This technical information has been contributed by
REDCO Rubber Engineering and Development Co.

Click on Company Name for a Detailed Profile

Rubber Molding Terms

Rubber Molding

Abrasion Resistance - A rubber compound's capability to withstand mechanically caused deterioration.

Accelerated Life Test - A test made to replicate in a short period of time the breakdown resulting from normal working conditions.

Accelerator - A substance that increases the speed of vulcanization when used in small quantities in conjunction with vulcanizing agents.

Activator - A compound used to increase the effectiveness of an accelerator, small amounts at a time.

Adhesion - Tendency of rubber to cling or bond to any surface it contacts.

Aftercure - The continuance of vulcanization, even after the energy source has been taken away.

Air Checks - Depressions and marks on the surface of rubber, caused by air trapped during the molding process.

Autoclave - Uses steam under pressure to vulcanize rubber products.

Backrind - A defect in the molding process, where the rubber near the parting line sinks below the surface and the parting line ends up ragged and torn.

Batch - The result of a mixing operation.

Blank - Rubber compound that fills a mold.

Bloom - A discoloration of rubber, caused by a liquid or solid migrating towards the surface.

Breakout Friction - The necessary force to start the sliding between a rubber seal and its mating surface.

Chalking - The development of a powdery residue on a rubber surface as a result of surface breakdown.

Checking - Small cracks on the surface of rubber, usually from environmental damage.

Compression Set - The permanent deformation of rubber after removing the compression.

Conducting Rubber - Rubber that is able to conduct electricity.

Crosslink - A chemical bond between polymer chains.

Cure Date - The date of completion of the molding process for a rubber product.

Deflashing - Any of a variety of processes for waste edge removal from molded rubber parts.

Dispersion - The application of force used to evenly disperse various compounds through rubber.

Durometer - An instrument that measures the hardness of rubber.

Dusting - Applying powder to rubber to prevent adhesion to something else.

Dynamic Seal - A seal necessary for the prevention of leaks beyond parts that are in relative motion.

Elasticity - A characteristic of rubber, describing its tendency to return to its initial shape after warping.

Elongation - Extension of rubber when exposed to stress.

Extruder - A machine that forces rubber through a hole that shapes it into the finished product.

Fatigue Breakdown - The wearing out of elastomers after repeated deformations.

Flexural Strength - The flexing capability of a material with no permanent deformation or breakage.

Flow - Capability of uncured rubber to move in the mold and runner system in the molding procedure.

High Consistency Rubber (HCR) - Rubber processed on a rubber mill that has a much greater viscosity than liquid silicone rubber.

Hysteresis - The process of mechanical energy changing to heat in rubber under strain.

Insert - A material that rubber is chemically or physically bonded to during the molding process.

Logy - Slow recovery rate of rubber after stress.

Mastication - The softening of raw rubber by mechanical and atmospheric forces.

Monomers - A chemical compound that is able to endure polymerization.

Non-Fill - A defect that occurs when the rubber does not completely fill out the mold.

Parting Line - A line on the surface of rubber resulting from where the two halves of the mold met.

Peptizer - A material that is used to quicken the softening of rubber compounds under heat or mechanical action.

Pigment - An insoluble compound that gives rubber its color.

Plasticity - The degree to which rubber will retain deformation.

Polymerization - Chemical reaction in which one or more simple materials are transformed into complex materials that have different properties from the originals.

Reinforcing Agent - A substance that is added to rubber to increase its resistance to the harms of the vulcanization process.

Scorch - The result when rubber vulcanizes too quickly.

Spew - Extra material that leaks from the mold as it closes.

Splice - The term for the uniting of two parts of vulcanized rubber to make a whole.

Vulcanization - A thermo-setting reaction that involves the use of pressure and heat, and results in highly increased elasticity and strength of materials like rubber.

This technical information has been contributed by
REDCO Rubber Engineering and Development Co.

Click on Company Name for a Detailed Profile

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