Home » Glossary


PTFE coated fabric & Silicone coated fabrics
PTFE coated fiberglass fabric & silicone coated fiberglass fabric

PTFE coated tapes & PTFE film tapes
PTFE coated fiberglass tapes & PTFE film tapes

Industrial belts
PTFE coated fiberglass belts & Silicone coated fiberglass belts

A | B | C | D | E | F | G | H | I | J | L | M | N | O | P | R | S | T | U | V | W | Y | Z


PTFE Fabrics, Belts and Tapes Common Applications Glossary


Blister Packaging

A method of heat-sealing a plastic bubble to a cardboard surface to create product display packaging. The blister pack die is covered with Precision Coating’s PRECISIONTAPE™ PTFE coated fiberglass tape for release.



A company that converts polyethylene film into bags by heat-sealing the seams. Converters use Precision Coating’s PRECISIONFAB™ PTFE coated fiberglass fabrics, and Precision Coating’s PRECISIONTAPE™ PTFE coated fiberglass tape.

Form-Fill Sealing

Packaging equipment that forms a bag from film, by heating the seam; fills the bag with a product and then seal that bag closed. The sealing jaws and other surfaces are covered with Precision Coating’s PRECISIONTAPE™ PTFE coated fiberglass tapes.


Fusing Press Belts

This is a machine used in the textile industry to manufacture clothing. Typically fusing presses have a top and bottom belt. These belts basically touch and fuse the layers of cloth together. Precision Coating’s PC-10 SP30 (anti-static) or PC-14 SP30 (anti-static) are most commonly used for fusing belts.

Heat Sealing

The sealing together of 2 or more layers of packaging films, generally to close the package or bag. Precision Coating’s PRECISIONFAB™ PTFE coated fiberglass fabrics or PRECISIONTAPE™ PTFE coated fiberglass tapes are the most commonly used to cover the heat-sealing surfaces. The heat conducts through the tape or fabric and seals the film. The PTFE coating allows for the heated film to release from the sealers.


Over Wrapping

The same packaging heating and sealing process as tray packaging.  Precision Coating’s PRECISIONFAB™ PTFE coated fiberglass fabric conveyor belts are used to move the product over the heated platens.


Rotary Band Sealers

Packaging equipment used in the Pharmaceutical and Food processing industries. Rotary band sealers are used to seal or close the top of a pouch after a product has been inserted. The bands are made of either a single ply of PRECISIONFAB™ PTFE coated fiberglass fabrics or two plies (2 Ply Belts) laminated together.

Shrink Tunnel

Packaging equipment with a small oven and a Silicone coated fiberglass fabric conveyor belt. The belts convey packages with heat shrinking film through the hot oven. The heat from the oven shrinks or wraps the film tightly around the package.  Our PRECISIONSIL™ products are commonly used for this application.


Shrink Wrapping

Products are loosely wrapped in shrinkable films. When exposed to heat the shrink film wraps tightly around the package. The L  Bar sealer that is used to seal the shrink film loosely around the package is covered with Precision Coating’s PRECISIONTAPE™ PTFE coated fiberglass tape and/or PRECISIONFAB™ PTFE coated fiberglass fabric. Our PRECISIONFAB™ and PRECISIONTAPE™ are also the most commonly used to cover the sealing wires.

Side Sealing

Products are wrapped in packaging film with all the folds coming together on the ends of the package. Two PRECISIONFAB™ PTFE coated fiberglass fabric side sealing belts are running in tandem while the wrapped package passes between them. These belts run over heated platens that then seal the ends of the packages.

Tray Packaging

Typically food such as poultry and meat are placed on Styrofoam trays, and then wrapped with packaging film. The film is then folded to the underside of the tray. The package is then placed on a PRECISIONFAB™ PTFE coated fiberglass tear resistant fabric or a PRECISIONFAB™ conveyor belt over a heated platen sealing the film to the bottom of the tray.


Abrasion test: Determination of the rate of wearing away by friction.

Abrasion tester: A machine for determining relative abrasion resistance.


Belt: A flexible reinforced band placed around two or more pulleys to carry materials from one place to another.

Belt clamp: Beams or metal plates secured transversely on both sides of belt ends to hold the ends in a desired position.

Belt clamping device: A scraper or rotating device pressed against the belt surface to remove material stuck to the belt.

Belt conveyor: A mechanical system composed of suitable head, tail, bend pulleys and belt idlers or a slider bed to handle bulk materials, packages, or other objects placed directly upon it.

Belt drive: An assembly of power-driven pulley(s) used to transmit motion to a conveyor or elevator belt.

Belt grade: A classification of belting according to the quality and properties of the belt cover.

Belt modulus: The ratio of stress to strain.

Belt slip: The action that takes place, causing a differential movement between the pulley surface and the belt.

Belt slope tension: See tension, slope.

Belt surface finish: Final surface condition of belt.

Belt tracking switch: A limit switch actuated by the edge of a conveyor belt when the belt moves abnormally to either side of its centered path.

Belt training idler: An idler having a belt-actuated swivel mechanism to control the side runout of a conveyor belt.

Breaking strength: The tensile which a textile yarn or cable, a steel cord, or a belt is at rupture.

Butt seam: A seam made by placing the two pieces to be joined edge to edge.


Camber: The curvature of a belt relative to the center line (see bow).

Carcass: The fabric, cord and/or metal reinforcing section of any rubber product such as a belt, as distinguished from the rubber cover.

Carcass tear strength: The resistance of a belt against tearing.

Carcass tear test: The determination of the tension at which a belt may be torn.

Center-to-center: The distance between the center of two pulleys or idlers. Also called centers or center distance.

Cleated belt: Transverse raised sections on a conveyor belt to stabilize material carried up on incline.

Coefficient of friction: The ratio of the force required to move a package across a belt surface to the weight of the package.

Conductivity: Quality of power of conducting or transmitting heat or electricity.

Conveyor: A system for the continuous movement or transport of bulk materials, packages or objects along a predetermined path.

Conveyor belt: A belt that carries materials from one place to another.

Conveyor belt stretch: The increase in belt length which takes place when tension is imposed. Stretch is either elastic or permanent. Elastic stretch is a temporary change in length which varies directly with the pull. Permanent stretch is the residual change in length after tension has been removed; it generally accumulates over a period of time.

Conveyor width: In belt conveyors, the width of a belt.

Copolymer: A substance consisting of molecules characterized by the repetition of two or more types of monomeric units.

Cord fabric: A fabric with plied or cabled yarns in the wrap direction and a lightweight filling yarn spaced only sufficiently to process the fabric.

Count: In fabric, the number of warp ends, the number of filling picks, or both in a square inch of fabric.

Counter weight: In conveyor belting, the weight applied to the take-up assembly to maintain proper belt tension.

Cover splice: The transverse joint formed by connecting two lengths of cover stock.

Creep: (1) The deformation occurring with the lapse of time in both cured and uncured rubber, in a body under stress in addition to the immediate elastic deformation. Some related terms and properties are stress-relaxation, hysteresis, damping, flow, compression set and viscosity. See Cold Flow. (2) In belts, the action of a belt alternately losing speed on the driving pulley and gaining speed on the driven pulley.

Crown: The difference between the diameter at the center and at the edges of a pulley or a roll.

Crowned pulley: A pulley with a greater diameter at the center, or other points, than at the edges.

Cure: The act of vulcanization.

Cure time: Time required, at a given temperature, to produce optimum physical properties in an elastomer.

Curing temperature: The temperature at which the rubber product is vulcanized.

Cut edge: The uncovered edge of a laminated product, such as a belt, created by cutting after vulcanization.

Cut resistance: The ability of a belt cover to withstand the cutting action of sharp objects.


Delamination: The separation of layers of material in a laminate.

Dielectric strength: The measure of electric potential strength of a rubber product. Measure of its ability as an insulating compound to resist passage of a disruptive discharge produced by an electric stress. Measured as volts per mil of thickness.

Dip coat: A thin coat on a surface obtained by dipping the material to be coated into the coating materials.

Drive: An assembly of electrical and mechanical parts that provide motive power to a belt.

Drive factor: A numerical factor used for calculating the belt minimum slack side tension required for a given driving condition and/or configuration.

Drive pulley: A pulley mounted on a drive shaft which transmits power to the belt.

Dynamic fatigue: Loss in properties of a material when continually subjected to flexing and/or cyclic stress.


Edge wear: Damage to the edge of a belt by abrasion.

Effective tension: Difference between the tight side and the slack side tension at the drive pulley providing the necessary pull to move the load.

Elastomer: An elastic rubber-like substance, such as natural or synthetic rubber.

Elongation: Increase in length expressed numerically as a fraction or percentage of initial length.

Endless belt: A belt made endless without a joint.

Extruded: Forced through die of tubing machine in either solid or hollow cross section.

Extrusion: A process whereby heated or unheated plastic forced through a shaping orifice becomes a continuously formed piece.


Fabric: A planar structure produced by nonwoven or interwoven yarns, fibers, or filaments.

Fabric count: The number of warp ends per inch and the number of filling picks per inch.

Fabric design: The combination of size and numbers of fibers or yarns, in both warp and filling, and the manner in which they are processed.

Fabric impression: A pattern in the cover of a belt formed by contact with a fabric during processing.

Fatigue: The weakening or deterioration of a material caused by a repetition of stress or strain.

Feeder belt: A belt that discharges material onto another conveyor belt.

Filling yarns: The transverse yarns in a fabric.

Finger splice: Belt ends cut into mating fingers.

Fisheye: A small globule that has not blended completely into the surrounding material.

Flanged pulley: A pulley with a raised rim at the edges for the purpose of keeping the belt on the pulley.

Flat belt: (1) A belt the cross section of which is in the general form of a rectangle: (2) A belt which operates on a smooth flat bed or straight idlers or rollers.

Flat press: A belt finishing press with flat platens, between which the belt is heated and compressed.

Flex cracking: A surface cracking induced by repeated bending or flexing.

Flex life: The relative ability of a rubber article to withstand dynamic bending stresses.

Flex life test: A laboratory method used to determine the life of a plastic product when subjected to dynamic bending stresses.

Flexibility: The ability to be bent repeatedly without cracking.

Flexing: The bending of a belt.

Friction: (1) The resistance to motion of a belt due to the contact between two surfaces. (2) Improperly used to indicate the bond between two surfaces.

Fusion: An irreversible process during which a PVC compound or platisol undergoes a physical change and becomes a homogenous mixture by the mutual salvation of the PVC resin and the plasticizer in the compound, as a result of heating to an appropriate temperature.


Glass fiber: Glass extruded through a die with many fine holes into continuous filaments.


Hardness: Property or extent of being hard. Measured by extent of failure of the indentor point of any one of a number of standard hardness testing instruments to penetrate the product.

Head pulley: The terminal pulley at the discharge end of the conveyor.

Head-tail drive: A belt driving system using one or more powered pulleys at or near both the head and tail pulleys with each pulley independently driven.

Herringbone weave: The longitudinal appearance of a row of parallel lines slanting at an angle in the opposite direction to another row of slanting parallel lines.


Idler: (1) A non powered pulley around which a belt travels (2) a nonpowered roll or rolls supporting a belt.

Idler stand: The mechanical system that supports an idler pulley.

Inside length: A belt length measured along its inside circumference.

Installation allowance: The amount by which the center distance can be adjusted so a belt can be installed without damaging.


Joint: The area where two ends of a belt are fastened together, either by heat and pressure or mechanical means. See also splice.


Lagged drive pulley: See lagged pulley.

Lagged pulley: A pulley having its surface covered with lagging.

Lagging: A smooth or embossed covering on a pulley to increase friction between belt and pulley.

Laminate: A product made by bonding together two or more layers of material.

Laminated: Build up from thinner layers.

Lap joint: An elevator joint where one end of the belt laps over the other end with the leading edge on the bucket side.

Lap: A part that extends over itself or a like part.

Lap seam: A seam made by placing the edge of one piece of material extending flat over the edge of the second piece of material.

Leno weave: An open mesh fabric in which the warp yarns are held by the filling yarns with the filling yarns twisted around alternating warp yarns in opposite direction.

Lightweight belt: A belt with a rated maximum working tension of less than 160 pounds per inch width.

Load support: The ability of a fully loaded conveyor belt to bridge the idler gap without creasing into the idler gap and carry material without excessive sag between the carrying idler pulleys.

Load weight: The weight of material per unit of time.

Loading angle: The angle to the horizontal at which material is loaded onto a conveyor belt.

Loading impact: The energy with which material is loaded onto a conveyor belt.

Longitudinal: A lengthwise direction.

Longitudinal seam: A seam joining two materials in the length of the finished product.

Loop edge: A selvage formed by having the filling loop around a catch cord or wire, which is later withdrawn, leaving small loops along the edge of the cloth.


Minimum pulley diameter: The smallest pulley diameter around which a belt is recommended to operate.

Minimum tension: See tension, minimum.


Necking down: A localized decrease in the cross-sectional area of a product.

Net endless length: The manufactured length necessary to provide proper initial fit and tensioning of a belt on a specified drive.

Nip: The clearance between two rolls of a calendar.


Offset idlter: The center carrying roller which is offset and transversely lapping the troughing idlers.

Operating tensions: The tension of longitudinal sections of a belt system (tight side and slack side) when moving material, as distinguished from tension when the belt is running empty.

Oven: A low-pressure hot air chamber used for the purpose of heating, drying, baking or vulcanizing rubber product. See Aging.

Oxidation: The reaction of oxygen on a rubber product, usually detected by a change in the appearance or feel of the surface or by a change in physical properties.


Package conveyor: A conveyor which transports packaged, boxed, or bagged material.

Permanent stretch: Elongation permanently removed from belting when it is first used.

Permeability: The quality or condition of allowing passage of liquids or gases through a rubber layer.

Physical properties: A measure of mechanical characteristics of a material.

Plain weave: The simplest type of weave with both adjacent warp and filling yarns crossing over and under each other.

Plate finish: A finish resulting from contact with commercially smooth but not polished press platens.

Plied yarn: A yarn made by twisting together two or more single yarns.

Ply: A layer of rubberized fabric.

Ply adhesion: The force required to separate two adjoining strength reinforcing members in a rubber product.

Ply separation: Lack of adhesion between plies.

Ply tensile: The ultimate breaking strength of a belt expressed in force per width per ply.

Porosity: The condition of containing numerous small holes or voids.

Press: A machine consisting of two or more heated plates which can be brought together and separated by hydraulic pressure or mechanical action.

Press lap: The area of overlap of one press cure length on the next.

Press length: The length of a belt which can be pressed at one time.

Press marks: Irregularities in the surface of a vulcanized product caused by the press ends or by corresponding irregularities in the press surface.

PTFE (polytetrafluoroethylene): PTFE has the lowest coefficient of friction of any known solid and the highest operating temperatures of the fluoropolymers.

Pulley: A cylinder, mounted on a central axis rod.

Pulley projection: The amount a pulley face width extends beyond belt edge.

Pulley wear cover: (1) Elastomeric material attached to the pulley to minimize pulley surfaces wear (2) Additional belt bottom cover thickness where extraordinary wear is anticipated.


Return idler: A roll(s) that supports a belt on its return run.

Rotary press: A vulcanizing machine consisting of a rotating, heated drum with a flexible steel band partially encircling the drum, which continuously advances a material while under pressure and heat between drum and band.

Run: The distance or route covered by a conveyor.


Sag: The amount of vertical deflection of a conveyor belt from a straight line between idlers, usually expressed as a percentage of the spacing between idlers.

Sag belt tension: The minimum tension in any portion of the carrying run of a belt necessary to prevent excessive sag of the belt between idlers.

Scraper: A device for cleaning the surface of belting.

Screw take-up: A take-up for a conveyor system in which movement of a pulley-bearing block is accomplished by means of a screw. See also take-up.

Seam: The place where two edges of fabric or elastomer are adjacent to each other to form a single ply or layer.

Seaming strip: A strip of polymeric material laid over and/or in a seam to fill any voids between the adjacent plies of material.

Self-aligning idler: An idler having a belt-activated swivel mechanism to control the side movement of an operating conveyor belt.

Selvage: The lengthwise woven edge of a fabric.

Semi-cure: A partial or incomplete cure.

Sheeting: A form of plastic in which the thickness is very small in proportion to length and width and in which the plastic is present as a continuous phase throughout.

Skive: A cut made on an angle to the surface to produce a tapered or feathered cut.

Slack side tension: The lesser of the tensions in a belt on an operating conveyor. Usually immediately following the drive pulley.

Slider bed: A stationary surface on which a belt slides.

Slider bed conveyor: A conveyor belt operating all, or in part of its length, over a flat support surface as opposed to being supported by a series of rollers.

Slip: The action that takes place, causing a differential movement between the pulley surface and the belt.

Slip and sequence system: An interlocking belt conveyor system that stops the system when the speed of the conveyor belt drive pulley exceeds a certain speed of the conveyor belt.

Slit belt: A belt cut to lesser width.

Slit edge: The square finished edge of a belt after trimming to width.

Snub pulley: A pulley adjacent to a drive pulley that increases the arc of contact on the drive pulley to increase the effectiveness of the drive.

Solid woven belt: A type of conveyor belt wherein the carcass is a single ply consisting of multiple layers of warp and filling yarns interwoven. The carcass usually is impregnated and/or coated with polymeric compound.

Splice: Methods for joining the ends of belting together using a mechanical fastener.

Spread coat: To apply a thin coat of material over a surface determined by means of a knife, bar, or doctor blade.

Square edge: An edge of plastic-covered belting finished against rectangular irons.

Starting tension: The tension necessary to accelerate a belt from rest to normal operating speed.

Static friction: The resistance which must be overcome to start a body sliding down a belt surface.

Stitching: A method of butting or joining two pieces of material together, usually by means of a stitcher roller.

Straight face pulley: A pulley without any crown.

Strain: Deformation resulting from a force applied to a body.

Stress: Force applied to a body that results in the body being deformed.

Stress-strain: The relationship of force and deformation in a body during compression, extension, or shear. In a belt this is the relationship of tension (stress) and resulting elongation (strain).

Stretch: An increase in length.


Tail end: The end of a conveyor, usually near its loading points.

Tail pulley: The belt pulley near the loading end of the conveyor system.

Take-up: (1) Removal of slack or stretch in a belt (2) An assembly of structural and mechanical parts to maintain proper belt tension.

Take-up pulley: A pulley which can move in space due to gravity, a spring, or other forces in order to maintain relatively constant tension in a specific strand of a belt.

Take-up travel: The distance the take-up can move during the belt operation.

Tandem drive: A belt driving system employing two adjacent powered pulleys.

Tape line measurement-maximum length: The inside circumference of a belt measured around the pulley surfaces when the take-up idler(s) are moved out to where they take up all the belt slack their movement permits.

Tape line measurement-minimum length: The inside circumference of a belt measured around the pulley surfaces when the take-up idler(s) are moved in for the installation of the shortest belt possible.

Telescoped roll: At the outside end of a roll of belting, turns of the belting progressively loosened and moved outward from the remainder of the evenly wound turns of the belting.

Tensile strength: The maximum force, stress, applied to a specimen at rupture.

Tensile stress: The force applied to stretch a test piece (specimen).

Tension: Stress on a material tending to cause extension of the material.

Tension, effective: In a belt drive, it is the difference between the two tensions in a belt as it approaches and leaves a driving or driven pulley. In a two-pulley drive, it is the difference between tight and slack side tensions. Being a measure of power requirement, it is sometimes referred to as horsepower pull.

Tension, maximum: (1) The highest tension occurring in any portion of a belt drive. In a two-pulley drive it is the tight side tension. (2) In conveyors, the maximum tension may occur at a point other than the drive pulley.

Tension minimum: The lowest tension occurring in a belt in a conveyor or elevator system under operating conditions.

Tension rating: Maximum safe working tension recommended by a belt manufacturer.

Tension ratio: In an operating belt system, the ratio of the larger to the smaller tension as the belt approaches and leaves a driving or driven pulley.

Tension, slack side: In a belt system, where the two portions of the length of a belt on either side of a driving or driven pulley have different tensions, the slack side tension is the smallest of the two.

Tension, slope: The tension in an inclined belt caused by the weight of the material being elevated in addition to the belt weight and independent of friction and other sources of tension.

Tension, take-up: The amount of tension in each of the runs of belting approaching and leaving the take-up pulley, the total of which is the force exerted by the take-up device.

Tension, tight side: In an operating conveyor system, the greater of the tensions as the belt approaches and leaves the drive pulley.

Tension, working: The maximum working tension for a fabric or belt recommended by the manufacturer.

Terminal, position: The maximum working tension for a fabric or belt recommended by the manufacturer.

Terminal pulley: The pulley at or near the discharge end of a conveyor belt system.

Textile: A general term applied to yarn, cord, nonwoven, or woven fabric made from a fibrous material.

Tolerances: The limiting values for a dimension.

Traction: The friction between a drive pulley and the conveyor belt.

Training idler: An idler mounted on a mechanical device, actuated by the belt moving against it to make the belt run straight.

Transfer system: A combination of mechanisms to move objects or bulk material to or from a conveyor.

Transition distance: The distance between the last fully troughed idler and the flat driving or discharge pulley.

Transition idler: A troughed belt idler having a lesser degree of trough than the previous carrying idlers.

Transverse: A crosswise direction of a belt.

Transverse cord breaker: A cord fabric laid in the top cover at the right angles to the belt edges.

Transverse rigidity: Resistance to belt deformation in the belt crosswise direction.

Transverse seam: The joint, across the belt, of two ends of a fabric ply in the belt or cover material.

Troughing idlers: An idler system which supports a belt in a troughed configuration. Usually it consists of a center horizontal roll with an inclined roll on each side. See also catenary idler.


Ultimate elongation: Elongation at rupture.

Ultimate strength: The force required to rupture a specimen.

Ultimate tensile: Tensile stress at rupture.

Undercure: A less than optimal state of vulcanization which may be evidenced by tackiness or inferior physical properties.

Uncured: Not vulcanized.


Vertical curve: The portion of a conveyor belt where the angle of incline increases.

Viscosity: The flow property of a material.

Vulcanization: A process over a range in temperature during which a polymeric compound, through a change in molecular structure (e.g., crosslinking) becomes less plastic and causes changes in the physical and chemical properties of the resulting elastomer.

Vulcanized splice: A joint in a belt made by means of vulcanization.

Vulcanized splice step length: The longitudinal distance between steps in the splice.


Warp: (1) The yarns that run lengthwise in a woven fabric or jacket. (2) The total deviation from a straight line of a hose when subjected to internal pressure.

Warp-yarn: (1) A longitudinal yarn in a fabric. (2) A corner yarn in a braid.

Weave: A fabric pattern description denoting a specific relationship of warp and filling yarns at specific locations in the fabric.

Winged pulley: A pulley with radial vanes extending from a supporting structure to the center shaft to minimize trapping material that otherwise would build up and damage the belt.

Wire hook fastener: A mechanical fastener consisting of wires capable of being driven through the belt end and bent back into the belt by a special tool device.

Working tension: Stress on the belt when the belt is loaded with conveyor material and moving.

Woven fabric: A flat structure composed of two series of interlacing yarns of filaments, one parallel to the fabric and the other transverse.


Yarn: A generic term for continuous strands of textile fibers or filaments in a form suitable for knitting, weaving, or otherwise intertwining to form a textile fabric. It may comprise (1) a number of fibers twisted together (2) a number of filaments laid together without a twist (a zero-twist yarn) (3) a number of filaments laid together with more or less twist or (4) a single filament with or without twist (a mono-filament).

Yarn number: The number of hanks in a pound of spun yarn.

Yield point: The stress in a material at which a substantial increase in strain occurs with a minimum increase in stress.

Yield strength: The stress at which a material exhibits a specified limiting permanent set. Determined by a measurable value of plastic yielding of the material, above which the material is considered to be damaged and below which the damaging effects are considered to be negligible.


Zero load: A reference load applied in taking an initial reading and prior to determining compressibility or extensibility.