The high-speed and high-precision motorized spindle is the future development trend of the CNC machine tool field, and has become the focus of research in the world. High-speed motorized spindles tend to develop in the direction of high precision, high speed, low energy consumption, high efficiency, and high reliability. We undertake a through, systematic review of the development history perspective of the research on precision bearing technology, dynamic balancing technology, thermal error measurement and compensation technology with regard to the key technologies of high-speed motorized spindles. On this basis, the current level of development of key technologies for high-speed motorized spindles is analyzed, and the objective advantages and disadvantages of existing technologies are summarized. Finally, the development tendency of high-speed motorized spindle technology is predicted and foreseen.

The internal structure of a high-speed motorized spindle is compact, and a large amount of heat is generated in the process of high-speed operation, which causes thermal deformation of the parts. The thermal characteristics of the motorized spindle become worse when the temperature increases, which seriously affects its machining accuracy. It is difficult to avoid the thermal error of motorized spindle and it accounts for a large proportion of the total error. How to restrain the thermal elongation of motorized spindle and establish an accurate thermal error model is particularly important. This paper reviews the methods of thermal error prevention and thermal error modeling compensation for the motorized spindle. By introducing several methods of thermal error suppression, optimization of temperature measurement points, and thermal error modeling theory, analyzes and discusses the advantages and disadvantages of various methods. Finally, prospects the future development of thermal error research of motorized spindle.

Background: While the CNC (Computerised Numerical Control) machine spindle is driving the tool to cut the workpiece, impurities such as cutting fluid splash, metal chips, or metal dust tend to enter the internal system of the spindle. Optimization of the spindle sealing design can significantly improve the durability of the motorized spindle. A high-speed motorized spindle is the primary heat source of CNC machine tools. Under current conditions, a cooling and lubrication system is the main measure to control the heat of a high-speed motorized spindle. Objectives: This paper introduces the current research progress in bearing lubrication and new spindle sealing structures. Methods: The research on bearing lubrication is sorted by comparing the relevant literature on bearing lubrication; some sealing structures are introduced by giving examples of patents on motorized spindle seals. Results: This paper reviews the bearing lubrication research and spindle sealing structure and provides an outlook on the future development of bearing lubrication technology and spindle sealing structure. Conclusion: The High-speed motorized spindle is the primary heat source of CNC machine tools. Bearing lubrication can effectively control the motorized spindle heat; a motorized spindle sealing structure can prevent impurities from causing damage to the internal parts of the spindle and improve the service life of the motorized spindle.