Overview

ISO 22514-6:2013 - Statistical methods in process management - Capability and performance - Part 6 - defines methods for calculating process capability and process performance statistics when product or process characteristics are best treated as a multivariate quantity. The standard focuses mainly on bivariate normal distributions (two-dimensional) but is applicable in principle to higher-dimensional multivariate normal cases. It provides definitions and calculation approaches (extensions of classical C and Cpk indices) for assessing capability where features are correlated or tolerance regions are non-rectangular.

Key topics and requirements

Multivariate quantity and tolerance region: Treats feature vectors (e.g., x, y coordinates) and tolerance regions such as ellipses, circles or other multivariate shapes rather than independent univariate limits.
Index types: Introduces different index families (notably Type I - probability-based - and Type II - geometry/area-based) and further variants (e.g., Ic, IIc) for capability/performance measurement.
Calculation formulas: Provides formulae for capability and performance indices for multivariate normal data; derivations and informative examples are included in annexes.
Assumptions and prerequisites:
- Data are assumed to follow a multivariate normal distribution (primarily bivariate).
- The measuring system’s capability should be demonstrated prior to process capability assessment.
- Recommended minimum sample size to estimate PCI is preferably at least 125.
Scope limitation: The standard defines and describes methods but does not evaluate which method is preferable for specific situations - selection is left to the user’s judgement.

Practical applications

ISO 22514-6 is practical for cases where treating features jointly gives a more accurate assessment than separate univariate analyses:

Geometric tolerances (e.g., 2D or 3D hole position, slot dimensions)
Dynamic magnitudes such as shaft imbalance
Correlated material properties or chemical parameters
Approval of production processes, supplier comparisons, contract compliance, complaint and damage analyses

Benefits include a single comprehensive statistic for correlated features, correct handling of non-rectangular tolerance regions (ellipsoids, circles), and more realistic capability/performance assessment where interdependencies matter.

Who should use this standard

Quality engineers and process engineers assessing multivariate product features
Metrologists and statisticians implementing capability studies
Suppliers and customers defining multivariate capability limits in contracts
R&D and manufacturing teams dealing with correlated dimensional or functional characteristics

Related standards

ISO 22514-1 (General principles and concepts)
ISO 22514-2 (Time-dependent process models)
ISO 22514-5 (Attribute characteristics)
ISO 22514-7 (Capability of measurement processes)

Keywords: ISO 22514-6:2013, multivariate normal distribution, process capability, process performance, multivariate PCI, bivariate normal, tolerance region, capability index.

Overview

Key topics and requirements

Multivariate quantity and tolerance region: Treats feature vectors (e.g., x, y coordinates) and tolerance regions such as ellipses, circles or other multivariate shapes rather than independent univariate limits.
Index types: Introduces different index families (notably Type I - probability-based - and Type II - geometry/area-based) and further variants (e.g., Ic, IIc) for capability/performance measurement.
Calculation formulas: Provides formulae for capability and performance indices for multivariate normal data; derivations and informative examples are included in annexes.
Assumptions and prerequisites:
- Data are assumed to follow a multivariate normal distribution (primarily bivariate).
- The measuring system’s capability should be demonstrated prior to process capability assessment.
- Recommended minimum sample size to estimate PCI is preferably at least 125.
Scope limitation: The standard defines and describes methods but does not evaluate which method is preferable for specific situations - selection is left to the user’s judgement.

Practical applications

ISO 22514-6 is practical for cases where treating features jointly gives a more accurate assessment than separate univariate analyses:

Geometric tolerances (e.g., 2D or 3D hole position, slot dimensions)
Dynamic magnitudes such as shaft imbalance
Correlated material properties or chemical parameters
Approval of production processes, supplier comparisons, contract compliance, complaint and damage analyses

Who should use this standard

Quality engineers and process engineers assessing multivariate product features
Metrologists and statisticians implementing capability studies
Suppliers and customers defining multivariate capability limits in contracts
R&D and manufacturing teams dealing with correlated dimensional or functional characteristics

Related standards

ISO 22514-1 (General principles and concepts)
ISO 22514-2 (Time-dependent process models)
ISO 22514-5 (Attribute characteristics)
ISO 22514-7 (Capability of measurement processes)

Keywords: ISO 22514-6:2013, multivariate normal distribution, process capability, process performance, multivariate PCI, bivariate normal, tolerance region, capability index.

SIST ISO 22514-6:2014 PDF

Технические детали

Abstract

Overview

Key topics and requirements

Practical applications

Who should use this standard

Related standards

Похожие стандарты

Abstract

Overview

Key topics and requirements

Practical applications

Who should use this standard

Related standards

Похожие стандарты

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