Metrology
Metrology is the science of measurementDimensional metrology is that branch of Metrology which deals with measurement of “dimensions“ of a part or workpiece (lengths, angles, etc.)Dimensional measurements at the required level of accuracy are the essential link between the designers’ intent and a delivered product.
Aspects of Metrology
Reference standard metrologyEngineering Metrology
Basic Measurement Devices
Surface PlatesTest StandsDial GagesMicrometers and VerniersGage Blocks
Dimensional Metrology Needs
Linear measurementsAngular measurementsGeometric form measurements Roundness Straightness Cylindricity Flatness, etc
Dimensional Metrology Needs
Geometric relationships Parallel, perpendicular, etc. Concentric, runout, etc.
Controlled surface texture
Communicating Dimensional Metrology Needs
Geometric Dimensioning and Tolerancing (GDT)“The language of dimensional metrology”Standard symbols, etc., on part drawings.
Specification of Linear Tolerances
Angular Specifications
Angular Tolerances
Flatness Specification
Flatness Tolerances
Straightness Specification
Straightness Tolerance
Roundness Specification
Roundness applies to every section
Roundness Tolerances
Surface Profile Without Datums
Line Profile Without Datums
Surface Profile with Datums
Profile of a line with datums is similar
Surface Profile with Datums
Cylindricity Specifications
Cylindricity Tolerances
Surface Texture Specification
Surface Texture
Perpendicularity Specification
Perpendicularity Measurements
Parallelism Specification
Parallelism Measurements
Concentricity Specification
Concentricity Tolerances
Concentricity Measurements
Concentricity Measurements
Circular Runout Specifications
Circular Runout Tolerances
Total Runout Specifications
Total Runout Tolerances
Position Specifications
Position Tolerances
Simulated Datum
Datum Selection
