Glossary of Stamping and Drawing Terms

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Adapter - 1) The lower section of a die on which the part rest. Sometimes called a boss, die post, locator, riser, and stool. 2) A device for connecting two parts of an apparatus not originally intended.

Aerial Cam - A cam attached to the upper half of the die with a driver on the bottom half of the die. Sometimes called a flying cam, dog leg cam, or walking cam.

Air draw - A draw operation performed in a single action press with the blankholder pressure supplied by an air cushion.

Air-Hardening Steel - An alloy steel that will harden by cooling in air from a temperature higher than its transformation range.

Alloy - A material composed of two or more chemical elements of which at least one is an elemental metal. The resultant material combines the physical attributes of the ingredient elements.

AKDQ - Aluminum Killed Drawing Quality

Annealing - Process involving the heating and cooling of a metal. Commonly used to induce softening. Term refers to treatments intended to alter the material's mechanical or physical properties or to produce a definite microstructure.

Anvil Steel - The lower steel or adapter against which the hem steel finishes or flattens the hem.

Arbor Press - A press originally developed for forcing arbors or mandrels into holes and similar assemblies.

Automatic Press - A press whose action is synchronized with mechanically fed work.

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Back-Draft - The area of a part that cannot be formed when in die position with direct vertical travel of the press ram.

Back-Ups - Spacer plates mounted behind a die detail to reinforce that detail.

Ball Seat - A teardrop shaped area machined in the shank of a punch by a ball nose cutter. This allows the punch to be accurately located and locked in a retainer by a ball.

Barbering - Rough grinding, by hand, the excess stock in a die.

Bead - Any rib-like projection whether on a die section or on a part, such as strengthening beads on a part.

Bellmouth - The angular condition on the working surface of a trim or form steel caused by excessive wear.

Bend Angle - The angle through which a bending operation is performed.

Bend Radius - The inside radius of the bent section.

Bendability - The minimum bending radius attainable by a given material.

Bending - The straining of material, usually flat sheet or strip metal, by moving it around a straight axis lying in the neutral plane. The metal flow takes place within the plastic range of the metal, so that the bent part retains a permanent set after removal of the applied stress. The cross section of the bend inward from the neutral plane is in compression while the rest of the bend is in tension.

Bending or Press Brake – An open-frame single-action press that is used for bending and forming strip, plate, and sheet.

Binder - The upper and lower holding surfaces that control metal flow around a shape to be formed in a draw operation.

Binder Ring - The part of a draw die that holds the workpiece against the draw ring to control metal flow; sometimes called binder or blank holder.  

Bladesteel - A long narrow trim steel quite often mounted from the side.

Blank - A pre-cut metal shape ready for subsequent operations.

Blank Development - Technique of determining the optimum size and shape of a blank.

Blanking - The operation of cutting or shearing a piece of stock to a pre-determined contour.

Blank Holder - The part of a forming die which holds the blank by pressure against a mating surface of the die to control metal flow and prevent wrinkling. A blank holder is also called binder, binder ring, or ring.

Blank Holder Force - The force that is applied to the perimeter of a sheet during a deep drawing operation to suppress wrinkling and control metal flow

Bolster Plate - A plate secured to the press bed for locating and supporting the die assembly.

Boss - A raised portion of a casting, die, or part such as bossed for tie slots on die shoes.

Bottoming Blocks - Adjustable blocks mounted under a pad to determine the proper height of the pad when the die is closed.

Bottoming the Die - Bringing the die home. Taking it to the bottom.

Box Cam - A precision made box containing cam slide and driver.

Breakage - The space, per side, between the punch and die on a trim or pierce die. Also called clearance or die clearance.

Breathing - The non-desired action of a die member moving away from the force applied.

Bubble Die - A pre-draw to gain material in the areas of a deep draw to help prevent splits in these areas.

Buckling - A bulge, bend, kink or other wavy condition of the workpiece caused by compressive stresses.

Bulging - The process of increasing the diameter of a cylindrical shell or expanding the outer walls of any shell or box shape whose walls were previously straight.

Burr - A thin ridge or roughness left by cutting operations such as slitting, shearing, trimming, blanking, or sawing.

Burring - A common term for deburring or smoothing the rough cut edges of metal.

Button - A small cylindrical die steel with an opening larger than the punch point size, generally by a percentage of the thickness of the material being pierced.

Bypass - A generic term referring to the amount that one steel passes over or through another steel.

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C-Frame Press - A press having uprights or housing resembling the letter "C". Also called gap frame or overhanging press.

Cam - A device to move or do work at an angle to the press stroke.

Cam Action - A motion at an angle to the direction of an applied force achieved by a wedge or cam.

Camber - A slight convexity or bulging of a sheet strip or plate as might appear when looking along the edge.

Cam Driver - A block with one or more angular surfaces which applies force by the vertical movement of the press to mating angular surfaces on a cam slide.

Cam Slide - A device to perform work at an angle to the press stroke. The most common angle is 90 degrees.

Canning - A dished distortion in a flat or nearly flat sheet metal surface.

Carbon Steel- A steel that owes its specific properties chiefly to the presence of carbon, without substantial amounts of other alloying elements.

Carburizing - A process that introduces carbon into a solid ferrous alloy by heating the metal in contact with a carbon material, solid, liquid, or gas to a temperature above the transformation range and holding it at that temperature for a period of time.

Carburr - A small carbide mill cutter usually one-half inch or less in diameter. It is designed to remove stock from hardened tool steel.

Carrier Strip - The area of a stock strip that ties the parts together and carries them through a progressive die until the final operation.

Case - The surface layer or case of a ferrous alloy that has been made substantially harder than the interior or core.

Case Hardening - Any process of hardening a ferrous alloy so that the case or surface is substantially harder than the core or interior.

Cast - A solid reproduction of the outside surface of a part, detail, or model. Normally made of plaster.

Chain Slots - Machined or cast slots in the upper and lower die shoe and large adapters for handling purposes.

Chair - A precision ground block which has a slot or hole on one surface and a leg off the opposite surface from the slot or hole.

Chamfer - The beveled edge of a hole or edge to eliminate a sharp corner.

Chicago Screw - A socket head cap screw with the head and the upper portion of the body turned down, leaving a minimum number of threads on the end of the body.

Chute - A trough in which blanks, workpieces, scrap or parts are fed or conveyed away from a die or press.

Clearance - 1) The space, per side, between the punch and die. Also called breakage on trim and/or pierce dies. 2) The space between any two details to avoid interference.

Coining - A closed die squeezing operation in which all surfaces of the sheet metal are confined or restrained, resulting in a well defined imprint of the die on the workpiece.

Coin Straightening - A combination coining and straightening operation performed in special cavity dies designed to impart a specific amount of working in specified areas of a forging to relieve the stresses developed during heat treatment.

Cold Developing - The initial development of a blank or part on paper or in wax during the designing of a die.

Cold Heading - The process of upsetting the ends of a bar, wire, or tube stock while cold.

Cold Working - Working of a metal, such as bending or drawing, to deform it plastically and produce strain hardening.

Column Press - A four-post single slide press.

Compound Die - Die designed to perform more than one operation on a part with one stroke of the press, such as blanking and piercing. All functions are performed simultaneously within the confines of the blank size being worked.

Compressive Strength - The maximum compressive stress a material is capable of developing. With a brittle material that fails in compression by fracturing, the compressive strength has a definite value. In the case of ductile, malleable, or semi-viscous materials (which do not fail in compression by a shattering fracture), the value obtained for compressive strength is an arbitrary value dependent on the degree of distortion that is regarded as effective failure of the material.

Compressive Stress - The stress that causes an elastic body to deform (shorten) in the direction of the applied load.

Construction Hole - The hole in which the centerline is used as a dimensional location for other holes or surfaces. Sometimes referred to as a point of origin or coordinating hole.

Contouring - Machining surface shape on die member.

Corrugating - Forming of sheet metal into a series of straight, parallel, alternating ridges and grooves on a rolling mill equipped with matched roller dies or a press brake equipped with specially shaped punch and die.

Corrugations - Transverse ripples caused by a variation in strip shape during hot or cold reduction.

Crank Press - A mechanical press whose slides are actuated by a crankshaft.

Crimping - The forming of relatively small corrugations in order to set down and lock a seam, to create an arc in a strip of metal, or to reduce an existing arc or diameter. See also corrugating.

Critical Temperature - The temperature to which a metal must be heated to produce metallurgical changes, such as hardening. Also known as transformation temperatures.

Crown - 1) A shape ground into a flat roll to ensure flatness of cold (and hot) rolled sheet and strip. 2) The upper part of a press frame. On hydraulic presses, the crown usually contains the cylinder. On mechanical presses, the crown contains the drive mechanism

Cup - 1) Any cylindrical part or shell closed at one end. 2) The product of the first drawing operation.

Cupping - 1) The first step in deep drawing. 2) The fracture of severely worked rods or wire in which one end looks like a cup and the other a cone.

Cupping Test - A mechanical test used to determine the ductility and stretching properties of sheet metal. Also can be used to determine the effectiveness of lubricants. See Tinius Olsen Cup Draw Test.

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Deep Drawing - The drawing of deeply recessed parts from sheet material when the depth of the recess equals or exceeds the minimum part width.

Deflection - The amount of deviation from a straight line or plane when a force is applied. Used to specify the allowable bending of the bed, slide, or frame at rated capacity with a load of predetermined distribution.

Deformation Limit - In drawing, the limit of deformation is reached when the load required to deform the flange becomes greater than the load-carrying capacity of the cup wall. The deformation limit is the ratio of the maximum blank diameter that can be drawn into a cup without failure to the diameter of the punch.

Developed Blank - A sheet metal blank that yields a finished part with minimal or no trimming.

Die - A tool, usually containing a cavity, that imparts shape to solid, molten, or powdered metal primarily because of the shape of the tool itself. Used in many press operations including blanking, drawing, forging, and forming.

Die Assembly - The parts of a die stamp or press that hold the die and locate it for the punches.

Die Clearance - Clearance between a mated punch and die that is commonly expressed as clearance per side.

Die Cushion - A press accessory located beneath or within a bolster or die block to provide an additional motion or pressure for stamping operations that is actuated by air, oil, rubber or springs.

Die Height - The distance from the finished top face of the upper shoe to the finished bottom face of the lower shoe immediately after the die operation and with the work in the die.

Die Holder - A plate or block, on which the die block is mounted, having holes or slots for fastening to the bolster plate or the bed of the press.

Die Impression - The portion of the die surface that shapes a forging or sheet metal part.

Die Life - 1) The number of parts or the length of time that a die is usable. 2) The usable portion of a punch or die block. 3) The portion of the die steel surface between the cutting edge and slug clearance.

Die Line - A line or scratch resulting from the use of a roughened tool or the dragging of a foreign particle between tool and product.

Die Post - Lower section of die on which the part nest. Also called locator or plug.

Die Lubricant - A compound that is sprayed, swabbed, or otherwise applied on the workpiece of die surfaces before or doing the forming or forging process to reduce friction. Lubricants also facilitate release of the part from the dies and provide thermal insulation.

Die Match - The alignment of the upper (moving) and lower (stationary) dies in a hammer or press.

Die Pad - A movable plate or pad in a female die that is used for part ejection by mechanical means, springs, or fluid cushions.

Die Radius - The radius on the exposed edge of a deep-drawing die over which the sheet flows in forming drawn shells.

Die Set - Upper and lower die shoes assemblies (punch and die holders). Usually includes the guide pins, guide pin bushings, and heel blocks.

Die Shoe - The lower section of a die set where the adapter, die steels, guide posts and punches an mounted.

Die Space - The maximum space within a press for mounting a die.

Die Stamping - The general term for a sheet metal part that is formed, shaped, or cut by a die.

Dimpling - Localized indent forming of sheet metal.

Dings - A small unwanted mark or dimple in a part. Usually caused by dirt or material in the die.

Distortion - Any deviation from a desired contour or shape.

Dog Leg Driver - A cam driver designed to ensure positive cam-slide travel in both directions.

Dope - A drawing compound used to lubricate the stock during a forming operation.

Double-Action Die - A die in which pressure is first applied to a blank through the blank-holder and is then applied to the punch.

Double-Action Mechanical Press - A press having one slide within the other, the outer slide usually being toggle or cam operated, resulting in independent paralleled slide movements.

Dowel - A round pin, usually case hardened that fits into a corresponding bole to align two die members.

Draft - Taper given to a die so as to allow the part to fall through the die or be removed.

Draw - Deformation mode associated with metal flow from the blank-holder into the die cavity to aid in the forming of the part.

Drawability - A measure of the feasible deformation of a blank during a drawing process often determined by the percentage of reduction in diameter of a blank when it is drawn to a shell of maximum practical depth.

Drawing Compound - A substance applied to prevent pickup and scoring during deep drawing or pressing operations by preventing metal-to-metal contact of the workpiece and die. It is also known as a die lubricant.

Draw Bead - Rib-like projections on a draw ring or blank-bolder for controlling the rate of metal flow.

Draw Die - A specific type of form die that involves forcing the flat sheet of metal into a die cavity with a punch while bolding the workpiece around the cavity to control metal flow.

Draw Marks – Impressions, such as scratches, burnished areas, and similar marks left on the surface of the workpiece by a draw die. Also known as skid lines.

Draw Plate - A circular plate with a hole in the center that is contoured to fit a forming punch. It is used to support the blank during the forming cycle.

Draw Radius - Radius at the edge of a die or punch over which sheet metal is drawn.

Draw Ring - The part of a draw die that holds the workpiece against the blank-holder in which the metal is drawn over the inner edge by the punch.

Ductility - The property of a material that permits it to sustain permanent deformation in tension without rupture.

Dutchman - A u-shaped device for tying sections of dies together either by design or to repair a die which has been broken.

Dwell - The time interval in which there is no movement of a member.

Dwell Cam - A cam that can be moved into position and held there while the press continues to cycle.

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Earing - The formation of scalloped edges around the top of a drawn shell. Results from directional differences in the plastic-working properties of rolled metal with, across, and at angles to the direction of rolling.

Eccentric - The offset portion of the driveshaft that governs the stroke or distance the crosshead moves on a mechanical or manual shear.

Edger - The portion of a die impression that distributes metal during forging into areas where it is most needed in order to facilitate filling the cavities of subsequent impressions to be used in the forging sequence.

Edging - 1) In sheet metal forming, the reducing of the flange radius by retracting the forming punch a small amount after the stroke, but before release of the pressure. 2) In rolling, the working of metal in which the axis of the roll is parallel to the thickness dimension. Also called edge rolling. 3) In forging, the working of a bar between contoured dies while turning it between blows to produce a varying rectangular cross section.

Effective Draw - The maximum limits of forming depth that can be achieved with a multiple-action press. Sometimes called maximum draw or maximum depth of draw.

Ejecting - The removal of a part from a die by an air blast or mechanical means. The ejector is the means.

Elasticity - The property of a material which relates to its ability to return to its original size and shape after incurring deformation.

Elastic Deformation - A change in dimensions that is directly proportional to an increase or decrease in applied force. This deformation is recoverable when the applied force is removed.

Elastic Instabilities - A section of a part that has two equilibrium positions and can be manually switched between each position. Elastic instabilities are created when a highly deformed area is constrained on all sides by regions of less deformed areas. Also referred to as oil canning.

Elastic Limit - The maximum stress a material can sustain without any permanent deformation remaining upon complete release of the stress.

Elephant Ears - Cast or welded projections in the shape of an ear on the outboard section of a die that are used for handling the die with chains.

Elongation - The degree of permanent extension of a material prior to fracture. Elongation occurs during the forming operation.

Elongation Percent - The extension of a uniform section of a specimen expressed as a percentage of the original gage length. Elongation % = (Lx - Lo) / Lo x 100 where Lo is the original gage length and Lx is the final gage length.

Emboss - A shallow indentation or raised design that generally results in material stretch and little change in metal thickness.

Equalizer Pins - A pin used in conjunction with pressure pins to distribute and balance the load on a die cushion. Also called balancing pins.

Extractor - A mechanism attached to a press for removing a part from a die. It is sometimes called iron hands.

Extruding - 1) The turning up or drawing out of a flange around a hole which has been punched in a previous operation (hole flanging). 2) The punching and flanging of a hole in one operation generating a slug.

Eye Bolt - A bolt having a looped head designed to receive a hook or rope.

Eyeleting - he displacing of material about an opening in sheet or plate so that a lip protruding above the surface is formed.

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Factor - Rib-like projections on a draw ring or blank holder for controlling metal flow.

Filler Cam - A dwell type cam-slide that generally fits the part shape and retracts to permit loading and unloading of the part.

Finish Form - Forming a panel shape to the finish position.

Finite Element Method (FEM) - Method of analysis developed for prediction of practical forming of the instantaneous velocities, strain rates, strains, stresses and temperatures within the deforming metal.

Flange - A projecting rim or edge of a part that is usually narrow and constant width for stiffening or fastening.

Flange Steel - A steel used in forming in which a narrow strip at the edge of a sheet or part is bent down along a straight or curved line.

Flash - The excess metal attached to a part after a forming operation.

Flattened Hem - A flange that is folded back over upon itself. It is used primarily for appearance and removal of dangerous sheared edges.

Flattening - The truing of metal surfaces by the use of restrike dies or other methods.

Floating Form Punch - A draw die punch that is supported by air cylinders instead of being tied to the inner press ram. This allows adjustment for the amount of preform desired and helps to eliminate binding between the punch and the die.

Flying Cut-Off Device - A Cutting die, Saw Or wheel that cuts work to length while it is moving.

Flying Shear - A machine for cutting continuous rolled products to length. It does not require a halt in rolling, but moves along the runout table at the same speed as the product while performing the cutting, and then returns to the starting point in time to cut the next piece.

Foil - Metal that is in sheet form and less than 0. 15 mm thick.

Follow Die - A progressive die consisting of two or more parts in a single holder. It is used with a separate lower die to perform more than one operation (such as piercing and blanking) on a part in two or more stations.

Formability - The ability of a material to stretch or draw without fracture.

Forming - Changing the shape of a metal piece which does not intentionally reduce the metal thickness and which produces a useful shape.

Forming Die - A die in which the shape of the punch and die is directly reproduced in the metal with little or no metal flow.

Free-Shoe Die - A die constructed so that the upper shoe is linked to the lower shoe and not secured in any way to the press ram. It is used for blanking or secondary cutting optsatiom

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Gage - 1) A device used to position work in a die accurately. 2) Another name for a checking fixture which is used to check parts. 3 ) The thickness of sheet or the diameter of wire.

Gage Pin - A round gage normally used to position work from the edge of the part.

Galling - A build-up of metal from a sheet metal part on the surface of a steel. Also can be worn grooves in the surface of a steel.

Gang Die - A series of dies mounted on a die plate.

Gas Cylinder - A gas charged cylinder used in place of springs or die cushions in applications in which high initial pressure is required.

Gibs - Guides or shoes that ensure the proper parallelism, squareness, and sliding fit between press components. They are usually adjustable so that they can compensate for wear and to establish operating clearance.

Grid Analysis - A method to measure the nearness to failure of sheet metal parts during the forming operation.

Guide Pin - Pin or post usually fixed in the lower shoe and accurately fitted to bushings in the upper shoe to insure precise alignment of the two members of a die set. Also called a guide post or rider pin.

Guide Pin Bushing - A replaceable insert normally in the upper shoe to provide accurate alignment of both upper and lower die shoes. Also called bushing, guide post bushing or rider pin bushing.

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Handling Core - Cast cores in the upper and lower shoes used for handling purposes.

Handling Ring - A device bolted to the side of a mold die for handling of the mold.

Heel Block - A block or plate usually mounted on or attached to a lower die and serving to prevent or minimize deflection of punches or cams.

Heel Plate - A wear plate used on the heel block.

Heel Post - A male member that has either a machined wear surface or wear plates mounted to it. It is mated with a heel block. It helps to maintain die alignment and absorbs lateral pressures produced within the die.

Hem Die Plus - The amount of stock added to a part in an area to be hemmed to compensate for the amount the part reduces in size along the flange radius when hemmed.

Hem Steel - The steel in a hem die that finishes and flattens the hem.

Hemming Die - A die which folds the edge of the part back over on itself, such as on a door assembly.

High Collar Lock Washer - A special type of lock washer that is thicker than standard and smaller in diameter than standard. Designed to fit in a standard counterbored hole for a socket head cap screw.

Hold Down - An object used to secure a workpiect.

Homing The Die - Adjusting press ram/slide so the die is on bottom or on the stop blocks at the bottom of the press stroke. Known as bottoming the die.

Horizontal Cam - See Straight Cam.

Horn - Lower section of the die on which the part nests. Also called an adapter, boss, die post, locator, master, master plug and stool.

Hot Developing - The development of a blank or part during the tryout of the die.

Hot Shear - A term used for a quick, but temporary fix of a trim steel.

Hydraulic Press - A press in which fluid pressure is used to actuate and control the ram.

Hydraulic Press Brake - A press brake in which the ram is actuated directly by hydraulic cylinders.

Hydraulic Shear - A shear in which the crosshead is actuated by hydraulic cylinders.

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Inpact Line or Marks - The line or marks on the part that is caused by impact of the flanging steel or draw ring. Its size can be controlled by the size of the radius on the flange steel or draw ring. Also called draw line.

Inching - A control process in which the motion of the working members is precisely controlled in short increments.

Inclinable Press - A press whose main frame may be tilted backward, usually up to a 45 degree angle, to facilitate ejection of parts by gravity through an open back.

Incline Cam - A cam that travels at an angle (other than 90 degrees) to the press stroke.

Insert - A separate steel which is mounted upon or into another section to aid in ease of repair or to extend wearability. May be of a similar to or dissimilar metal than parent metal.

Inverted Die - A die in which the conventional positions of the punch and mating die cavity are reversed, with the punch on bottom (similar to a stretch-form die).

Iron Hand - Automated extractor that removes the part from the previous press operation.

Ironing - An operation in which the thickness of the shell wall is reduced and its surface smoothed.

I.S.M. - Abbreviation for inside the metal.

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"J" Hook - A type of turnover shaped like a "J" for lifting or turning over dies or die sections.

"J" Number - Designation to identify special accounts or projects that cover the cost of new die work or engineering changes. Also called project numbers.

Jig Border - A machine to locate and machine holes accurately.

Joggle - An offset surface consisting of two adjacent, continuous, or nearly continuous short radius beads of opposite curvature.

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Keeper - A block, pin, or spool used to retain the stripper plate or pad for the designed range of travel.

Kellering Aid - A model, skin, casting or template used an a hydro-tel for the tracer to follow.

Key - A block partially mounted in a pocket at the perimeter of a die member to locate or add support to that die member. It is accessible without removing the die member.

Kidney - A bulge outside of the finish form area on a draw punch or cavity to take up loose metal or to help control the draw process. Also called a sausage.

Kiss Off - The area of two mating surfaces of a mold that determines the parting line.

Knockout - A mechanism for releasing workpieces from a die.

Knockout Pin - A power-operated plunger installed in a die to aid in the removal of the finished forging.

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Lancing - Cutting along a line in the workpiece without producing a detached slug from the workpiece. Used to separate two parts from a double-attached die.

Land - The reduced area of a die block or punch that is reground when sharpening is required.

Lead Hit - A method of determining the location of the cutting edge on a steel by building approximately 1/4 inch of lead on top of the cutting edge and shearing lead with mating steel.

Leveling - The flattening of rolled sheet, strip, or plate by reducing or eliminating distortions.

Leveling Blocks - Blocks used to control the shut height and levelness of a die in a spotting press.

Lifter - A mechanism for raising a part in a die to a height for advancing it to another station, as in a progressive die or for ejecting it from the die.

Liftout - The mechanism that is also known as "knockout".

Limit Switch - A type of electric switch used to control the operations of the press or automation.

Limiting Dome Height (LDH) - The greatest depth that a material can withstand under the stretching of a hemispherical punch. This is a standard measurement of stretchability.

Limiting Draw Ratio (LDR) - The greatest ratio of blank diameter to punch diameter that can be successfully cup-drawn to a particular depth. This is a standard measurement of drawability.

Line Dies - A sequence of stamping dies that perform all operations for completing a stamped part.

Locator - Lower section of a die on which the part nest.

Locking Bead - A bead or projection designed to prevent metal flow in a forming operation (usually found in stretch-form dies).

Low Profile Screw - A special socket head cap screw which has a head height approximately 1/2 that of a nominal socket head cap screw.

Low Spot - A local inboard condition on a panel that results in a shallow area adjacent to strained metal. It is undesirable on outer skin panels.

Lubricant - Any substance that reduces the friction and/or wear between surfaces.

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Marforming Process - A rubber-pad forming process that was developed to form wrinkle-free shrink flanges and deep-drawn shells. The sheet metal blank is clamped between the rubber pad and the blankholder before forming begins.

Marriage Gap - Space between the trim edge of the inner panel and the inside of metal of the outer panel flange before hemming.

Master - 1) The lower section of a die on which the part nests. It is also called a master plug, adapter, boss, die post, horn, locator, and stool. 2) The section of die used to govern the form or contour of the mating die section. 3) A wood model or die aid.

Match - The condition in which a point in one die half is aligned properly with the corresponding point in the opposite die half

Mating Flange Area - The area of inner panel covered by flange of outer panel.

Mating Surface - The area of an inner panel that is in contact with outer panel.

Maximum Elongation - The maximum engineering strain the material can take until fracture. Also called fracture strain.

Mechanical Press - A forging press with an inertia flywheel, a crank and clutch, or other mechanical device that are used to operate the ram.

Mechanical Press Brake - A press brake using a mechanical drive consisting of a motor, flywheel, crankshaft, clutch, and eccentric to generate vertical motion.

Mechanical Working - The subjecting of a material to pressure exerted by rolls, hammers, or presses in order to change the shape or physical properties of a material.

Metal Clearance - The running clearance on the bottom of press stroke between flange steels or male and female form steels.

Mill Edge - The normal edge produced in rolling.

Modified Flat Hem - A modified flat hem is believed to create better reflection characteristics on the finished panel assembly.

Modulus of Elasticity - The ratio of stress to strain during elastic deformation when material is under uniaxial tension. The measure of rigidity or stiffness of a metal.

Multiple Die - A die used for producing two or more identical parts at one press stroke.

M-Value - The intensity of the internally distributed forces or components of forces that resist a change in the volume or shape of a material that is or has been subjected to external forces. Stress is expressed in force per unit area. Stress can be normal (tension or compression) or shear.

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N Value - The strain-hardening exponent is equal to the slope of the true stress/true strain curve up to maximum load, when plotted on log-log coordinates. The n-value relates to the ability of a sheet material to be stretched in metalworking operations. The higher the n-value, the better the formability (stretchability)..

Necking - 1) The reduction of the crosssectional area of metal in a localized area by uniaxial tension or by stretching. 2) The reduction of the diameter of a portion of the length of a cylindrical shell or tube.

Nest - 1) To stack like parts within one another to occupy a minimum space. 2) A plate having an opening to conform to the contour of a part used to locate the part in a die. 3) To lay out a blank so that the outlines of parts produced will interlock with each following and each preceding part and require the minimum amount of material.

Nesting - The process of accurately locating and holding the part in a die or fixture by using gages or the part's form.

Normalizing - A process of heating the steel above the critical temperature and cooling it freely in air. Normalizing does leave the metal in a uniform, unstressed condition but may not leave it machinable.

No Stock Movement - On progressive dies, this is the bottom portion of the press stroke during which the coil feed cannot move the strip.

Notching - The cutting out of various shapes from the edge of a strip, blank, or part.

Nutter Die - A die that incorporates nutter units to clinch nuts into sheet metal parts.

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O.S.M. - Stands for OutSide of Metal.

Offset Yield Strength - The stress at which the strain exceeds by a specified amount (the offset) an extension of the initial proportional portion of the stress-strain curve. Expressed in force per unit area.

Oil Canning - Distortion of a flat or nearly flat surface by finger pressure and its reversion to normal.

Olsen (Tinius) Ductility Test - A cupping test in which a piece of sheet metal, restrained except at the center, is deformed by a standard steel ball until fracture occurs. The height of the cup at the time of fracture is a measure of the ductility.

Open Hem - A flange that is folded back over upon itself with the edge of a mating part between the fold.

Orange Peel - The texture of steel that appears like and orange, either from the steel mill or after forming.

Oscillating Die - A universal die which contains a cutoff type sub-die that pivots in a horizontal plane with each press stroke. This allow the blanking of rectangular, triangular, or trapezoid shaped blanks of various angles and sizes.

Overbending- Bending metal further than is called for in the final shape in order to allow for springback.

Overcrown - 1) The term used to signify that the curvature of a surface is too high. 2) Used for the overbending of a curved surface to compensate for springback.

Overhanging Press - A gap press in which the frame overhangs the bed.

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Pad - The general term used for that part of a die which delivers holding pressure to the metal being worked.

Pad Drivers - Blocks used to compress the pad ahead of the stock while blanking or rimming. Also to equalize pressure on the pad to eliminate the cocking of the pad.

Pad Retainer Pins - The pins that go in the side of a stripper plate or pad to retain it for the designed range of travel.

Pad Window - See window.

Parting - A specific cutting operation in which complete severance of the stock strip is achieved by punching out a piece of stock material (scrap) from between the piece parts.

Pedestal - See punch riser.

Percent Strain Safety - A measure of how close a strain state is to failure with regards to a forming limit diagram. Percent strain safety is calculated by dividing the difference between the major strain to failure and the actual major strain by the major strain to failure. A zero percent strain safety indicates material failure.

Percent Total Elongation - The amount of extension a material can withstand before fracture in a tensile test.

Percent Uniform Elongation - The amount of extension a material can withstand before necking in a tensile test.

Perforator - A specific name for a punch that falls in the cutting punch category.

Permanent Set - The deformation or strain that is remaining in a previously stressed body after release of the load.

Pickoff - An automatic device for removing the finished part from a die after it has been stripped or released from the die.

Pick-&-Place - An electrically or mechanically driven mechanism, attached to and controlled by a press, for loading and removing a part from a die.

Pickup - Small particles of oxidized metal adhering to the surface of a mill product.

Pick-up - See scoring.

Pierce Block - An individual die pan that contains one or more pierce holes or die buttons.

Pierce Button - See button.

Pierce Punch - See perforator and punch.

Piercing Die - A die that cuts out a slug in sheet or plate material.

Piggy Back Cam - A cam which is actually two cams. The bottom cam is normally a dwell cam and the top cam is normally a straight cam.

Pilot - A pin or projection provided for locating work in a die from a previously punched hole. Also called locating pin or pilot pin.

Pinch Trimming - Trimming the edge of a part by punching or pushing the flange or lip of the part over the cutting edge of a draw or stationary punch.

Pitch - See progression.

Pitch Notch - A notch cut on one side of a stock strip in a progressive die to control stock width and progression of the stock. Also called French Cut and French Notch.

Plastic Anisotropy - The concept that a material has a preferred strain direction. In sheet material, plastic anisotropy is measured as the ratio of width strain to thickness strain. It also is an indicator of the directional differences in a rolled material like sheet.

Plastic Deformation - The permanent (inelastic) distortion of metals under applied stresses that strain the material beyond its elastic limit. This ability of metals to flow in a plastic manner without fracture is the fundamental basis for all metalforming processes.

Plastic Flow - The event which takes place when a substance is deformed perminently without rupture.

Plastic Hit - A method of determining the cutting edge of a steel from the mating steel by assembling the die so the trim steels are just short of entering. Then applying epoxy plastic to the top of the steel and against the mating steel which has a parting agent on it and allowing it to harden before disassembling. Sometimes called shooting plastic.

Plasticity - The property of a substance that permits it undergo a permanent change in shape without rupture.

Plastic Working - The processing of a substance by causing a permanent change in its shape without rupture.

Platen - See Press Slide.

Plunger - See Press Slide.

Pneumatic Spring - A one way air cylinder that has a large hollow shaft and a check valve on the air supply at the cylinder which eliminates the need for a surge tank.

Pogo Stick - An adjustable rod which holds an indicator for checking the level of a press ram.

Point of Origin - A point from which other dimensions are taken.

Polishing Bob or Cone - See Standing Bob.

Preformed Part - A partially formed part which will be subjected to one or more subsequent operations.

Preheating - A general tern used to describe heating applied as a preliminary to some further thermal or mechanical treatment.

Pre-Hem Contact Path - Angle between a line that is formed by a point on the pre-hem steel at first contact with flange to the same point at end of pre-hem and the mating surface.

Pre-Hem Flange Angle - Angle measured from the mating flange area to the pre-hemmed flange.

Pre-Hem Force - Maximum force required to bend flange to pre-hem position.

Pre-Hem Springback - Elastic recovery that follows plastic deformation when the pre-hem load is removed.

Press - A machine having a stationary bed or anvil and a slide (ram or hammer) that has a controlled reciprocating motion toward and away from the bed surface and at right angle to it. The slide is guided in the frame of the machine to give a definite path of motion.

Press Bed - The stationary and usually horizontal pan of a press that serves as a table to which a bolster plate or lower die assembly is mounted.

Press Brake - An open-frame single-action press that is used to bend, blank, corrugate, curl, notch, perforate, pierce, or punch sheet metal or plate.

Press Capacity - The rated force that a press is designed to exert at a predetermined distance above the bottom of the stroke of the slide.

Press Forming - Any sheet metal forming operation that is performed with tooling by means of a mechanical or hydraulic press.

Press Load - The amount of force that is exerted in a given forging or forming operation.

Press Ram - See Press Slide

Press Slide - The main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened. Sometimes called the ram, press ram, slide plunger, or platen.

Pressure Pin - A pin used in conjunction with a die cushion to transfer pressure from the cushion to the bottom of a die pad. Also called cushion pins or air pins.

Profiling - Machining or grinding the outline of die members.

Progression - The precise linear travel of the stock strip at each press stroke and is equal to the interstation distance. Also called pitch, advance, or feed.

Progressive Die - A die with two or more stations arranged in line for performing two or more operations on a part; one operation usually being performed at each station. The parts are connected by a carrier strip until the final parting or cutoff operation.

Progressive Forming - Sequential forming at consecutive stations with a single die or separate dies.

Puckering - A wavy condition in the walls of a deep drawn part.

Punch - The male member of a complete die.

Punch Line - The outline of the draw punch in the plan view of a blueprint.

Punch Riser - A block of steel or welded construction to which punch steels or punch retainers are mounted. Also called stool or pedestal.

Punch Shoe - The upper section of a die set to which bushings and punch steels are usually mounted.

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No Q entries presently.

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Rabbit Ear - A recess in a die corner to allow for wrinkling or folding of the part.

Radial Draw Forming - The forming of sheet metal by the simultaneous application of tangential stretch and radial compression forces. This operation is done gradually by tangential contact with the die member. It is characterized by very close dimensional control.

Ram - See press slide.

Recall - The distortion of a part along the flange line where the part lifts off the die steel. This is caused by insufficient pad pressure or by a pad that gives insufficient part coverage.

Redrawing - Second and following drawing operations in which the part is deepened and reduced in cross-sectional dimensions.

Reduction - 1) In cupping and deep drawing, it is a measure of the percentage of decrease from blank diameter to cup diameter or of the diameter reduction in redrawing. 2) In forging, extrusion, rolling, and drawing, it is the ratio of the original to the final cross-sectional area or the percentage of decrease in cross-sectional area.

Register - When the workpiece is brought into the required position by the pilots.

Relief - Clearance obtained by removing metal either behind or beyond the cutting edge of a punch or die. Also called undercut or back-off.

Residual Stress - Stress that is left within a material as the result of non-uniform plastic deformation or by drastic gradients of temperature from quenching or welding.

Restrike - To sharpen radii, form, or detail in previously formed areas of a part. Used to eliminate springback. Sometimes referred to as Spank.

Reverse Redrawing - A second or subsequent redrawing operation performed in the opposite direction to the original drawing.

Rider Pin - See Guide Pin.

Ring - See Blank Holder.

Riser - 1) A sub plate on which die steels are mounted. 2) A block of steel or welded construction to which punch steels or punch retainers are mounted. Also called Pedestal, Punch Riser, or Stool. 3) A plate welded construction or casting mounted to the bottom of the lower die shoe to facilitate scrap removal, and regulate feed height. 4) A cast spacer between the inner ram and the draw punch in a toggle draw die. Also called Punch Riser.

Riser Block - A plate inserted between the top of the press bed and the bolster to decrease the height of the die space.

Rod - A solid round section, usually 3/8 inch or greater in diameter, whose length is great in relation to its diameter.

Roll Bending - The curving of sheets, bars, and sections by means of rolls.

Roll Flattening - The flattening of sheets that have been rolled in packs by passing them separately through a two-high cold mill with virtually no deformation.

Roll Forging - A process of shaping stock between two driven rolls that rotate in opposite directions and have one or more matching sets of grooves in the rolls. It is used to produce finished parts or preforms for subsequent forging operations.

Roll Forming - A forming process used to produce long components of various cross sections. The sheet metal is formed by passing it through a succession of progressively shaped contoured rolls.

Roller Leveling - Leveling by passing flat sheet metal stock through a machine having a series of small-diameter staggered rolls that are adjusted to produce repeated reverse bending.

Roll Straightener - A mechanism equipped with rolls to straighten sheet or strip stock. Usually used with a feed mechanism.

Roll Straightening - The straightening of metal stock of various shapes by passing it through a series of staggered rolls. The rolls are usually in horizontal and vertical planes.

Rope - The radius on the outside edge of a hemmed part where the diameter of the edge is at least four times the stock thickness. The rope is used for materials having insufficient ductility to form an open hem.

Rose Bud - The result of cutting or tearing/piercing and flanging of a hole in one operation without generating a slug. Referring to extruding or spearing.

Rough Blank - A blank used in a forming or drawing operation.

Rubber Duck - A flexible skin of a part made out of latex covered fiberglass and used in the designing of a die.

Rubber Pad Forming - A sheet metal forming operation for shallow parts in which a confined, pliable rubber pad attached to the press slide (ram) is forced by hydraulic pressure to become a mating die for a punch or group of punches placed on the press bed or baseplate. Developed in the aircraft industry for the limited production of a large number of diversified parts, the process is limited to the forming of relatively shallow parts, normally not exceeding 1.5 inches deep.

Run Marker - See Run Stamp.

Run Numbers - See Run Stamp.

Run Stamp - Stamp used in a die to stamp the date the part was run. Also called Run Marker, Run Numbers, or Date of Run.

Running Clearance - The amount of clearance designed on a die between two mating, steels to allow for stock thickness at bottom of press stroke.

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Safety Pin - A pin which is used to prevent the movement of an object while working on or near that object. Used on incline cams, iron hands, etc.

Sanding Bob - A small, tightly rolled, and glued emery cloth designed to be mounted on a mandrel and used on a hand grinder for polishing.

Sausage - See Kidney.

Scaling - A process used for spotting large contoured area by using a spotting stick. See also Spotting Stick.

Scoring - 1) The marring or scratching of any formed part that is caused by metal pickup on the punch or die. 2) The reduction in thickness of a material along a line to weaken it intentionally along that line.

Scrap - Pieces or parts not normally usable.

Scrap Cutter - A shear or cutter operated by the press or built into a die for cutting scrap into sizes for convenient removal from the die or disposal.

Scrap Strip - See Skeleton.

Screw Press - A high-speed press in which the ram is activated by a large screw assembly powered by a drive mechanism.

Shadow - See Low Spot.

Shaving - A secondary shearing or cutting operation in which the surface of a previously cut edge is finished or smoothed by removing a small amount of stock.

Shear - 1) A machine or tool for cutting material by the closing motion of two sharp, closely adjoining edges. 2) An inclination between two cutting edges, such as between two straight knife blades or between the punch cutting edge and the die cutting edge, so that a reduced area will be cut each time. This lessens the necessary force, but increases the required length of the working stroke. Referred to as angular shear. 3) The act of cutting by shearing dies or blades, such as in a squaring shear. 4) The type of force that causes two contiguous parts of the same body to slide relative to each other in a direction parallel to their plane of contact. 5) The damage done to the cutting edges of trim steels by misalignment.

Shear Knives - Tols used for lancing the part in a forming operation to control fracturing of the part while forming.

Shear Strength - The maximum shear stress a material can sustain. Shear strength is calculated from the maximum load during a shear or torsion test.

Shear Stress - 1) Stress that exists when parallel planes in metal crystals slide across each other. 2) The stress component tangential to the plane on which the forces act.

Shearing - The parting of material that results when one blade forces the material past an opposing blade.

Shedder - A pin, rod, ring, or plate operated by mechanical means, air, or a rubber cushion that either ejects blanks, parts, or scrap from a die or releases them from punch, die, or pad surface.

Sheet - Any material or piece of uniform thickness and of considerable length and width as compared to its thickness. Metal pieces under 1/4 inch thick are called sheets and those 1/4 inch or thicker are called plates.

Sheet Forming - The plastic deformation of a piece of sheet metal by tensile loads into a three-dimensional shape that is often without significant changes in sheet thickness or surface characteristics.

Shim - A thin piece of material used between two surfaces to obtain a proper fit, adjustment, or alignment.

Shimmy Cam - A cam designed to move in one direction and then reverse direction during the down stroke of the press so work- is done in both directions.

Shoe - A term referring to the upper or lower component of a die set.

Shut Height - The distance from the top of the bed to the bottom of the slide with the stroke down and adjustment up. The shut height of a press is the maximum die height that can be for normal operation taking the bolster into consideration.

Single-Action Die - A form die that has no blankholder action since it is used with a single-action press without the use of a draw cushion.

Single-Action Press - Press with a single slide. Usually without any other motion or pressure device.

Sizing - A secondary press working operation to obtain dimensional accuracy by metal flow.

Skeleton - The strip of stock from a progressive die starting at the point of entry through the last station. Also called Stock Strip, Scrap Strip, or Carrier Strip.

Skid Lines - Lines seen on the finished part when the stock slips on a draw punch. This is caused by the die not being timed correctly or when the forming of a shape is at such an off angle.

Skid Marks - See Draw Marks.

Sled Runner - An adjustable tripper for activating an air-operated valve which controls automation. Also called Striker.

Slide - 1) See Press Slide. 2) See Cam Slide.

Slide Adjustment -The distance that a press slide position can be altered to change the shut height of the die space.

Slide Counterbalance - A device used on the slide of large and small presses to reduce vibration and to assist the brake and clutch in functioning properly. Counterbalances are actuated by springs or air pressure. Tbey relieve much of the load of the slide and punch from the press connection and shaft. Reducing the friction on the brake.

Slide Hammer - A weight that slides along a rod with a head on one end and threads on the other end. Normally used to pull dowels and details. Commonly called a Dowel Puller.

Slitting - Cutting or shearing along single lines to cut strips from a sheet or to cut along lines of a given length or contour in a sheet or workpiece.

Slug - A small piece of material produced in piercing or punching holes in sheet material.

Slug Tralls - 1) Passage ways for slugs to fall out of trim and pierce dies. 2) Slug marks in draw and form dies.

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Spalling - The flaking off of particles from a surface.

Spank - See Restrike.

Spearing - See Spear Punching or Extruding.

Spear Punching - The process of cutting or tearing a hole in metal that does not generate a slug. The metal is pushed back to form a jagged flange on the back side of the hole.

Spider - A plate that bridges two or more transfer pins and distributes force equally. Commonly used for lifters, light weight pads, and positive knockouts.

Spleen - See Draw Bead.

Split Die - A die made of parts that can be separated for ready removal of the workpiece. Also known as Segment Die.

Spool - A cylindrical headed keepeR that is fastened by one or more socket head screws used to retain and control pad travel.

Spot Face - The process of providing a smooth surface for a fastener. Also called sump. Also refers to the smooth area around a hole for a fastener.

Spotting - The fitting of one part of a die to another by applying marking die/color to the surface of the finished part and bringing it against the surface of the intended mating part. The high spots being marked by the transferred color.

Spotting Aid - See Skin or Cast.

Spotting Rack - See Skin or Cast.

Spotting Scale - A thin hardened steel rule type material used to locate high points or areas when spotting large form areas such as hood punches.

Spotting Stick - A thin strip of wood used to located high points or areas when spotting large form areas such as hood punches. The stick is usually made of mahogany. See also Scaling.

Springback - The extent to which metal tends to return to its original shape or position after undergoing a forming operation.

Spring Can - A sheet metal cylinder open at one end and closed at the other. Used to retrain the various segments of a spring if it breaks.

Spring Plate - A separately mounted plate used to retain and provide access to die springs.

Springback - The extent to which metal tends to return to its original shape or position after undergoing a forming operation.

Springback Allowance - The allowance designed into a die for bending metal a greater amount than specified for the finished piece, to compensate for spring-back.

Squeeze Block - A piece of steel with a spring-loaded pin held under tension by a screw. Used to check distance between two parallel surfaces or press ram adjustment.

Staking - The process of permanently fastening two parts together by recessing one pan within the other and then causing plastic flow of the material at the joint.

Stamp - 1) The general term to denote all press workings. 2) To impress lettering or designs by pressure into the surface of a material.

Standoff Blocks - See Stop Blocks and Leveling Blocks.

Starting Ring - See Pre-Hem Steel.

Starting Steel - See Pre-Hem Steel.

Steel Rule Die - A die employing a thin strip of steel formed to the outline of a part and a flat metal plate or block of wood for the punch. Used to cut non-metallic materials, soft metals, and low-run, prototype, sheet metal parts. Also called Cookie Cutter Die.

Stitch And Run Die - Staking same size blanks together with each stroke of the press forming a continuous strip. Then feeding this stacked strip through the die as in a coil.

Stock Guide - A device used to direct a strip or sheet material through the die.

Stool - 1) Lower section of a die on which the part nests. Also called Lower Adapter, Boss, Die Post, Horn, Locator, or Master Plug. 2) A base for a punch retainer to enable the punch to reach thru the pad or stripper. Also called a Pedestal, Punch Riser, and Riser.

Stop - 1) A device for positioning stock or parts in a die. 2) A mechanism that initiates the stopping action of a press after its complete cycle. 3) A device which initiates the stopping action of a press at the start of opening troubles tor protect the die and/or the operator, such as misfeed and buckling of strip stock or nondischarge of blank.

Stop Pin - A device for positioning stock or parts in a die.

Stock Strip - See Skeleton.

Stop Blocks - Blocks normally located near each rider pin to prevent the die from closing too far. Also called Standoff blocks and Bottoming Blocks.

Storage Blocks - Urethane blocks generally used in trim and pierce dies to prevent chipping of steels during storage and handling. Also aids in noise reduction, leveling the press ram, and reducing die shock.

Straight Cam - A cam that travels 90 degrees to press stroke. Also called Horizontal Cam.

Straight-Side Press - An upright press open front and back with the columns (uprights) at the ends of the bed.

Straightener Rolls - See Roll Straightener.

Strain - The deformation or change in size or shape of a body that is produced by stress applied to that body.

Strain Aging - The changes in ductility, hardness, yield point, and tensile strength that occur when a metal or alloy that has been cold worked is stored for some time. In steel, strain aging is characterized by a loss of ductility and a corresponding increase in hardness, yield point, and tensile strength.

Strain Hardening - The increase in strength of a metal caused by plastic deformation at temperatures which are lower than the recrystallization tempmature.

Stress - The internal force or forces set up within a body by outside applied forces or loads.

Stress Cracking - The fracturing of parts which have retained residual stresses from cold forming, beat treating, rapid cooling, or corrosion.

Stress Relief - A heat treat process which is used to reduce residual stresses in a steel.

Stretch Drawing - The process of holding a blank with an upper and lower ring. The lower ring is mounted on a nitrogen actuated pressure pad. Both upper and lower rings are lowered to a dwell position stretching the material over the lower die. The upper die then closes to complete the forming operation of this die.

Stretch Forming - The shaping or forming of a sheet by stretching it over a formed shape.

Stretcher Leveling - The leveling of a piece of sheet metal is the removing of warp and distortion by gripping the sheet at both ends and subjecting it to a stress higher than its yield strength.

Stretcher Straightening - A process for straightening rod, tubing, and shapes by the application of tension at the ends of the stock. The products are elongated a definite amount to remove warpage.

Stretcher Strains - Elongated markings that appear on the surface of some sheet materials when deformed past the yield point. These markings lie approximately parallel to the direction of maximum shear stress and are the result of localized yielding.

Strip - Flat-rolled, metal product of some maximum thickness and width arbitrarily dependent on the type of metal. It is narrower than sheet.

Stripper- A device for removing the workpiece or part from the punch.

Stripper Plate - A plate (solid or moveable) used to strip the workpiece or part from the punch. It may also guide the stock.

Stripper Punch - A punch that serves as the top or bottom of the die cavity and later moves farther into the die to eject the part or compact.

Stripping - The removing the workpiece or part from the punch.

Stroke of the Press - The reciprocating motion of a press slide that is specified as the number of inches between the terminal points of the motion.

Sump - A formed recess area of a part usually for clearance.

Support Plate - A plate that supports a draw ring or draw plate. It also serves as a spacer.

Surface Distortion - Wrinkles formed on the grade-A surfaces of panels due to improper hemming operation.

Surge Tank - A tank designed to accept a volume of air, gas, or oil on the compression stroke of a cylinder and to provide an extra volume of air, gas or oil on the power stroke of the cylinder. Prevents excess pressure build-up in a cylinder or lines.

Swift Cup Test - A test in which circular blanks of various diameter are clamped in a die ring and deep drawn into a cup by a flat-bottomed cylindrical punch. The ratio of the largest blank diameter that can be drawn successfully to the cup diameter is known as the Limiting Drawing Ratio (LDR) or deformation limit.

Swivel Ring - A load-centering eye bolt which allows the eye to pivot 180 degrees and the base to swivel 360 degrees to reduce the stress on the bolt and eliminate bending failure

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Tempering (Drawing) - A heat treating process for removing internal stresses in metal at temperatures above those for stress relieving.

Tensile Strength - The maximum force that a material is capable of prior to crack initiation or failure.

Tensile Stress - Stress that causes two parts of an elastic body on either side of a typical stress plane to pull apart. Contrasted by compressive stress.

Tension - The internal force or forces set up within a body that cause extension and stretching.

Test Coupon - A sample of a material used for checking the properties of that material.

Third Action - A term used to show the action at the bottom of the press stroke that produces form in the opposite direction of the upper press ram.

Throat (Gap) - The open space in a gap-frame press behind the slide center line.

Tie Rod - A device consisting of a steel rod, threaded at both ends for nuts, for tying sections of dies together either by design or to repair a die that has been broken.

Toggle Draw Die - See Double-Action Die.

Toggle Drawing Press - A press in which the outer or blankholder slide is actuated by a series of toggle joints and the inner slide by the crankshaft or eccentrics.

Toggle Press - Any mechanical press in which a slide or slides are actuated by one or more toggle joints.

Transfer Die - A die where the parts are blanked before or at the beginning of theoperations and a mechanical transfer device which is part of the die moves the workpieces from station to station. This type of die is run in a conventional press.

Transfer Press - A press having an integral mechanism for transfer and control of the workpiece.

Trimming - Term applied to the operation of cutting scrap off a partially or fully shaped part to an established trim line.

Triple Action Press - A press having three moving slides. Two slides are moving in the same direction and a third lower slide moving upward through the fixed bed in a direction opposite to the blankholder and inner slides. This permits reverse-drawing, forming or beading operations while both upper actions are dwelling.

Turnover Device - An automated, mechanical device which turns over a part between production operations.

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U-Bend Die - A die used in press-brake forming that is machined horizontally with a square or rectangular crosssectional opening that provides two edges over which metal is drawn into a channel shape.

Ultimate Strength - The maximum stress that a material can sustain without fracture. It is determined by dividing maximum load by the original cross-sectional area of the specimen. Also known as Nominal Strength or Maximum Strength.

Undercrown - The term used to signify that the surface does not have enough height to the curvature.

Underdrive Press - A press in which the driving mechanism is located within or under the press bed or below the floor line.

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V-Bend Die - A die used in press-brake forming that is usually machined with a triangular cross-sectional opening to provide two edges as fulcrums for accomplishing three-point bending.

Vent - A small hole in a punch or die for admitting air to avoid suction holding or to relieve pockets of trapped air which would prevent proper die closure or action. It also reduces press tonnage required.

Vent Mark - A small protrusion resulting from the entrance of metal into die vent holes.

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Walking Cam - See Aerial Cam.

Warp - Opposed to hem curved outboard and hem deflection, warp is the term used for the local curve at the hem edge.

Wear Plates - Plates made of hardened tool, steel, or bronze. Used where dies receive the greatest wear to enable resurfacing and shimming of the plates to renew wear surfaces. Normally they are used in pairs.

Web - 1) A narrow strip that connects the part to the skeleton or adjoining part. 2) Any narrow section of a die connecting one section to another.

Window - A separately mounted steel used to gain access to perishable details or other die components. Also called Pad Window, Stripper Insert, or Insert.

Work (Strain) Hardening Coefficient - See Strain Hardening.

Workability - See Formability.

Wrap Forming - See stretch forming.

Wring Fit - Class of fit between a slip fit and a press fit. Usually requiring a slight twisting action to put the parts together.

Wrinkling - A wavy condition on metal parts due to buckling under compressive stresses.

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No X entries presently.

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Yield - Evidence of plastic deformation in structural materials. Also known as Plastic Flow or Creep.

Yield Point -The first stress in a material that is less than the maximum attainable stress and at which an increase in strain occurs without an increase in stress.

Yield Strength - The stress at which a material exhibits a specified deviation from proportionality of stress and strain. Compare with Tensile Strength.

Yield Stress - The stress level of highly ductile materials, such as structural steels, at which large strains take place without further increase in stress.

Young’s Modulus or Elastic Modulus - The stress at which a material initially exhibits permanent plastic deformation in a tensile test.

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No Z entries presently.