Below you can find some of the terms commonly used in the manufacturing of molded rubber-metal parts. We recommend that you review these terms before looking at the relevant tables and graphs.

External mixer A basic machine comprising cylinders turning at different speeds for mastication. Resulting surface tension helps blend the ingredients with the rubber gum.
Flame resistance Resistance of vulcanized rubber to flaming and burning.
Resistance to alkaline (concentrated) Resistance of vulcanized rubber to concentrated base (e.g. concentrated sodium hydroxide, concentrated potassium hydroxide).
Resistance to alkaline (diluted) Resistance of vulcanized rubber to diluted base (e.g. diluted sodium hydroxide, dilute potassium hydroxide).
Resistance to alcohol Resistance of vulcanized rubber to alcohol
Antioxidant Protective agents to enhance the resistance of vulcanized rubber to oxidation.
Antiozonant Protective agent to enhance the resistance of vulcanized rubber to ozone attacks.
Resistance to acid (concentrated) Resistance of vulcanized rubber to concentrated acid (e.g. concentrated acetic acid, concentrated sulfuric acid).
Resistance to acids (diluted) Resistance of vulcanized rubber to dilute acid (e.g. diluted acetic acid, diluted sulfuric acid).
Abrasion resistance Resistance of vulcanized rubber to surface abrasion.
Resistance to weathering Resistance of vulcanized rubber to structural degradation that results from weathering including combined effects of oxidation, ozone, light and heat.
Starter (Activator) Chemicals that activate the accelerator in a vulcanization reaction.
Weld line Thin boundary line is visible on molded rubber and plastic parts after molding. Separate material flows that fail to meld together is the main reason behind this occurrence.
Resistance to vegetable oils Resistance of vulcanized rubber to vegetable oils (e.g. castor oil).
Resistance to steam Resistance of vulcanized rubber to steam.
CNC This means “computer numerical control”. And often used synonymously with lathes and milling machines that come with an electronic control unit and a keypad allowing either manual or electronic data entry. It is actually a feature that can be found in many benches.
Burr Excess, unwanted material that overflows from the mold during production and stays attached to the product. It is either avoided through mold design or removed in a process called deburring.
Shrinkage Both plastics and rubber materials after molding (e.g. compression, injection) undergo a sudden drop in temperature. This results in a reduction of the volume of the material, an incident called shrinkage. The end-product is designed with this shrinkage amount.
Tensile strength tester A lab device frequently used in the rubber and plastics industry. It measures mechanical attributes like elasticity, elongation, deformation and tensile strength in accordance with respective methods and standards.
Impact resistance Resistance of vulcanized rubber to physical shocks.
Natural rubber Rubber made of organic latex. Denoted with NR
Filler Substances that are added to the blend to reinforce the rubber or reduce the cost of the compound. Carbon black, silica, calcium carbonate, kaolinite and phenolic resins are some examples of the most frequently used fillers.
Low temperature property Vulcanized rubber at low temperatures elasticity, permanent deformation, tensile strength and so on. indicates the ability to maintain such features.
Eccentric press A mechanical machine press, working principles of which are based on the transfer of force (torque) via a rotating flywheel. It is used to die to cut shapes out of steel sheets.
Extrusion A primary production technique to process rubber and plastics. An extruder machine providing uninterrupted material feeding is key to the process. It is frequently used in the manufacturing of variable length profiles.
Elastic deformation Deformasyon bir kuvvet etkisi altında kalan malzemenin ilk halinden şekilsel olarak sapmasıdır. Kuvvet etkisi ortadan kalktığında malzemenin ilk haline geri dönmesi elastik (geçici) deformasyon olarak adlandırılır.
Elasticity Capacity of material to return to its original shape upon removal of the deforming force.
Elastomer Elastomers are polymers with high elasticity. The word elastomer is used interchangeably with rubber. Should a distinction be needed the word elastomer is preferred to describe the vulcanized rubber.
Dielectric strength Resistance of vulcanized rubber to the conduction of electricity. Rubbers used to manufacture electrical cables are desired to have high dielectric strength to act as an insulator while rubbers used in tire production are preferred to act as a conductor so they will not store any static load.
Injection A primary production technique to process rubber and plastics. The system involves horizontal and vertical injection machines used for molding. Material is melted and mixed in a pot called barrel by an extruder screw and then injected with high pressure into the mold and allowed to cool down.
Flex resistance Capability of vulcanized rubber to preserve its structural properties after repeated exposure to compressive forces.
Gas permeability Capacity of vulcanized rubber to impede the passage of gas molecules through.
Retarder Chemicals used to slow down the unnecessarily quick vulcanization of rubber blend to avoid scorch.
Cavity A term used to describe the openings on a mold that contain shapes of the product to be manufactured. A mold with nine exact cavities would fabricate nine copies of the same product in a single cycle.
Resistance to halogen liquids Resistance of vulcanized rubber to halogenated fluids like chlorofluorocarbon or hydrofluorocarbon.
Blend Semi-fluid state of the mixture after mastication in a mixer.
Rubber slicer Cutting machinery used to slice the masticated blend to proper dimensions in proportion to cavities on the mold. The ability to precision processing allows minimization of waste and flash.
Resistance to animal fats Resistance of vulcanized rubber to various kinds of animal fat.
Accelerator Additives used to speed up a vulcanization reaction that would otherwise take hours to complete. They assure the economic sustainability of the process.
Hydraulic press It is a manufacturing machine that operates according to the principles of fluid power and transfers the force generated on the hydraulic cylinders onto the mold. Hydraulic presses equipped with heaters and vacuum pumps are often used for vulcanization.
Heat resistance Capacity of vulcanized rubber to preserve its properties at high temperatures.
ISO 9001 A quality management system standard that became highly popular in the 90s. The most up-to-date version, ISO 9001:2000, is still in wide use by many companies today.
Calendar A relatively simple machine consisting of cylinders rotating in opposite directions. It is mainly used to shape rubber blends into sheets.
Mold A system of metal pieces and supporting components that represent the core of production molding. Inverting shapes or cross sections for the desired products are fabricated on the mold. There are many different types and designs such as rubber molds, plastic injection or casting molds. In the manufacture of plastics and rubber, there are three basic mold systems: compression, injection and transfer mold.
Tool shop The factory unit that houses various metalworking machines such as lathes, milling machines, drillers and CNC machining centers as well as numerous measuring equipment required for mold making.
Internal batch mixer Sealed rubber mixing machine that is isolated from the external environment and employs two tangential rotors that crush the ingredients of the blend together. It is named after its inventor, Fernley Banbury (simply “Banbury”), who developed the first prototype of the machine in 1916.
Rubber Polymers that exhibit high elasticity and low compression set. The term generally is used to identify unvulcanized rubber gum, ready to be added to the mix.
Rubber mix It is used to describe the state where the primary rubber polymer is mixed up with other additives like filler, cure agent, accelerator, activator and protective chemicals ready to get masticated. Synonymous with rubber recipe or formula.
Seal Since natural sheep hair or felt is used in traditional first sealing elements, this name has been used synonymously with the sealing element in Turkish. Today, except for very exceptional applications, all seals are manufactured from elastomeric, plastic or metal materials by industrial methods.
Compression A primary production technique to process rubber. Material, either placed or cast into the mold, is subjected to heat and pressure for a certain period. It is most frequently used in the production of oil seals
Tensile strength Maximum tensile force the vulcanized rubber can resist before the break.
Copolymer A polymer composed of two types of monomers.
Latex The milky organic substance obtained from the rubber tree (Hevea brasiliensis). Latex is purified by removing water from the liquid and then processed into a natural rubber.
Mastication Process of turning a dry rubber mix into a dough-like rubber blend in a mixer. Main compound ingredients along with other additives and processing aids such as softeners are added at this stage.
Monomer Molecules representing the structural building blocks of polymers that tend to come together to build long molecular chains.
Resistance to oxidation Resistance of vulcanized rubber to oxygen attacks.
Resistance to oxygenated fluids Resistance of vulcanized rubber to oxygenated fluids like methanol, ethanol or MTBE.
Autoclave Boiler-like apparatus used to vulcanize rubber with high pressure and heat.
Resistance to ozone Resistance of vulcanized rubber to ozone attacks.
Special gravity Density of a material relative to water (1 g/cm3).
Cure agent Formula component at the center of the vulcanization process that helps to build cross-links between the rubber polymer chains allowing the rubber to gain a stable structure. Sulfur and peroxide are the two most preferred cure agents.
Vulcanization time Time required to complete the vulcanization process at the production station. It is of great importance to find out and apply the correct vulcanization time to assure the desired mechanical properties.
Polymer Long molecular chains with high molecular weight composed of one or more self-repeating molecular building blocks (monomers) joined together by covalent bonds.
Polymerization AThe reaction where the same or different types of monomers in a suitable environment are joined together to form polymers.
Plastic deformation Deformation is defined as deviation from the initial physical form for a solid material under stress. Upon removal of the deforming force if the material fails to return to its original shape it is called plastic deformation.
Resistance to radiation Resistance of vulcanized rubber to effects of radiation.
Recipe (Formula) It is the formula of the desired elastomeric material. shown in PHR (parts per hundred of rubber). The amount of each ingredient is adjusted according to 100 units of the main rubber polymer. Rubber polymer, cure agent, accelerator, activator, oils and protective additives are all part of this formula.
Rheometer A widely-used lab device that measures the visco-elastic properties of materials. It is very useful to find out the optimal vulcanization time for a rubber compound.
Synthetic rubber Rubbers made of petroleum products. Most of the rubber varieties used today are synthetic (e.g. SBR, NBR, IR).
Hardness Resistance of a material to plastic deformation. Different Shore scales are used to measure hardness in polymers.
Service temperature Upper limit of the temperature range a vulcanized rubber can successfully perform within.
Resistance to water Resistance of vulcanized rubber to water.
Swelling Increase in volume of a material left in a liquid for a certain period due to the absorption of the liquid.
Thermoplastic A term used to classify polymers that initially soften and then melt upon exposure to heat and solidify when cooled down. Ignoring the degradation of the polymer over time a thermoplastic material can be melted and solidified as many times as desired.
Thermoset Thermosetting polymers, when subjected to heat, become harder and receive a stronger and more stable form. Unlike thermoplastic materials, thermosetting polymers cannot be remolded because of their irreversible structure.
Viscosity Resistance of a material to flow under shear stress.
Vulcanization A reaction that creates the elastomeric structure by cross-linking the polymer chains. In practice, the blend of rubber along with a proper curing agent (e.g. sulfur, peroxide) is kept in a suitable environment at a certain temperature for a certain period. As a result plastic properties get replaced by strong, stable elastic qualities. It’s an irreversible reaction.
Oil seal Used interchangeably with rotary shaft seal. Please click to see the basic parts of an oil seal.
Resistance to lubricating oil Resistance of vulcanized rubber to lubricating oils.
Tear strength Resistance of vulcanized rubber to tearing. It is defined in standards as load or force required to induce some predefined length of rupture.
Softener Mostly oil-like additives included in the formula to soften the blend and improve its capacity to be processed.