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Metal forming and welding glossary - R
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A recess in a die corner
to allow for wrinkling or folding of the part.
The forming of sheet
metals by the simultaneous application of tangential stretch and radial
compression forces. The operation is done gradually by tangential contact
with the die member. This
type of forming is characterized by very close dimensional control.
Driven (movable) part of a metalforming machine.
This includes a number of rapidly evolving techniques for making prototypes
and models quickly thus allowing designers to check their designs and
make any necessary changes before investing in expensive tooling. A
CAD model of the part is
required and the model is usually built layer by layer.
A type of flat surface-straight edge hemming process where pre-hemming
and final hemming operations are combined by the use of a rocker (rotary)
Rear cut off
A device on a slide
forming machine driven by a cam
that is mounted on the rear shaft allowing the removal of a slug
from the strip, thus
providing the ability to produce a blank
with special end shapes.
As opposed to hem curved outboard and hem deflection recoil is the
term used for the local curve at the hem
See impact line.
The second and successive deep-drawing
operations in which cuplike shells are deepened and reduced in cross-sectional
In cupping and deep
drawing, a measure of the percentage of decrease from blank diameter
to cup diameter, or of the diameter reduction in redrawing. In forging,
and drawing, either
the ratio of the original to the final cross-sectional area or the percentage
of decrease in cross-sectional area.
Reduction in area
The difference between the original cross-sectional area and the smallest
area at the point of rupture in a tensile
test that is usually stated as a percentage of the original area.
When the workpiece
is brought into the required position by the pilots.
The weld metal built up above the surface of the two abutting sheets or plates in excess of that required for the size of the weld specified.
Clearance obtained by removing metal either behind or beyond the cutting
edge of a punch or die.
Also called undercut or back-off.
Operation in turret
press fabrication denoting the release of the workholders, movement
of the X axis to a new position on the workpiece,
and the regripping of the workpiece so that a sheet larger than the
X axis table travel can be fabricated, all under computer numeric control
Extent to which parts from multiple lots are identical.
Final cold rolling operation, usually done to achieve specific thickness
control and improved finish.
A tank used to store fluid for a hydraulic system - this maintains
the fluid an even temperature by allowing circulation and cooling from
the tank sides.
The realigning or adjusting of dies
or tools during a production run; not to be confused with the operation
setup that occurs before a production run.
Macroscopic stresses that are set up within a metal as the result of
deformation. This deformation may be caused by cold working or by
drastic gradients of temperature from quenching or welding.
Resistance butt welding (RPW)
A group of resistance welding processes in which the weld occurs simultaneously over the entire contact area of the parts being joined.
Resistance Projection Weld (RPW)
Resistance Spot Welding (RSW)
Melting and joining action of two adjoining metal surfaces created
by the thermal reaction of the metal to the flow of an electrical current
forming a weld nugget.
Refers to a group of welding processes such as spot and seam welding that produce coalescence of faying surfaces where heat to form the weld is generated by the resistance of the welding current through the workpieces. Some factors influencing heat or welding temperatures are the proportions of the workpieces, the electrode materials, electrode geometry, electrode pressing force, weld current and weld time, etc. Small pools of molten metal are formed at the point of most electrical resistance (the connecting surfaces) as a high current (100–100 000 A) is passed through the metal. In general, resistance welding methods are efficient and cause little pollution, but their applications are limited to relatively thin materials and the equipment cost can be high.
To sharpen radii, form, or detail in previously formed area of a part.
Also used to eliminate spring back. Also called spank.
Redrawing of a sheet
metal part in a direction opposite to that of the original drawing.
A sheet metal flange
made by shrinking, as opposed to one formed by stretching.
(Inside-out Redrawing) A second or subsequent redrawing operation
performed in the opposite direction to the original drawing.
A subsequent part drawing
usually denoting new corrected or improved version.
A written notice describing the nature of changes to a drawing.
A long V-shaped or radiused indentation used to strengthen large sheet
metal panels. A long, usually thin protuberance used to provide flexural
strength to a forging (as in a rib-web forging).
A coating defect consisting
of a flow mark defect with an appearance similar to corduroy fabric.
Ribbing usually occurs when the flow marks (ribs) from application on
the coater do not flow out and level the surface of the coating.
A term applied to a common method of winding strip
steel layer upon layer around an arbor or mandrel.
The pin or post, usually fixed in the lower shoe of a die
and accurately fitted to bushings in the upper shoe to insure precise
alignment of the two members of a die set. See guide
That 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.
See blank holder.
A sub plate on which die
steels are mounted. A block of steel or welded construction to which
punch steels or punch
retainers are mounted. Also called pedestal, punch riser, or stool.
A plate, welded construction, or casting mounted to the bottom of the
lower die shoe to
facilitate scrap removal,
regulate feed height, obtain shut
height, etc. A cast spacer between the inner ram
and the draw punch in a toggle draw die.
A plate inserted between the top of the press
bed and the bolster.
Internally threaded fastener designed to be used as a rivet from one
side of a workpiece
or assembly and to provide threads for a screw or bolt to be used in
assembly of a mating part.
An indentation hardness test based on the depth of penetration.
Rockwell (Hardness Tester)
A device used to determine the hardness of the steel strip.
A solid round section 9.5 mm (3/8') or greater in diameter, whose length
is great in relation to its diameter.
The curving of sheets,
bars, and sections by means of rolls.
The flattening of sheets
that have been rolled in packs by passing them separately through a
two-high cold mill with virtually no deformation.
Not to be confused with roller leveling.
A metal shape that has been processed using roll
Roll formed shape,
A roll formed shape which is closed by mechanically fastening or a
welding the two strip
Roll formed shape, open
A roll formed shape with a linear or curved contour in which the two
ends of the shape are not brought together.
A continuous bending
operation in the metal forming process, which sheet
or strip metal is plastically
deformed along a linear axis by being passed through a series of roller
dies and progressively shaped to the desired contour.
The area of material next to the penetrating edge of a piercing
punch, or die edge
of the blanking station,
where the material yields, i.e. flows in the direction of the applied
force, creating a rounded edge. Also known as pull down.
Tandem sets of rolls used in roll forming
to shape the metal stock in a series of progressive stages to form the
desired cross-sectional configuration.
A mechanism equipped with rolls to straighten sheet
or strip stock. Usually
used with a feed mechanism for press
The straightening of metal stock of various shapes by passing it through
a series of staggered rolls (the rolls usually being in horizontal and
vertical planes) or by reeling in two-roll straightening machines.
A deforming instrument having a work-engaging, work-deforming, peripheral
surface which is generated by a line revolving about an axis. The roller
will cyclically move into and out of contact with a work surface during
the work, relative movement occurring, during deformation.
A staggered system of rolls used to flatten the steel without any appreciable
reduction in gauge.
Roller leveler breaks
Obvious transverse breaks on sheet
metal usually about 3 to 6 MM (1/8" to 1/4") apart that are
caused by the sheet fluting during roller leveling.
These will not be removed by stretching.
A term applied to the operation of shaping and reducing metal in thickness
by passing it between rolls which compress, shape and lengthen it following
the roll pattern.
Rolling direction (in rolled metal)
The direction, in the plane of the sheet,
perpendicular to the axes of the rolls during rolling.
Equipment used for rolling down metal to a smaller
size or to a given shape employing sets of rolls tie contours of which
determine or fashion the product into numerous intermediate and final
shapes, e.g., blooms, slabs, rails, bars, rods, sections, plates, sheets
See pull down.
See Root Of Joint and Root Of Weld, shown below.
A crack in the weld or base metal which occurs at the root of a weld.
The edge of a part to be welded which is adjacent to the root.
The portion of the prepared edge of a member to be joined by a groove weld which is not beveled or grooved.
Root of joint
That portion of a joint to be welded where the members approach closest to each other. In cross section, the root of a joint may be a point, a line, or an area.
Root of weld
The points at which the bottom of the weld intersects the base metal surfaces.
The separation between the members to be joined at the root of the joint.
The radius on the outside edge of a hemmed part where the diameter
of this edge is at least four times stock thickness. The rope is used
for materials with insufficient ductility
to form an open hem.
Preferred for lower strength materials.
The result of cutting or tearing (piercing)
and flanging of a hole in one operation without generating a slug.
Referring to extruding
A sheet metal cutting
machine with two rotating-disk cutters mounted on parallel shafts driven
Rotary slide machine
A vertical forming
machine with the ability to place several forming slides radially around
the center tool and produce intricately formed stampings
and wire forms.
A blank for a forming
or drawing operation,
usually of irregular outline, with necessary stock allowance for process
metal, which is trimmed after forming or drawing to the desired size.
A milling cutter with serrated flutes or teeth. Also called corn-cobs.
Roughness (normal and extreme)
Units: mm (SI), mils (Imperial) The 'normal' range of RMS (root mean
square) surface roughness which lies within the capacity of the process.
As with mass, an 'extreme' range is also stored. Surface roughness is
determined by the nature of the process: the smoothness of mold surfaces
in casting and molding or the depth of cut in machining.
It can usually be refined by machining, grinding and polishing.
Extent to which a feature is circular.
A flexible skin of a part made out of latex covered fiberglass and
used in the designing of a die.
A sheet metal forming
process in which rubber is used as a functional die
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. Used where the screw hole in the detail does not align with
the threaded hole in the mounting surface. Also called Chicago screws,
Eberly screws, or Kelly screws.
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 40
mm (1.5 in.) deep. Also known as the Guefin process. Variations of the
Guerin process include the Marforming process, the fluid-cell process,
and fluid forming.
See run stamps.
See run stamps.
Run out flange
Feature on a formed part which is designated by the designer to absorb
the tolerance accumulations created by multiple forming
Stamps used in a die to
stamp the date the part was run. Normally this is a Julian date (see
Julian date). Also
called run marker, run numbers, or date of run.
The amount of, clearance designed in a die
between two mating steels to allow for stock thickness at bottom of
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