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Design Guidelines GLOSSARY

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2-D--Having two dimensions, lacking depth.

3-D--Having three dimensions, showing depth.

ASCII--Acronym for "American Standard Code for Information Interchange."

Abrasion Resistance--Ability of a coating to withstand rubbing, scraping and eroding forces.

Abrasive--Sharp mineral particles, used for metal removal.

Abrasive Media--Matrix used to carry the mineral particles for the purpose of material removal.

Acidic Etching--Removal of surface contamination by corrosive treatment.

Adaptor--A block used to mount a form tool to a slide.

Air Bending--Forming operation in which a metal part is formed without the punch and die closing completely on the part. See Press Brake Chapter.

Air Hardening Steel--An alloy steel which will form martensite with high hardness when cooled in air from its proper hardening temperature.

Alloys--Base metal with other metal or non-metal constituents melted together into a new molecular structure.

Alodine--Commercial trade name for a chromate conversion coating over aluminum.

Aluminum Alloy--Pure aluminum which has been melted together with other constituents to achieve specific physical and mechanical properties.

Aluminum Oxide--Hard mineral of aluminum and oxygen (Al03) used as an abrasive.

Annealed--Softest possible state of any material.

Annealing, Full--Heat treating process wherein metal is heated to a temperature above its critical range, held at that temperature long enough to allow full recrystallization, then slowly cooled through the critical range. Annealing removes working strains, reduces hardness, and increases ductility.

Anode--Positively charged electrode.

Anodizing--Process of applying a controlled oxide layer to the surface of aluminum.

Archive--The storage of files in the form of tape or disk for long periods of time.

Arcs--Partial circles used to describe rounded corners of material and show bends in material.

Artificially Aged--Hardening process of material accelerated by temperature.

Austempering--A heat treating operation in which austenite is quenched to and held at a constant temperature (usually between 450F and 800F) until transformation to bainite is complete. In some steels at certain hardness levels, bainite is tougher than quenched and tempered structures.

Austenite--The solid solution in which gamma iron is the solvent. Austenite is a structure and does not refer to composition. Austenite is the structure from which all quenching heat treatments must start.

Austenitic Stainless Steel--Non-magnetic stainless steel. Not hardenable through heat treatment; good corrosion resistance.

Automatic Spinning--The art of forming metal over a mold using an automatic (Computer Controlled or Template) spinning lathe.

AutoCAD--A brand name of CAD software prevalent in the marketplace.

Auxiliary Slide--A bed mounted, cam operated slide typically used for forming on a slide forming machine.


bis -- Acronym for "bits into sound."

bps--Acronym for "bits per second." Refers to the rate at which a data communications line can transfer information. Bits per second can be faster than baud rate when data compression is used.

Back Gauge--Stop located in the rear of a metal forming or fabricating machine which is used to position the workpiece during an operation.

Banding, Metallic or Non-Metallic--Strong, lightweight ribbons, generally of steel or nylon, applied under tension to strap packages on a pallet.

Bar Coding--Machine readable alphabetic and/or numeric information used for identification of packaged parts.

Bark--An older term used to describe the decarburized skin that develops on steel bars heated in a non-protective atmosphere.

Barrel Tumbling--Process in which parts to be deburred are put together with abrasive material into a many-sided barrel and slowly rotated for prolonged periods for the purpose of burr removal.

Basecoat--See "Primer."

Bed--Bottom transverse structural member on metalforming machine.

Belt Sanding--Metal removing process in which an abrasive impregnated endless cloth belt does the cutting.

Bend Radius--Inside radius of a formed feature.

Bend Relief--Clearance notch at an end of a flange to allow bending without distorting or tearing adjacent material.

Bending--Generally applied to forming. Creation of a formed feature by angular displacement of a sheet metal workpiece. See also "Drawing" and "Forming."

Bi-Planar--Refers to surfaces which meet at an angle in different planes.

Blank--(1) Sheet metal stock from which a product is to be made. (2) Workpiece resulting from blanking operation.

Blanking--Die cutting of the outside shape of a part.

Bleed-Out--Leaching of entrapped plating solutions, causing surface discoloration and corrosion.

Blind End Fastener--Internally threaded fastener which is manufactured with one end closed such that, when installed, it forms a gas and moisture resistant seal.

Blind Fastener--Fastener which is capable of being permanently installed and used in a workpiece with access from only one side.

Blind Rivet--Rivet which is capable of being installed and used in a workpiece or assembly with access from only one side.

Bottoming--Forming operation in which the punch and the die is closed completely on the workpiece. See Press Brake Chapter.

Bow Distortion--Out of flatness condition in sheet material commonly known as "Oil Canning" in which, with the edges of the sheet restrained, the center of the sheet can be popped back and forth but cannot be flattened without specialized equipment. This condition is sometimes inherent in the material as received from the supplier and sometimes the result of multiple punching or forming operations. See chapter on CNC Turret and Laser Fabrication.

Brass--Alloy of copper and zinc.

Break-Off--See "Breakout."

Breakout--Fractured portion of the cross section of a cut edge of stock. A condition naturally occurring during shearing, blanking, punching and other cutting operations.

Bridges--See "Micro Ties."

Bright Annealing--Annealing work in a protective atmosphere to prevent discoloration as the result of heating. In some atmospheres oxides may be reduced.

Brinnell Hardness Testing--A method of testing the hardness of material. This test is usually used on softer materials and castings in which a carbide ball is pressed into the material for a given period of time and then removed. The resulting impression is measured for the width along with a value determines hardness of the material.

Brushing or Etching--Mechanical or chemical cleaning of parts before further processing.

Buffing--Polishing method employing soft cloth to carry very fine polishing compounds. Burn Mark--Heat discoloration created in the contact area of a welding electrode.

Burnish--Smooth or shiny area above the breakout on a sheared edge. Also called shear or cut band.

Burr--Raised, sharp edge inherent in cutting operations such as shearing, blanking, punching and drilling.

Burr Direction--Side of the stock on which burrs appear.

Burr-Free--Edge without sharp protrusions.

Burr Height--Height to which burr is raised beyond the surface of the material.

Burr Rollover--Condition of burr displacement resulting from mechanical deburring operation.

Bus Bar Copper--Copper with minor alloying constituents and high conductivity used for electrical applications.

Butt--End to end.


CAD--Acronym for "Computer Aided Design." See CAD chapter.

CAM--Acronym for "Computer Aided Manufacturing."

CNC--Industry acronym for "Computer Numerical Control."

CNC Turret Press--Automatic punch press indexing the material and selecting the intended tool out of the rotary tool holding device (turret) totally by computer control for piercing, blanking and forming workpieces as programmed.

Cadmium Plating--Electrolytic process for metal coating in which commercially pure cadmium is the anode.

Cam--A device used to control the motion of slide forming machine slides and attachments, and die components.

Camber--Gradual deviation from straightness of the edge of sheet or coil stock caused during the slitting operation.

Cam Chart--A chart created by the tool designer assuring that the sequence of operations of a complicated part fall within the 360 degree slide forming machine cycle.

Cam Trim--Removing excess material after the part has been drawn or formed. This is done with a cam activated operation, usually as a secondary operation.

Capillary Action--Liquid trapping action caused by the closeness of two surfaces and the surface tension of the liquid.

Carbon Steel--Steel which owes its properties chiefly to various percentages of carbon without substantial amounts of other alloying elements.

Carbonitriding--A heat treatment for steel which adds carbon and nitrogen from an atmosphere rich in such elements.

Carburizing--Adding carbon to the surface of steel by heating it in contact with carbon rich gases.

Case--The surface layer of a steel whose composition has been changed by the addition of carbon, nitrogen, or other material at high temperature.

Case Hardening--A heat treatment in which the surface layer of a steel is made substantially harder than the interior by altering its composition.

Cathode--Negatively charged electrode.

Cellular Dividers--Slotted cardboard sheets designed to be interleaved in a master carton producing individual pockets to separate parts.

Center--The point which is defined midway between the extents of a hole in both the X and Y directions.

Center Tool--See mandrel.

Chain Dimensioning--Drafting practice which dimensions repetitive features from each other rather than a common datum.

Checks--Surface ripples and cracks induced by forming.

Chemical Etching--Removal of metal through chemical erosion process.

Chromate--Post-treatment wash (non electrolytic) coating which is used over zinc, cadmium, treated aluminum and other plating operations to seal the surface of the coating, prevent oxidation and, in certain cases, improve the electrical characteristics of the coating. May be clear, yellow or blue to visually indicate that the product has been coated.

Chromate Conversion--Application of a salt or ester of chromic acid to a metal workpiece by dipping or spraying. The coating is generally used to seal the surface of the workpiece to enhance electrical properties or reduce corrosion.

Circle--A continuous arc starting and ending at the same point.

Clad Shape--A roll formed shape made up of two materials simultaneously fed into the roll forming mill to produce a composite section.

Clamp Marks--Slight indentations at the edge of one side of stock caused by pressure from turret press holding devices. See also "Work-holder Mark."

Clinch Fastener--See "Inserted Fastener."

Clock-Spring Material--Alloy steel available in a pre-hardened condition between RC 45 and 52.

Co-Engineering--Process in which the customer and the supplier review and modify a design to simplify manufacturability of a part.

Co-Planar--Having all elements, features, dimensions or functions existing in one geometric plane.

Coating System--Consists of a number of coats separately applied in a predetermined order at suitable intervals to allow for drying or curing.

Coat--Paint, varnish or lacquer applied to a surface in a single application (one layer) to form a properly distributed film when dry.

Coil Breaks (Crossbreak)--Defective condition of ridges or marks across the width of sheet or coil caused by improper coiling or leveling.

Coining--Compressive metal flowing action. See also, "Bottoming."

Cold Rolled Steel--Steel which was reduced to final thickness in the cold state by a rolling mill. Creates a smooth surface with slight skin hardness.

Cold Weld--Defective weld due to improper contact or inadequate heat during welding.

Cold Worked--Material hardened naturally through forming at ambient temperatures.

Cold Working--Plastic deformation of a metal at a temperature low enough so that recrystallization does not occur during cooling.

Collapsible Tool (Segmented)--A "mold" having a removable center core which keeps the perimeter pieces in place during spinning.

Color--One aspect of appearance; a stimulus based on visual response to light, and consisting of the three dimensions of hue, saturation, and lightness.

Color Chips--Paint samples.

Color Match--Pair of colors exhibiting no perceptible difference when observed under specified conditions.

Commercial Grade--Standard materials commonly available through supply houses.

Communications Software--A computer program that enables one computer to connect with another computer.

Compound Die--Tool used to pierce, form and blank a part at the same time, with one stroke of the press.

Compress--To condense electronic files for ease of transfer and storage.

Concealed Head Fastener--Fastener installed in a blind hole.

Concentricity--Dimensional relationship of 2 or more items sharing a common center line.

Conditional Match--Perceived identity of color exhibited by a pair of colors, each with different spectral distribution curves.

Conductive Paint--Organic coating that conducts electrical current.

Conductivity--Ability of a material to conduct electricity or heat.

Connecting Lines--Two lines on a part drawing tangent.

Continuous Radius--A roll formed shape with a continuous curve or sweep in one or more planes.

Continuous Wave--Power output mode of lasers using a constant discharge.

Conventional Spinning--The art of forming metal over a mold using multiple passes and hand pressure.

Conversion Coating--Treatment, either chemical or electrochemical, of the metal surface to convert it to another chemical form which provides an insulating barrier of exceedingly low solubility between the metal and environment, but which is an integral part of the metallic substrate. It provides greater corrosion resistance to the metal and increased adhesion of coatings applied to the metal.

Core--The interior part of a steel whose composition has not been changed in a case hardening operation.

Core Hole--Hole diameter required before cutting or forming internal threads.

Corner--Three surfaces meeting at one point.

Corner Radius--Outside radius.

Corrosion Resistance--The ability of a substance to resist deterioration due to a reaction with its environment.

Counterboring--Machining or coining operation to generate a cylindrical flatbottomed hole.

Countersinking--Machining or coining operation to generate a conical angle on a hole.

Critical-to-Function (CTF) Dimensions--In the absence of dimensional drawings, a means of communicating by CAD dimensions critical to success of the design, tolerance and other non-geometrical information. Generally, simpler than a complete fabrication drawing because of fewer dimensions.

Cross-Hatch Pattern--Repetitive lines crossing each other at an angle, such as a coarsely woven cloth.

Cross-Sections--Sectional views.

Crystalline Structure--Arrangement of molecules in geometric patterns in a solidified material.

Cumulative Tolerance--Progressive accumulation of tolerances resulting from multiple operations or assembly of multiple parts.

Curvature--The tendency for steel strip to retain some of the coil set of the wound coil when it is uncoiled. Also called "coil set."

Cut Band--See "Burnish."

Cut Lengths--Standard sheet sizes of material received from service centers, such as 3' x 8' or 4' x 12'.

Cut-Off--Process by which strips of material or finished parts are cut from a coil or strip of raw material.

Cut-Tape Test--A paint adhesion test consisting of the application of an adhesive tape to a dried coating and rapidly removing the tape with a swift, jerking motion.

Cutoff Press--Any one of several types of cutoff methods in a roll forming line.


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Go to the Design Guidelines Overview

Excerpt taken from Design Guidelines for Metal Stampings and Fabrications -- 2nd Edition copyright © 1995 Precision Metalforming Association

Purchase the new Third Edition of Design Guidelines for Metal Stampings and Fabrications copyright © 2004 Precision Metalforming Association at Marketplace today!


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