HPGL--Acronym for "Hewlett Packard Graphics Language."
Half Shearing--Partial penetration piercing, creating a locating button with a height of about 1/2 material thickness.
Hard Tooling--Tooling made for a specific part. Also called "dedicated tooling."
Hardenability--The fundamental characteristic of a steel which determines the ease of preventing the transformation of austenite to anything else but martensite during the quench.
Hardware--(1) The physical components of a computer system. (2) Fasteners inserted into a sheet metal part.
Hardware List--Information that should be conveyed to the part supplier specifying part numbers, description and quality of fasteners.
Heat Sink--Good thermal conductor used to remove destructive heat from an area.
Hem (Dutch Bend)--Edge of material doubled over onto itself for the purpose of safe handling or to increase edge stiffness.
Hold-Down Marks--Slight indentations or scuff marks on one side of the stock which can result from the pressure of hold down devices during shearing operations.
Hole Rollover--Rounding of the top edge of a pierced feature caused by the ductility of the metal, which flows in the direction of the applied force.
Hole-to-Feature--Dimension between the center of a hole and another feature.
Hole-to-Form--Distance from the center line of a hole to the edge of a formed feature.
Hole-to-Hole--Dimension between centers of holes.
Homogenizing--An annealing treatment at a fairly high temperature designed to eliminate or reduce chemical segregation.
Host Computer--An unattended computer that can be accessed by other (remote/client) computers.
Hot Dip--Application of a metal coating on a substrate by immersion in a molten metal bath.
Hot Rolled Steel--Steel which was rollerformed from a hot plastic state into final shape; characterized by a rough, scaly surface.
Hue--(1) Attribute of a color by means of which a color is perceived to be red, yellow, green, blue, purple, etc. White, black and grays possess no hue. (2) The name of a color of a finish, as viewed subjectively.
Hydraulic Press--Machine which exerts working pressure by hydraulic means.
Hydrogen Embrittlement--Loss of ductility of a material due to absorption of hydrogen gas during heat treatment an electrolytic process or during acid cleaning.
IGES--Acronym for "Initial Graphics Exchange Specification."
Impact Resistance--Ability to resist deformation from impact.
Inboard Mill--A roll forming machine with a housing only on one end of the roll tooling shaft.
Inclusions--Particles of impurities (usually oxides, sulphides, or silicates) which separate from the liquid steel and are mechanically held during solidification. In some grades of steel, inclusions are made intentionally high to aid machinability.
Indexable Tool Stations--Special tool positions in a turret press which are equipped with numerically controlled servo drives rotating the punch and die together to profile contours, nibble angles or for other special applications.
Inductance Instrument--Instrument which is used to measure thickness of applied coatings to metal substrates. Unlike magnetic thickness gauges, inductance gauges can measure either conductive or non-conductive coatings on magnetic or non-magnetic substrates.
Induction Hardening--A form of hardening in which the heating is done by induced electrical current.
Insert--See "Inserted Fastener."
Inserted Fastener--Variety of pins, nuts, studs, standoffs or special hardware which are installed in a workpiece by inserting it into a specifically punched hole. See chapter on Inserted Fasteners.
Inside Radius-- See "Bend Radius."
Inspection Criteria--Characteristics by which the part will be evaluated both dimensionally and cosmetically.
Interrupted Quench--Stopping the cooling cycle at a predetermined temperature and holding at this temperature for a specific time before cooling to room temperature. Usually done to minimize the likelihood of cracking, or to produce a particular structure in the part.
ISO Drafting Standard--Regulation for the creation of technical drawings published by the International Organization of Standards.
Isothermal Treatment--A type of treatment in which a part is quenched rapidly down to given temperature, then held at that temperature until all transformation is complete.
King Post--See mandrel.
LASER--Acronym for "Light Amplification by Stimulated Emission of Radiation."
Lanced and Formed Tab--See "Formed Tab."
Lanced Tab--See "Formed Tab."
Lap-Welded Joint--Welded seam in which the two metal pieces to be joined overlap one another.
Laser Welding--Metal melting and fusing using the energy of a concentrated coherent light beam.
Layer--A CAD file is like a layered stack of clear transparency films with design information on the different layers. They are superimposed on each other. One can look down through all of the layers at once, or only selected layers.
Lead Screw--Drive system which converts rotary to linear motion.
Lead Time--Time required to manufacture a product from order placement until availability. It includes planning, engineering, tool design and construction, acquisition of materials, scheduling, fabrication, finishing and packaging.
Leg Size--Width and height of the filler bead of welding material.
Lever Arms--A scissors-like apparatus used to apply pressure to the spinning blank.
Linear Slide Machine--A vertical slide forming machine with the ability to place several opposing slides arranged in a linear fashion on both the front and back sides of the tooling area providing the ability to produce complicated stampings as well as assemblies.
Lines--A straight line segment between two points.
Line Width--Thickness of a line in CAD drawings.
Load Up--Accumulation and compaction of metal particles between the abrasive grit of a grinding belt disc or wheel rendering it ineffective.
Lock Seam Tube--A hollow (closed) roll form shape mechanically fastened using the roll form tooling.
Mac®--Abbreviation used to designate a MacIntosh computer, manufactured by Apple Computer.
MIG Weld (Metal Inert Gas) or GMAW (Gas Metal Arc Weld)--Metal melting and fusing process using a continuous metal consumable electrode with an inert gas around the electrode to shield against oxidation.
Magnetic Thickness Gauge--Device, applicable only to ferrous substrates, which measures the thickness of non-conductive coatings.
Mandrel--Usually a fixed tool on a slide forming machine that metal is formed against by the action of a slide-mounted form tool.
Manganese (Mn)--Lustrous redish-white metal of hard brittle and therefore non malleable character. Element number 25 of the periodic system. Atomic weight 54.93.
Manufacturability--The degree to which a product can be efficiently and accurately produced using modern manufacturing methods.
Martempering or Marquenching--Martemper-ing is a form of interrupted quenching in which the steel is quenched rapidly from its hardening temperature to about 450°F, held at 450°F until the temperature is uniform, then cooled in air to room temperature. Actual hardening does not occur until the air cooling starts and is accomplished with a minimum temperature differential. Martempering is indicated for low to medium alloy steels when distortion may be a problem.
Martensite--A ferritic material with distinctive needle like structure which is always present in heat treat hardenable steel.
Martensitic Stainless Steel--Select group of 400 or 500 Series stainless steel which are magnetic and hardenable by heat treating.
Masking--Temporary shielding of a portion of a product to selectively prevent the application of a coating.
Master Carton--Large box, generally 42 in. wide, 48 in. long and 30 in. high, made from heavy test cardboard and designed to fit a standard pallet.
Master Die--Universal tool receptacle for holding changeable tool systems.
Master Document--An original file retained in case of subsequent errors to a copy.
Material Utilization--Extent to which optimal use of material is approached.
Mechanical Assemblies--Part combinations attached by mechanical means through the use of hardware.
Mechanical Fastener--Device clamping two or more components together by mechanical force, such as rivets, screws, etc.
Mesh--Number of holes per inch in sieves used to sort mineral abrasive particles into specific grit sizes.
Metal Thinning--Thickness reduction during any forming operation.
Metameric Match--See "Conditional Match."
Micro Alloying--Specific alloy combination usually designed for special strength, ductility or flexibility.
Micro Ties--Thin bridges of metal which are left to hold parts in place during turret punch fabrication.
Mill Edge--See "Edge Deckle."
Model--(1) Pre-production sample made with limited emphasis on tolerance to test a design concept. See, also, "Prototype." (2) A computer graphic depicting exact geometry of a part.
Modem--A device used to transfer electronic files via telephone lines.
Mold Lines--Lines in a drawing connecting the inner radius and outer radius of a bend and showing the extent of bend.
Multiple Level Forming--A sequence of slide forming operations at different elevations of the center tool.
Excerpt taken from Design Guidelines for Metal Stampings and Fabrications -- 2nd Edition copyright © 1995 Precision Metalforming Association
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