Glossary of Technical Terms 611
electrohydraulic forming: A type of high-
energy-rate forming in which a high-voltage
discharge from a capacitor bank vaporizes
an initiation wire and surrounding wire. The
gases formed during the vaporization expand
rapidly, applying pressure to the outer
surface of the workpiece and forcing into
a die. Also known as “capacitor discharge
forming” and “spark forming.” (Ch. 33)
electrolytic grinding: A form of
electrochemical machining where electric
current is passed between a metal bonded
grinding wheel (the cathode) and the work
(the anode) through an electrolyte to dissolve
the work. The dissolved material is removed
by the grinding wheel. (Ch. 20)
electromachining: A category of machining
processes in which electrical current is used
to remove material through erosion rather
than direct physical contact. (Ch. 31)
electron beam machining (EBM): A process
that uses a high-energy, highly focused beam
of electrons to weld or cut materials. (Ch. 32)
electroplating: A process in which a layer
of one metal is deposited on the surface of
another metal by the use of an electrical
current. (Ch. 30)
emulsifiable oil: Cutting fl uid composed of
oil droplets that are suspended in water by
blending the oil with emulsifying agents and
other materials. Provides increased cooling
capacity over straight cutting oils with
reduced misting and fogging. (Ch. 10)
encoder: A transducer in the motor that drives
a CNC axis that measures the position of the
moving axis and provides electronic feedback
to the controller. (Ch. 22)
engineer: A trained professional who uses
applied mathematics, science, and knowledge
of manufacturing to design industrial
products and processes. (Ch. 2)
etchant: The fl uid used to erode material in a
chemical machining process. Usually a strong
aqueous alkaline solution. (Ch. 32)
explosive forming: A type of high-energy-rate
forming in which the material is shaped by
pressure resulting from the detonation of an
explosive charge. The workpiece, die, and
explosive charge are submerged in water,
which distributes the force of the blast evenly
over the outer surface of the workpiece.
(Ch. 33)
external thread: A screw thread cut on an
outside surface. (Ch. 16)
F
face milling: Machining large, fl at surfaces
parallel to the cutter face. (Ch. 18)
facing: In lathe work, cutting across the end of
a workpiece to create a fl at surface. (Ch. 14)
fastener: Any device used to hold two objects
or parts together, such as bolts, nuts, screws,
pins, keys, rivets, and chemical bonding
agents or adhesives. (Ch. 8)
feature: A general term applied to a physical
portion of a part. (Ch. 4)
feature control frame: A symbol used
to defi ne the geometric tolerancing
characteristics of a feature. It contains the
geometric characteristic symbol, allowable
tolerance, and datum reference letter(s).
(Ch. 4)
feed: The rate at which work moves into the
cutter or the cutter moves into the work.
(Ch. 12, 14, 18)
ferrous: Containing iron. (Ch. 28)
file band: A band machine accessory used to
obtain a smooth, uniformly fi nished surface.
A series of small fi le segments make up the
fi le band. The segments interlock to form a
continuous fi le. (Ch. 21)