1 / 193

Geometric Dimensioning and Tolerancing

Geometric Dimensioning and Tolerancing. Unit 3 – How the GDT System Works. Geometric Tolerancing Workbook. Everyone should have a workbook to follow along. It contains necessary reference information along with class exercises.

ora-hudson
Télécharger la présentation

Geometric Dimensioning and Tolerancing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Geometric Dimensioning and Tolerancing Unit 3 – How the GDT System Works

  2. Geometric Tolerancing Workbook Everyone should have a workbook to follow along. It contains necessary reference information along with class exercises. Page numbers in yellow on the slides match pages in the workbook.

  3. Plus/Minus Tolerancing Drawing with plus/minus or directly toleranced dimensions All ANGLES ±1º 3.2

  4. Manufactured part with variation How do you verify conformance? 3.2

  5. Plus/Minus Tolerancing for unopposed surfaces is not clear. 24.3 MAX A variety of interpretations are possible. 24.3 MAX 24.3 MAX 2.12

  6. All ANGLES ±1º 3.2

  7. Hole Bar Assembly HOLE BAR Function: Part mounts in corner and large hole must clear the blue pin. 3.2

  8. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  9. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 Hole is .750 Pin is .740 .010 Must clear Ø.740 Pin Clearance 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  10. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole is .750 Pin is .740 .010 Must clear Ø.740 Pin Clearance 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  11. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole is .750 Pin is .740 .010 Must clear Ø.740 Pin Clearance 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  12. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 ±.005 establishes a .010 square tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  13. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole moves right and clears the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  14. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole moves left and clears the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  15. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole moves down and clears the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  16. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole moves up and clears the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  17. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole moves diagonal up and over and interferes with the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  18. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole moves diagonal down and over and interferes with the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  19. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Hole moves diagonal up and over and interferes with the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  20. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 ± . 0 0 5 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 ± . 0 0 5 . 7 5 0 Hole moves diagonal down and over and interferes with the pin Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  21. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  22. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 .010 Must clear Ø.740 Pin .010 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  23. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 ± . 0 0 5 ± . 0 0 5 .010 .014 Across Corners Must clear Ø.740 Pin .010 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  24. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 Problem - Square tolerance zone allows more tolerance across the corners than the flats. ± . 0 0 5 ± . 0 0 5 .010 .014 Across Corners Must clear Ø.740 Pin .010 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  25. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 . 7 5 0 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 To solve this problem some designers cut the tolerance to +.0035. This gives .010 across corners but only .007 across flats 5 ± . 0 0 3 ± . 0 0 5 ± . 0 0 5 5 ± . 0 0 3 .007 .010 Across Corners Must clear Ø.740 Pin .007 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  26. HOLE BAR In the past this is how designers calculated hole locations with Plus/Minus tolerancing 1 . 5 0 0 5 ± . 0 0 3 ± . 0 0 5 2 . 5 0 0 . 7 5 8 ± . 0 0 5 . 7 5 0 5 ± . 0 0 3 In the 1930’s, Stanley Parker from the Royal Torpedo factory in Scotland came up with the idea of using round tolerance zones rather than square zones. Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.3

  27. HOLE BAR First, make all the dimensions locating the holes basic, (without tolerance) by placing a box around the dimensions. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  28. HOLE BAR First, make all the dimensions locating the holes basic, (without tolerance) by placing a box around the dimensions. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  29. HOLE BAR Since Geometric Tolerancing is a feature based system, use the position symbol to locate the feature 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  30. HOLE BAR Next, specify that the tolerance zone should be round with the diameter symbol. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  31. HOLE BAR Next, specify the total tolerance of .010 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  32. HOLE BAR The axis of the hole can move up and down and around anywhere within the round tolerance zone. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  33. HOLE BAR The axis of the hole can move up and down and around anywhere within the round tolerance zone. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  34. HOLE BAR The axis of the hole can move up and down and around anywhere within the round tolerance zone. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  35. HOLE BAR The axis of the hole can move up and down and around anywhere within the round tolerance zone. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  36. HOLE BAR The axis of the hole can move up and down and around anywhere within the round tolerance zone. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  37. HOLE BAR The axis of the hole can move up and down and around anywhere within the round tolerance zone. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  38. HOLE BAR The axis of the hole can move up and down and around anywhere within the round tolerance zone. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M .010 diameter tolerance zone Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  39. HOLE BAR Still a problem. Must establish a Datum Reference Frame. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M Must clear Ø.740 Pin 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  40. HOLE BAR Still a problem. Must establish a Datum Reference Frame. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in assembly 2 . 5 0 0 3.6

  41. HOLE BAR Produced part is imperfect and not square 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M Imperfect part 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  42. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  43. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  44. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  45. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  46. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  47. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  48. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  49. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

  50. HOLE BAR How do you place an imperfect datum reference frame? It rattles around. 1 . 5 0 0 2 . 5 0 0 . 7 5 8 . 7 5 0 . 0 1 0 A B C M 1 . 5 0 0 Part mounted in DRF 2 . 5 0 0 3.6

More Related