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GB/T 40742.1-2021 English PDF (GBT40742.1-2021)

GB/T 40742.1-2021 English PDF (GBT40742.1-2021)

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GB/T 40742.1-2021: Geometrical product specifications (GPS) -- Geometrical precision verification -- Part 1: Basic concept and measurement -- Symbol, terminology, measuring conditions and procedures

This document specifies the basic concept and measurement, terminology, symbol, measuring conditions and procedures of geometric precision verification. This document applies to the detection and verification of geometrical characteristics such as product size, shape, position, surface structure.
GB/T 40742.1-2021
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 17.040.40
CCS J 42
Geometrical product specifications (GPS) - Geometrical
precision verification - Part 1: Basic concept and
measurement - Symbol, terminology, measuring conditions
and procedures
ISSUED ON: OCTOBER 11, 2021
IMPLEMENTED ON: MAY 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the PEOPLE Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions... 7
4 Symbols ... 8
5 Measuring conditions ... 8
6 Measurement process ... 9
Appendix A (Normative) Relevant symbols and descriptions in engineering drawings and/or technical documents ... 13
Appendix B (Informative) Relationship to GPS matrix model ... 17
References ... 19
Geometrical product specifications (GPS) - Geometrical
precision verification - Part 1: Basic concept and
measurement - Symbol, terminology, measuring conditions
and procedures
1 Scope
This document specifies the basic concept and measurement, terminology, symbol, measuring conditions and procedures of geometric precision verification. This document applies to the detection and verification of geometrical characteristics such as product size, shape, position, surface structure.
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 version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document. GB/T 1182, Geometrical product specifications (GPS) - Geometrical tolerancing - Tolerances of form, orientation, location and run-out
GB/T 18779.1, Geometrical Product Specifications (GPS) - Inspection by
measurement of workpieces and measuring equipment - Part 1: Decision rules for proving conformance or non-conformance with specifications
GB/T 18779.2, Geometrical Product Specifications (GPS) - Inspection by
measurement of workpieces and measuring equipment - Part 2: Guide to the estimation of uncertainty in GPS measurement, in calibration of measuring equipment and in product verification
GB/T 19022, Measurement management systems - Requirements for measurement processes and measuring equipment
GB/T 24637.1, Geometrical product specifications (GPS) - General concepts - Part 1: Model for geometrical specification and verification
GB/T 24637.2, Geometrical product specifications (GPS) - General concepts - Part 2: Basic tenets, specifications, operators, uncertainties and ambiguities [Source: JJF 1001-2011, 4.5]
3.5
Measurement procedure
A detailed description of a measurement, based on the measurement model and the calculations required to obtain the measurement results, according to one or more measurement principles and the given measurement method.
Note 1: The measurement procedure is usually written in sufficient and detailed documentation for the operator?€?s convenience.
Note 2: The measurement procedure may include a statement about the target uncertainty of measurement.
Note 3: The measurement procedure is sometimes referred to as Standard Operation Procedure (abbreviated to SOP).
[Source: JJF 1001-2011, 4.6]
4 Symbols
The relevant symbols involved in the detection and verification of geometric characteristics such as size, shape, position, and surface structure shall comply with the provisions of Appendix A.
5 Measuring conditions
5.1 The measuring conditions that affect the measurement results mainly include temperature, temperature change rate, humidity, lighting, vibration, dust amount, cleanliness, electromagnetic interference and other factors. The environmental conditions required for the effective operation of the measurement process shall be documented. The measuring conditions generally include measurement environmental conditions, measurement personnel, etc. This document mainly regulates the measurement environmental conditions.
5.2 The measuring equipment shall be used and stored under the environmental conditions required by the specification, so that it can meet the expected operating requirements, so as to ensure the accuracy and validity of the measurement results. 5.3 The environmental factors affecting the measurement shall be monitored and recorded in the measurement process. When the environmental factors which affect the measurement deviate from the specified conditions, the measurement results shall be corrected and recorded.
5.4 When online measurement is performed at the production site, necessary measures shall be taken to ensure that the environmental conditions meet the operating requirements of the measuring equipment.
5.5 Unless otherwise required, the ideal environmental conditions for geometric precision verification are as follows:
-- The standard measurement temperature is 20 ??C;
-- It shall be clean and dry indoors;
-- The environmental conditions ?€? in terms of noise, anti-vibration, dust-proof, anti- corrosion, anti-magnetic and shielding ?€? of the measurement room shall meet the requirements for environmental conditions of the measurement items carried out indoors;
-- Indoor lighting shall facilitate the measurement work.
6 Measurement process
6.1 General
The geometric precision verification objects involved in this document are mainly size, shape, orientation, position and surface structure. During the measurement, each measurement process shall be planned, validated, implemented, documented and controlled, and the influence quantities that affect the measurement process shall be identified and considered.
The complete specification of each measurement process shall include all relevant measuring equipment identification, measurement procedures, measurement software, conditions of use, operator capabilities and other factors affecting the reliability of the measurement results, where the measurement procedure shall be written in sufficient and detailed documents to guide the operator to carry out the measurement. 6.2 Measurement process design
6.2.1 General
The measurement process design shall be carried out according to the requirements of the user, the organization and the laws and regulations. The content of measurement process design mainly includes:
-- Definition of the measured object and the measurement task;
-- Definition of the expression form and accuracy requirements of measurement results;
equipment); at the same time, advanced nature of the measuring equipment, measurement efficiency, operating conditions, requirements for operators, traceability methods for realizing the value, and economic rationality shall be considered.
Note 2: When selecting a measurement method, consider cost and efficiency under the premise of ensuring that the target uncertainty can be achieved (GB/T 18779.2). Note 3: Refer to the specification requirements of GB/T 24637.2 for the design of the inspection operation set.
Note 4: The measurement process specification document can be formulated with reference to GB/T 19022.
6.2.5 Measurement results and verification
Operate according to the actual inspection operation set, to obtain the measurement results, which shall include the measured value of geometric error and the uncertainty of measurement. See GB/T 18779.2 for the evaluation, expression and management specifications of uncertainty of measurement; perform a conformity assessment according to the measurement results and the tolerance specification of the measured feature, as shown in GB/T 18779.1.
6.3 Specification and implementation of the measurement process
The specification of the measurement process needs to comply with the following requirements during the implementation process:
a) The measurement shall ensure that the measuring equipment, environmental conditions and fixtures meet the relevant regulations in the measurement model; b) The measurement personnel shall understand the measurement target,
measurement scheme, and be familiar with the operation of the measuring equipment;
c) Before the measurement is carried out, it is necessary to ensure that the preparations for the measurement ?€? such as the preheating and calibration of the equipment, import of the measurement model data ?€? are completed;
d) The measurement operation process shall follow the corresponding measurement specifications; the use of the measuring equipment shall be carried out in accordance with the instrument manual;
e) During the measurement, in consideration of the fluctuation of the environment (temperature, humidity, etc.) over time, monitoring measures shall be taken to ensure that the environmental conditions are always within the allowable working range of the measuring equipment;
f) Statistical analysis shall be carried out for the measurement results, so as to detect deviations caused by measurement or process in a timely manner;
g) The uncertainty of measurement, which is a parameter associated with the measurement result, shall be analyzed and evaluated.
6.4 Standardization of the measurement method
To ensure that the measurements are carried out in the same way, the measurement method shall be standardized, and all measurements shall be carried out according to the specified standard methods. There shall be a written document specifying all the details of the measurement to be carried out, including how to obtain and prepare the test piece.
The measurement method shall be a standardized and robust method, that is, the measurement results will not produce unexpected large changes to small changes in the measurement process. If there is a large change in the measurement process, appropriate precautions shall be taken or a warning shall be issued. In developing a standard measurement method, efforts shall be made to eliminate or reduce the offset of measurement data.
Some similar test procedures can also be used to test the correctness and precision of established and newly standardized measurement methods, where the results obtained from the latter case should be considered as initial estimates, because the correctness and precision vary with the accumulation of laboratory experience.
The documentation for establishing the measurement method shall be clear and complete. All the important operations involving the procedure?€?s environment, reagents and equipment, initial inspection of equipment, and preparation of test samples shall be included in the measurement method. Measurement results and calculations, as well as the number of significant figures shall be clearly stated.

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