measurements

1. Metrology
Metrology is the science of measurement
Dimensional 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.

2. Aspects of Metrology
Reference standard metrology
Engineering Metrology

3. Basic Measurement Devices
Surface Plates
Test Stands
Dial Gages
Micrometers and Verniers
Gage Blocks

4. Dimensional Metrology Needs
Linear measurements
Angular measurements
Geometric form measurements
 Roundness
 Straightness
 Cylindricity
 Flatness, etc

5. Dimensional Metrology Needs
Geometric relationships
 Parallel, perpendicular, etc.
 Concentric, runout, etc.
Controlled surface texture

6. Communicating Dimensional
Metrology Needs
Geometric Dimensioning and
Tolerancing (GDT)
“The language of dimensional
metrology”
Standard symbols, etc., on part
drawings.

7. Specification of Linear
Tolerances

8. Angular Specifications

9. Angular Tolerances

10. Flatness Specification

11. Flatness Tolerances

12. Straightness Specification

13. Straightness Tolerance

14. Roundness Specification
Roundness applies to every section

15. Roundness Tolerances

16. Surface Profile Without
Datums

17. Line Profile Without Datums

18. Surface Profile with Datums
Profile of a line with datums is similar

19. Surface Profile with Datums

20. Cylindricity Specifications

21. Cylindricity Tolerances

22. Surface Texture Specification

23. Surface Texture

24. Perpendicularity Specification

25. Perpendicularity Measurements

26. Parallelism Specification

27. Parallelism Measurements

28. Concentricity Specification

29. Concentricity Tolerances

30. Concentricity Measurements

31. Concentricity Measurements

32. Circular Runout Specifications

33. Circular Runout Tolerances

34. Total Runout Specifications

35. Total Runout Tolerances

36. Position Specifications

37. Position Tolerances

38. Simulated Datum

39. Datum Selection