GB/T 18779.4-2020Geometrical product specifications (GPS)-Inspection by measurement of workpieces and measuring equipment - Part 4: Background on functional limits and specification limits in decision rules (English PDF)

1 Scope

This part of GB/T 18779 specifies the main assumptions under the theoretical ideal judgment rule in GB/T 18779:1: Given these

The rule should be the reason for the default rule and the factors that need to be considered before applying different judgment rules:

This part is applicable to all specifications involved in the GPS general standard (see GB/T 20308), that is, the standard compiled by SAC/TC240:

Including workpiece specifications (usually given in the form of specification limits) and measuring equipment specifications (usually given in the form of maximum allowable error):

2 Normative references

The following documents are indispensable for the application of this document: For dated reference documents, only the dated version applies to this article

Pieces: For undated references, the latest version (including all amendments) applies to this document:

GB/T 18779:1 Technical Specification for Product Geometrical Quantity (GPS) Measurement Inspection of Workpieces and Measuring Equipment Part 1: Inspection According to Specifications

Rules for determining qualified or unqualified inspection (GB/T 18779:1-2002, eqvISO 14253-1:1998)

3 Terms and definitions

The following terms and definitions defined in GB/T 18779:1 apply to this document:

3:1

Reverse engineering

Analyze the shape, size and function of the finished workpiece or prototype and use this information to create a design process for similar products:

3:2

Product functional level

Evaluate the completeness of product functions from an overall perspective:

3:3

Productattributefunctionallevelproductattributefunctionallevel

Evaluate the completeness of product functions from specific attributes:

Note: The overall product function level depends on the function level of all product attributes:

3:4

Workpiece functional level

Evaluate the overall completeness of the product function composed of the considered artifacts and a set of qualified artifacts:

3:5

Workpiececharacteristicfunctionallevel

Evaluate the completeness of the product function composed of the considered artifact and a set of qualified artifacts from specific attributes: These attributes are affected by the considered […]