GB/T 17421.1-2023 Test code for machine tools- Part 1 : Geometric accuracy of machines operating under no-load or quasi-static conditions
1 Scope
This document specifies methods for testing the accuracy of machine tools, operating either under no-load or under quasi-static conditions, by means of geometric and machining tests. The methods can also be applied to other types of industrial machines.
This document covers power-driven machines, which can be used for machining metal, wood, etc., by the removal of chips or swarf material or by plastic deformation. It does not cover power-driven portable hand tools.
This document relates to the testing of geometric accuracy. It is not applicable to the operational testing of the machine tool (vibrations, stick-slip motion of components, etc.) or to the checking of characteristics (speeds, feeds).
This document does not cover the geometric accuracy of high-speed machine motions where machining forces are typically smaller than acceleration forces.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1 Geometrical Product Specifications (GPS) - Standard reference temperature for geometrical product specification and verification
Note: GB/T 19765-2005 Geometrical Product Specifications (GPS) - Standard reference for geometrical product specification and verification (ISO 1:2002, IDT)
ISO 230-2 Test code for machine tools - Part 2: Determination of accuracy and repeatability of positioning of numerically controlled axes
Note: GB/T 17421.2-2023 Test code for machine tools - Part 2:Determination of accuracy and repeatability of positioning of numerically controlled axes (ISO 230-2:2014, IDT)
ISO 230-4 Test code for machine tools - Part 4 : Circular tests for numerically controlled machine tools)
Note: GB/T 17421.4-2016 Test code for machine tools - Part 4 : Circular tests for numerically controlled machine tools (ISO 230-4 : 2005, IDT)
ISO 230-6 Test code for machine tools- Part 6: Determination of positioning accuracy on body and face diagonals (Diagonal displacement tests)
Note: GB/T 17421.6-2016 Test code for machine tools - Part 6 : Determination of positioning accuracy on body and face diagonals (Diagonal displacement tests) (ISO 230-6 : 2002, IDT)
ISO 230-7 Test code for machine tools - Part 7: Geometric accuracy of axes of rotation)
Note: GB/T 17421.7-2016 Test code for machine tools - Part 7:Geometric accuracy of axes of rotation (ISO 230-7:2006,IDT)
ISO 841 Industrial automation systems and integration- Numerical control of machines- Coordinate system and motion nomencla-ture
Note: GB/T 19660-2005 Industrial automation systems and integration-Numerical control of machines - Coordinate system and motion nomenclature (ISO 841:2001, IDT)
ISO 1101 Geometrical Product Specifications (GPS) - Geometrical tolerancing - Tolerances of form, orientation, location and run-out]
Note: GB/T 1182-2018 Geometrical product specifications (GPS) - Geometrical tolerancing - Tolerances of form, orientation, location and run-out (ISO 1101:2017, MOD)
ISO 12181-1:2011 Geometrical product specifications (GPS) - Roundness- Part 1: Vocabulary and parameters of roundness
Note: GB/T 24632.1-2009 Geometrical Product Specifications(GPS) - Roundness - Part 1:Vocabulary and parameters of roundness (ISO/TS 12181-1 :2003,IDT)
ISO 12780-1:2011 Geometrical product specifications (GPS)- Straightness- Part 1: Vocabulary and parameters of straightness
Note: GB/T 24631.1-2009 Geometrical product specifications(GPS) - Straightness - Part 1:Vocabulary and parameters of straightness (ISO/TS 12780-1 : 2003, IDT)
ISO 12781-1:2011 Geometrical product specifications (GPS) - Flatness- Part 1 : Vocabulary and parameters of flatness]
Note: GB/T 24630.1-2009 Geometrical Product Specifications (GPS) - Flatness - Part 1 : Vocabulary and parameters of flatness (ISO/TS 12781-1:2003, IDT)
ISO 14253-1 [Geometrical product specifications (GPS)-Inspection by measurement of workpieces and measuring equipment - Part 1: Decision rules for proving conformance or non-conformance with specifications
Note: GB/T 18779.1-2022 Geometrical product specifications (GPS) - Inspection by measurement of workpieces and measuring equipment - Part 1 : Decision rules for verifying conformity or nonconformity with specifications (ISO 14253-1 : 2017, IDT)
3 Terms and definitions
3.1 General
For the purposes of this document, the terms and definitions given in ISO 230-2, ISO 230-4, ISO 230-7, ISO 841, ISO 12181-1, ISO 12780-1 and ISO 12781-1 and the following apply.
This document uses metrological definitions, which take into account actual motions, real lines and surfaces accessible to measurement taking into account the limitations introduced by the construction or the practicality of geometric verification.
Note 1: In some cases, geometric definitions (definitions of run-out, etc.) have been retained in this document, in order to eliminate any confusion and to clarify the language used. However, when describing test methods, measuring instruments and tolerances, metrological definitions are taken as the basis.
Note 2: For the alphabetical list of terms and definitions, see the index.
3.2 Terms for machine coordinate system and motion nomenclature
3.2.1
machine coordinate system
right-hand rectangular system with the three principal axes labelled X, Y and Z, with rotary axes about each of these axes labelled A, B and C, respectively. See Figure 1.
3.3 Terms for static compliance and hysteresis
3.3.1
structural loop
assembly of components, which maintains the relative position between two specified objects
Note: A typical pair of specified objects is a cutting tool and a workpiece, in which case the structural loop includes the spindle, bearings and spindle housing, the machine headstock, the machine slideways and frame, and the fixtures for holding the tool and workpiece. For large machines, the foundation can also be part of the structural loop.
[Source: ISO 230-7: 2006, 3.1.13, modified]
3.3.2
static compliance
linear (or angular) displacement per unit static force (or moment) between two objects, specified with respect to the structural loop, the location and direction of the applied forces, and the location and direction of the displacement of interest
Note 1: Static compliance is reciprocal to static stiffness. Static compliance is preferred because of its additive properties.
Note 2: The term "cross compliance" is used when displacement and force are not measured in the same direction.
3.3.3
play
condition of zero stiffness over a limited range of displacement due to clearance between the components of a structural loop
[Source: ISO 230-7: 2006, 3.1.21]
3.3.4
hysteresis
linear (or angular) displacement between two objects resulting from the sequential application and removal of equal forces (or moments) in opposite directions
[Source: ISO 230-7: 2006, 3.1.22]
3.3.5
setup hysteresis
hysteresis of the various components in a test setup, normally due to loose mechanical connections
[Source: ISO 230-7: 2006, 3.1.22.1]
3.3.6
machine hysteresis
hysteresis of the machine structure when subjected to specific loads
[Source: ISO 230-7: 2006, 3.1.22.2]
