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Metal forming and welding glossary - D
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Date of run
See run stamps.
Theoretically exact planes, lines or points from which other features
are located on design drawings.
The maximum clear distance between the pressing
surfaces of a press when the surfaces are in the usable open position.
Where a bolster plate is supplied, it is considered the pressing surface.
See also shut height.
To remove the sharp, knife-like edge from parts. Decrease the height
of die space.
Commonly referred to as hard
tooling. This is tooling made to produce a specific part.
The fabrication process of flat rolled steel to make drawn parts. The
part is mechanically formed through or in a die. The blank diameter
is reduced; the blank contracts circumferentially as it is drawn radially
inward. Deep drawing is characterized by the production of a parallel-wall
cup from a flat blank
of sheet metal. The blank
may be circular, rectangular, or a more complex shape. The blank is
drawn into the die cavity by the action of a punch.
Deformation is restricted to the flange areas
of the blank. No deformation occurs under the bottom of the punch-the
area of the blank that was originally within the die opening. As the
punch forms the cup, the amount of material in the flange decreases.
Deep drawing is also called cup drawing or radial
draw forming. See deep drawing
Parts or applications that require deep drawing
to meet their fabrication requirements. Examples would include are motor
shells, fenders, quarter panels, and door panels for automotive parts
and battery cases for AA or AAA batteries.
Metals that have been subjected to the deep drawing metal stamping
Anything that renders the steel unfit for the specific use for its
intended use such as punchmarks, roll marks, oil spots, and scratches.
However, what is defective for one user may be prime steel for another.
The amount of deviation from a straight line or plane when a force
is applied to a press
member. Generally used to specify the allowable bending
of the bed, slide,
or frame at rated capacity with a load of predetermined distribution.
The process of metal forming
the solid material into shape by applying forces to it.
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 (limiting
draw ratio, LDR) is defined as the ratio of the maximum blank
diameter that can be drawn into a cup without failure,
to the diameter of the punch.
Deformation is forming
the solid material into shape by applying forces to it. Because the
material is in the solid state, the forces required are high and for
this reason, metals with very high yield
stresses are deformed hot. However, many commonly used metals can
be deformed at room temperature eliminating the need for expensive heating
equipment. The most well known deformation processes are forging,
rolling and extrusion,
which can produce components of a variety of shapes. Forming sheets
into various shapes is also a type of deformation processes. Cold forming
gives a better surface finish than hot forming and cold-formed parts
generally have a higher yield strength than those that are hot-formed
because the work hardening is retained.
A fluid forming process in which cylindrical and conical sheet
metal parts are formed by a modified rubber bulging punch.
The punch, equipped with a hydraulic cell, is placed inside the workpiece,
which in turn is placed inside the die. Hydraulic pressure expands the
Filler metal that has been added during a welding operation.
Individual parts of the die. Also known as steels,
sections, die sections, and back-ups.
A sheet metal blank
that yields a finished part without trimming or with the least amount
Tool with a void or cavity that is precisely fitted to a punch
used to solid, molten, or powdered metal primarily because of the shape
of the tool itself. Die-casting and powder metallurgy dies are sometimes
referred to as molds.
A movable plate or pad in a female die; usually used for part ejection
by mechanical means, springs, or fluid cushions.
See skin or cast.
The parts of a die stamp or press
that hold the die and locate it for the punches.
A block, often made of heat treated steel, into which desired impressions
are machined or sunk and from which closed die forgings or sheet
metal stampings are
produced using hammers or presses.
In forging, die blocks
are usually used in pairs, with part of the impression in one of the
blocks and the rest of the impression in the other. In sheet metal forming,
the female die is used in conjunction with a male
The machined recess that gives a forging
or stamping its shape.
Amount of space between the punch
and die opening.
A large pressurized cylinder, generally housed beneath the bed
of a press used to apply
upward pressure to the lower die. The die cushion is actuated by air,
oil, rubber, springs, or a combination of these.
Die cut inserts
Packaging elements, generally of cardboard, which are machine blanked
to a specific shape in order to precisely fit a part contour.
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.
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.
The portion of the die surface that shapes a forging
or sheet metal part.
The productive life of a die impression,
usually expressed as the number of units produced before the impression
has worn beyond permitted tolerances.
A line or scratch resulting from the use of a roughened tool or the
drag of a foreign particle between tool and product.
In forging or forming,
a compound that is sprayed, swabbed, or otherwise applied on die
surfaces or the workpiece
during the forging or forming process to reduce friction. Lubricants
also facilitate release of the part from the dies and provide thermal
insulation. See also lubricant.
Die maker's friend or helper
See profile grinder.
Scratches, scrub marks, indentations, galling or burnishing of sheet
The alignment of the upper (moving) and lower (stationary) dies in
a hammer or press. An
allowance for misalignment (or mismatch) is included in forging tolerances.
Lower section of die on which the part nests. Also
called an adapter, boss,
master, master plug,
and stool. Guide post
where wear plates
Die proof (cast)
A casting of a die impression made to
confirm the accuracy of the impression.
The radius on the exposed edge of a deep drawing
die, over which the sheet
flows in forming drawn shells.
The assembly of the upper and lower die shoes (punch
and die holders), usually including the guide
pin bushings, and heel
blocks. This assembly takes many forms, shapes, and sizes and is
frequently purchased as a commercially available unit. Two (or, for
a mechanical upsetter, three) machined dies used together during the
production of a die forging.
The upper and lower plates or castings that constitute a die
set (punch and die
holder). Also a plate or block upon which a die holder is mounted,
functioning primarily as a base for the complete die assembly. This
plate or block is bolted or clamped to the bolster plate or the face
of the press slide.
The maximum space (volume), or any part of the maximum space, within
a press for mounting
The general term for a sheet
metal part that is formed, shaped, or cut by a die
in a press in one or
Coatings on flat rolled
products where the thickness of the coating on the one side is heavier
than the other side.
A measurement describing size and/or appearance of a part feature.
A range by which a product's width and gauge can deviate from those
ordered and still meet the order's requirements. Also see commercial
of a relatively small, shallow indentation into sheet
metal. In aircraft/aerospace industries, the stretching of metal into
a conical flange for
a countersunk head rivet.
A small unwanted mark or dimple in a completed part. These are usually
caused by dirt or material in the die.
An interruption of the typical structure of a weldment, such as lack of homogeneity in the mechanical, metallurgical, or physical characteristics of the material or weldment. A discontinuity is not necessarily a defect.
Any deviation from a desired contour or shape.
Doctor blade steel strip:
and tempered spring steel strip, usually blued, produced from approximately
.85 carbon cold rolled
spring steel strip specially
selected for straightness and good edges. Sometimes hand straightened
or straightened by grinding and cut to desired lengths. This product
is used in the printing trade as a blade to uniformly remove excess
ink, called dope, from the rolls providing the origination of the name.
Dog leg cam
A cam attached to the
upper half of the die with a driver on the bottom
half of the die. Also called an aerial
cam, flying cam, or walking cam.
Dog leg driver
A cam driver designed
to ensure positive cam-slide travel in both directions.
A drawing compound used to lubricate
the stock during a forming
A condition that may occur on a laser wherein the laser essentially
produces a feature twice destroying the part's edge and causing out
of dimension condition.
Press utilizing two
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 two independent
parallel movements by means of two slides, one moving within the other.
The inner slide or plunger
is usually operated by a crankshaft and the outer or blank
holder slide, which dwells during the drawing
operation, is usually operated by a toggle mechanism or by cams.
See slide, triple
Same as double action mechanical press that is run automatically.
A round pin, usually case hardened, that fits into a corresponding
hole to align two die members.
A weight that slides along a rod with a head on one end and threads
on the other end that is normally used to pull dowels and details. This
weight and rod combination is commonly called a dowel puller. See slide
The taper given to a die so as to allow the part
to fall through the die or be removed.
Holes placed in the part that are nonfunctional except to allow for
See drawing, deep drawing.
An insert or rib-like projection on the draw ring
or hold-down surfaces that aids in controlling the rate of metal flow
during deep draw operations. Draw beads are especially useful in controlling
the rate of metal flow in irregularly shaped stampings.
A specific type of form die that basically involves
forcing the flat sheet
of metal into a die cavity with a punch
while holding the workpiece
around the cavity to control metal flow.
Draw die punch
A punch that is tied to the inner press ram.
See impact line.
Impressions such as scratches, burnished areas, and similar marks left
on the surface of the workpiece,
part, or panel by a draw die. Also called skid
A circular plate with a hole in the center contoured to fit a forming
punch used to support the blank
during the forming
The radius at the edge of a die or punch
over which sheet metal
Holding device in a die to control material flow
and wrinkling during
forming. Also referred
to as a binder.
A measure of the feasible deformation of
a blank during a drawing
process. A measure of the percentage of reduction in diameter of a blank
when it is drawn to a shell of maximum practical
depth. The general formability
and ductility of a metal.
A term used for a variety of forming
operations, such as deep drawing a sheet
metal blank; redrawing
a tubular part; and drawing rod, wire, and tube. The usual drawing
process with regard to sheet metal working in a press
is a method for producing a cup-like form from a sheet metal disk by
holding it firmly between blank
holding surfaces to prevent the formation of wrinkles while the
punch travel produces the required shape. In metal forming, the stretch
rig or compressing of a sheet metal part into a die
by a punch to create
a 3-dimensional part. The process of cold forming a flat pre-cut metal
blank into a hollow vessel without excessive wrinkling, thinning, or
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. Also known as die lubricant.
Drawing quality (DQ)
Draw quality steel that is a more flexible grade of steel. Flat-rolled
products produced from either deep drawing
rimmed steel or extra deep drawing aluminum
killed steels. Special rolling
and processing operations aid in producing a product that can withstand
extreme pressing, drawing or forming,
without creating defects.
A process where material is mechanically formed by tension through
or in a die.
Sheet metal that has been mechanically formed by use of tension though
a die or in a die.
A block with one or more angular surfaces that applies force by the
vertical movement of the press
to mating angular surfaces on a cam
A qualitative, subjective, property of material that indicates the
extent that it can be deformed without fracture
in normal metal working operations such as rolling,
extrusion, or fabrication.
A unshaped device for tying sections of dies together either by design
or to repair a die which has been broken.
Portion of a press cycle
during which the movement of a member is zero or at least insignificant.
Usually refers to the interval when the blank
holder in a drawing operation is holding
the blank while the punch
is making the draw or the interval between the completion of the forging
stroke and the retraction of the ram.
A cam that can be moved
into position and held there while the press
continues its cycle. Also see filler
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