What makes ball screws, used in high-end equipment, so superior?
Jan 07, 2026
In high-end equipment such as nanoscale focusing servo systems for semiconductor lithography machines, precision drive chains for industrial robot joints, and high-speed assembly platforms for new energy vehicle battery modules, ball screws serve as core transmission and execution components, undertaking crucial functions of motion conversion and positioning control. From five-axis CNC machine tools to aerospace attitude adjustment mechanisms, from precision medical imaging equipment to high-end intelligent manufacturing production lines, all high-end equipment with stringent requirements for transmission accuracy, dynamic response, and reliability uses ball screws as its core transmission solution. This article systematically analyzes the core technological advantages of ball screws and their suitability in high-end equipment, starting from their technical principles and engineering characteristics.
The core technological advantage of ball screws stems from their innovative transmission principle. Compared to the surface contact sliding friction transmission of traditional sliding screws, ball screws employ a rolling friction transmission mechanism: high-precision balls are embedded as the transmission medium in the closed loop formed by the screw helical raceway and the nut raceway, converting the relative sliding between the screw and the nut into the rolling motion of the balls.
Based on this innovation in the rolling friction principle, ball screws primarily possess highly efficient transmission characteristics. From the perspective of transmission efficiency, the mechanical transmission efficiency η of ball screws can reach 90%~98%, while that of ordinary sliding screws is only 20%~40%. According to the power balance equation, under the condition of constant load F and transmission stroke s, the driving torque M is inversely proportional to the transmission efficiency η. Therefore, using ball screws can reduce the output torque requirement of the drive motor to less than 1/3 of that of sliding screws. This characteristic not only significantly improves energy utilization efficiency, but more importantly, it reduces the heat generation power of the transmission system. For high-end equipment, thermal deformation of the transmission system is one of the core error sources affecting positioning accuracy. Low heat generation can effectively control the thermal elongation of the screw, ensuring the temperature stability of the equipment during long-term continuous operation, providing a fundamental guarantee for high-precision control.
Precision positioning performance is the core technical indicator for ball screws to adapt to high-end equipment, and it is also a key advantage that distinguishes them from ordinary transmission components. In the field of high-end manufacturing, positioning accuracy and repeatability directly determine the processing/operation quality of equipment. For example, the wafer alignment accuracy requirement of semiconductor lithography machines is ≤±5nm, and the positioning accuracy requirement of five-axis CNC machine tools is ≤±1μm. Ball screws ensure precise positioning through three core technologies: first, high-precision helical raceway grinding technology, using ultra-precision grinding machines to achieve a raceway profile error ≤0.001mm; second, preload technology (such as double-nut washer preload and single-nut variable lead preload), eliminating axial backlash and generating a slight interference to achieve zero backlash in reverse transmission; and third, low-heat design, combined with a temperature control system to suppress thermal deformation.
High rigidity and long lifespan are core engineering characteristics that allow ball screws to adapt to the harsh operating conditions of high-end equipment. The transmission systems of high-end equipment often face harsh conditions such as heavy loads (e.g., clamping forces in all-electric injection molding machines can reach thousands of kN), high-frequency start-stop (e.g., joint movement frequencies of industrial robots ≥10Hz), and impact loads, placing extremely high demands on the rigidity of transmission components. Ball screws, through preload design, achieve negative axial clearance (interference fit). Utilizing the elastic deformation of the balls to generate preload force, axial stiffness can be increased by more than three times. Compared to sliding screws, deflection under the same load can be reduced by more than 60%, ensuring stable motion accuracy under heavy load conditions.
From a lifespan perspective, the low wear characteristics of rolling friction make the fatigue life of ball screws significantly superior to that of sliding screws. Using high-quality materials such as GCr15 bearing steel, combined with carburizing and quenching (surface hardness HRC≥60), ultra-precision grinding, and a labyrinth seal + grease lubrication system, wear and impurity intrusion can be effectively suppressed. According to the life calculation model of ISO 3408 standard, under rated dynamic load, the rated life (L10) of a ball screw can reach millions of cycles, which is 5 to 10 times that of a conventional sliding screw. Engineering test data shows that ball screws with optimized preload parameters can extend their continuous service life from 30,000 hours to 50,000 hours under 80% rated load, significantly reducing maintenance downtime and spare parts replacement costs for high-end equipment and improving overall equipment efficiency (OEE).
High-speed response and flexible adaptability are key characteristics of ball screws for meeting the dynamic control requirements of high-end equipment. In terms of high-speed performance, the DN value (shaft diameter d × speed n) of ball screws can exceed 140,000, far exceeding the upper limit of the DN value for sliding screws (≤50,000). Combined with a high-speed ball circulation structure (such as an internal circulation reverser type), high-speed transmission with a maximum speed ≥3000 rpm can be achieved. In servo control systems, the synergistic effect of low friction coefficient and high rigidity can shorten the system's step response time to the millisecond level, improving dynamic tracking accuracy. In engineering applications, the welding equipment for new energy vehicle battery packs utilizes lightweight ball screws (carbon fiber composite nuts) and dynamic preload compensation technology, reducing acceleration time from 0.2s to 0.08s, increasing production line cycle time by 50%, and raising daily capacity from 1200 sets to 1800 sets. Humanoid robot joints employ small-lead, high-precision ball screws, achieving an angular velocity of 1.5 rad/s and a repeatability of 0.01° under a 20kg load, meeting the requirements of multi-degree-of-freedom collaborative control.
The flexibility of the structural design allows the ball screws to adapt to the installation and operating conditions of various high-end equipment. Classified by ball recirculation method, external recirculation (insertion type, end cap type) is suitable for large lead and high-speed scenarios, while internal recirculation (reversing type) has the advantages of compact structure and stable operation, and can adapt to narrow installation spaces. In terms of materials and surface treatment, stainless steel (SUS440C) with hard chrome coating can be used for corrosive conditions, Inconel alloy with aluminum nitride coating can be used for high-temperature conditions, and carbon fiber reinforced composite nuts can be used for lightweight requirements, reducing weight by more than 50% compared to steel nuts. Furthermore, by customizing the lead (e.g., micro-lead ≤1mm, large lead ≥20mm), thread direction (left-hand, right-hand, bidirectional), and installation method (fixed-fixed, fixed-floating), precise adaptation to high-end equipment transmission systems can be achieved, improving system integration efficiency.
With the development of intelligent manufacturing technology, ball screws are evolving towards integration and intelligence, becoming a core component of intelligent transmission systems. By incorporating built-in temperature, vibration, and displacement sensors, data such as temperature, vibration amplitude, and positioning error during the transmission process can be collected in real time. Combined with an industrial internet platform, this enables status monitoring and fault early warning. Dynamic preload compensation technology based on AI algorithms can correct accuracy deviations caused by thermal deformation and wear in real time, further improving the stability of transmission accuracy. Regarding breakthroughs in domestic technology, domestically produced ball screws have achieved mass production with C0-level precision. Through the adoption of independently developed ultra-precision grinding processes and material formulations, they have successfully entered the supply chains of international high-end machine tool manufacturers such as AgieCharmilles (Switzerland) and DMG MORI (Germany), providing core transmission component support for the high-end transformation of Chinese manufacturing.
In summary, the technological advantages of ball screws stem from the fundamental innovation of their rolling friction transmission principle. Through the synergy of high-precision structural design, optimized material processes, and intelligent control technology, a multi-dimensional performance balance of high-efficiency transmission, precise positioning, high rigidity, long lifespan, and flexible adaptability is achieved, precisely matching the stringent requirements of high-end equipment for transmission systems.
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