In industrial products, shaft parts are suitable for the maintenance of one or more NC machine tools. They are used to support transmission parts such as gears and pulleys in machines to transmit torque or motion. Shaft parts are rotating parts, whose length is larger than the diameter. They are generally composed of the outer cylindrical surface, conical surface, inner hole, thread and corresponding end face of the concentric shaft. The shaft whose aspect ratio is less than 5 is called a short shaft, and the shaft whose aspect ratio is greater than 20 is called a slender shaft. Most of the shafts are in between.