Manufacturing Glossary

Abrasion Resistance:
The ability of a rubber compound to withstand mechanical wear.
Adhesion:
Material sticking or holding against another material.
Blemish:
A defect or deformity on the surface of a rubber component.
Blister:
A raised or bubbled blemish on a custom rubber component caused by an air pocket.
Bloom:
A milky discoloration caused by the migration of compounds on the surface of a rubber component after molding or storage.
Brittleness:
The tendency of a rubber product to crack, break or snap under pressure; fragility.
Clamping Force:
The amount of pressure placed on a mold to keep it closed during a molding life cycle.
Cold Runner:
A channel in a rubber mold that carries molding material to mold cavities during injection molding processes.
Color Streaks:
A rubber product defect characterized by a variation in color or a streaking pattern in the molded component.
Compression Molding:
The molding process in which rubber compound is placed in a heated cavity, which is compressed and filled.
Deflashing:
The process of removing the excess rubber material (or flash) from a molded product.
Delamination:
A molded rubber defect characterized by the forming of several layers of material or the appearance of separate layers on the surface of a component.
Die:
A manufacturing tool used to stamp or cut out a rubber material during compression.
Durometer:
A tool used to measure the hardness of rubber products.
Elasticity:
The ability of rubber to return to its original state after removing force such as compression.
Elastomer:
A polymer with similar elasticity to rubber.
Flash:
Excess molding material on the surface or joints of rubber products.
Flow:
The ability of heated rubber, silicone or other polymers to pass through channels and runners into mold cavities.
Flow Marks:
A manufacturing defect caused by improper flow of rubber material indicated by a wavy surface.
Gasket:
A component used to retain liquids or gases or a seal caused by the compression of two machined materials.
Gate:
The opening of an injection, compression or transfer mold that ensures flow of rubber, silicone or other polymers.
Hardness:
The measurement of resistance to force of a polymer component.
Heat Sealing:
Method of sealing or joining rubber products by applying constant heat and pressure.
Injection Molding:
A manufacturing molding process in which rubber, silicone or other polymer materials are heated and forced through runners into a mold.
Injection Ram:
The screw or pin that places pressure on the heated compound and forces it into a mold cavity.
LCP:
Liquid crystal polymer.
LIM:
Liquid injection molding is a manufacturing process that uses LSR in an injection molding machine.
LSR:
Liquid silicone rubber is the silicone material used in the liquid injection molding process.
Machining:
The process of cutting, molding, shaping or finishing products by machine.
Material Hopper:
A container used to store raw polymer materials and pour them into a machine for manufacturing processes.
Mold Cavity:
The hollow space of a mold where the rubber or silicone is shaped.
Mold Storage:
The process in which custom molds are organized, maintained and stored. ARP catalogs their custom molds and stores them in a climate controlled room.
Monomers:
A molecule that can go through the process polymerization.
Multi-Shot:
The molding process that provides the ability to shoot two or more materials into a mold.
O-Ring:
A torus shaped mechanical gasket used to seal liquids or gases.
Oscillating Seal:
The inner or outer member of this seal circles around the axis of a shaft.
Overflow:
A receptacle for excess rubber compound ensuring the cavity mold is completely filled.
Overmold:
A molding process that allows previously molded parts to be reinserted forming a new layer of polymer material around the first component.
Oxidation:
The chemical reaction of oxygen with rubber involving the transfer of electrons, reducing elastomer strength. This can cause rubber components to crack or become brittle.
Permeability:
The ability of a liquid or gas to diffuse through a rubber or other polymer product or component.
Polymers:
A long molecular chain material formed by the combination of multiple individual units.
Pressure Injection:
Pressure placed on the injection ram where the rubber materials are injected into a mold.
Quad Ring:
An elastomeric ring seal or gasket with a four lobed cross-section.
Radial Seal:
Compression applied to the inside and outside of an o-ring gasket.
Resins:
Injection moldable materials such as silicone, rubber, other polymers.
RMA:
Rubber Manufacturers Association.
Rubber Natural:
Raw or crude rubber produced from certain plants and vegetables.
Runner:
A mold’s distribution system that rubber material travels through to the cavities.
Short Shot:
A lack of rubber material caused by either low pressure, cool temperatures, injection speed, etc.
Shrinkage:
The contraction of rubber material after molding and cooling.
Silicone Molding:
The manufacturing process in which liquid silicone rubber is heated and injected through a series of runners into a mold producing pliable products such as gaskets, seals and membranes.
Sprue:
A passage liquid rubber material passes through on its way into the mold during injection molding.
Stringiness:
A string like or fibrous remnant on a rubber component left over from a previous injection shot.
Substrate:
The adhesive material used to coat or bond to the surface of another material.
Thin-Wall Injection Molding:
A specialized version of injection molding focusing on the manufacturing of thin or light rubber components.
Tonnage:
Measurement of size or carrying capacity of a shipping vessel; weight measured in tons.
Transfer Molding:
A molding process in which rubber compound is placed in a pot that is part of the mold, heated and squeezed through sprues and runners into the mold cavity.
Two-Shot:
Refers to a type of mold used in injection molding, more specifically for overmolding. The first shot of rubber material is injected into the mold with space left for a second shot, usually for rubber of a different type or color.
Viscosity:
The measurement of resistance to flow under stress.
Voids:
The absence of material or empty space in a mold where rubber material did not fill.
Vulcanization:
The irreversible thermal process converting polymers or rubber into a more durable and resistant compound.
Warping:
A defect that results in a twisted or distorted rubber product usually caused by incorrect temperature.
Weld Line:
A defect that results in a discolored line where two flow fronts converge.