The basic conceptual deviation of CNC parts processing is caused by the use of similar processing motion modes or similar CNC knives. It is usually called the basic concept deviation of processing, because there are deviations in the basic concepts of processing. If the basic conceptual deviation is within the allowable range, such treatment methods are still feasible. Production processing deviation, installation deviation, and damage in the use of CNC lathes will immediately harm the precision of the processing of commodity workpieces. Among them, the rotating fitness exercise of important organic tool spindle, the uniform straight line fitness exercise of the machine tool guide rail, and the deviation of the transmission gear of the transmission system of the CNC lathe. CNC processing accurate positioning deviations include incorrect deviations and precise positioning side production processing deviations. When processing commodity workpieces on CNC lathes, try to choose many graphics characteristics on the commodity workpiece as a precise positioning specification in the production process. If the selected accurate positioning reference is inconsistent with the design reference of the scheme, the reference will not be deviated. The precise positioning surface of the commodity workpiece and the precise positioning electronic devices of the fixture work together cause accurate positioning pairs. Due to the inadequate positioning and processing processing of accurate positioning and the accurate positioning, the large position changes in the commodity workpiece caused by the mutual cooperation between the vice -positive gaps are called accurate positioning and the production processing is not accurate deviation. The non -precise production and processing deviation of accurate positioning sideline has always appeared during the return analysis method, and it is not easy to occur during the semi -compensation method processing.