Comparative Research on Selection of Ground and Rolled Ball Screws with the Same Specifications

When selecting ball screws of the same specifications, the performance gaps between ground ball screws and rolled ball screws are often ignored. Multi-dimensional comparisons including load capacity, long-term service life and operating accuracy serve as the core basis for rational selection.

1. Accuracy Difference

   Ground ball screws own overwhelming advantages in accuracy. Their lead accuracy, surface finish and straightness are far superior to rolled ball screws, which can meet ultra-high precision demands of CNC machine tools, semiconductor equipment for positioning and repeated positioning. Rolled ball screws have inherent limits on accuracy grades, only applicable to general automation equipment, packaging machinery and other scenarios with low-to-medium precision requirements.

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3. Load Capacity

   Ground ball screws are made of high-quality alloy steel with complete quenching, tempering and other heat treatments, featuring high surface hardness and fatigue resistance. They deliver outstanding rigidity, torque stability and load capacity under heavy-load and high-frequency working conditions. Though the rolling forming process densifies the metal structure of rolled ball screws, their material grade and heat treatment standards are inferior to ground ones. They can only handle regular working conditions and perform poorly under heavy loads.

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7. Service Life

   The core indicator of screw service life lies in accuracy retention instead of fracture failure. Ground ball screws feature high surface hardness and low wear, maintaining factory precision for a long time during continuous operation. Rolled ball screws have relatively lower surface hardness and rougher surfaces, leading to faster wear and poor precision retention. Nevertheless, the ultimate service life of both types is also greatly affected by raw materials, heat treatment processes and product quality.

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9. Performance Impact from Manufacturing Processes

   The grinding process consists of multiple precision machining steps, with inspection, straightening and stress relief heat treatment arranged between procedures, ensuring excellent concentricity between thread raceways and shaft journals. Rolled ball screws are one-step extruded. Stress and deformation generated during rolling and heat treatment cannot be corrected afterwards, resulting in poor concentricity, large torque fluctuation, extra operating noise and vibration.