose fibers are<br />
oriented in two directions in its plane.<br />
Binder: Coating which is applied to the surface of a chopped glass mat or preform and then<br />
cured to hold bundles or ends together in a stable form during the roving operation.<br />
Birdnest: A large, tangled up collection of continuous glass bundles unable to run through the<br />
guide eye into roving creel. In the field, it can also be a large tangled collection of roving which<br />
does not run through the tube or guide eyes to the chopper.<br />
Bismaleimide (BMI): A polyamide that cures through an addition rather than a condensation<br />
reaction, thus avoiding problems with volatiles forming. It is produced by a vinyl-type<br />
polymerization of a pre-polymer terminated with two maleimide groups. BMI has an<br />
Intermediate temperature capability (between epoxy and polyamide).<br />
Bisphenol A: A condensation product formed by the reaction of two molecules of phenol with<br />
acetone (A). This polyhydric phenol is a standard resin intermediate along with epichlorohydrin<br />
in the production of epoxy resins.<br />
Blade Packing: Glass bundles or chopper fuzz which build up and pack between the blades of a<br />
chopper. Blade packing can result in poor choppability. If it falls off, it usually does not wetthrough,<br />
causing blisters or porosity.<br />
Blanket: Fiber or fabric plies that have been laid up in a complete assembly and placed on or in<br />
the mold all at one time (flexible bag process). It is also, the form of bag in which the edges are<br />
sealed against the mold.<br />
Bleeder Cloth: Woven or non-woven layer of material used in composite parts manufacturing<br />
that allows excess gas and resin to escape during cure. The bleeder cloth is removed after the<br />
curing process and is not part of the final composite.<br />
Blister: Flaw either between layers of laminate or between the gel coat film and laminate.<br />
BMC: Bulk Molding Compound (Thermoset).<br />
Bobbin: The spool or shipping package on which textile yarns are wound.<br />
Bond Strength: Amount of adhesion between bonded surfaces. The stress required to separate a<br />
layer of material from the base to which it is bonded, as measured by load/bond area.<br />
Boron Fiber: Fiber produced by vapor deposition of elemental boron, usually onto a tungsten<br />
filament core, to impart strength and stiffness.