>> Saturday, 7 February 2009
ABS (Acrylonitrile-butadiene-styrene) - Blends of copolymers or styrene-acrylonitrile copolymer with butadiene-acrylonitrile rubber.
Accumulator - Auxiliary cylinder and piston (plunger) mounted on injection molding machine. It is used to provide extremely fast molding cycles through accumulation of molten plastic from the main extruder (reducing plastication time) and forces the plastic into the mold during filling at high speed and pressure (reducing fill time).
Acetal resins - The molecular structure of the polymer is that of linear acetal, consisting of unbranched polyoxmethylene chains.
Achromatic color - A neutral color (white, gray or black) that has no hue.
Acrylic - Polymethylmethacralate
Additives - Used to enhance processing, performance, appearance, and/or economics of the basic plastic formulation.
Aesthetics - The sum total of the visual response (color, shape, feel, etc.) to the appearance of a part.
Amorphous phase - Devoid of crystallinity; no definite order. The plastic is normally processed at the amorphous phase temperature.
Annealing - A process of holding a material at a temperature near, but below, its melting point. The objective being to permit stress relaxation without distortion of shape.
Anti-stat - An additive to dissipate static charges. Adds lubricity.
Antioxidant - Additive that minimizes or prevents the effects of oxygen attack on the plastic (e.g. yellowing or degradation). Such additives may render the plastic brittle or to lose mechanical properties.
ASTM - Abbreviation for American Society and Testing and Materials, said to be the largest non-governmental standards-writing body in the world.
Average or mean - The sum of the numerical values in a sample divided by the number of observations.