Engineering Definitions

A recess in a die corner to allow for wrinkling or folding of the part.

Source: The OHIO State University

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) die set.

Source: The OHIO State University

As opposed to hem curved outboard and hem deflection recoil is the term used for the local curve at the hem edge

Source: The OHIO State University

The second and successive deep-drawing operations in which cuplike shells are deepened and reduced in cross-sectional dimensions.

Source: The OHIO State University

(1) 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. (2) In forging, extrusion, rolling, and drawing, either the ratio of the original to the final cross-sectional area or the percentage of decrease in cross-sectional area.

Source: The OHIO State University

The difference between the original cross-sectional area and the smallest area at the point of rupture in a tensile test; usually stated as a percentage of the original area.

Source: The OHIO State University

When the workpiece is brought into the required position by the pilots.

Source: The OHIO State University

Clearance obtained by removing metal either behind or beyond the cutting edge of a punch or die. Also called undercut or back-off.

Source: The OHIO State University

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.

Source: The OHIO State University

Stresses left within a metal as the result of non-uniform plastic deformation or by drastic gradients of temperature from quenching or welding.

Source: The OHIO State University

A variable observed or measured in an experiment, sometimes called a dependent variable. The response variable is the outcome of an experiment and is often a quality characteristic or a measure of performance of the process.

Source: The OHIO State University

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

Source: The OHIO State University

To sharpen radii, form, or detail in previously formed area of a part. Also used to eliminate spring back. Also called spank.

Source: The OHIO State University

(1) The striking of a trimmed but slightly misaligned or otherwise faulty forging with one or more blows to improve alignment, improve surface condition, maintain close tolerances, increase hardness, or effect other improvements. (2) A sizing operation in which coining or stretching is used to correct or alter profiles and to counteract distortion. (3) A salvage operation following a primary forging operation in which the parts involved are rehit in the same forging die in which the pieces were last forged.

Source: The OHIO State University

Redrawing of a sheet metal part in a direction opposite to that of the original drawing.

Source: The OHIO State University

A sheet metal flange made by shrinking, as opposed to one formed by stretching.

Source: The OHIO State University

(1) A long V-shaped or radiused indentation used to strengthen large sheet metal panels. (2) A long, usually thin protuberance used to provide flexural strength to a forging (as in a rib-web forging).

Source: The OHIO State University

(1) A sub plate on which die steels are mounted. (2) A block of steel or welded construction to which punch steels or punch retainers are mounted. Also called pedestal, punch riser, or stool. (3) 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. (4) A cast spacer between the inner ram and the draw punch in a toggle draw die. Also called punch riser.

Source: The OHIO State University

A plate inserted between the top of the press bed and the bolster to decrease the height of the die space.

Source: The OHIO State University

A solid round section 9.5 mm (3/8 in.) or greater in diameter, whose length is great in relation to its diameter.

Source: The OHIO State University

The curving of sheets, bars, and sections by means of rolls.

Source: The OHIO State University

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.

Source: The OHIO State University

A process of shaping stock between two driven rolls that rotate in opposite directions and have one or more matching sets of grooves in the rolls; used to produce finished parts or preforms for subsequent forging operations.

Source: The OHIO State University

A metal forming process used to produce long components of various cross sections. The sheet metal is formed by passing it through a succession of progressively shaped power-driven contoured rolls.

Source: The OHIO State University

A mechanism equipped with rolls to straighten sheet or strip stock. Usually used with a feed mechanism for press working.

Source: The OHIO State University

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.

Source: The OHIO State University

Obvious transverse breaks on sheet metal usually about 3 to 6 MM ('/8 to '/4 in.) apart that are caused by the sheet fluting during roller leveling. These will not be removed by stretching.

Source: The OHIO State University

Leveling by passing flat sheet metal stock through a machine having a series of small-diameter staggered rolls that are adjusted to produce repeated reverse bending.

Source: The OHIO State University

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.

Source: The OHIO State University

Preferred for lower strength materials.

Source: The OHIO State University

The result of cutting or tearing (piercing) and flanging of a hole in one operation without generating a slug. Referring to extruding or spearing.

Source: The OHIO State University

A sheet metal cutting machine with two rotating-disk cutters mounted on parallel shafts driven in unison.

Source: The OHIO State University

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.

Source: The OHIO State University

A milling cutter with serrated flutes or teeth. Also called corn-cobs and multi-tooth cutters.

Source: The OHIO State University

A flexible skin of a part made out of latex covered fiberglass and used in the designing of a die.

Source: The OHIO State University

A sheet metal forming process in which rubber is used as a functional die part.

Source: The OHIO State University

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 Guerin process. Variations of the Guerin process include the Marforming process, the fluid-cell process, and fluid forming.

Source: The OHIO State University

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.

Source: The OHIO State University

The amount of clearance designed in a die between two mating steels to allow for stock thickness at bottom of press stroke.

Source: The OHIO State University