Multipurpose shaft parts are one of the more commonly used typical parts. It is mainly used to support transmission parts, transmit torque and bear loads. Shaft parts are rotating body parts, whose length is greater than the diameter, and are generally composed of the outer cylindrical surface, conical surface, inner hole, thread and corresponding end surface of the concentric shaft. According to different structural shapes, shaft parts can be divided into optical shaft, stepped shaft, hollow shaft and crankshaft. Shafts with an aspect ratio less than 5 are called short shafts, those greater than 20 are called slender shafts, and most shafts are in between.