In the future, the development trend of CNC industry will be in the direction of "better service for customer technology". CNC machine tools include but are not limited to high precision, fast speed and high efficiency. At the same time, they should also develop to green manufacturing, flexible manufacturing, information technology, production words and so on. However, all changes are inseparable. The operation technology is the soul of CNC machine tool industry.

　　The principle and usage of point by point comparison interpolation method for CNC machine tools are as follows:

　　After a pulse is given in X or Y coordinate direction, a pulse equivalent displacement of the machining point is generated along the corresponding direction, and then the position of the new machining point and the required curve are compared. Then, according to the deviation of the table of NC machine tool, the direction of the next step should be determined, so as to reduce the deviation distance and reduce the error of the actual processing curve and the required processing curve.

　　① The working beat of CNC machine tool is to judge the deviation position of machining point from the specified curve and determine the feed direction.

　　② According to the result of deviation judgment, the tool is controlled to feed a part relative to the workpiece contour to approach the given contour, so as to reduce the deviation.

　　③ The new machining point is calculated, and the fixed curve deviation is used as the basis for the next deviation judgment.