How to Choose Ball Spline Preload: T0 Clearance vs T1 Light Preload

Answer: Ball spline preload is selected by accuracy class: choose T0 clearance (no preload, lowest friction) for high-speed, low-load motion where smooth travel matters most; choose standard preload or T1 light preload when you need zero rotational play and repeatable positioning, typical for pick-and-place, semiconductor and robot Z-axis applications. UVT ball splines offer precision grades (standard / H / P) and preload classes (T0 clearance, standard, T1 light preload) across shaft diameters from 2 mm to 100 mm.

Why preload matters in a ball spline

A ball spline transmits torque while moving linearly. The balls run in spline grooves and, without preload, a small rotational clearance exists between sleeve and shaft. Preload removes that clearance by applying an interference fit between ball and groove, which stiffens the assembly and improves positioning repeatability - at the cost of slightly higher friction.

Preload class comparison

4-step selection method

1. Define the accuracy target: if the application requires repeatable positioning (0.01 mm class), choose T1 light preload; if it only requires smooth linear travel, T0 is enough.
2. Check speed and acceleration: high-speed reciprocation (SMT mounters at 860 mm/s and 10 G, 15 mm stroke) favours low-friction options; preload raises friction and heat at very high speeds.
3. Verify stiffness needs: preloaded units resist tilting and torque variation better - needed for vertical Z-axis shafts that carry cantilevered loads.
4. Confirm with duty-cycle data: send us your load, speed, acceleration, stroke and frequency; we calculate life and recommend the preload class for your working conditions.

Typical applications by class

• T0 clearance: conveyor lifts, light assembly, long-stroke low-load tables
• Standard: general automation and transfer axes
• T1 light preload: SMT mounter nozzle shafts, semiconductor handlers, SCARA and assembly robot Z-axes, ATC systems in machining centers

Preload and accuracy are specified together on UVT ball splines (precision grades H and P available). For a selection table matched to your shaft diameter and load, see our technical support page or contact us with your duty cycle. UVT Transmission - precision ball splines for semiconductor, SMT, robotics and medical equipment.