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CARBIDE INSERT TERMS:

 

ABRASION RESISTANCE: The ability of a material to withstand a change in dimension due to a rubbing action.
ABRASIVE WEAR: The wear that occurs on a tool in use due to the rubbing action in machining. See Flank Wear.
ANVIL (SEAT, SHIM): A removable part of a tool holder designed to provide support for the cutting insert. See Insert Package.
ATTACK ANGLE (LEAD ANGLE, SIDE CUTTING EDGE ANGLE): Term preferred by some to avoid confusion over the meaning of Side Cutting Edge Angle. See Lead Angle.
BACK RAKE (TOP RAKE): The angle of inclination of the face of the tool away from the end cutting edge. It is measured in a plane perpendicular to the base of the tool and parallel to the side cutting edge. See Rake.
BAR (BORING BAR): A tool holder specifically designed to support cutting tools in a boring operation. Deep-hole boring often requires a long, round (or "bar-shaped") tool holder that is supported on one end.
BUILDUP:  See Build Up Edge.
BUILD UP EDGE: An adhering deposit of work material on the tool face (rake face) adjacent to the cutting edge.
CHAMFER: A bevel on the cutting edge of a cutting tool for the purpose of increasing its strength. The angle is measured from the cutting face downward and will generally vary from 25 to 45 degrees.
CHIPBREAKER: A groove or irregularity in the face of a tool, or a separate piece fastened to the tool or tool holder, to cause the chip to break into short sections, or curl.
CHIPBREAKER INSERT: An insert with a built-in chipbreaker. This generally consists of a groove around the top face of the insert near the periphery.
CHIPPING: The breakdown of cutting edges by loss of fragments broken away during the cutting action.
CLEARANCE: The angle below or behind the cutting edge, which allows the cutting-edge to be forced into the work. Without clearance, the tool will not cut. It is also the term used for secondary relief in some cases. See Relief.
CRATER: A grooved area or depression caused by chips rubbing-away or eroding a groove or well in the top (the rake face) of the insert behind the cutting edge of a tool.
CUTTING EDGE: That part of the face edge along which the chip is separated from the work. The cutting edge consists of the side cutting edge, the nose, and the end cutting edge.
CUTTING SPEED: In turning, the peripheral velocity of the workpiece at the cutting radius. It is measured in surface feet per minute, sfm.
DEFORMATION: The permanent change in the shape of a cutting tool due to cutting forces and temperature. This generally occurs in high-speed or heavy machining.
DEPTH OF CUT: The distance between the bottom of the cut and the uncut surface of the work, measured in a direction at right angles to the machined surface of the work. This is the difference in height between the machined and un-machined surfaces.
EDGE PREPARATION: A conditioning of the cutting edge, such as honing or chamfering. See Chamfer, Honing.
END CUTTING EDGE ANGLE: The angle between the cutting edge on the end of the tool and a line perpendicular to the side edge of the straight portion of the tool shank.
END RELIEF ANGLE: Angle between the portion of the end flank immediately below the cutting edge and a line drawn through that cutting edge at right angles to the base of the tool holder. See Clearance, Relief.
ENTRANCE ANGLE: The angle that the side-cutting edge of a tool makes with the machined surface of the work, measured on the cutting-edge side of the tool point.
FACE (RAKE FACE): That surface of the cutting tool on which the chip impinges as it is separated from the work.
FEED: In turning, the distance moved by the tool into or along the work for each revolution of the work. It is measured in inches per revolution, ipr.
FLANK: That surface adjacent to the cutting edge and below it when the tool is in a horizontal position for turning.
FLANK WEAR (ABRASIVE WEAR): The wear that occurs along the flank of a tool, below and immediately adjacent to the cutting edge, while cutting. This wear reduces the clearance angle of the tool until failure finally occurs. See Wear Land.
HEAT CHECK: Many small cracks in the surface caused by grinding too rapidly, without proper coolant, or with too much pressure during grinding.
HONED: Abrasively finished, generally by rubbing, using a wet compound and abrasives.
HONING: The process of rounding or blunting the cutting edge with abrasives for increased edge strength. It may be done by hand or by machine. See Edge Preparation.
INCLUDED ANGLE: A measurement of the total angle within the interior of a piece. The angle between any two intersecting lines or surfaces. The corner angle of an insert.
INSCRIBED CIRCLE (IC): The circle that can be constructed internal to any closed figure or shape so that all sides of the figure are tangent to the circle. The inscribed circle is most often used to describe the dimensions of a triangle, pentagon, hexagon, octagon, or trigon.  The IC of a square or parallelogram is equal to the perpendicular distance between opposite sides; the IC of a round insert is the same as the insert diameter.
INSERT: The cutting tip, made of hard material that is mechanically applied to the tool holder for use. It can generally be indexed to present more than one cutting edge.
INSERT PACKAGE: The complete assembly that fits into the insert pocket of a tool holder. This includes such components as a seat, setscrew, insert, chipbreaker, clamp, and clamp screw.
INSERT POCKET: The space that has been machined out of a tool holder to receive the insert package (seat, insert, chipbreaker, etc.)
LAPPING: An abrasive finishing process involving rubbing with a wet compound. Commonly used to achieve a high degree of flatness on inserts.
LEAD ANGLE (SIDE CUTTING EDGE ANGLE, ATTACK ANGLE): The angle between the side cutting edge and the projected side of the tool shank or holder, which leads the tool into the work. See Attack Angle.
MACHINABILITY RATING: A numerical value expressing the ease or difficulty of machining a particular workpiece material in comparison with AISI B 1112 cold-rolled steel being turned at 180 sfm, which is rated at 100 percent.
NEGATIVE LAND (K-LAND): A bevel along the cutting edge causing the rake to become more negative. It may range from 3 to 5 degrees and is measured off the top face of the insert. See Chamfer.
NEGATIVE RAKE: A rake angle that is less keen or more blunt than zero rake. See Rake
NEUTRAL RAKE: A rake angle of zero degrees. This angle is perpendicular to the surface of the work and neither positive or negative. See Rake.
NOSE: The corner angle formed by joining the side and end cutting edges of a tool.
NOSE RADIUS: The radius on the tool between the end and side cutting edges.
PIN-TYPE-INSERT: An indexable cemented-carbide cutting-tool insert with a hole in the center used to locate the insert and clamp it in place by means of a pin in the tool holder. The need for a top clamp is thus avoided.
POCKET: See Insert Pocket.
POSITIVE RAKE: A rake angle that is keener or more acute than zero rake. See Rake.
PRECISION INSERT: An insert (Code G in the third position) that is ground on all surfaces to specified dimension plus or minus 0.0012 inch on the cutting point and plus or minus 0.005 inch on the thickness. See Super Precision Insert.
PREHONED: Machined honed to a uniform size by the insert manufacture. See Honing.
RAKE: The angle of inclination between the face of the cutting tool and the work. If the face of the tool lies in a plane through the axis of the work (on a round workpiece), the tool is said to have zero, or neutral, rake. If the inclination of the tool face makes the cutting edge keener or more acute than when the rake angle is zero, the rake is defined as positive. If the inclination of the tool face makes the cutting edge less keen or more blunt than when the rake angle is zero, the rake is defined as negative. See Back Rake, Side Rake.
RAKE FACE: See Face.
RELIEF: The clearance angle behind or below the cutting edge, allowing the cutting edge to be forced into the work. It is sometimes divided into primary relief (adjacent to the cutting edge) and secondary relief (beyond the primary relief.) Depends on both the clearance angle of the insert and the insert attitude in the tool holder.
SEAT (ANVIL, SHIM): A removable part of a tool holder, designed to support the cutting insert.  See Anvil, Insert Package.
SFM (SURFACE FEET PER MINUTE): Peripheral velocity of the workpiece at cutting radius. See Cutting Speed.
SIDE CUTTING EDGE ANGLE LEAD ANGLE, ATTACK ANGLE): The angle between the side cutting edge and the projected side of the shank or holder. See Lead Angle.
SIDE RAKE: The inclination of the face of the tool away from the side cutting edge. It is measured in a plane perpendicular to the top plane of the cutting edge. See Rake.
SIDE RELIEF ANGLE: The angle between the side flank immediately below the side cutting edge and a line drawn through the side cutting edge perpendicular to the base.
SPEED (CUTTING SPEED, SURFACE SPEED): See Cutting Speed.
SUPERPRECISION INSERT: An insert ground on all surfaces to closer tolerance than a precision insert. There are several classes of super precision inserts with tolerances on the nominal point dimension ranging from plus or minus 0.0002 inch to plus or minus 0.001 inch and, on thickness dimensions from plus or minus 0.001 inch to plus or minus 0.005 inch.
TOOLHOLDER: A tool component that mechanically holds the insert and that, in turn, is mechanically affixed to a tool-carrying component of the machine tool, such as a turret. Loosely, a tool-shank for insert type lathe tooling.
TOP RAKE (BACK RAKE): The angle of inclination of the tool face away from the end cutting edge. It is measured in a plane perpendicular to the base of the tool and parallel to the side cutting edge. See Rake.
TRANSVERSE RUPTURE STRENGTH: Breaking strength of a material in a standard bending test. Measured in pounds per square inch (psi) in the U.S. Generally used as an indication of the toughness of a cutting-tool material although certain limitations exist. For example, the test is static and may not provide a good prediction of performance in a dynamic cutting mode.
UTILITY INSERT: An insert (Code U in the third position) ground on the top and bottom surface only, with a common tolerance of plus or minus 0.005 inch.
WEAR LAND: A flat area worn on the relieved flank face of the insert, below or behind the cutting edge. The depth of wear affects size and finish, and the width of the wear land is a good indicator for comparing insert performance or for determining the proper time to change or index the tool. See Abrasive Wear, Flank Wear.
WORKING ANGLE: Those angles between tool and work that depend not only on the shape of the insert but also on its position with respect to the work as determined by the tool holder.
ZERO RAKE (NEUTRAL RAKE): See Rake.

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Last modified: October 02, 2001