ISO 21143:2020

Overview

ISO 21143:2020 - Technical product documentation - Requirements for digital mock-up virtual assembly test (VAT) for mechanical products - specifies requirements for conducting a digital mock‑up virtual assembly test prior to physical production. The standard applies to 3D nominal models with theoretically exact dimensions and sets out a structured VAT workflow (preparation, implementation, review) to verify mechanical interface compatibility, detect interferences, and validate assembly feasibility and ergonomics.

Key topics and technical requirements

• VAT process and workflow
  • Three phases: preparation, implementation, review.
  • Emphasis on test planning, model certification, environment configuration and closed‑loop verification.
• Test plan components
  • Test objectives, tasks, methodologies, process flow, test bill of materials (BOM), and schedule.
• Model preparation
  • Product models (allowing controlled simplification and lightweighting while preserving key geometry and kinematics).
  • Environment models (shop floor, tooling, fixtures).
  • Virtual operator models (ideal human models for ergonomics).
  • Model qualification and documentation requirements.
• VAT implementation requirements
  • Interference inspection (static and dynamic): detect parts occupying the same space or unacceptable clearances.
  • Assembly feasibility analysis: analyze assembly sequences, paths and procedures; ensure movement mechanisms function correctly.
  • Ergonomics evaluation: use virtual operators to assess human factors and optimize assembly operations.
• Review and reporting
  • Validate that preparation, plan, process and report requirements are met; document findings and corrective actions.

Practical applications

• Early detection and resolution of fit, clearance and interference issues before physical prototyping.
• Validation of mechanical interfaces across units, sub‑systems and integrated products.
• Optimization of assembly sequences and shop‑floor procedures to improve on‑site assembly efficiency.
• Ergonomics assessment to reduce workplace risk and improve operator accessibility.
• Support for reducing prototype cost and shortening product development cycles through virtual assembly simulation.

Who uses this standard

• Design and mechanical engineers performing CAD/CAM and DMU (digital mock‑up) activities
• Manufacturing and process engineers planning assembly lines and tooling
• Technical product documentation teams responsible for compliant design deliverables
• Quality, validation and systems engineers coordinating supplier integration and pre‑production testing

Related standards

• ISO 17599 - General requirements of digital mock‑up for mechanical products (referenced)
• ISO 29845 - Technical product documentation - Document types (referenced)

ISO 21143:2020 is a practical standard for organizations implementing virtual assembly testing and assembly simulation to improve product readiness, reduce on‑site issues, and streamline production validation.