Ball Spline vs. Linear Guide vs. Ball Screw Spline: A Selection Guide for Engineers

Answer: Choose a linear guide when the axis only carries load along a straight path; choose a ball spline when it must also transmit torque while moving linearly; and choose a ball screw spline when it must rotate and feed precisely in one unit. The decisive question is simple: does your axis need torque transmission while moving linearly?

Three mechanisms, three jobs

Ball spline selection - key inputs

1. Torque to transmit (N-m) - determines shaft diameter and spline groove size.

2. Radial / axial load (N) - determines ball count and preload class.

3. Stroke - limited stroke (compact, high-frequency reciprocation) or infinite stroke (free travel along full shaft).

4. Speed and acceleration - affects inertia, heat and life; lightweight series reduce moving mass.

5. Mounting and environment - flange type for direct bolting; stainless steel and surface treatments (PVD, DLC) for clean-room and corrosive environments.

Life must be read with duty cycle

Never evaluate a ball spline by a single "life" number. Life depends on working conditions - load, speed, acceleration, stroke and frequency. UVT's 4 mm non-standard spline achieved 500 million reciprocations under severe conditions; your application should be calculated with its own duty cycle. UVT provides life calculation support with working-condition data.

Replacement and customization

UVT ball splines are designed as direct replacements for major brands (TBI, THK, NB, IKO) in common sizes with identical mounting dimensions. For non-standard requirements, UVT offers custom shaft diameter, stroke, flange interface, materials and surface treatments with prototype delivery in 2-3 weeks.

Send your model number, drawings and working conditions - UVT engineers confirm feasibility, life and lead time, usually within 1 business day.