ISO 10243:2019

Overview

ISO 10243:2019 - Tools for pressing: Compression springs with rectangular section - Housing dimensions and colour coding - is the international standard that specifies housing dimensions and a colour-coding system for set compression springs made from rectangular wire used in press tooling. Published as the third edition (2019), the document standardizes how these springs are described and selected for pressing and moulding tools, while explicitly excluding detailed material, life‑cycle or full geometric quality requirements.

Key topics and technical requirements

• Scope and applicability: Applies to compression springs manufactured from rectangular wire that are already set; it does not prescribe material, cross‑sectional details, surface treatment or fatigue life.
• Classification by spring rate: Springs are classified into four spring rates - light (green), medium (blue), strong (red) and extra strong (yellow). The standard assigns a colour code to each rate to simplify visual identification and inventory control.
• Housing dimensions and identifiers: The standard defines housing/clearance dimensions (hole and rod diameters), and the geometric arrangement referenced in a schematic (Figure 1).
• Dimensional tolerances: Tolerances for free length (L0) are specified (see Table 1), helping ensure interchangeability in tool assemblies.
• Performance tables: Technical tables (Tables 2–5) give spring rates, corresponding hole/rod diameters, free lengths and forces - including force at maximum operating deflection - for each classification and size range.
• Terms and definitions: Uses a limited definition of spring rate (force per unit deflection) consistent with ISO terminology sources.

Practical applications

• Standardizes selection and replacement of rectangular‑section compression springs in press tools, moulds and stamping dies.
• Facilitates interchangeability, inventory management and maintenance by combining dimensional specs with an easy colour‑coded identification method.
• Helps tool designers dimension housings and select springs to meet required force/deflection behavior without managing bespoke part descriptions.
• Useful in procurement and quality control as a reference for accepting spring assemblies and housings used in production tooling.

Who should use ISO 10243:2019

• Toolmakers, die and mould designers
• Press tooling manufacturers and assemblers
• Maintenance and production engineering teams
• Procurement and quality engineers specifying spring components for press applications

Related standards

• ISO 26909:2009 - referenced for the definition of spring rate terminology.
• Refer to national adoption documents or the ISO catalogue for implementation guidance.

Keywords: ISO 10243:2019, compression springs with rectangular section, housing dimensions, colour coding, spring rate, press tooling, interchangeability.