Due to the use of a numerical control system and a servo system, the feed accuracy of the left and right grinding wheels can reach 1 μm during the machining process, which makes the machining accuracy of the machine tool very high. At the same time, since the amount of fast forward, rough grinding, and fine grinding are all controlled by the program during the processing, the repeatability of the same batch of workpiece dimensions is improved, so the processed products have good dimensional dispersion and ensure the stability of processing quality . CNC vertical grinders are modified by adding grinding heads to existing machine tools such as lathes and planers at that time. They have simple structure, low rigidity, and vibrations during grinding. Operators must have high skills to grind. A precise workpiece. The workpiece is clamped on the worktable or installed on the electromagnetic worktable by electromagnetic attraction, and the surface of the workpiece is ground with the periphery or end face of the grinding wheel. It can grind cylindrical and conical inner hole surface. Ordinary grinders are only suitable for single piece and small batch production. Automatic and semi-automatic internal grinders can perform automatic measurement in processing in addition to the work cycle, and are mostly used in mass production.