Glossary

Electromagnetic, nondestructive testing method in which eddy-current flow is induced in the test object. Detects changes in flow caused by variations in the object.

Gage mounted in the spindle of a vertical mill and used, while rotating, to find the center of a part relative to the toolholder.

Conditioning of the cutting edge, such as a honing or chamfering, to make it stronger and less susceptible to chipping. A chamfer is a bevel on the tool’s cutting edge; the angle is measured from the cutting face downward and generally varies from 25° to 45°. Honing is the process of rounding or blunting the cutting edge with abrasives, either manually or mechanically.

Hand, gripper, toolholder, magnet, spray gun, drill, welding head or other electronic/mechanical device for holding workpieces and/or performing functions.

Maximum stress that a material can sustain without deforming.

Property of a material to deform under stress and recover its original shape and dimensions after release of stress.

Process similar to conventional electrical-discharge machining except a grinding-wheel type of electrode is used. See EDM, electrical-discharge machining.

Process that vaporizes conductive materials by controlled application of pulsed electrical current that flows between a workpiece and electrode (tool) in a dielectric fluid. Permits machining shapes to tight accuracies without the internal stresses conventional machining often generates. Useful in diemaking.

Variation on electrochemical machining designed to remove burrs and impart small radii to corners. The process normally uses a specially shaped electrode to carefully control the process to a specific area. The process works on material regardless of hardness.

Variation on electrochemical machining that uses a conductive, rotating abrasive wheel. Chemical solution is forced between the wheel and the workpiece. Shape of the wheel determines the final shape.

Operation in which electrical current flows between a workpiece and conductive tool through an electrolyte. Initiates a chemical reaction that dissolves metal from the workpiece at a controlled rate. Unlike with traditional cutting methods, workpiece hardness is not a factor, making ECM suitable for difficult-to-machine materials. Takes such forms as electrochemical grinding, electrochemical honing and electrochemical turning.

Combination of electrochemical grinding and electrical-discharge machining. Material is removed by both processes. The workpiece and the grinding wheel never come into contact as in any other electrical-discharge-machining process. See EDG, electrical-discharge grinding.

In tensile testing, the increase in the gage length, measured after fracture of the specimen within the gage length, usually expressed as a percentage of the original gage length.

Reduction in the normal ductility of a metal due to a physical or chemical change. Examples include blue brittleness, hydrogen embrittlement and temper brittleness.

Suspension of one liquid in another, such as oil in water.

Milling cutter held by its shank that cuts on its periphery and, if so configured, on its free end. Takes a variety of shapes (single- and double-end, roughing, ballnose and cup-end) and sizes (stub, medium, long and extra-long). Also comes with differing numbers of flutes.

Operation in which the cutter is mounted on the machine’s spindle rather than on an arbor. Commonly associated with facing operations on a milling machine.

Limit below which a material will not fail.

1. Isothermal reversible reaction in which a liquid solution is converted into two or more intimately mixed solids on cooling, the number of solids formed being the same as the number of components in the system. 2. Alloy having the composition indicated by the eutectic point on an equilibrium diagram. 3. Alloy structure of intermixed solid constituents formed by the eutectic reaction.

Cutting-fluid additives (chlorine, sulfur or phosphorus compounds) that chemically react with the workpiece material to minimize chipwelding. Good for high-speed machining. See cutting fluid.

Conversion of an ingot or billet into lengths of uniform cross section by forcing metal to flow plastically through a die orifice.