The spline screw in the SCARA (Selective Compliance Assembly Robot Arm) four-axis robot is a key transmission component, mainly used to achieve high-precision linear motion and rotational motion (θ axis, usually the fourth axis) of the robot in the vertical direction (Z axis). The following is its detailed use and description: 1. Main use Z-axis lifting motion: The spline screw converts the rotational motion of the motor into precise linear motion, driving the end effector of the robot arm (such as grippers, suction cups, etc.) to move up and down in the vertical direction. Rotational motion transmission: The spline structure transmits torque at the same time to achieve the rotation of the fourth axis (such as the rotation of the end tool), meeting the needs of assembly, screw tightening and other operations. High precision and rigidity: Suitable for scenarios that require repeatable positioning accuracy (such as ±0.01mm) and resistance to lateral forces (such as precision assembly and handling). Synchronous motion: When the Z-axis lifting and rotational motions work together (such as inserting parts), the spline screw can ensure the synchronization of the two motions. 2. Structural description Spline part: The external spline cooperates with the internal spline sleeve to transmit the rotational torque (θ axis), while allowing the shaft to slide up and down in the spline sleeve (Z axis), realizing the combination of rotation and linear motion. Screw part: The precision ball screw converts the rotation of the servo motor into linear motion, providing high-precision, low-friction lifting drive. Integrated design: The spline and the screw are usually integrated on the same shaft, saving space and simplifying the transmission chain. 3. Core features High load capacity: The spline structure disperses torque and radial force, suitable for cantilever loads (such as horizontally extended robotic arms). Low backlash: The preloaded ball screw and spline cooperate to reduce the motion gap and improve the repeatability. Compactness: The integrated design reduces external transmission components and adapts to the narrow joint space of the SCARA robot. Durability: Hardened steel or coating technology is used, which is wear-resistant and has a long life (such as more than 20,000 hours). 4. Typical application scenarios Electronic assembly: PCB board plug-in, chip handling (requires Z-axis precision lifting + rotation alignment). Automated production line: screwing, gluing (rotation and pressing action). Medical equipment: reagent packaging, test tube operation (dust-free, low vibration requirements). 5. Comparison with other transmission methods Characteristics Spline screw Timing belt + guide rod Linear motor Accuracy High (μm grade) Medium (affected by belt elasticity) Very high Load capacity High (suitable for heavy loads) Medium-low Medium Cost Medium Low High Maintenance complexity Regular lubrication Belt replacement Almost maintenance-free 6. Selection considerations Accuracy level: Select C3/C5 screw according to the task. Dust-proof design: Sealed spline sleeve prevents dust from entering (such as IP54 protection). Lubrication method: Automatic lubrication or maintenance-free grease design. Through the composite function of the spline screw, the SCARA robot can efficiently complete complex movements with limited degrees of freedom, becoming the mainstream choice in 3C, automotive electronics and other fields.

In modern automated machinery, ball screws serve as the core transmission component that converts rotary motion into precise linear movement. Standard ball screw models fit universal equipment, yet many specialized automation, medical, micro-electronic, and precision instrument projects demand customized dimensions, materials, and load performance. Our SHUNTAI custom miniature grinding ball screws (MIA0401, MIA0401b, MIA0601) are engineered exclusively for non-standard industrial motion scenarios. Built from premium GCr15 bearing steel with both rolled and ground machining processes, these compact ball screws deliver long service life, ultra-smooth operation, and customizable specs to match your unique mechanical design constraints. What Makes Non-Standard Custom Ball Screws Indispensable? Unlike off-the-shelf standard ball screws, custom non-standard ball screws are fully adjusted to your project’s exact engineering requirements. They solve pain points that generic transmission parts cannot address: Customized dimensional limits for tight spaces Many miniature automation devices, lab testing equipment, and compact actuator systems have strict spatial restrictions. We fully customize core parameters including screw diameter, overall length, lead, and nut outline size to fit confined installation layouts without sacrificing motion precision. Our MIA mini series specializes in ultra-small diameter micro screw structures ideal for compact machinery. Specialized material matching for harsh working environments Our base material is high-strength GCr15 bearing steel for standard precision applications. For special working conditions such as corrosion exposure, high-temperature operation, or medical clean environments, we support custom material upgrades including stainless steel and high-temperature wear-resistant alloys to extend component lifespan under extreme conditions. Custom load & speed performance design High-load industrial actuators and high-speed precision inspection equipment have divergent motion demands. We redesign the ball circulation track, thread profile, and nut structure for custom ball screws, boosting load capacity, lowering friction, and enabling stable high-speed reciprocating movement for your equipment. Custom manufacturing & surface finishing processes Beyond standard rolling and grinding machining, we provide exclusive custom processing solutions: special thread grinding tolerances (C3/C5/C7 precision grades), customized surface hardening, anti-rust coating, and tailored end-machining features to match your coupling, bearing, and assembly structure perfectly. Core Advantages of SHUNTAI MIA Custom Miniature Ball Screws Our tailored micro ball screws are widely adopted across global precision manufacturing sectors: Medical automation equipment & laboratory testing instruments Optical inspection machinery & semiconductor micro-processing devices Small automated actuators, robotics joint micro-drives Precision measuring instruments & miniature CNC equipment Packaging automation compact linear drive modules Why Choose SHUNTAI as Your Custom Ball Screw Supplier? As a professional ball screw manufacturer specializing in non-standard customization, we deliver end-to-end custom service: from technical drawing review, structural optimization design, sample trial production, to mass manufacturing. Our engineering team collaborates closely with overseas buyers to resolve all unique motion transmission challenges, improving your equipment’s overall stability, precision, and operational efficiency. Whether you need micro miniature ball screws from the MIA series or large-size heavy-load custom ball screws, send us your technical drawings and parameter requirements for a free technical consultation and quotation. Final Words Generic standard ball screws often force engineers to compromise on equipment design. Custom non-standard ball screws eliminate design limitations, letting you build machinery fully aligned with your performance targets. Our SHUNTAI MIA series precision miniature custom ball screws balance compact size, reliable durability, and flexible customization, making them the ideal linear motion solution for your specialized industrial projects. Contact our team today to discuss your custom ball screw specifications and unlock optimized linear transmission performance for your machinery!