Glossary Terms

Robot designed for industrial use. Primarily used as a material-handling device but also used for changing tools, assembling parts, and manipulating special tools and measuring devices. Depending on design, an industrial robot can be programmed to perform a task by means of a controller, or it can be “walked” through the required movements by utilizing a digitizing system that translates movements into commands that the robot can be “taught.” See robot; teaching pendant.

Dimension that defines the inside diameter of a cavity or hole. See OD, outer diameter.

Imaginary circle that touches all sides of an insert. Used to establish size. Measurements are in fractions of an inch and describe the diameter of the circle.

Process of physically checking a part or product to ensure that it meets specific, predetermined dimensions. Because errors can be caused by out-of-tolerance measuring instruments as well as out-of-spec parts, it is important to periodically check the measuring tools for accuracy. See calibration.

Parts and components produced to specified tolerances, permitting them to be substituted for one another. Essential to mass production, permitting the high-volume output that results in economies of scale. Less critical to operating costs in computer-integrated manufacturing operations but facilitates maintenance and repair. See CIM, computer-integrated manufacturing; modular design, construction.

Process of generating a sufficient number of positioning commands for the servomotors driving the machine tool so the path of the tool closely approximates the ideal path. See CNC, computer numerical control; NC, numerical control.

Cutting tool repeatedly enters and exits the work. Subjects tool to shock loading, making tool toughness, impact strength and flexibility vital. Closely associated with milling operations. See shock loading.

1. Casting metal into a mold produced by surrounding (investing) an expandable pattern with a refractory slurry that sets at room temperature, after which the wax, plastic or frozen-mercury pattern is removed through the use of heat. Also called precision casting or lost-wax process. 2. Part made by the investment-casting process.

Surface-hardening process in which nitrogen ions are accelerated under an electric potential in a closed chamber and become embedded in the surface of the parts being treated, where they interact with minor constituents of the treated metal to form nitrogen compounds.

Impact test in which a V-notched specimen, fixed at one end, is subjected to a sudden blow delivered by the weight at the end of a pendulum arm. The energy required to break off the free end is a measure of the impact strength or toughness of the material. See Charpy test.

Tooling usually considered to be a stationary apparatus. A jig assists in the assembly or manufacture of a part or device. It holds the workpiece while guiding the cutting tool with a bushing. A jig used in subassembly or final assembly might provide assembly aids such as alignments and adjustments. See fixture.

High-precision machining (a sophisticated form of milling) that originally pertained to jig and fixture manufacturing. Basic jig-boring processes include centering, drilling, reaming, through and step boring, counterboring and contouring.