A washer like device of a relatively hard material placed in the gland between the o-ring and groove side wall, also called a back up ring. Blemish: Deformity on the surface of a molded product.    Brittleness: The tendency to crack when deformed. BUNA N: A general term for the copolymer butadiene and acrylonitrile also referred to as NBR or Nitril [..]

Average material expansion per one degree change in temperature, expressed as a fraction of the initial dimension. Cold Flexibility: O-Ring flexibility (resistance to cracking and breaking) at low temperatures. Cold Resistant: The ability of an o-ring to function at low temperatures. Compound: A mixture of an elastomer and other ingredients to prod [..]

The tendency of a material to return to its original shape after deformation. Elastomer: A general term used to describe both natural and synthetic polymers possessing the resilience to return to ---its original shape after deformation. Elongation: Percentage increase in original length of a specimen produced by a tensile force applied to the speci [..]

Front surface of a seal. Filler: Relatively inexpensive and inert material added to an elastomer to reinforce or modify properties. Flash: The excess material protruding from the surface of a molded part at the mold junctions. Flaws: Surface imperfections that occur infrequently. Flexural Strength: Ability of a material to flex without permanent di [..]

Static seal effected when a deformable material is sandwiched and compressed between two mating surfaces. Gates: The openings in an injection or transfer mold that ensure even flow into the cavity. Gate Mark: A raised spot or small depression on the surface of an injection or transfer molded part where gates interface the cavity. Gland: Complete ca [..]

Measurement of the resistance to penetration of an indenture into a cured rubber sample. Heat Aging: Loss of physical properties as a result of exposure to heat. Heat Resistance: Rubber compounds capacity to undergo exposure to some specified level of elevated temperature and retain a high level of its original properties. Heteropolymer: polymer co [..]

The inside diameter of an o-ring Injection Molding: Process where preheated rubber is injected under pressure through a series of runners and into a closed mold cavity.

The mechanical trapping of gasses, liquids or solids within the folds of a substance during working or solidification. O.D.: The outside diameter of an o-ring. O-Ring: Solid elastomer ring seal of circular cross-section. Oscillating Seal: In this application the inner or outer member if the gland moves in an arc around the axis of a shaft, most com [..]

A collar or gasket used to seal mechanical devices to retain fluids under pressure or seal out foreign matter. Permanent Set: Amount of deformation in a rubber part after a distorting load has been removed. Permeability: Measure of the ease with which a liquid or gas can pass through a material. Polymer: A long molecular chain material formed by th [..]

Society of Automotive Engineers. Scorching: Premature curing of rubber during storage or processing, usually caused by excess heat. Shaft: Rotating or reciprocating component that operates within a cylinder or housing. Shelf Aging: The potential degradation of seal performance capabilities due to exposure of o-ring elastomers to stressful environme [..]