table top hemmer (hemming gate)

Lamb’s table top hemmer.

tangent bending

The forming of one or more identical bends having parallel axes by wiping sheet metal around one or more radius dies in a single operation.  The sheet, which may have side flanges, is clamped against the radius die and then made to conform to the radius die by pressure from a rocker-plate die that moves along the periphery of the radius die.  See also wiperforming (wiping).

tangent modulus

The slope of the stress-strain curve at any specified stress or strain.  See also modulus of elasticity.

tear drop hem

Preferred for lower strength materials.

tempering (drawing)

A heat treating process for removing internal stresses in metal at temperatures above those for stress relieving, but in no case above the lower critical temperature internal stresses in metal at temperatures above those for stress relieving, but in no case above the lower critical temperature.

tensile strength

Tensile strength is the ratio of maximum load to original cross-sectional area.  Also known as ultimate strength.  Compare with yield strength. “The maximum stretching that a material is capable of withstanding without breaking under a gradually and uniformly applied load. The strength calculated at the maximum load, in a tensile test, by dividing the maximum load by the original cross-sectional area.

tensile stress

A stress that causes two parts of an elastic body, on either side of a typical stress plane, to pull apart.  Contrast with compressive stress.

tension

The internal force or forces set up within a body, which cause or tend to cause, extension or stretching.

test coupon

A sample of a casting or steel used for checking the properties of that casting or steel.

the female of a complete die

A complete tool used in a press for any operation or series of operations such as forming, impressing, piercing, and cutting.  The upper member or members are attached to the slide (or slides) of the press and the lower member is clamped or bolted to the bed or bolster with the die members being so shaped as to cut or form the material placed between them when the press makes a stroke.  The female part of a complete die assembly as described in the previous sentence.  (Automotive Steel Partnership, 1991, p.4-5).

thickness strain analysis (tsa)

The ultimate strength of a material, measured in pounds per square inch in tension on the original cross section tested, which, if exceeded, causes sectional deformation leading to ultimate rupture.” (Automotive Steel Partnership, 1991, p. 17).

third action

A term used to show the action at the bottom of the press stroke to produce form in the opposite direction of the upper press ram.  Usually, done in a triple action press.

three-point bending

The bending of a piece of metal or a structural member in which the object is placed across two supports and force is applied between and in opposition to them.  See V-bend die.

throat (gap)

The open space in a gap-frame press behind the slide center line.

throw

The distance from the centerline of the crankshaft or main shaft to the centerline of the crankpin or eccentric in crank or eccentric presses.  Equal to one half of the stroke.  See also crank press and eccentric press.

tie rod

(1) 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 which has been broken. (2) Steel rods, threaded at both ends for nuts, used to hold the bed, uprights, and crown of a press together under a predetermined compressive load.

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

(1) Any mechanical press in which a slide or slides are actuated by one or more toggle joints. (2) A term applied to double and triple action presses.

tool order number

See project number.

torsion

A twisting deformation of a solid or tubular body about an axis in which lines that were initially parallel to the axis become helices.

torsional stress

The shear stress on a transverse cross section resulting from a twisting action.

total elongation

“The comparison between the original and final thickness converted to strain readings and plotted on thickness strain diagrams. The thickness is measured by pointed micrometers, or by ultrasound gage.  From the final thickness and original thickness ratio, T_F / T_O, an actual strain level can be developed based on constant volume and plotted on a thickness strain diagram.” (Hogarth, D.J., Gregoire, C.A., Caswell, S. L., 1991, p. 88).

transfer die

(1) A die where the parts are blanked before or at the beginning of the operations and a mechanical transfer device which is part of the die moves the workpieces from station to station.  This type is run in a conventional press. (2) A succession of small or sub dies all mounted in one transfer press to make a part with the parts being moved from one die to another with a mechanical transfer device which is part of the press.

transfer pin

See pressure pins.

transfer press

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

trim edge

Outermost edge, which defines the perimeter of the part.

trimming

The 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 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.

tryout

Preparatory run to check or test equipment, lubricant, stock, tools, or methods prior to a production run.  Production tryout is run with tools previously approved; new die tryout is run with new tools not previously approved.

turnover

A handling device which screws into a die or die section for handling or turning over.  Usually referring to a J-hook, but also called a die hook or handling hook.  Also see turnover device.

turnover device

A device to turn over a part between production operations.  Sometimes called a turnover.