NF ISO 22514-8
Statistical methods in process management - Capability and performance - Part 8 : machine performance of a multi-state production process
ISO 22514-8:2014 aims to define the evaluation method to quantify the short-term capability of a production process (capacity of the production tool, widely termed capability), i.e. the machine performance index, to ensure compliance to a toleranced measurable product characteristic, when said process does not feature any kind of sorting system.If the production process integrates a sorting system, then this one (clearing away nonconforming parts) should be analysed independently.ISO 22514-8:2014 does not aim to define evaluation methods of the capability of a production process that is gauged through long-term observation (capability process or performance process indices).ISO 22514-8:2014 defines the principles guiding the development of indicators for quantifying capability, and the statistical methods to be employed.The characteristics used to evaluate production process capability have statistical distributions, and it is presumed, a priori, that at least one of these distributions is multi-modal. A distribution is presumed to be multimodal if it results from the marked effect of at least one cause inducing a significant difference between the produced items.ISO 22514-8:2014 applies, for example, to characteristics generated by processes such as the following: multi-cavity casting, multi-fixture machining, batch load treatments.Each cavity, fixture, or position in the batch load corresponds to a different state. The multi-state process can be understood as the result of the combination of different states within the same process (e.g. cavity, fixture, position in the batch load).
ISO 22514-8:2014 aims to define the evaluation method to quantify the short-term capability of a production process (capacity of the production tool, widely termed capability), i.e. the machine performance index, to ensure compliance to a toleranced measurable product characteristic, when said process does not feature any kind of sorting system.
If the production process integrates a sorting system, then this one (clearing away nonconforming parts) should be analysed independently.
ISO 22514-8:2014 does not aim to define evaluation methods of the capability of a production process that is gauged through long-term observation (capability process or performance process indices).
ISO 22514-8:2014 defines the principles guiding the development of indicators for quantifying capability, and the statistical methods to be employed.
The characteristics used to evaluate production process capability have statistical distributions, and it is presumed, a priori, that at least one of these distributions is multi-modal. A distribution is presumed to be multimodal if it results from the marked effect of at least one cause inducing a significant difference between the produced items.
ISO 22514-8:2014 applies, for example, to characteristics generated by processes such as the following: multi-cavity casting, multi-fixture machining, batch load treatments.
Each cavity, fixture, or position in the batch load corresponds to a different state. The multi-state process can be understood as the result of the combination of different states within the same process (e.g. cavity, fixture, position in the batch load).
Le présent document définit une méthodologie permettant d'évaluer l'aptitude d'un processus de production sur le court terme à respecter une caractéristique mesurable tolérancée du produit, même si des causes identifiées induisent une distribution multimodale.
- Avant-proposiv
- Introductionv
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1 Domaine d'application1
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2 Références normatives2
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3 Termes et définitions2
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4 Symboles et abréviations6
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5 Analyse technique préliminaire du processus7
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5.1 Généralités7
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5.2 Identification des facteurs intrinsèques7
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5.3 Détermination des modes spécifiques au processus7
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6 Vérifications préliminaires avant de calculer les indices de performance machine8
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6.1 Système de mesure8
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6.2 Définition du plan d'échantillonnage pour l'estimation de la dispersion intrinsèque globale8
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7 Estimation de la dispersion intrinsèque globale et calcul des indices de performance machine9
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7.1 Généralités9
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7.2 Vérification de l'absence de valeurs aberrantes dans l'ensemble des résultats de mesure obtenus10
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7.3 Détermination des étendues des dispersions intrinsèques locales11
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7.4 Détermination des positions des dispersions intrinsèques locales12
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7.5 Dispersion intrinsèque globale: type et estimation13
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7.6 Calcul des indices d'aptitude Pm et Pmk15
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7.7 Seuils d'acceptation des indices de performance machine16
- Annexe A (informative) Modes qualifiant un procédé de traitement18
- Annexe B (normative) Tests statistiques35
- Bibliographie40
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