Graduating Machine

a machine used for marking lines (gradations) on rulers, scales, and reticules. Longitudinal, circular, and special scales may be cut with discrete linear or angular displacement of the article on which the scale is being marked and with rectilinear displacement of the stylus. There are manual, semiautomatic, and automatic types of graduating machines.

Longitudinal graduating machines are designed to cut uniform scales 100-2,000 mm long; on circular machines, graduation is performed for diameters of 250-1,000 mm. Sper cial graduating machines inscribe divisions according to logarithmic, trigonometric, and other functions on plane or cylindrical surfaces. They usually operate on the principle of comparison of reference scales.

Graduating machines are ranked in four accuracy classes, depending on the error when inscribing divisions. Machines of the first class (the most accurate) can cut up to 3,600 divisions per meter with an error of 1 percent for linear scales and 0.1” for circular scales. Machines in the second to fourth classes have larger errors, for example, 1-5 percent and 10’, respectively, for linear and circular scales in the second class. Particularly accurate graduating machines exist in which the workpiece is positioned with respect to the stylus by means of a photoelectric microscope according to the gradations on a standard scale.

Graduating machines have devices to correct for errors. The error of such machines is ±0.1 micron per gradation. Such machines are mounted on a vibration-insulating foundation in a booth where the temperature is maintained at 20° ± 0.05°C. The machines operate automatically in the booth under constant temperature conditions.