There are many kinds of machine tool parts, which can be divided into: shaft parts, gear parts, machine tool guides, etc. according to structural characteristics, functions and load characteristics.
Selection of machine tool shaft parts
The machine tool spindle is the most important shaft part in the machine tool. The working conditions of the spindle are different depending on the type of machine. According to the size and type of the load when the spindle is working, it can be roughly divided into four categories: (1) light load spindle. The working load is small, the impact load is not large, and the shaft neck wear is not serious, such as the main shaft of a general lathe. These shafts are generally made of 45 steel, which are tempered or normalized, and are hardened by high-frequency surface quenching in areas where wear resistance is required. (2) Medium load spindle. Medium load, severe wear and a certain impact load, such as milling machine spindle. Generally made of alloy quenched and tempered steel, such as 40Cr steel, after quenching and tempering treatment, it is required to be surface hardened and strengthened. (3) Heavy duty spindle. The working load is large, and the wear and impact are serious, such as the combined machine tool spindle with large working load. It is generally made of 20CrMnTi steel and treated by carburizing and quenching. (4) High precision spindle. Some machine tool spindles do not have a large working load, but the precision requirements are very high, and the deformation after heat treatment should be extremely small. Wear should be minimal during operation, such as the spindle of a precision boring machine. It is generally made of 38CrMoAlA special nitrided steel. After quenching and tempering treatment, it is nitrided and dimensionally stabilized. In the past, almost all of the spindles were made of steel, and light-duty and medium-load spindles were already made of ductile iron.
Selection of machine tool gear Mechanical Parts

Machine tool gears are divided into three categories according to working conditions: (1) light-duty gears. The rotation speed is generally not high, and it is mostly made of 45 steel, which is treated by normalizing or quenching and tempering. (2) Medium duty gear. It is generally made of 45 steel. After normalizing or quenching and tempering, high-frequency surface hardening is strengthened to improve the bearing capacity and wear resistance of the gear. For large-size gears, it is necessary to use alloyed and tempered steel such as 40Cr. Most of the gears in the drive system and the feed system are mostly in this category. (3) Heavy duty gears. For some working loads, especially those with high running speed and large impact loads, most of them are made of 20Cr, 20CrMnTi and other carburized steel. After carburizing and quenching treatment. For example: some important transmission gears in the gearbox.
Machine tool guide material selection
The accuracy of the machine guide rail has a great influence on the accuracy of the entire machine. It must be prevented from deformation and wear, so the machine guide rails are usually made of gray cast iron, such as HT200 and HT350. Gray cast iron has good wear resistance under lubricating conditions, but its anti-wear particle wear ability is poor. In order to improve the wear resistance, the surface of the guide rail can be quenched.