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The concept and design of ball screws can be traced back to the late 19th and early 20th centuries. During the industrial revolution, with the development of the machinery industry, people's demand for linear motion became more and more urgent. Previously, a combination of a screw and nut was commonly used to achieve linear motion, but friction and imprecise properties limited the accuracy and efficiency of the system. In this context, the ball screw was proposed and developed. Ball screws utilize the rolling relationship between the balls and the screw, resulting in low friction and precise linear motion. In the design of the ball screw, the balls are arranged on the threaded track of the screw. When the screw rotates, the balls roll on the track, converting the rotary motion into linear motion. The introduction of the ball screw has greatly improved the performance of the linear transmission system, increasing the efficiency, stiffness and precision of the transmission. They are widely used in various fields, such as machine tools, robots, automated production equipment, stage lighting systems, printing machinery, etc., providing these systems with high precision, high speed and reliable linear motion. With the continuous advancement of science and technology and manufacturing technology, the design and manufacture of ball screw are also continuously improved and optimized. Modern ball screws have achieved higher load capacity, longer service life, higher stiffness and better reliability. They have become essential key elements in many mechanical systems, providing important support for industrial automation and production.

Trapezoidal screw: Pure sliding friction - brass (good self-lubrication) has a very low efficiency of 60%, a simple structure, low cost and no precision, large surface contact load, large starting resistance, resulting in creeping and creeping during ultra-low speed operation. Trapezoidal screws can be selected when there is no precision requirement, a large axial load is required, the budget is low and the cost needs to be reduced, the speed is low, and the occasion is not important. Ball screw: It realizes high-efficiency and low-friction transmission through rolling media, with an efficiency of more than 90%. Compared with surface contact, ball is point contact, with smaller load, higher precision and higher cost. The speed of the screw is limited, and it is best to control it within 1500rpm. If the screw is too long, it needs to be pressed down to within 1000rpm. Unit movement of the screw: lead (pitch, Pb) [Fixed seat]: Angular contact bearings are used in pairs to constrain the axial direction of the screw and are mainly used to bear the axial force of the screw [Support seat]: Deep groove ball bearings are used alone, purely to support the tail of the screw, so that it does not run around and can slide axially [Fixed + Support]: The most classic structure [Fixed + Free]: There is no way to put it, there is no place to install the support seat (short stroke, structural requirements), the speed cannot be too high, and the load should not be too large [Fixed + Fixed]: Not suitable for high-speed operation, heating will cause the screw to deform and get stuck, very good rigidity, high precision [Support + Support]: No precision, loose mechanism, small load, almost no requirements for motion performance---hand-cranked adjustment mechanism Nut structure of ball screw [External circulation]: Better high-speed performance, complex structure, higher cost [Internal circulation]: Slightly lower cost, more compact structure, easy to install Ball Screw precision C0 C1 .......C7 C10 ... The larger the number, the worse the accuracy and the lower the cost The screw rods of C7 and later are processed by extrusion molding --- rolled screw rods: high production efficiency----cheap, short delivery time The screw rods of C5 and earlier are processed by whirlwind milling + grinding --- ground screw rods: low production efficiency---very expensive, high accuracy The most used: C7 Ball Screw Preload Effectively prevent the nut seat from offsetting due to clearance when the load is large (improve the dynamic accuracy of large loads) Increases internal stress, greater resistance, and increased heat generation

Regular inspection and adjustment of the gap between the ball screw and the support seat is an important measure to ensure the accuracy, stability and life of mechanical equipment. The following are detailed steps and precautions: 1. Inspection steps Manual inspection Turn off the power of the equipment, rotate the screw manually, and feel whether there is abnormal resistance or looseness. Push and pull the screw axially to check whether there is obvious gap (usually the allowable axial clearance should be less than 0.01-0.05mm, refer to the equipment manual for details). Dial indicator measurement Fix the dial indicator near the support seat and the probe against the end face of the screw. Push and pull the screw axially and record the change in the dial indicator reading, which is the axial gap. If the gap exceeds the standard (such as exceeding the manufacturer's recommended value), it needs to be adjusted. Operation status inspection Run the equipment at a low speed to observe whether there is vibration, abnormal noise or positioning deviation. Use a vibration analyzer or stethoscope to assist in diagnosing abnormalities. 2. Adjustment method Adjust the preload of the support seat Angular contact bearing support seat: adjust the preload through the locking nut (refer to the manufacturer's torque value). Loosen the locking nut and tighten it gradually with a torque wrench, while turning the screw to ensure smoothness. Remeasure the gap after pre-tightening until it reaches the standard. Deep groove ball bearing support seat: If the gap is too large, you may need to replace the bearing or add a gasket. Replace worn parts If the gap is still too large after adjustment, check whether the bearing, screw nut or support seat is worn. Replace worn bearings or screw nuts (note to replace angular contact bearings in pairs). Calibrate parallelism and coaxiality Use a micrometer to check the parallelism of the screw and the guide rail (generally ≤0.02mm/m). If the mounting surface of the support seat is deformed, it needs to be reprocessed or corrected with a gasket. 3. Maintenance cycle and precautions Cycle recommendation Ordinary equipment: Check once every 3-6 months. High-precision/high-frequency equipment: monthly inspection or by running hours (such as 500 hours). New equipment needs to be re-tightened after 1 month of first operation. Key points Use the original factory specified grease to avoid mixing different greases. After adjustment, it is necessary to run the test without load, and then gradually load and verify. Record the data of each inspection to track the wear trend. Safety tips Be sure to turn off the power and release the system pressure before adjustment. Avoid excessive pre-tightening, otherwise it will cause the bearing to heat up and reduce its life. 4. Tools and consumables Necessary tools: dial indicator, torque wrench, feeler gauge, micrometer. Consumables: grease, seals, spare bearings (models must match). Through systematic inspection and adjustment, the transmission error can be effectively reduced and the service life of the ball screw system can be extended. If the problem is complex (such as screw bending), it is recommended to contact professional maintenance personnel. If you have any questions, please contact us. Any ball screw problem can be solved.

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.

The fundamental difference between ball screws and trapezoidal screws lies in their operating principles: ball screws rely on "rolling friction," whereas trapezoidal screws rely on "sliding friction." This underlying difference directly dictates the significant disparities in their performance, cost, and application scenarios. Core Performance Comparison Table Comparison Criteria Ball screw Trapezoidal lead screw Type of Friction Rolling friction (recirculating steel balls within the nut) Sliding friction (direct contact between thread surfaces) Transmission Efficiency Extremely high Relatively low Transmission Precision High (enables micron-level positioning and backlash elimination) Low to medium (inherent backlash, prone to wear) Self-locking Capability No self-locking capability (requires a brake for vertical applications) Typically self-locking (prevents sliding down when the lead angle is small) Operating Speed/Frequency Suitable for high-speed, high-frequency, continuous operation Suitable for low-speed, low-frequency, intermittent operation Service Life and Maintenance Long service life and minimal wear, but requires effective lubrication and dust protection Wears relatively quickly, but resistant to contamination, simple structure, low maintenance Operating Noise Low (primarily the sound of steel balls colliding) Low to medium (may produce noise during dry friction) Cost and Price High (precision manufacturing; high system cost) Low (simple structure, cost-effective) How do you choose the right type based on actual needs? In practical mechanical design or equipment selection, the choice can be made based on the following key criteria: 1. Scenarios for choosing "Ball Screws" High precision and high repeatability: e.g., CNC machine tools, laser cutting machines, semiconductor packaging equipment, automated robots, etc. High-frequency, continuous motion: Equipment operates uninterrupted for long periods daily, requiring high transmission efficiency and effective heat control. High-speed movement: Linear axes requiring rapid response and high-speed motor drive. 2. Scenarios for choosing "Trapezoidal Lead Screws" Limited budget/cost sensitivity: Low requirements for positioning accuracy (e.g., millimeter-level) and a focus on high cost-effectiveness. Need for vertical self-locking: e.g., hand-cranked lifting platforms, medical bed lifts, simple valve actuators, etc. The nut does not slide down on its own during power outages or when the motor is not holding torque (Note: large-lead trapezoidal screws may lose self-locking capability). Low-frequency, short-stroke use: e.g., adjustment mechanisms, manual positioning fixtures, or mechanisms that operate only occasionally. Harsh operating environments: In environments with high dust levels or a lack of regular lubrication and maintenance, trapezoidal screws (using engineering plastic or bronze nuts) offer greater tolerance.

In the fields of industrial automation and CNC machine tools, ball screws are the core transmission element that converts rotational motion into linear motion. Many people often make an intuitive mistake when selecting a screw: simply thinking that "the thicker the lead screw, the heavier things can be lifted." In fact, the "carrying capacity" of a ball screw is a comprehensive index determined by the force direction, static/dynamic mechanical limits, and system installation constraints. For specialized applications, such as a precision ball screw for medical device applications, understanding the load-bearing capacity of the screw rod is especially important. It is not only related to whether the mechanical structure can push and pull normally, but also directly determines the operating accuracy and service life of the equipment. Core force principle: only "push and pull" is allowed, "side attack" is strictly prohibited First of all, it is necessary to clarify the most fundamental force characteristics of the ball screw: it can only bear axial force. • Ideal state: All load forces are concentrated along the central axis of the screw (thrust or pull). • Physical taboos: The screw nut is extremely taboo against bearing radial forces or overturning moments. If the structure is improperly designed, allowing the screw to directly hang heavy objects or bear lateral cutting forces will cause the balls to be unevenly stressed in the raceway, leading to eccentric wear, vibration, and even the slide rail becoming stuck or broken in a short period of time. This is particularly important when using a customized 4005 non-standard ball screw, as its design should be matched to the specific load, installation conditions, and operating requirements of the equipment. Engineering standard practice: Linear guides or guide shafts must be configured in the mechanism to absorb all lateral weight and tilting moments, so that the ball screw purely plays the role of "providing axial push and pull power". Two core parameters for selection: dynamic load vs static load In the sample manual provided by the manufacturer, the two most critical indicators for evaluating load-bearing capacity are the rated dynamic load and the rated static load. 1. Rated dynamic load: determines "how long it can be used" It refers to the constant axial load that 90% of the screws can withstand without metal fatigue spalling when the rated operating life of a set of identical ball screws is revolutions (1 million revolutions). Selection rule of thumb: The average axial load in actual work is usually controlled within 10% ~ 30% of the dynamic rated load. If the screw is operated under high load for a long time, the life of the screw will be reduced exponentially. 2. Rated static load: determines "whether it will be crushed" It refers to the ultimate axial load when the contact surface between the most stressed ball and the raceway produces the maximum permanent deformation (indentation) when the screw is stationary or running at very low speed. Once the actual impact force exceeds, pits that are difficult to detect with the naked eye will appear inside the raceway. After that, every time the nut passes through a pit, it will vibrate violently, and the accuracy will be lost instantly. The “three physical limits” that determine the actual load capacity Even if the rated load of the selected nut is large enough, in the real physical world, the actual load capacity of the screw will be limited by the following three boundary conditions: 1. Instability limit of pressure rod (slenderness ratio and compressive yield) When the ball screw is subjected to axial thrust (compressive stress), if the screw is too thin or too long, it will be "bent" from the middle like a bamboo pole. This phenomenon is called strut instability. 2. Load bottleneck of support bearings The ball screw nut pushes the load, but the reaction force on the nut will eventually be transmitted to the fixed end support bearings (such as angular contact ball bearings) at both ends of the screw. In many high-load conditions, the screw itself is not broken, nor is the nut. Instead, the fixed seat bearing is crushed first. The allowable axial load of the bearing must be checked when selecting. Correction of operating environment and working conditions When calculating the actual force, the theoretical axial force must be multiplied by the working condition coefficient to derive the equivalent dynamic load: • 1. Smooth and impact-free (such as optical instruments, precision measuring equipment) • 2. General automation • 3. Heavy load/strong impact Summary Evaluating and improving the load-bearing capacity of ball screws is essentially a system engineering balance: • Structurally: Use guide rails to absorb lateral forces to ensure that the screw only bears pure axial force. • Calculation: Calculate the required, combined with the expected life, and leave sufficient margin with the impact coefficient. • Physically: Verify the instability limit of the pressure rod under long strokes and ensure that the end fixed bearing can match the same endurance level. Only when the screw body, support bearings and guide rail structure are considered as a whole can the stability and durability of the mechanical system be ensured while maximizing the load-bearing potential.

In the transmission systems of automated equipment, CNC machine tools, and precision slides, ball screws are core power components, and their load-bearing capacity directly determines the equipment's operational stability, positioning accuracy, and service life. Many common problems in equipment, such as screw bending and deformation, ball wear and jamming, positioning misalignment, and short-term failure, are caused by over 80% of issues stemming from unreasonable initial load-bearing selection, incomplete load calculations, and neglecting the load-bearing limits of the operating conditions. Most beginners only consider the screw diameter when selecting a ball screw, ignoring core load-bearing requirements such as dynamic and static loads, force types, installation methods, and safety factors. While the specifications may seem compatible, long-term overloading can lead to potential equipment failures. Today, we will comprehensively explain the load-bearing requirements of ball screws from five dimensions: load classification, core load-bearing parameters, practical calculation standards, key factors affecting load-bearing capacity, and key points to avoid selection pitfalls, making them suitable for most precision transmission scenarios. I. First, distinguish the three core loads of ball screws. The load-bearing capacity of a ball screw is not a single value. During equipment operation, it will bear various complex loads. Only by comprehensively calculating all forces can the load-bearing specifications be accurately matched, avoiding omissions that lead to under-caliber selection. 1. Axial Load (Core Load, Must Be 100% Calculated) This is the most important form of force on the ball screw and the core basis for load selection. It refers to the tensile or compressive force along the screw axis. The total axial load during equipment operation consists of three parts: cutting load, inertial load, and frictional resistance load. It is a key indicator determining whether the screw can operate stably. 2. Radial Load (Strictly Prohibited from Exceeding Limits, Zero Tolerance for Precision Equipment) The lateral force perpendicular to the screw axis is the radial load. If the radial load exceeds the limit due to equipment installation deviations, slide eccentricity, or force misalignment, it will directly cause uneven wear between the balls and raceways, screw bending, rapid decay of positioning accuracy, and even jamming or abnormal noise. Precision CNC machine tools and semiconductor equipment basically require the radial load to be close to zero. 3. Torque Load (Extra Force Must Be Eliminated) This includes torsional torque and overturning torque, mostly caused by non-parallel installation, slide misalignment, and load eccentricity. Torque loads disrupt the uniform contact between the balls and raceways, exacerbating localized stress concentration and significantly reducing the lifespan of the ball screw. Proper design must completely avoid this through structural optimization. II. Core Load-Bearing Parameters: Static Load and Dynamic Load The load-bearing specifications of all ball screws ultimately boil down to two core parameters: rated static load (Coa) and rated dynamic load (Ca). These two parameters have completely different application scenarios and verification standards, and both are indispensable. 1. Rated Static Load (Coa): The safety baseline for static/low-speed conditions Definition: The maximum permissible load generated at the contact point between the balls and raceways when the screw is stationary or operating at extremely low speeds. Its core function is to prevent permanent plastic deformation of the raceways. It represents the upper limit of load-bearing capacity for equipment shutdown, static conditions, and low-speed operation. Load Requirements: The actual maximum static load must be less than the rated static load, and a safety margin must be reserved. For conventional automated equipment, a safety factor of 1.5-2.0 is used. For heavy-load conditions and vibration/impact conditions, this needs to be increased to 2.0-3.0 to completely avoid permanent accuracy failure due to static deformation. 2. Rated Dynamic Load Ca: The Core of Lifespan under High-Speed ​​Cyclic Conditions Definition: The rated load that the lead screw can withstand for a long period of time during continuous high-speed reciprocating motion and cyclic operation. This directly determines the fatigue life of the lead screw and its suitability for the normal operating conditions of the equipment. III. Practical Load Calculation: Calculating the Suitable Load in One Step Many selection errors are due to relying solely on sample parameters without performing actual load calculations. After calculation, a safety factor must be added: Selected Load = Total Calculated Load × Safety Factor. For ordinary assembly lines and light-load equipment, a safety factor of 1.2-1.5 is used; for CNC machine tools, heavy-load equipment, and high-frequency start-stop equipment, a factor of 2.0 or higher is used to avoid impact loads damaging the lead screw. In addition, long-stroke lead screws must have their allowable buckling load checked. The longer the stroke and the smaller the lead screw diameter, the lower the allowable compressive load. Once the critical value is exceeded, the lead screw will bend and become unusable. This is the most easily overlooked load requirement for long-stroke equipment. IV. Five Key Factors Affecting the Load Capacity of Ball Screws The actual load capacity of ball screws of the same specifications varies greatly under different working conditions, installations, and materials. The core influencing factors are fivefold: 1. Screw Shaft Diameter and Base Diameter: The larger the outer diameter and the thicker the base diameter of the screw, the larger the cross-sectional area, resulting in stronger axial compressive and tensile strength, and significantly improved buckling load capacity. Heavy-duty, long-stroke equipment preferentially uses large-base diameter screws, as their load capacity stability is far superior to that of smaller diameter screws. 2. Ball Size and Quantity: The larger the ball diameter and the more circulating balls, the larger the contact area between the balls and the raceway, resulting in higher overall load capacity and stiffness. Heavy-duty screws typically employ large balls and multi-circuit designs to increase the overall load limit. 3. Installation and Support Method: The installation method directly determines the effective load-bearing stroke and buckling critical load of the screw: Fixed + fixed support offers the best load capacity and is suitable for long-stroke heavy-load applications; Fixed + support is the next best; Cantilever support offers the worst load capacity and is only suitable for short-stroke, light-load applications, strictly prohibited for heavy-load use. 4. Operating Speed ​​and DmN Value Under high-speed conditions, the effective load-bearing capacity of the lead screw will decrease slightly due to centrifugal force and rolling friction of the balls. The DmN value of conventional precision lead screws can reach over 120,000. Beyond the rated speed range, the actual load-bearing ratio needs to be reduced to avoid premature aging caused by high-speed load accumulation. 5. Lubrication and Operating Environment Sufficient lubrication can reduce rolling friction loss and ensure stable load-bearing capacity. Dust, oil, and high-temperature environments will accelerate raceway wear, leading to a continuous decrease in the actual effective load-bearing capacity and shortening service life. V. Avoiding Pitfalls in Load-Bearing Selection 1. Only Considering Diameter, Without Checking Dynamic and Static Loads For lead screws of the same diameter, the dynamic and static loads vary greatly depending on the brand and structure (single nut/double nut, standard/heavy load). Selecting a screw solely based on diameter can easily lead to overloading due to insufficient capacity. 2. Neglecting Axial Buckling Check: Short-stroke lead screws have a low buckling risk, simplifying calculations; however, long lead screws with a stroke exceeding 800mm must be checked for compressive buckling load. Many lead screw bending failures in long-stroke equipment originate from this. 3. Using a Uniform Safety Factor: A large safety factor is unnecessary for stable, low-speed operation to avoid cost waste; however, for high-frequency start-stop, impact loads, and vibration conditions, a larger safety margin is necessary, and generic standards cannot be applied. 4. Neglecting Radial and Torque Loads: Forcing lead screws to bear radial forces and overturning moments is the primary cause of precision lead screw failure. Installation and commissioning must ensure coaxiality of the transmission and prevent eccentric loading. VI. Summary: Core Requirements for Ball Screw Load Bearing 1. Force Priority: Focus on axial load, eliminating radial and torque overloads. Comprehensively calculate composite loads, without overlooking inertial, frictional, and machining loads. 2. Dual-Core Parameters:Simultaneously verify both rated static and rated dynamic loads; neither is dispensable. 3. Working Condition Adaptation:Match safety factors based on stroke, speed, start/stop frequency, and impact conditions. For long strokes, focus on verifying buckling load. 4. Structural Backup:Match appropriate installation and support methods to ensure coaxiality, structurally avoiding additional forces and guaranteeing load-bearing stability. Proper load-bearing verification and selection not only completely resolves issues like ball screw deformation, premature aging, and jamming, but also maximizes equipment precision and reduces subsequent maintenance costs. It represents the most cost-effective optimization step in mechanical transmission design.