Fabrication Specific

Air Bending

One of the three types of bending for sheet metal where the outside mold line is not pressed against the die.

Air Bend Force Chart

A chart used to calculate the tonnage required for a bend based on thickness, tooling and length.


Annealing is a treatment for metals where a material is heated above the recrystallization temperature maintained for a period of time and then cooled. Annealing is used to soften material, relieve internal stresses and improve its cold working properties.


The process of cold working metal to achieve a desired profile.

Bend Line

The line across the metal where the punch comes in contact with the metal and the bend begins.

Bump Bending

Also known as Step Bending, the process for forming a large radius with conventional tooling by performing a series bends in close proximity.


The process of cutting flat patterns from stock sheeting, done typically with lasers, water jets, plasmas or punch presses.

Bottom Bending

One of the three types of bending for sheet metal where the radius of the punch tip is pushed into the sheet metal.

Box Bending

The process of bending a 4 sided sheet metal box.


One of the three types of bending for sheet metal where the punch penetrates into the sheet metal under high tonnage forming a consistent bend.

Cross Break

Light bends added to sheet metal in order to stiffen its surface.


The deflection along a bend due to the tooling or brake not being able to apply equal tonnage along the bend. Crowning is controlled on modern brakes with internal hydraulic systems which can help equalize pressure.


A forming process which leaves a circular, closed loop at the end of the sheet. This forms a safe edge for handling and stiffens the part’s edge.

Flange Length

The length of the workpiece when measured from the apex to the edge of the bend.

Flat Pattern

The general term for the unfolded, flattened, geometry of a part.


Very thin sheet metal made from typically malleable metals such as aluminum and gold.

Gage, Gauge

The thickness of the metal organized by numbers, the smaller the number the thinner the metal.


Steel which has been galvanized and then subsequently annealed.


In order to prevent rust steel is dipped into molten zinc which alloys itself with the surface of the steel.


A section of the metal inside a bend which is not bent, but rather forced into the bend in order to stiffen the piece.


A flange that reaches 180° or more. Hems can be flattened, left open or in a variety of tear drop shapes.


Also known as an offset bend, this is when two bends of the same angle, but opposite direction, are used to create a ‘z’ shaped profile.


A light bend typically between 5° and 15° which is used to stiffen a flat piece of metal.

Large Radius Bending

Also known as R Bending, large radius bending is when the inside radius is greater than 8 times the material thickness.


Length of the workpiece from the edge to the outside tangent point of the bend radius.

Neutral Axis

An imaginary line within the bend where the material goes through no compression or stretching during the bend process.

Obtuse Angle

A geometry term for an angle which is greater than 90°.

R Bending

Bending with an inside radius greater than 8 times the material thickness.

Reflex Angle

A geometry term for an angle which is greater than 180°

Sharp Bend

When the radius of the bend is less than %63 of the material thickness, seen commonly with hemming applications.

Spring Back

The amount to which the workpiece resists bending by returning to its original shape.

Step Bending

Also known as bump bending, the process for forming a large radius with conventional tooling by performing a series bends in close proximity.

Straight Angle

A geometry term for an angle which is equal to 180°.


General dimensioning and tolerances of bends and sheet metal.


General term for the dies, punches and holders found on press brake equipment.

Work Piece

The general term for the sheet metal part being bent.

Tooling Specific


Tooling with an angle less than 90°.


Intermediate tooling which converts an American Style punch holder to a European Style, or vice versa. They can also be used to lengthen the punch holder.


A die where the v opening can be changed by turning a screw mechanism to spread the two sides of the v.

American Style

Tooling for press brakes comes in two main forms; American and European.


Tooling specifically designed to form boxes with flanges on 2, 3 and 4 sides.


Tooling which is used to form sheet metal channels.


Tooling which creates an open circular roll at the end of the sheet, this is different than hemming.


The bottom section of a press brake tool which typically features a v shaped groove.

Die Holder

Attached permanently to the lower beam this clamping mechanism will hold the die or rail in position.

Die Set

The term applied to a specific combination of holder, die, punch and any spacers or rails.

European Style

Press brake tooling comes in two main forms, European and American. European style tooling has an offset between the center of the tool and where it is clamped to the brake.

Goose Neck Punch

A term for punches with deep profiles to allow for large return flanges when bending.


Tooling which is specially designed to produce hems in to stages, without tool change over.


Offset tooling is a combination punch and die which has a Z shape and performs two bends in one stroke to produce a jog, or offset, in the metal.


The upper section of tooling which generally features a v shaped profile matching the die.

Punch Holder

A clamping mechanism which holds the punch, allowing for easy switching of punches.


Tooling specifically designed for forming a larger radius in the work piece.


Tooling which ads a round or v shaped grooved to the sheet metal in a single stroke.

Sash Punch

A generally straight thin tool with a sharp relief offset at the bottom, used for bending special relief profiles.

Sash Die

A thin single v die with a center tang, allowing for tighter profiles to be bent around the die.


Punch and Die sets which are designed to prepare and close seams on one or more pieces of sheet metal.


The act of adding material to the bend process in order to compensate for distortion along the bend line.

Spacer Block

An intermediate piece of tooling which adds height to the die holder.

Squaring Arm

A device which attaches to and moves with the press brake and work piece to hold work pieces square, or at a set angle.

Straight Punch

Also known as sword punches these are characterized by long, straight, thin punches used for bending symmetrical profiles.

Two, Three & Four Sided Die

A specialized die which has a square shape and a special profile cut into each side to allow for multiple setups from a single die.


An intermediary holder which is seated in the die holder and adds height, or a special profile, to the die holder. This also allows for quick accurate switching of dies.

Rolla V

A specialized die which has two half cylinders which support the flanges as the work piece is bent.

Rotary Die

Rotary dies have a cylindrical shape with v cut along its axis is seated in a saddle.


A locating protrusion on a piece of tooling which fits into a matching groove. Typically found at the center of American Tooling.


Tooling which does not evenly distribute the tonnage front to back and thus creates a thrust force on the punch holder. Often seen in 30°-60° type tooling.

Urethane Die

Press brake dies which incorporate a urethane pad to aid in the bending process.

Window Punch

A bend setup which creates an open area above the punch to allow deep drawn parts to pass through.

Wipe Die

Wiping die bending is performed by holding the sheet between a pad and die then sliding the wiping punch across the face bending the sheet metal which protrudes from the pad and die.


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