Abstract: The ratio of executed to skipped measurement movement commands required for actual measurement and a correction value when skipping a measurement movement command are determined and then updated according to past (hysteresis) measurement data. The actual thermal displacement measurement during an executed measurement movement command is performed at a proper rate to improve the machining efficiency of an NC machine tool and minimize an error due to the correction.

Abstract: A numerical control device can perform machining processes in a short time while maintaining high precision, regardless of the order at which programs are commanded. Consecutive blocks of a numerical control program are retrieved on a block-by-block basis, and a pre-execution in-position value and a post-execution in-position value for each of the blocks of the numerical control program are set and stored in a ROM. The block of the numerical control program is executed in accordance with at least one of the corresponding pre-execution in-position value and the post-execution in-position value.

Abstract: A machine tool includes a spindle head (4) movable in a predetermined direction, a spindle (9) attached to the spindle head (4) for undergoing machining of a workpiece, a column (3) supporting the spindle head (4), the column (3) being movable over a predetermined plane (X-Y plane) perpendicular to the predetermined direction so that the spindle head (4) is movable over a plurality of machining regions (22L, 22R), a plurality of palettes (23L, 23R) each detachably mounting the workpiece and movable into and away from its associated machining region, and a table (13) mounting the plurality of palettes (23L, 23R) thereon. In one aspect of the invention, an external operation box (101) is provided from which a selected program number is entered and is impressed on an input port of a CPU (100). The CPU (100) calls a machining program identified by the selected program number to thus perform machining of the palette loaded on the associated machining region.

Abstract: A method for preparing numerical control data for a machine tool by displaying various kinds of operation information on a display for causing data necessary for preparing the numerical control data to be inputted and by inputting the data in accordance with the displayed information, comprising the steps of selecting a working operation input screen for inputting working operations in accordance with first indications on the display, inputting working operations at the selected working operation input screen, selecting a working program input screen for inputting working programs, and inputting data in accordance with second indications of input items required for working operations, the second indications being displayed on the display by reading inputted working operations. As a result, a series of working programs are inputted to prepare the numerical control data.