Machining Fundamentals 614
incremental positioning: A programming
mode, indicated by the G91 code, in which
the coordinate values for any point are
interpreted relative to the location of the
previous point. (Ch. 23)
indexable insert cutting tool: Widely used for
turning and milling operations, the inserts are
manufactured in a number of shapes and sizes
for different turning geometries. As an edge
dulls, the next edge is rotated into position
until all edges are dulled; the inserts are then
discarded. (Ch. 14)
internal grinding: A cutting operation done to
secure a fi ne surface fi nish and accuracy on
inside diameters. Work is mounted in a chuck
and rotated. During the grinding operation,
the revolving grinding wheel moves in and
out of the hole. (Ch. 20)
internal thread: A screw thread cut on the
inside surface of a piece. Internal threads are
made on the lathe with a conventional boring
bar and a cutting tool sharpened to the proper
shape. (Ch. 16)
International System of Units (SI): The
metric system of weights and measures.
Abbreviated SI (Systeme International). Also
called the SI Metric system. (Ch. 5)
J
jig: A device that guides a cutting tool
and aligns it to the workpiece so that all
parts produced are uniform and within
specifi cations. (Ch. 9)
job shop: A machine shop where specialized
or experimental work is machined or where
the production runs are very small. (Ch. 2)
just-in-time (JIT) inventory system: An
inventory management system in which
parts and materials are scheduled for arrival
at the time needed and not before. (Ch. 26)
K
key: A small piece of metal embedded partially
in the shaft and partially in the hub to
prevent rotation of the gear or pulley on the
shaft. (Ch. 8)
keyway: The slot or recess in a shaft that holds
the key. (Ch. 17)
knife-edge blade: A vertical band machine
tool used to cut material that would tear or
fray if machined by a conventional blade.
Such materials include sponge rubber, cork,
cloth, corrugated cardboard, and rubber. (Ch.
21)
knurling: The process of impressing diamond
or straight-line patterns onto a metal surface
by rolling with pressure to improve the
appearance and provide better grip. The rolls
are called knurls. (Ch. 15)
L
Laminated Object Manufacturing (LOM):
A rapid prototyping technique that uses
progressive layers of inexpensive solid sheet
material, each layer bonded to the previous
layer, to form the model. (Ch. 26)
laser: A device that produces a narrow and
intense beam of light. Stands for Light
Amplifi cation by Stimulated Emission of
Radiation. (Ch. 32)
lathe: A machine in which a workpiece in
a work-holding device is rotated while a
stationary cutting tool is forced against
it. Some operations performed on a lathe
include turning, boring, facing, thread
cutting, drilling, and reaming. (Ch. 1)
lathe center: A pointed work-holding device
used to accurately align the workpiece along
an axis. More frequently referred to as a
center. (Ch. 14)