Glossary Terms

In grinding, the wheel’s tendency to accumulate workpiece material between its abrasive points. In milling, drilling and other operations, excessive packing of chips in cutter flutes or at cutter edge.

CNC feature that evaluates many data blocks ahead of the cutting tool’s location to adjust the machining parameters to prevent gouges. This occurs when the feed rate is too high to stop the cutting tool within the required distance, resulting in an overshoot of the tool’s projected path.

Investment-casting process in which a wax pattern is used.

Group of carbon steels designated by American Iron and Steel Institute numerical classification as AISI 1005, 1006, 1008, etc., up to AISI 1026, for a total of 16 grades. They are softer and more ductile than other carbon steels.

Substance that reduces friction between moving machine parts. Can be liquid (hydrocarbon oil), solid (grease) or gaseous (air). Important characteristics are to prevent metal-to-metal contact between moving surfaces, be a cooling medium, aid chip removal and protect surfaces from rust and corrosion.

Measure of the relative efficiency with which a cutting fluid or lubricant reduces friction between surfaces.

Miscellaneous, or auxiliary, functions constitute on/off type commands. Used to control actions such as starting and stopping of motors, turning coolant on and off, changing tools, and clamping and unclamping workpieces.

The relative ease of machining metals and alloys.

A relative measure of the machinability of a metallic work material under specified standard conditions. Machinability rating is expressed in percents, with the assumption that the machinability rating of AISI 1212 free-machining steel is 100 percent.

Process of giving a workpiece a new configuration by cutting or shaping it. Typically performed on a machine tool or machining center. Includes cutting and shaping all kinds of materials, not just metals. Generally associated with precision and high-quality fit. See metalcutting, material cutting; metalforming; metalworking.

CNC machine tool capable of drilling, reaming, tapping, milling and boring. Normally comes with an automatic toolchanger. See automatic toolchanger.

Workholding device used on surface grinders and milling machines for holding ferrous parts with large, flat sides. Holding power may be provided by permanent magnets or by an electromagnetic system. See chuck.