Geometric Dimensioning and Tolerancing Unit 4 – Position Verification

Coordinate Measuring Machine (CMM) Typical ‘bridge’ CMM is composed of 3 axes. A touch probe indicates contact with a body. Typical precision measured in microns or micrometers (10-6 m)

CMM

Position Tolerance Verification This unit covers some simple verification techniques for position tolerancing.

3.6 C B A Position Tolerancing Verification Actual Manufactured Part 1 2 . 5 7 8 1 C B A ± M Size of hole is produced at .750 (MMC). X² + Y² = Z² - Pythagorean Theorem 2X .005 = Ø.010 Tol Zone X² + Y² = Z X² + Y² = Diameter Tol Zone 2 Actual Manufactured Part .005 .004 The following slides illustrate how a position tolerance may be verified. The object is not to make everyone experts in inspection but impart some general knowledge on the verification procedure. The material explains the verification principles of geometric tolerancing. This discussion will prepare the students for the verification exercises they must complete in unit 4. This material is covered at the end of unit 3 or at the beginning of unit 4. To ensure continuity, the Hole Bar in the model set is used to explain the verification principles and then in unit 4 the students will work similar position verification exercises. 1.504 Actual 2.503 Actual .003 1.500 Let us check this part to see if the hole location is within tolerance. 2.500 3.6

Chart that can be used to convert plus/minus values to position tolerance. See also inch chart on rear cover of pocket guide and metric chart on rear inside cover of pocket guide. 4.7/4.8

3.6 C B A Position Tolerancing Verification Actual Manufactured Part 1 2 . 5 7 8 1 C B A ± M Since the hole is produced at MMC (.750), it is allowed .010 position tolerance. The actual calculated position of the hole falls within the .010 zone. 2X .005 = Ø.010 Tol Zone Actual Manufactured Part .005 .004 The following slides illustrate how a position tolerance may be verified. The object is not to make everyone experts in inspection but impart some general knowledge on the verification procedure. The material explains the verification principles of geometric tolerancing. This discussion will prepare the students for the verification exercises they must complete in unit 4. This material may be covered at the end of unit 3 or at the beginning of unit 4. To ensure continuity, the hole bar from the model set is used to explain the verification principles and then in unit 4 the students will work similar position verification exercises. 1.504 Actual 2.503 Actual .003 1.500 2.500 3.6

3.6 C B A Position Tolerancing Verification Actual Manufactured Part 1 2 . 5 7 8 1 C B A ± M Size of hole is produced at .755. Let us try another example, this time the hole is produced at .755. Is the location good or bad? Actual Manufactured Part .005 The following slides illustrate how a position tolerance may be verified. The object is not to make everyone experts in inspection but impart some general knowledge on the verification procedure. The material explains the verification principles of geometric tolerancing. This discussion will prepare the students for the verification exercises they must complete in unit 4. This material may be covered at the end of unit 3 or at the beginning of unit 4. To ensure continuity, the Hole bar is used to explain the verification principles and then in unit 4 the students will work similar position verification exercises. 1.505 Actual 2.506 Actual .006 1.500 Let us check this part to see if the hole location is within tolerance. 2.500 3.6

4.7/4.8

3.6 C B A Position Tolerancing Verification 1 8 ± 7 M 2 . 5 7 8 1 C B A ± M If the hole is produced at .755, it is allowed a position tolerance of .015. The calculations show the hole is produced within a .0156 zone, so the hole location is out by .0006. 2X .0078 = Ø.0156 Tol Zone .0078 .005 The following slides illustrate how a position tolerance may be verified. The object is not to make everyone experts in inspection but impart some general knowledge on the verification procedure. The material explains the verification principles of geometric tolerancing. This discussion will prepare the students for the verification exercises they must complete in unit 4. This material may be covered at the end of unit 3 or at the beginning of unit 4. To ensure continuity, the Hole bar is used to explain the verification principles and then in unit 4 the students will work similar position verification exercises. 1.505 Actual 2.506 Actual .006 1.500 The above part may be repaired by opening the size of the hole by .0006. 2.500 3.6

4.5 Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. 4.5

4.5 MMC =Smallest Hole MMC = Smallest Hole .371 Class Exercise Position Verification At MMC- Inch As drawn MMC =Smallest Hole Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. MMC = Smallest Hole .371 4.5

4.5 Actual Size of Hole Actual Size of Hole .371 .376 Class Exercise Position Verification At MMC- Inch As drawn Actual Size of Hole Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. Actual Size of Hole .371 .376 4.5

4.5 .005 Position Plus .005 Departure from MMC .010 Class Exercise Position Verification At MMC- Inch As drawn .005 Position Plus .005 Departure from MMC .010 Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. Position + Departure from MMC = .010 .371 .376 .010 4.5

4.5 X Deviation .371 .376 .010 -.004 Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. X Deviation .371 .376 .010 -.004 4.5

4.5 Y Deviation Y Deviation .371 .376 .010 -.004 +.002 Class Exercise Position Verification At MMC- Inch As drawn Produced part Y Deviation The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. Y Deviation .371 .376 .010 -.004 +.002 4.5

This conversion chart may be found in the workbook as well as on the pocket guide. There are two charts available, one is metric and the other is inch. 4.7

4.5 From Chart .371 .376 .010 -.004 +.002 .0089 Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. From Chart .371 .376 .010 -.004 +.002 .0089 4.5

4.5 From Chart .371 .376 .010 -.004 +.002 .0089 X Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. From Chart .371 .376 .010 -.004 +.002 .0089 X 4.5

Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. .371 .376 .010 -.004 +.002 .0089 X 4.5 .371

Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. .371 .376 .010 -.004 +.002 .0089 X 4.5 .371 .379

Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. .371 .376 .010 -.004 +.002 .0089 X 4.5 .371 .379 .013

Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. .371 .376 .010 -.004 +.002 .0089 X 4.5 .371 .379 .013 +.004

Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. .371 .376 .010 -.004 +.002 .0089 X 4.5 .371 .379 .013 +.004 +.005

4.7

Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. .371 .376 .010 -.004 +.002 .0089 X 4.5 .371 .379 .013 +.004 +.005 .0128

Class Exercise Position Verification At MMC- Inch As drawn Produced part The upper drawing on this slide is the part print. The lower drawing is a produced part and its associated actual measured dimensions. The instructor should use this graphic to explain the procedure to the students. .371 .376 .010 -.004 +.002 .0089 X 4.5 .371 .379 .013 +.004 +.005 .0128 X

POSITION Hole Verification at MMC 4.3

4.14 Workshop Exercise 4.6 - Inch Have the students work the problems and afterwards click thru the slides and provide the answers. Walk around and make sure students are understanding the problems. 4.14

Workshop Exercise 4.6 - Inch 4.14