polymer processing

Tensile strength - The resistance of a material to longitudinal tension stress. Thermal conductivity - Ability of a material to conduct heat. Thermal degradation - Deterioration of material by heat. Thermal diffusivity - The ability of a material to transfer heat per unit time and area. Thermoplastic - Capable of being repeatedly softened by heat and hardened by cooling. Thermoset - A material that will undergo or has undergone a chemical reaction by the action of heat, catalysts, ultraviolet light,etc. Three-plate mold - Mold with two parting lines, one for part and the other to free trapped cold runner. Two-plate mold - Mold with one parting line used to free both part and runner.

Daylight opening - Clearance between the two platens of the press in the open position. Decompression - See Suckback Degradation - A deleterious change in the chemical structure of a plastic. Degating - The removal of material left on a plastic part formed by the opening through which material was injected into the mold cavity. Degree of polymerization - The average number of monomer units per polymer molecule, a measure of molecular weight. In most plastics, the molecular weight must reach several thousand to attain worthwhile physical properties. Density - Mass per unit volume of a substance, exposed in units such as grams per cubic centimeter, pounds per cubic foot or pounds per gallon. Desiccant - A substance capable of absorbing water vapor from air or other gaseous material, used to maintain low humidity in a storage or test vessel. Draft - The degree of taper of a side wall or the angle of clearance designed to facilitate ejection of parts from the mold. Dry coloring - ...