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Design Guidelines GLOSSARY

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Scale--(1) Thick oxide coating on material normally associated with hot working. (2) Deposit formed from solution directly in place upon a confining surface.

Scallop--Edge condition resulting from nibbling a feature in a turret press.

Scrap--Leftover, unused material relegated to recycling.

Selective Perforation--Hole or slot pattern over a specific portion of a workpiece, normally used for ventilation purposes.

Self Extracting Archive File--A library file that can automatically create a group of (CAD) files without requiring the operator to have any special knowledge, or use special software.

Self Fixturing--Part designed to be self-locating into proper position to another part with the use of built-in locators.

Self Locking Fastener--Fastener which is machined with interference threads or which has a nylon insert or other locking mechanism to securely hold mating fasteners in high torque or vibration applications.

Semi-Gloss--A gloss range between high gloss and eggshell, approximately 35 to 90 on the 60 degree gloss scale.

Semi-Perfs--See "Half Shear."

Shake Aparts--Term designating a family of parts on a sheet which are held by "Micro Ties" so small that the parts can be removed from the sheet after CNC punching by simply shaking the sheet.

Shaker Parts--See shake "Aparts."

Shear Form--See "Lanced Tab."

Shear-to-Feature--Shearing of an edge of stock to an exact dimension from an already existing feature.

Shear Spinning--The art of forming metal over a mold in one pass using hand or hydraulic pressure.

Shearing--Cutting force applied perpendicular to material causing the material to yield and break.

Shielding Gas--Inert gas used for oxidation protection during welding.

Shim Steel--Steel which has been rolled thin to a hard condition and very close tolerance.

Shunting--Short circuiting of a (weld) current through a previously applied weld nearby.

Shut Height--Clearance in a press between ram and bed with ram down and adjustment up.

Silicon Carbide--Mineral used for abrasive metal removal.

Silkscreening--Printing process using special inks being pressed through a finemeshed fabric which has been prepared by a photo process to let the ink pass through in predetermined patterns of lettering and graphics.

Single Action--Press utilizing one moving element.

Sinkhole--In welding, a dimple on the surface of stock caused by shrinking of the weld during cooling.

Skid Marks (Roll Slip)--Polished or burnished streaks across the stock surface resulting from improperly set roller driven material processing equipment. Skid marks are transverse to the direction of rolling.

Skin Packaging--Thin poly film which is stretched or heat shrunk over parts for protection or display.

Skin-pass--Single cold rolling process on material after a heat treating process.

Slide Forming--A high-volume stamping process in which a machine with multiple slides sequentially performs various operations (i.e. - blanking, piercing, forming, etc.).

Slot-to-Form--Distance from a slot edge to the inside edge of a formed feature.

Slug--Scrap from a piercing operation.

Slug Marks--Surface defects caused by scrap being indented into the metal surface.

Soft Tooling--A term generally applied to the fabrication of metal parts using computer controlled technology incorporating CNC turret presses, laser profilers and press brakes.

Solids--The ability of the CAD software to realize that a volume is filled with solid matter. These CAD systems can display a design so that it looks like a solid object. Includes recognition of surfaces and wireframes.

Solution Heat Treat--High temperature process in which an alloy is heated to the suitable temperature for the alloy constituents to be in a totally soluble condition for the purpose of creating a homogeneous alloy. Through rapid cooling the constituents stay in this solution state. Metal so treated is left in a super saturated unstable state and may tend to age harden at ambient temperatures.

Solvent Based--Paint type in which a volatile liquid is used to dissolve or disperse the film-
forming constituents.

Spatter--In welding, droplets of matter deposited as contaminants.

Spectral--Adjective referring to spectrum. See "Spectrum."

Spectrophotometer--Device for the measurement of spectral transmittance, spectral reflectance, or relative spectral emittance.

Spectrum--Spatial arrangement of components of radiant energy in order of their wavelengths, wave number or frequency.

Specular Gloss--Relative luminous fractional light reflectance from a surface in the mirror or specular direction. Expressed as a ratio of incident to reflected light.

Spheroidizing--A heat treating process used to change all of the carbides in steel to rounded particles, or spheroids. A completely spheroidized structure is the softest and most workable structure for any composition.

Spinning Blank--A circular disk made from sheet or plate metal.

Spot Face--Circular flat surface as a bearing area for hardware.

Spring Back--Partial rebounding of formed material caused by its elasticity.

Spring Loaded Panel Fasteners--Inserted fastener which is equipped with a floating captive screw, spring and retainer such that the hardware will remain in the panel, ready for use, when the panel has been disassembled from its mating component.

Squareness--Measure of perpendicularity of adjacent edges or surfaces.

Stack-Ups--Tolerance accumulations.

Stainless Steel--Various ferritic alloys exhibiting high oxidation resistance through the alloying with chromium and nickel.

Standard Vee Die--See "V Die."

Stiffening Rib--Embossed feature in a sheet metal workpiece which is added to make the part more rigid.

Stains--Discoloration on the surface of sheet metal, caused during mill processing.

Staking--Method of fastening using displaced material for retention.

Stock Check--A device used to grip the material as the feed retracts, preventing movement of the material during the forming cycle.

Stock Reel--A powered or non-powered device used to support a coil of material as it is fed into the machine.

Stock Straightener--A machine mounted device consisting of a series of adjustable rolls used to straighten wire or strip stock as it comes off the coil.

Stretcher Leveled--A flattening process in which a material is stretched to achieve a desired flatness tolerance.

Stretch Wrap--See "Skin Packaging."

Strip Edge Forming--The use of a rolling technique to edge roll slit strip with shaped edge rolls to provide an edge finish equal to the material's surface finish. Also called edge conditioning.

Stripper--Mechanical hold-down device applied to the workpiece during the punching process.

Stripper Marks--Imprints on one side of the stock around pierced holes, caused by punch strippers.

Stripping--Process of disengaging tooling from the workpiece.

Strips--Sheet material, sheared into narrow long pieces.

Stroke--RAM travel from top dead center (TDC) to bottom dead center (BDC).

Substrate--Original material surface to which a coating is applied.

Surface--The ability of the CAD software to recognize that a closed geometric shape represents a surface of a part. Includes recognition of wireframes.

Surface Inclusions--Debris rolled into the skin of material causing a depression or thinly coated pocket.

Surgical Stainless Steel Types--Any of the 300 series stainless steels with an 18% chromium and 8% nickel content. Also includes the PH type of stainless steels.

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TIG Weld (Tungsten Inert Gas)--Process using a nonconsumable tungsten electrode and a shielding gas, with filler material optional.

T.I.R.--Total indicator reading. Absolute sum of all dimensional variance.

Tack Weld--Usually refers to a temporary weld used to hold parts in place while more extensive, final welds are made. In some sheet metal applications, tack welds may provide sufficient strength to eliminate the need for an "all-around" fillet weld.

Tap Drill Size--See "Core Hole."

Tape--A flexible plastic wound strip coated with magnetic oxide and used for storing electronic data.

Tape Adhesion Test--Adherence test for painted surfaces conducted by cross hatching the surface with a sharp knife in a 1/8 inch grid pattern, applying tape (usually 3M Scotch #600 or #250), allowing to sit for a specified period, and then removing with a quick pull perpendicular to the surface of the part. Adherence is measured by the percentage of paint remaining within the grid. See the Painted Parts Chapter.

Tapping--Operation to create internal threads by either cutting or forming.

Temper Designation--Identifying systems to denote the hardness of a particular material.

Tempering--Reheating quenched steel to a temperature below the critical range, followed by any desired rate of cooling. Tempering is done to relieve quenching stresses, or to develop desired strength characteristics.

Tensile Strength--Breaking strength of a material when subjected to a stretching force.

Test File--A CAD system file used to test the compatibility of supplier and customer CAD systems.

Text Files--A file containing words, but no pictures.

Texture--Structure of a surface as it affects appearance or feel.

Thickness--Gauge or depth of material.

Thread Rolling Tap--Tool to generate internal threads by displacing and flowing metal into a thread shape.

Ties--See "Micro Ties."

Tolerance--Permissible variation from a specification for any characteristic of the product.

Tooling Holes--Openings provided in parts for location purposes during production.

Tool (mandrel, chuck)--The "mold" from which the part is made.

Torque--Turning force.

Transfer--Exchanging electronic data from one medium to another.

Transfer Die--Variation of a progressive die where the part is transferred from station to station by a mechanical system. Mainly used where the part has to be free from the strip to allow operations to be performed in a free state.

Transfer Mechanism--Apparatus used to move a part between die stations.

Transfer Protocol--The mutually agreed upon setting used by two computers in data transmission.

Tungsten Electrode--Current carrier made from the metal tungsten for its high heat resistance.

Turret--Rotary tool holding device in CNC punch presses.

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.

Twist--The rotation of two opposing edges of material in opposite directions.

UNIX--A computer operating system. The more complex CAD systems require UNIX.

Ultrasonic--Sound vibration above the audible range.

Undercut--Condition of the stock resulting from welding or grinding below a desired plane.

Unfolded--The act of developing a flat pattern.

V Die--Tool used in conjunction with a V punch.

V Punch--Vee shaped tool used for angle forming.

Vibratory Finishing--Burr removal process in which an appropriate number of parts, depending on part size and abrasive material, is accelerated and decelerated by mechanical means inside of a drum-like enclosure.

Viewing Angle--Inclination from which a surface is observed, i.e. looking straight at the object = 90.

Viewing Time and Distance--Specified period to inspect a surface condition at a preset dimension from the eye.

Viscosity--Internal friction within a fluid which makes it resistant to flow.

Void--Area in a weld in which insufficient filler material is deposited.

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Water-Borne--Generic designation for a variety of organic finishes which indicates that they are compounded with water as a dilutant rather than a volatile organic solvent.

Water-Soluable--Substance which dissolves in water.

Watts per square inch--Measure of speed based on power level of laser cutting machine.

Webs--(1) Material between two openings or edges. (2) See "Micro Ties." (3) In some industries, thin material to be punched.

Weldability--Ability of a material to be fused successfully without special processing.

Weld Accessibility--Ease of reaching the weld area with the torch or electrode.

Weld Distortion--Depression or bulge on surface, caused by thermal expansion.

Weld Nut--Internally threaded hardware designed to be spot or projection welded onto sheet metal parts.

Weld Stud--Externally threaded hardware in various lengths in headed and head-less version, welded in place.

Weld-To-Edge Distance--Minimum distance from a spot weld to the material edge to create an acceptable spot weld.

Weld-to-Form Distance--Minimum distance from a formed area to electrodes to avoid shorting.

Weld-to-Weld Spacing--Minimum distance between spot welds to avoid shunting through the existing weld spot.

Wet Film Thickness--Thickness of the liquid coating film immediately after application.

Wet-Film Gauge--Device for measuring the film thickness of coatings prior to drying or curing.

Wipe Die--Forming tool using two opposing edges, separated by one material thickness, moving past each other to form material.

Wire Form--A formed metal part made from wire that is usually fabricated on a slide forming machine.

Wireframe--The capability of the CAD software to represent a design as a three dimensional arrangement of lines and arcs.

Wire Line--A standard dimension from the bed of the slide forming machine to the material, used in tool layout.

Work Hardening--Increase in tensile strength of material resulting from cold working process.

Workholder--Mechanical device which holds a workpiece.

Workholder Mark--Marring of material through the use of clamping device.

Work Hole--See "Tooling Hole."

Wrinkling--Condition in a paint film appearing as ripples: (1) produced intentionally as a decorative effect or (2) Defect caused by drying conditions or an excessively thick film.

Wrought--Describes material which has been plastically deformed into shape as by mill rolling.

Yield Strength--Maximum stress that can be applied without permanent deformation of material.

YMODEM--A protocol for transferring drawings electronic files.

Zinc Plating-- See "Electroplating."

ZMODEM--A protocol for transferring drawings electronic files.

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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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