|
date of run
|
See run stamps.
|
|
daylight
|
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.
|
|
deep drawing
|
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. Also called cup drawing or radial drawing.
|
|
deep drawing
|
The drawing of deeply recessed parts from sheet material through plastic flow of the 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 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.
|
|
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 (limiting drawing 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.
|
|
demarest process
|
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 punch.
|
|
details
|
Individual parts of the die. Also known as steels, sections, die sections, and back-ups.
|
|
developed blank
|
A sheet metal blank that yields a finished part without trimming or with the least amount of 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), in die casting, and in forming green powder metallurgy compacts. Die-casting and powder metallurgy
dies are sometimes referred to as molds.
|
|
die aid
|
See skin or cast.
|
|
die assembly
|
The parts of a die stamp or press that hold the die and locate it for the punches.
|
|
die block
|
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 punch.
|
|
die button
|
See button.
|
|
die cavity
|
The machined recess that gives a forging or stamping its shape.
|
|
die clearance
|
Clearance between a mated punch and die; commonly expressed as clearance per side. Also called clearance or punch-to-die clearance. See Figure D1a – b – c.
|
|
die cushion
|
A press accessory placed beneath or within a bolster plate or die block to provide an additional motion or pressure for stamping or forging
operations; actuated by air, oil, rubber, springs, or a combination of these
|
|
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 hooks
|
See turnover.
|
|
die impression
|
The portion of the die surface that shapes a forging or sheet metal part.
|
|
die life
|
The productive life of a die impression, usually expressed as the number of units produced before the impression has worn beyond permitted
tolerances.
|
|
die line
|
A line or scratch resulting from the use of a roughened tool or the drag of a foreign particle between tool and product.
|
|
die lubricant
|
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.
|
|
die match
|
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.
|
|
die pad
|
A movable plate or pad in a female die; usually used for part ejection by mechanical means, springs, or fluid cushions.
|
|
die post
|
- (1) Lower section of die on which the part nests. Also called an adapter, boss, horn, locator, master, master plug, and stool.
- (2) Guide post where wear plates are attached.
|
|
die proof (cast)
|
A casting of a die impression made to confirm the accuracy of the impression.
|
|
die radius
|
The radius on the exposed edge of a deep-drawing die, over which the sheet flows in forming drawn shells. (See Figure D2)
|
|
die set
|
(1) The assembly of the upper and lower die shoes (punch and die holders), usually including the guide pins, guide pin bushings, and heel blocks. This
assembly takes many forms, shapes, and sizes and is frequently purchased as a commercially available unit.
(2) Two (or, for a mechanical upsetter, three) machined dies used together during the production of a die forging.
|
|
die shoes
|
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.
|
|
die space
|
The maximum space (volume), or any part of 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 in a press in one or more operations.
|
|
dimpling
|
(1) The stretching of a relatively small, shallow indentation into sheet metal. (2) In aircraft, the stretching of metal into a conical
flange for a countersunk head rivet.
|
|
dings
|
A small unwanted mark or dimple in a completed part. Usually caused by dirt or material in the die.
|
|
direct (forward) extrusion
|
See extrusion.
|
|
distortion
|
Any deviation from a desired contour or shape.
|
|
dog leg cam
|
See aerial cam.
|
|
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” (Automotive Steel Partnership,
1991, p. 6).
|
|
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; the outer or blankholder slide, which dwells during the drawing operation, is usually operated by a toggle mechanism or by cams. See also slide.
|
|
double-action mechanical press
|
A press having one slide within the other, the outer slide usually being toggle or cam operated, resulting in independent parallel slide movements.
|
|
dowel
|
A round pin, usually case hardened, that fits into a corresponding hole to align two die members.
|
|
dowel puller
|
See slide hammer.
|
|
draft
|
The taper given to a die so as to allow the part to fall through the die or be removed.
|
|
draw bead
|
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. See Figure D3 for a schematic of a drawbead .
|
|
draw die
|
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 line
|
See impact line.
|
|
draw marks
|
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 marks.
|
|
draw plate
|
A circular plate with a hole in the center contoured to fit a forming punch; used to support the blank during the forming cycle.
|
|
draw radius
|
The radius at the edge of a die or punch over which sheet metal is drawn.
|
|
draw ring
|
The part of a draw die which holds the workpiece against the blank holder in which the metal is drawn over the inner edge by the punch. Also
called binder.
|
|
draw stock
|
The forging operation in which the length of a metal mass (stock) is increased at the expense of its cross section; no upset is
involved. The operation includes converting ingot to pressed bar using "V," round, or flat dies.
|
|
drawability
|
(1) A measure of the feasible deformation of a blank during a drawing process. (2) Percentage of reduction in diameter of a blank when it is
drawn to a shell of maximum practical depth.
(3) The general formability and ductility of a metal.(See Figure D4)
|
|
drawing
|
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 blankholding
surfaces to prevent the formation of wrinkles while the punch travel produces the required shape. See Figure D5 for an example.
|
|
drawing
|
The process of cold forming a flat pre-cut metal blank into a hollow vessel without excessive wrinkling, thinning, or fracturing.
|
|
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. Also known as die lubricant.
|
|
driver
|
See cam driver.
|
|
ductility
|
Ductility is a measure of the extent to which a metal can be deformed plastically before fracture. It is commonly defined by two parameters.
(See Figure D6)
|
|
dutchman
|
A unshaped device for tying sections of dies together either by design or to repair a die which has been broken.
|
|
dwell
|
Portion of a press cycle during which the movement of a member is zero or at least insignificant. Usually refers to (1) the interval when the blankholder in
a drawing operation is holding the blank while the punch is making the draw or (2) the interval between the completion of the forging stroke and the retraction of the ram.
|
|
dwell cam
|
A cam that can be moved into position and held there while the press continues its cycle. Also see filler cam.
|
