ISO/DIS 5458-2015 pdf free.Geometrical Product Specifications (GPS)一Geometrical tolerancing一Positional and pattern tolerancing.
ISO/DIS 5458 establishes complementary rules to ISO 1101 for geometrical tolerancing of form, orientation, location or run-out. These rules are applicable when:
one geometrical specification is applied to more than one geometrical feature considered individually or as united feature or as a pattern for GPS specification:
more than one geometrical specification is to be established simultaneously with orientation and/ or location constraints between them.
This International standard does not cover the use of the pattern (3.1):
when the least and maximum material requirement is applied (see ISO 2692);
when a datum is established from a collection of datum features without priority between them as a pattern (see ISO 5459).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1101, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form, orientation, location and run-out
ISO 8015, Geometrical product specifications (GPS) — Fundamentals — Concepts. principles and rules ISO 17450-1, Geometrical product specifications (GPS) — General concepts — Part 1: Model for geometrical specification and verification
ISO 17450-2, Geometrical product specifications (GPS) — General concepts — Part 2: Basic tenets, specifications, operators. uncertainties and ambiguities
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8015, ISO 1101, ISO 17450-1, ISO 17450-2 and the following apply.
4 Specification modifiers and symbols
For the purposes of this International Standard, the following specification modifiers and symbols apply (see Table 1).
5 Principles
5.1 General
In order to manage functional needs, the toleranced feature can be identifiedy as:
a single feature: complete or restricted;
— a pattern: homogeneous or non•homogeneous.
This International Standard deals only with a pattern.
This same functional need can be applied to several toleranced features, considered independently to each other or with constraint between them.
This pattern (homogeneous or non-homogeneous) can be constrained in orientation or in location from a datum system.
There is no functional difference in using or not using the concept of pattern when the specifications managing the patterns (composed by n geometrical features) use a datum system which locks all degrees of freedom of the related tolerance zones. However, when the concept of pattern is used there is only one result of measurement, and when the concept of pattern is not used there are n results of measurement.BS EN ISO 5458 pdf free download.