SIST EN ISO 8062-3:2023

Overview - EN ISO 8062-3:2023 (GPS for castings)

EN ISO 8062-3:2023 is a Geometrical Product Specification (GPS) standard that defines general dimensional and geometrical tolerances and machining allowance grades for castings using ± tolerances for indicated dimensions. It applies to cast metals and alloys produced by various casting processes and is intended for tolerancing of linear dimensions and a set of common geometric characteristics as delivered to the purchaser. The standard is process‑specific and complements broader GPS rules; it is not applicable to 3D CAD models that do not include indicated dimensions.

Key topics and technical requirements

• Scope and applicability
  • Applies to castings in all cast metals/alloys and various casting processes.
  • Covers linear dimensional tolerances (±) and specified geometrical tolerances only.
  • Does not cover angular dimensions, cylindricity, or other position tolerances not listed.
• Geometrical characteristics included
  • Straightness, flatness, roundness, parallelism, perpendicularity, symmetry, coaxiality.
• Tolerance systems and grades
  • Defines Dimensional Casting Tolerance Grades (DCTG) and Geometrical Casting Tolerance Grades (GCTG) for selecting tolerance values.
  • Specifies Required Machining Allowance Grades (RMAG) to guide post‑casting machining operations.
• Other technical elements
  • Draft angles (external/internal), surface mismatch (SMI), wall thickness considerations.
  • Rules for indication on drawings (general tolerances in title block, references per Clause 11).
  • Guidance on rejection criteria and acceptance.
• Informative annexes
  • Provide practical tables and examples (tolerance tables, RMAG grades, datum concepts, application examples, relation to GPS matrix).

Practical applications

• Use EN ISO 8062-3:2023 when specifying tolerances on engineering drawings for cast parts delivered to purchasers.
• Helps select practical tolerance grades and machining allowances during design, procurement and production planning.
• Useful for:
  • Designing cast components where machining allowances and cast tolerances must be coordinated.
  • Specifying general tolerances in production drawings (title block or referenced callouts).
  • Establishing quality control criteria and acceptance/rejection rules for incoming castings.

Who should use this standard

• Foundry engineers and process planners
• Design and mechanical engineers specifying cast parts
• Quality, inspection and metrology teams
• Procurement/specification writers and manufacturing engineers

Related standards

• ISO/TS 8062-2 (guidance on application of this document)
• ISO 5459 (datum system guidance)
• Other ISO GPS standards and the ISO 8062 series for complementary process‑specific rules

EN ISO 8062-3:2023 is a practical, industry‑oriented GPS standard for consistent tolerancing and machining allowance planning on cast components, helping align design intent, foundry capability and post‑cast machining.