ISO 22705-1:2021

Overview

ISO 22705-1:2021 - Springs: Measurement and test parameters - Part 1: Cold formed cylindrical helical compression springs specifies standardized measurement and test methods for the general characteristics of cold-formed, round-wire, cylindrical helical compression springs. The standard covers dimensional, geometric and static load characteristics used for quality control, inspection and design verification. Dynamic testing is excluded from this part.

Keywords: ISO 22705-1:2021, cold formed cylindrical helical compression springs, measurement and test methods, spring measurement standard, spring testing.

Key topics and technical requirements

The standard defines procedures and requirements for measuring and testing the following key parameters and conditions:

• Environmental conditions and required test environment for reproducible results
• Qualifications of personnel performing measurements and tests
• Geometries of guiding and supporting devices and appropriate fixturing
• Measuring and testing equipment suitable for spring inspection
• Dimensional and geometric parameters, including:
  • Free length (L0)
  • Outside diameter (De) and inside diameter (Di)
  • Total and active number of coils, coil direction
  • Applied end coils and ground surface/angles
  • Solid length and solid force
  • Spring load at specified deflections
  • Spring pitch / distance between coils
  • Perpendicularity and parallelism of end faces
  • Shear-off burr assessment
• Methods of measurement and test location on the product for each parameter
• Annex A (informative): calculation method for spring rate (R)

The document sets out the type of characteristic, recommended equipment, measurement conditions and step-by-step methods to ensure consistency across manufacturers and testing laboratories.

Practical applications and users

ISO 22705-1:2021 is intended for professionals involved in spring design, manufacture, procurement and quality assurance:

• Spring manufacturers and production engineers - for in-process inspection and acceptance testing
• Quality control and metrology labs - to implement repeatable test procedures and calibration routines
• Design and mechanical engineers - for verifying that components meet specified dimensional and static-load requirements
• Procurement and specification writers - to reference objective test methods in purchase orders and contracts
• Certification bodies and regulators - to harmonize compliance checks

Using this standard helps reduce interpretation variance, improve interchangeability of springs, and support reliable spring performance in assemblies across automotive, industrial, consumer and aerospace applications.

Related standards (if applicable)

• Other parts of the ISO 22705 series and related ISO standards addressing different spring types or dynamic testing (refer to ISO catalog for applicable parts).

Adopting ISO 22705-1:2021 in inspection and documentation improves product quality, traceability and supplier alignment when working with cold-formed cylindrical helical compression springs.