UNIT - 4 - FORM MEASUREMENT new STS PEC .pptx

FORM MEASUREMT in METROLOGY PEC

1. UNIT IV FORM MEASUREMENT

2. Screw thread Terminology:

3. Me a sur e m ent by B e nch micrometer: C l a m p Fiducial I nd i c a t o r M e a s u r i n g Anvils Holdingcentres M i c r o m e t e r h e a d Supports BENCHMICROMETER

4. Measurement by Bench micrometer: Then the cylinder is replaced by the threaded work piece and the new reading is taken

5. Measurement by Bench micrometer:

6. Measurement by Bench micrometer: Holdingcentre Measuringanvil H o l d i n g c e n t r e Measuringanvil StandardCylinder S c r e w T h r ea d Measurement of Major diameter

7. Measurement of Minor diameter

8. Measurement of Minor diameter of Internal threads: 1. Using taper parallels: For diameters less than 200mm the use of Taper parallels and micrometer is very common. Th e taper par a llels a r e pairs o f wed g es having redu ce d and parallel outer edges. The diameter across their outer edges can be changed by sliding them over each other.

9. Measurement of Minor diameter of Internal threads: Using rollers: For more than 200mm diameter this method is used. Precision rollers are inserted inside the thread and proper slip gauge is inserted between the rollers. The minor diameter is then the length of slip gauges plus twice the diameter of roller.

10. Measurement of Effective Diameter: One wire method Two Wires method Three wires method

11. One wire method:

12. Two wire method In this method wires of suitable size are placed between the standard and the micrometer anvils

13. Three Wire Method:

14. Derivation for the difference between Effective diameter and diameter under wire:

15. Deri v at i on f or fi n di n g Effe c t i ve di a m e ter by three wire method:

16. Where, S = Distance over wires De = Effective diameter P = Pitch r = Radius of wire h = Height of wire center above the pitch line H = Depth of thread d = Diameter of wire (2r)

17. Pitch measurement:

18. Pitch measuring machine:

19. Tool makers microscope:

20. Gear tooth Terminology:

21. Gear Measurement/Inspection: Types of inspection: Functional Inspection Analytical Inspection

22. Functional Inspection: Parkinson Gear testing machine (or) Rolling Gear Tester:

23. Analytical Inspection:

24. Pitch measurement: Direct angular measurement Point to point measurement (i.e. One tooth point to next toot point)

25. Direct Angular Measurement:

26. Tooth to Tooth measurement:

27. Profile checking: Optical projection method Involute measuring machine

28. Gear tooth vernier caliper method:

29. Tooth measurement: 1. Gear tooth vernier caliper method / Chordal thickness method

30. Finding width and depth of gear teeth

31. co nt d ,.,

32. co nt d ,.,

33. 2. Constant chord method:

34. co nt d ,.,

35. co nt d ,.,

36. c o n t d ,.,

37. C.L.A INDEX METHOD:

38. R.M.S AVERAGE METHOD:

39. TEN POINT HEIGHT METHOD:

40. Peak to Valley Method:

41. Form factor Method:

42. In d ica t ion o f surface i n engineering drawing:

43. Tomlinson Surface Meter:

44. Profilo m eter:

45. Taylor-Hobson Talysurf:

46. Roundness Measurement: Roundness is the measure of how closely the shape of an object approaches that of a mathematically perfect circle. Roundness measurement methods Diametral method Circumferential confining method Rotating between centers Measurement using V-block 5. Measurement by plotting polar graph 6. Three-point probe method 7. Accurate spindle method 8. Modern roundness measuring in s trum e n ts

47. Diametral method

48. Circumferential confining method

49. Rotating between center s Measurement using V-block

50. Measurement by plotting polar graph Small concentric circle Maximum circular diameter Actual profile of the Workpiece

51. Three point probe method Accurate spindle method