Understanding True Position with MMC in Calypso. Last Updated: 9/15/2014 True Position with MMC 1

Transcription

1 Understanding True Position with MMC in Calypso Last Updated: 9/15/2014 True Position with MMC 1

2 This presentation shows how MMC applied to features and datums effect the calculation and evaluation of True Position characteristics. For each case, the GD&T control frame for the True Position, Calypso characteristic window and Calypso custom printout to go with each True Position, and an explanation of each result is shown. Last Updated: 9/15/2014 True Position with MMC 2

3 The Print: -A- C B Ø 1.0 ± 0.1 typ 3 places A True Position Tolerance is given to this hole with MMC applied to feature and datums. Last Updated: 9/15/2014 True Position with MMC 3

4 Feature Actuals and True Position Callout: C Y=10 Ø 1.0 ± 0.1 typ 3 places -A- Ø 0.1 A B C B X=10.1 Last Updated: 9/15/2014 True Position with MMC 4

5 Calypso Characteristic: Calypso Report: Last Updated: 9/15/2014 True Position with MMC 5

6 Why the Answer?: -C- The result for True Position can be thought of as the diameter of a circle, centered at the target (basic dimensions), that contains the actual center. Y True Position Result = Ø 0.2 -B- True Position Tolerance = Ø 0.1 X Feature Target 10.1 Feature Actual Last Updated: 9/15/2014 True Position with MMC 6

7 Feature Actuals and True Position Callout: C Y=10 -A- Ø 1.0 ± 0.1 typ 3 places Ø 0.1 M A B C B X=10.1 Last Updated: 9/15/2014 True Position with MMC 7

8 Calypso Characteristic: Calypso Report: Last Updated: 9/15/2014 True Position with MMC 8

9 Why the Answer?: -C- When MMC is applied to the Feature, the Tolerance Band grows by the amount of the bonus. -B- Y X (bonus = actual Ø smallest allowable Ø for a hole at MMC) True Position Result = Ø 0.2 True Position Tolerance with Bonus = Ø 0.2 Feature Target Feature Actual 10.1 Last Updated: 9/15/2014 True Position with MMC 9

10 Feature Actuals and True Position Callout: C Y=10 -A- Ø 1.0 ± 0.1 typ 3 places Ø 0.1 A B M C B X=10.1 Last Updated: 9/15/2014 True Position with MMC 10

11 Calypso Characteristic: Calypso Report: Last Updated: 9/15/2014 True Position with MMC 11

12 Why the Answer?: -C- When MMC is applied to the ing Datum, the coordinate system center can move within a circle centered at the actual datum center, with a diameter of the bonus. In this case, the Y axis must go through the exact center of the clocking datum, since no MMC is applied there. Bonus on Ø 0.1 -B- True Position Result = Ø True Position Tolerance = Ø 0.1 Feature Target Feature Actual Last Updated: 9/15/2014 True Position with MMC 12

13 Feature Actuals and True Position Callout: C Y=10 -A- Ø 1.0 ± 0.1 typ 3 places Ø 0.1 A B C M B X= Last Updated: 9/15/2014 True Position with MMC 13

14 Calypso Characteristic: Calypso Report: Last Updated: 9/15/2014 True Position with MMC 14

15 Why the Answer?: Bonus on Clocking Ø 0.1 -C- -B- Y When MMC is applied to the clocking datum and not the centering datum, the origin of the coordinate system cannot change. The rotation, however, can change, so the Y axis passes through the bonus circle around the clocking datum s center. Since Rotation does not bring the feature center closer to the target center, the answer is the same as if no MMC is applied at all. True Position Tolerance = Ø 0.1 X True Position Result = Ø 0.2 Feature Target 10.1 Feature Actual Last Updated: 9/15/2014 True Position with MMC 15

16 Feature Actuals and True Position Callout: C Y=10 -A- Ø 1.0 ± 0.1 typ 3 places Ø 0.1 A B M C M B X=10.1 Last Updated: 9/15/2014 True Position with MMC 16

17 Calypso Characteristic: Calypso Report: Last Updated: 9/15/2014 True Position with MMC 17

18 Why the Answer?: Bonus on Clocking Ø 0.1 -C- Bonus on Ø 0.1 -B- Y X When MMC is applied to the ing Datum and the Clocking Datum, the Coordinate system is free to rotate and translate within the constraints of the bonus circles centered on both datums. The Coordinate system can move half of the datum bonus amount toward the feature center. True Position Result = Ø 0.1 True Position Tolerance = Ø 0.1 Feature Target 5 Feature Actual Last Updated: 9/15/2014 True Position with MMC 18

19 Feature Actuals and True Position Callout: C Y=10 -A- Ø 1.0 ± 0.1 typ 3 places Ø 0.1 M A B M C M B X=10.1 Last Updated: 9/15/2014 True Position with MMC 19

20 Calypso Characteristic: Calypso Report: Last Updated: 9/15/2014 True Position with MMC 20

21 Why the Answer?: Bonus on Clocking Ø 0.1 -C- Bonus on Ø 0.1 -B- Y X When MMC is applied to the Feature and Datums, all mobility of the Coordinate system discussed in previous slides apply, plus there is a larger overall tolerance zone for the feature. Calypso will bestfit until either the true position result is within tolerance, or the result cannot be improved further. True Position Result = Ø True Position Tolerance with Bonus = Ø 0.2 Feature Target Feature Actual 75 Last Updated: 9/15/2014 True Position with MMC 21