Computer Assisted Design. The use of computer programs to generate, analyze and modify designs. Extrusion dies and their supporting tools, for example, may be designed with the aid of computers.

Computer Assisted Manufacturing. The use of computers to monitor, regulate and control manufacturing processes.

The outer part of a hollow die, which shapes the outside of a hollow extrusion.

The surfaces in the aperture of a hollow die which form the outside contour of a hollow extrusion. These surfaces are located on that part of a hollow die which fits against the web or bridge base of the mandrel and are on the same plane as the mandrel bearing. See Bearings.

To form a molten material into a desired shape by pouring into a mold and letting it harden.

An alloy formulated for casting.

(Sodium Hydroxide, NaOH and derivatives). The active ingredient in an alkaline bath, generally with a pH higher than 10, which removes aluminum from used extrusion dies by etching. The primary ingredient, Caustic Soda (NaOH), dissolves the aluminum alloy by chemical reactions with no affect on the die steel.

See Prechamber, Pocket, Piastrina, and Weld Pocket. An area in the entry side of the die which serves to control flow of metal and in a solid die it permits a profile to be continuously extruded as metal from the succeeding billet face is welded to the previous rear face remaining in the cavity after shearing. The pocket generally follows the contour of the profile with milled depths varying from 0.040" to 1" or more depending upon its function.

In aluminum production: the electrolytic reduction cell, commonly called a pot, which alumina dissolved in molten cryolite is reduced to metallic aluminum. A series of cells connected electrically is called a pot line.

The difference in thickness between the middle and edges (average) of a sheet.

A white powdery deposit on the surface of the exposed paint film caused by weathering.

A bevel at the apex of an angle on a machined part to allow clearance and prevent interference when assembled with another machined part. The interference may occur from dirt, burrs, or incidental marring of the die surface. A chamfer aids in the assembly of closely fit machined parts. Large chamfers are sometimes used on the webs of hollow die entry ports to reduce the initial contact area between die and billet.

A surface defect consisting of alternating ridges and valleys at right angles to the direction of extrusion.

Numerous intermittent lines or grooves that are usually full width and perpendicular to the extrusion direction.

Removing metal from a piece by controlling chemical etching.

Improving the surface luster of metal by chemical treatment.

The angle filed on a bearing surface at the point where bearing and die face meet (where aluminum enters aperture). Choke length and choke angle may vary independently. The angle of choke generally falls between 1 2 degrees to 5 degrees.

Metal sheared from a vertical surface of a die forging, which is spread by the die over an adjoining horizontal surface.

A lug or boss added to a forging so that on center machining and forming may be performed with one setup or checking. This lug is finally machined or cut away.

A circular blank fabricated from plate, sheet, or foil.

An imaginary circle defining the maximum port entry for a given container liner where this diameter is typically approximately 75% to 90% of the die diameter.

The smallest circle that will completely enclose the cross section of an extruded shape.

A protective layer of pure aluminum or appropriate alloy to increase corrosion resistance and/or to allow for brazing, applied to the surface of aluminum.

A circular tool or block used for scraping the aluminum skull from the container liner's inside wall. The cleanout block diameter is greater than that of a dummy block and is sometimes called a scavenger block or cleanout disk.

Is similar to a cleanout block except that it is made from 2 or 3/4 inch mild steel plate.

Continuous film on the surface of a product.

A coating thickness greater than nominal in localized area of sheet, usually along edges, due to uneven application techniques.

A non-uniform extraneous deposit of coating on the coated sheet.

Failure of the coating to meet the agreed upon thickness limits measured in weight per unit area.

(1) A jamming of the mill by aluminum product while being rolled. (2) A piece of aluminum which for any reason has become so bent or twisted that it must be withdrawn from the rolling operation and scrapped.

The relative rate at which a substance expands on heating, compared to a standard rate.

Clockwise Coil: With the coil core vertical (eye to the sky) and viewed from above, a trace of the metal edge from the ID to the OD involves clockwise movement. Counter-Clockwise (Anti-Clockwise) Coil: With the coil core vertical (eye to the sky) and viewed from above, a trace of the metal edge from the ID to the OD involves counter-clockwise (anti-clockwise) movement.

Longitudinal bow in an unwound coil in the same direction as curvature of the wound coil.

The difference in coil set from edge to edge of a coiled sheet sample. It is measured with the sample on a flat table, concave side up, and is the difference in elevation of the corners on one end.

Longitudinal bow in an unwound coil in the direction opposite to the curvature of the wound coil.

(1) A linear discontinuity in a cast surface caused when meeting streams of metal fail to merge prior to solidification. (2) A forging defect developed by metal flowing into a section from two directions, resulting in a discontinuity at the junction.

Plastic (i.e., permanent) deformation of metal at such temperature and rate that strain-hardening occurs.

Out-of-round condition of coil often due to inappropriate tension.

A finishing process, or combination of processes, which alters the appearance of an aluminum surface via coating, chemical, and/or mechanical operations.

An aluminum alloy containing relatively large amounts of two or more other elements.

A joint that is both welded and joined mechanically.

Strength to resist outside pressure (as distinguished, for example, from bending or stretching forces).

Conformance to a common center as, for example, the inner and outer walls of round tube.

The term Heat-Exchanger Tube is preferred, unless specific reference to a condenser application is intended and purpose is to dissipate heat as efficiently as possible.

The ability of a substance to transmit heat, light or electricity. Aluminum has high electrical and thermal conductivity, making it useful in a wide range of electrical and heat-exchanging applications.

A tube used to protect electric wiring. See also Tubing, Electrical Metallic.

Conduit having dimensions of ANSI Schedule 40 pipe in standardized length and threaded ends.

The steel cylinder, usually fitted with a removable liner, having an inside diameter slightly larger than the billet to be extruded which holds and confines the billet during the extrusion cycle. Its length may vary with the press tonnage rating and manufacturer.

The removable, replaceable cylindrical unit of press tooling which holds or confines the billet during the extrusion cycle.

The interface between the container and the die. There must be sufficient clearance between the outer edge of the die port and the inner edge of the container opening to prevent extrusion of the billet skin or skull.

The difference in dimensions between the billet diameter and container liner internal diameter.

That portion of the outline of a transverse cross-section of an extruded profile that is represented by a curved line or curved lines.

An operation in which the extrusion is passed between rollers to adjust profile dimensions so that specified tolerances in angularity, cross-sectional space dimensions, flatness, and contour are achieved. Bow and twist may also be minimized or eliminated by contour rolling.

A chemical layer formed on the metal in the pretreatment process which aids in paint adhesion and corrosion resistance.

A hollow cylinder, on which a coiled product may be positioned, that forms the inside diameter of a coil.

See Blister, Core.

A distortion, buckle or twist condition that causes the corner(s) of the sheet to deviate from a perfectly flat place on which it rests.

The deterioration of metal by chemical or electrochemical reactions with substances in its environment.

Corrosion that progresses approximately parallel to the metal surface, causing layers of the metal to be elevated by the formation of corrosion product.

Corrosion associated with the current of galvanic cell consisting of two dissimilar conductors in an electrolyte or two similar conductors in dissimilar electrolytes. Aluminum will corrode if it is anodic to the dissimilar metal.

Corrosion occurring preferentially at grain boundaries (also termed intercrystalline corrosion).

Localized corrosion resulting in small pits or craters in a metal surface.

Failure by cracking resulting from selective directional attack caused by the simultaneous interaction of sustained tensile stress at an exposed surface with the chemical or electro-chemical effects of the surface environment. The term is often abbreviated SCC which correctly stands for stress corrosion cracking.

Superficial oxidation of the surface with a water film, in the absence of circulating air, held between closely adjacent metal surfaces.

Forming rolled metal into a series of straight parallel regular alternate grooves and ridges.

A piece a metal from which a test specimen may be prepared.

Yield expressed in terms of a given number of square inches in a pound. For metric units, use square meters per kilogram.

A paint film defect appearing as small, round bare spot on the painted part. This may be caused by gassing, incompatability, or silicones.

A macroscopic effect of numerous surface tears, transverse to the rolling direction, which can occur when the entry angle into the cold mill work rolls is large.

A sharp deviation from flat in the sheet which is transferred from processing equipment subsequent to the roll bite.

The strain in a metal that results from continuing constant stress.

Test to demonstrate adhesion characteristics of a paint or powder coated surface, performed by scribing a crosshatch pattern at specified intervals.

Pertaining to very low temperatures. Aluminum gains strength as temperature is reduced, making it an appropriate material for cryogenic applications.

The process of converting a liquid paint to a solid, durable film, usually accomplished by the action of heat and catalysts.

An undesirable condition caused by uneven rates of absorption or evaporation of moisture, uneven rates of contraction or expansion, or internal stresses in the material. Curl is most prevalent in laminated structures where the components have differing physical properties.