The study presents a method to improve the working accuracy of a numerically controlled machine tool by use of a minicomputer. The geometrical error of the machine tool is expressed as the polynominal of the third order of the coordinates from the measured data of the geometrical form of the master part fixed on the machine tool. Numerical control commands are modified on the basis of the general solution obtained in the study by the computer so as to compensate the geometrical error predicted by the error function. Experimental results by boring and end-milling on two different machining centers indicate the considerable improvement of the working accuracy.
