Overview
ISO 23848-1:2009 - "Machine tools - Ball splines - Part 1: General characteristics and requirements" sets international requirements for the geometric, mechanical and inspection-related characteristics of ball splines used in machine tools. The standard standardizes shapes and dimensions, test methods, inspection procedures, designation and marking for ball spline assemblies (spline shaft, spline outer race, balls, recirculation devices and seals).
Key topics and technical requirements
- Classification and grades: Ball splines are classified as type A (angular) or type R (radial) and divided into three precision grades: C1, C3 and C5 (symbols P, H or no symbol respectively).
- Shapes & dimensions: Nominal spline shaft diameters and outer-race boundary dimensions are specified (see Annex A).
- Groove twist: Tolerance on groove twist is defined and measured over a 100 mm travel (Table 2). Example maximum twist tolerances: C1 = 6 µm, C3 = 13 µm, C5 = 33 µm.
- Runout and accuracy: Radial and axial runout limits for spline grooves, part-mounting journals and outer races are provided (Tables 3–8). Total radial runout of the spline shaft relative to support journals is tabulated by nominal diameter and shaft length.
- Hardness: Minimum hardness for spline groove surfaces is specified as W 653 HV (≈ W 58 HRC).
- Test methods & environment: Standardized measurement methods are given for groove twist, runout and hardness; testing is performed under standard atmosphere 20 °C (ISO 554, class 15).
- Inspection, designation and marking: Procedures for inspection acceptance, standardized designation formats and marking requirements are included to ensure traceability and interchangeability.
Applications and users
ISO 23848-1 is essential for:
- Machine tool designers and OEMs specifying ball spline components for linear-plus-rotary motion systems.
- Ball spline manufacturers establishing product specifications and quality control procedures.
- Quality and metrology engineers performing acceptance testing and inspection.
- Procurement/specification engineers who require standardized designation and marking for component interchangeability.
Practical applications include precision feeds in CNC machines, linear actuators with torque transmission, robotics, and other systems requiring smooth axial translation while transmitting torque.
Related standards
- ISO 23848-2 - complements Part 1 by specifying dynamic and static load/torque ratings and rating life.
- Normative references used for testing include ISO 554 (standard atmospheres) and ISO 6507-1/2 (Vickers hardness test and calibration).
Keywords: ISO 23848-1, ball splines, machine tools, groove twist, spline shaft, spline outer race, runout, hardness, test methods, inspection, dimensions.