6/23/2016 Copyright 2016 Society of Manufacturing Engineers

Transcription

1 6/23/2016 Copyright 2016 Society of Manufacturing Engineers GEOMETRIC DIMENSIONING & TOLERANCING FUNDAMENTALS Form Controls & Datums - GDT2 TRT: 25:44 Minutes SCENE 1. GDT01A, CGS: FBI warning white text, centered GDT EXM, extended motion background WARNING The unauthorized reproduction or distribution of a copyrighted work is illegal. Criminal copyright infringement, including infringement without monetary gain, is investigated by the FBI and is punishable by fines and federal imprisonment. SCENE 2. GDT02A, SME logo open, with sound SCENE 3. GDT03A, GD&T open, with music & title: CGS: Geometric Dimensioning & Tolerancing Fundamentals GDT03P, CGS: Form Controls & Datums GDT03Y, edited peter carey narration GDT03C, dark blueprint background GDT03D, light blueprint background GDT03E, sound slug GDT03F, black video THIS IS THE SECOND OF THREE PROGRAMS EXPLORING GEOMETRIC DIMENSIONING AND TOLERANCING FUNDAMENTALS. IT S FOCUS IS ON FORM CONTROLS AND DATUMS. --- TOUCH BLACK --- SCENE 4. GDT2_04A, SME4315, 09:44:51:00-09:45:05:00 zoom out, looking at print with GD&T GDT2_04B, SME4315, 09:06:24:00-09:06:36:00 zoom in, fixture designer working on CAD GDT2_04C, SME4315, 09:31:50:00-09:32:11:00 zoom in, manufacture of fixture part GDT2_04D, SME4306, 06:14:41:00-06:15:05:00 zoom in, inspection of part THE GD&T, OR GEOMETRIC DIMENSIONING AND TOLERANCING, SYSTEM USES SYMBOLS, LETTERS, NUMBERS, AND MODIFIERS TO CLEARLY COMMUNICATE PRINT DESIGN REQUIREMENTS, WITH THE OVERALL GOAL BEING FOR DESIGN..., MANUFACTURING..., AND INSPECTION PERSONNEL TO ALL INTERPRET THE PRINT IN THE SAME MANNER.

2 6/23/2016 Copyright 2016 Society of Manufacturing Engineers SCENE 5. GDT2_05A, SME4307, 07:28:24:00-07:29:11:00 zoom out, inspection of crankshaft GDT2_05B, CGS: Flexible Tolerance Zone Shapes Reduced Drawing Assumptions Clearly Communicated Datums Fit & Function Based Tolerancing Allowances For Additional Tolerance/Bonus Tolerance International Usage & Understanding SOME OF THE MOST SIGNIFICANT BENEFITS OF GD&T INCLUDE: FLEXIBLE TOLERANCE ZONE SHAPES, REDUCED DRAWING ASSUMPTIONS, CLEARLY COMMUNICATED DATUMS, FIT AND FUNCTION BASED TOLERANCING, ALLOWANCES FOR ADDITIONAL TOLERANCE- SOMETIMES CALLED A BONUS TOLERANCE, AND INTERNATIONAL USAGE AND UNDERSTANDING. SCENE 6. GDT1_33A, ANI: 14 GD&T symbols, each symbol GDT2_06A, ANI: ASME GD&T standard GDT03D, light blueprint background AT THE HEART OF THE GD&T SYSTEM ARE THE FOURTEEN GEOMETRIC CHARACTERISTIC SYMBOLS, WHICH ARE DEFINED BY THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS, OR ASME STANDARD Y SCENE 7. GDT1_33A_01, ANI: 14 GD&T symbols, highlight form tolerances GDT1_33B, CGS: Form Tolerances GDT1_33C, ANI: isolate form tolerances GDT1_33D, CGS: Profile Tolerances GDT1_33E, ANI: isolate profile tolerances GDT1_33F, CGS: Orientation Tolerances GDT1_33G, ANI: isolate orientation tolerances GDT1_33H, CGS: Location Tolerances GDT1_33I, ANI: isolate location tolerances GDT1_33J, CGS: Runout Tolerances GDT1_33K, ANI: isolate runout tolerances GDT2_07A, SME4420, 11:10:38:00-11:10:56:00 measuring part, looking at print with GD&T THESE SYMBOLS ARE GROUPED INTO FIVE CATEGORIES: FORM TOLERANCES..., PROFILE TOLERANCES..., ORIENTATION TOLERANCES..., LOCATION TOLERANCES..., AND RUNOUT TOLERANCES. BY USING THESE SYMBOLS, ALONG WITH DATUM REFERENCES, THE FUNCTIONAL REQUIREMENTS

3 6/23/2016 Copyright 2016 Society of Manufacturing Engineers OF A PART OR ASSEMBLY ARE EFFECTIVELY COMMUNICATED. SCENE 8. GDT1_33A_01, ANI: 14 GD&T symbols GDT1_34B, ANI: straightness icon enlarged over 14 GD&T symbols GDT1_34D, ANI: flatness icon enlarged over 14 GD&T symbols GDT1_34F, ANI: circularity icon enlarged over 14 GD&T symbols GDT1_34H, ANI: cylindricity icon enlarged over 14 GD&T symbols GDT1_36B, ANI: profile of a line icon enlarged over 14 GD&T symbols GDT1_36D, ANI: profile of a surface icon enlarged over 14 GD&T symbols GDT1_39B, ANI: angularity icon enlarged over 14 GD&T symbols GDT1_39D, ANI: perpendicularity icon enlarged over orientation tolerances GDT1_39F, ANI: parallelism icon enlarged over 14 GD&T symbols GDT1_41B, ANI: position icon enlarged over 14 GD&T symbols GDT1_41D, ANI: concentricity icon enlarged over 14 GD&T symbols GDT1_41F, ANI: symmetry icon enlarged over 14 GD&T symbols GDT1_43B, ANI: circular runout icon enlarged over 14 GD&T symbols GDT1_43D, total runout icon enlarged over 14 GD&T symbols GDT1_33A_01, 14 GD&T symbols GDT2_08A, SME4351, 03:09:50:00-03:10:08:00 manufacturing operation GDT2_08B, SME4420, 11:32:48:00-11:33:05:00 inspection operation IT S COMMON TO ENCOUNTER SITUATIONS WHERE MORE THAN ONE OF THESE GD&T SYMBOLS COULD BE USED FOR A SIMILAR PART CALLOUT. THESE DIFFERENCES MIGHT AFFECT DOWNSTREAM MANUFACTURING OPERATIONS, INSPECTION AND TOLERANCE VERIFICATION ACTIVITIES. SCENE 9. GDT1_33A_01, ANI: 14 GD&T symbols GDT1_34A, ANI: form tolerances isolated GDT1_33B, CGS: Form Tolerances GDT1_16D, ANI: part drawing with hole, with GD&T GDT1_16E, ANI: part drawing with hole, with GD&T, datum A GDT1_16F, ANI: part drawing with hole, with GD&T, datum B GDT1_16G, ANI: part drawing with hole, with GD&T, datum C TO UNDERSTAND THE FINER POINTS OF EACH, THIS PROGRAM WILL INTRODUCE YOU TO THE FOUR SYMBOLS IN THE FIRST CATEGORY, FORM, THE CONCEPTS REGARDING THEIR USE; AND COVER THE PROPER IDENTIFICATION AND USAGE OF DATUMS IN THE GD&T SYSTEM. --- TOUCH BLACK ---

4 6/23/2016 Copyright 2016 Society of Manufacturing Engineers SCENE 10. GDT1_34A, ANI: form tolerances isolated GDT1_33B, CGS: Form Tolerances GDT1_34B, ANI: straightness icon enlarged over form tolerances GDT1_34C, CGS: Straightness GDT1_34D, ANI: flatness icon enlarged over form tolerances GDT1_34E, CGS: Flatness GDT1_34F, ANI: circularity icon enlarged over form tolerances GDT1_34G, CGS: Circularity GDT1_34H, ANI: cylindricity icon enlarged over form tolerances GDT1_34I, CGS: Cylindricity THE FOUR FORM TOLERANCE SYMBOLS INCLUDE: STRAIGHTNESS..., FLATNESS..., CIRCULARITY..., AND CYLINDRICITY. SCENE 11. GDT2_11A, ANI: form tolerances isolated GDT2_11B, ANI: straightness icon GDT2_11C, ANI: flatness icon GDT2_11D, ANI: circularity icon GDT2_11E, ANI: cylindricity icon GDT1_35B, ANI: datum surface in circle GDT1_35C, ANI: datum surface in circle, crossed out THESE SYMBOLS ONLY DEFINE AND CONTROL THE SHAPE OF A FEATURE INDIVIDUALLY. THEY NEVER CONTROL A RELATIONSHIP TO ANOTHER FEATURE. SINCE DATUMS ARE NEEDED ONLY WHEN ESTABLISHING A RELATIONSHIP BETWEEN TWO OR MORE FEATURES, FORM SYMBOLS NEVER REFERENCE DATUMS. --- TOUCH BLACK --- SCENE 12. GDT1_34B, ANI: straightness icon enlarged over form tolerances GDT1_34C, CGS: Straightness GDT2_12A, ANI: drawing with straightness tolerance GDT2_12B, ANI: part generated from drawing on blue background GDT2_12C, ANI: c.u. circle on top of part generated from drawing GDT2_12D, ANI: c.u. circle on top of part generated from drawing, straight line, GDT2_12E, ANI: c.u., theoretically straight part on blurred blue background GDT2_12F, ANI: drawing with straightness tolerance, GDT2_12G, ANI: drawing with straightness tolerance, tolerance lines appear GDT2_12H, ANI: drawing with straightness tolerance, tolerance lines STRAIGHTNESS IS A TWO-DIMENSIONAL TOLERANCE AND IS OFTEN APPLIED TO A SURFACE FEATURE. PERFECT, THEORETICAL STRAIGHTNESS WOULD MEAN THAT EVERY POINT ALONG A SURFACE ELEMENT FORMS AN ABSOLUTE, STRAIGHT LINE. SINCE PERFECT STRAIGHTNESS IS IMPOSSIBLE TO ACHIEVE, STRAIGHTNESS IS COMMONLY SPECIFIED WITHIN A TOLERANCE ZONE. IN THIS

5 6/23/2016 Copyright 2016 Society of Manufacturing Engineers GDT2_12I, ANI: nest EXAMPLE, THE STRAIGHTNESS TOLERANCE OF EACH TOP ELEMENT OF THE PART IS 0.5 MILLIMETERS. THIS MEANS THAT FROM ONE END OF THE PART TOP TO THE OTHER, ALL POINTS MAY DEVIATE ANYWHERE WITHIN TWO IMAGINARY PARALLEL LINES THAT ARE SPACED APART BY HALF A MILLIMETER. SCENE 13. continue previous shot GDT2_12B, ANI: part generated from drawing on blue background GDT2_13A, ANI: part generated from drawing with tolerance zone GDT2_13B, ANI: part generated from drawing with tolerance zone, 05. & arrows appear GDT2_13C, ANI: c.u. circle on top of part GDT2_13D, ANI: c.u. circle on top of part with 0.5 tolerance zone GDT2_13E, ANI: c.u. rough part surface GDT2_13F, ANI: nest IN GD&T, THE GIVEN TOLERANCE NUMBER IS ALWAYS A TOTAL TOLERANCE. SO THIS STRAIGHTNESS TOLERANCE ZONE SHOULD NOT BE THOUGHT OF AS A PLUS/MINUS TOLERANCE. RATHER, IT IS A TOTAL TOLERANCE OF 0.5 MILLIMETERS. THIS MEANS THAT THE ACTUAL PART SURFACE MUST FALL WITHIN THESE IMAGINARY PARALLEL LINES TO PRODUCE AN ACCEPTABLE PART. POINTS ON THE PART SURFACE CAN VARY GREATLY, AND STILL BE CONSIDERED STRAIGHT, AS LONG AS THEY DON T STRAY OUTSIDE THE STRAIGHTNESS TOLERANCE ZONE. SCENE 14. GDT2_14A, ANI: straightness drawing GDT2_14B, ANI: straightness drawing, tolerance GDT2_14C, ANI: cylinder GDT2_14D, ANI: cylinder with tolerance zone line, wide GDT2_14E, ANI: cylinder with tolerance zone line, close up GDT2_14F, ANI: cylinder, close up, rotation arrow GDT2_14G, ANI: cylinder with tolerance zone line, wide, dimensions GDT2_14H, ANI: cylinder with tolerance zone line, wide, center axis CYLINDERS MAY ALSO HAVE A STRAIGHTNESS TOLERANCE. TYPICALLY, STRAIGHTNESS IS VERIFIED ON A LINE ELEMENT - END TO END. ADDITIONAL LINE ELEMENTS ARE VERIFIED BY ROTATING AND INSPECTING THE PART MULTIPLE TIMES UNTIL A REASONABLE NUMBER

6 6/23/2016 Copyright 2016 Society of Manufacturing Engineers OF LINE ELEMENTS HAVE BEEN CHECKED. IN add circular tolerance zone???? Scene 26?? ADDITION, THE DIAMETER OF THE CYLINDER MUST ALWAYS BE WITHIN THE GIVEN SIZE TOLERANCE. A STRAIGHTNESS REQUIREMENT MAY ALSO BE APPLIED TO THE CENTER AXIS OF THE CYLINDER. SCENE 15. GDT1_34A, ANI: form tolerances isolated GDT1_34D, ANI: flatness icon enlarged over form tolerances GDT1_34E, CGS: Flatness GDT2_15A, SME3791, 11:07:59:00-11:08:10:00 injection mold opening, dropping part, then closing GDT2_15B, SME3783, 01:16:02:00-01:16:10:00 alternate shot, injection mold insert placed in mold cavity GDT2_15C, ANI: drawing with datum feature given flatness tolerance GDT2_15D, ANI: drawing with datum feature given flatness tolerance, datum GDT2_15E, ANI: drawing with datum feature given flatness tolerance, datum & tolerance FLATNESS IS ONE OF THE MOST COMMON GEOMETRIC TOLERANCES, AND IS USEFUL FOR MOUNTING SURFACES OR OTHER AREAS OF INTERFACE. OFTEN A DATUM FEATURE WILL BE GIVEN A FLATNESS TOLERANCE TO IMPROVE THE STABILITY OF THE DATUM. SCENE 16. GDT2_16A, ANI: drawing with flatness tolerance GDT2_16B, ANI: drawing with flatness tolerance GDT2_16C, ANI: drawing, top surface tolerance GDT2_16D, ANI: 3D part GDT2_16E, ANI: 3D part with bottom tolerance plane GDT2_16F, ANI: 3D part with bottom & top parallel tolerance planes GDT2_16G, ANI: 3D part with bottom & top parallel tolerance planes, arrows & 0.5 tolerance FLATNESS, LIKE STRAIGHTNESS IS COMMONLY APPLIED TO A SURFACE, BUT WHILE STRAIGHTNESS CONTROLS EDGES AND LINES BETWEEN TWO IMAGINARY PARALLEL LINES, FLATNESS REQUIRES A THREE-DIMENSIONAL SURFACE TO BE BETWEEN TWO IMAGINARY, PERFECTLY FLAT AND PARALLEL PLANES. IN THIS EXAMPLE, A FLATNESS TOLERANCE OF 0.5 MILLIMETERS IS ALLOWED. AS BEFORE, THIS TOLERANCE IS NOT CONSIDERED A PLUS/MINUS TOLERANCE, BUT A TOTAL, OR

7 6/23/2016 Copyright 2016 Society of Manufacturing Engineers ABSOLUTE, TOLERANCE. SCENE 17. continue previous shot GDT2_17A, ANI: c.u. circle on top of part GDT2_17B, ANI: c.u. circle on top of part with 0.5 tolerance zone GDT2_17C, ANI: c.u. rough part surface GDT2_17D, ANI: nest FOR AN ACCEPTABLE PART, EVERY POINT MAKING UP THE TOP SURFACE MUST FALL WITHIN THE INDICATED 0.5 MILLIMETERS TOLERANCE ZONE. SCENE 18. GDT2_18A, SME4254, 11:28:02:00-11:28:41:00 zoom out, cmm used to check flatness, straightness of stamping GDT2_18B, SME3171, 09:18:29:00-09:18:40:00 zoom in, optical comparator used to check straightness GDT2_18C, SME4142, 13:03:26:00-13:03:43:00 alternate shot, zoom out, optical comparator used to check straightness GDT2_18D, SME3171, 09:21:19:00-09:21:34:00 zoom in, levels being inspected on granite plate GDT2_18E, SME4143, 14:20:02:00-14:20:28:00 alternate shot, zoom in, square inspected on granite plate TO VERIFY STRAIGHTNESS AND FLATNESS ON PART SURFACES, THERE ARE SEVERAL METHODS THAT COULD BE EMPLOYED, SUCH AS THE USE OF A COORDINATE MEASURING MACHINE, OR CMM..., AN OPTICAL COMPARATOR..., OR INSPECTION OF THE PART ON A GRANITE INSPECTION PLATE. SCENE 19. GDT1_34F, circularity icon enlarged GDT1_34G, CGS: Circularity GDT2_19A, CGS: Roundness GDT2_19B, ANI: circularity drawing with FCF GDT2_19C, ANI: circularity drawing with FCF, highlight diameter GDT2_19D, ANI: 3D circularity part GDT2_19E, ANI: 3D circularity part with two tolerance zone circles, arrows, text GDT2_19F, ANI: c.u. partial diameter of part GDT2_19G, ANI: c.u. partial diameter of part with 0.2 tolerance zone GDT2_19H, ANI: c.u. rough part diameter surface GDT2_19I, ANI: roundness lines 01 GDT2_19J, ANI: roundness lines 02 GDT2_19K, ANI: roundness lines 03 GDT2_19L, ANI: roundness lines 04 GDT2_19M, ANI: roundness lines 05 GDT2_19N, ANI: roundness lines 06 GDT2_19O, ANI: roundness lines 07 GDT2_19P, ANI: blurred blue background GDT2_19Q, ANI: nest CIRCULARITY IS THE GD&T FORM SYMBOL USED TO DEFINE HOW CLOSE A ROUND FEATURE IS TO A TRUE CIRCLE. THIS SYMBOL, SOMETIMES CALLED ROUNDNESS, APPLIES A TWO-DIMENSIONAL TOLERANCE ZONE CONSISTING OF TWO IMAGINARY COAXIAL CIRCLES TO THE PART AT ANY RANDOM CROSS- SECTION. FOR AN ACCEPTABLE PART, ALL SURFACE ELEMENTS MUST STAY WITHIN THOSE TWO CIRCLES. BECAUSE CIRCULARITY IS TWO- DIMENSIONAL, AN INSPECTOR SHOULD IDEALLY VERIFY PART ROUNDNESS AT SEVERAL RANDOM

8 6/23/2016 Copyright 2016 Society of Manufacturing Engineers CROSS-SECTIONS. THERE IS NO REQUIREMENT THAT ALL CROSS-SECTIONS LINE UP WITH EACH OTHER, AS LONG AS THEY ALL MEET THE SIZE TOLERANCE ON THEIR OWN, AND THE TOTAL ENVELOPE MEETS THE SIZE TOLERANCE. SCENE 20. GDT2_19B, ANI: circularity drawing with FCF GDT2_20A, ANI: circularity drawing with no FCF GDT2_20B, ANI: circularity drawing, size tolerance GDT2_20C, SME4307, 07:27:05:00-07:27:30:00 inspecting circular end of crankshaft GDT2_20D, SME4307, 07:25:58:00-07:26:24:00 alternate shot, zoom out, inspecting circular end of crankshaft GDT1_61B, CGS: Rule #1 GDT1_61C, CGS: Unless otherwise specified, the limits of size of a feature prescribe the extent within which variations in geometric form, as well as size, are allowed. IN FACT, IF THE CIRCULARITY TOLERANCE WERE NOT SPECIFIED ON THIS PRINT, THE INDICATED SIZE TOLERANCE WOULD AUTOMATICALLY CONTROL CIRCULARITY. THIS IDEA, REFERRED TO AS RULE NUMBER ONE IN THE ASME STANDARD STATES THAT: UNLESS OTHERWISE SPECIFIED, THE LIMITS OF SIZE OF A FEATURE PRESCRIBE THE EXTENT WITHIN WHICH VARIATIONS IN GEOMETRIC FORM, AS WELL AS SIZE, ARE ALLOWED. SCENE 21. GDT1_34F, circularity icon enlarged GDT2_21A, ANI: cross out symbol GDT2_20A, ANI: circularity drawing with no FCF GDT2_20B, ANI: circularity drawing, size tolerance FOR THIS REASON, CIRCULARITY IS NOT A COMMONLY USED GD&T SYMBOL; OFTEN THE SIZE TOLERANCE IS ADEQUATE TO CONTROL THE ROUNDNESS OF A SHAFT OR A HOLE. SCENE 22. GDT1_34H, cylindricity icon enlarged GDT1_34I, CGS: Cylindricity GDT2_22A, ANI: cylindricity drawing with FCF GDT2_22B, ANI: 3D cylindricity part GDT2_22C, ANI: 3D cylindricity part with two tolerance zone circles, arrows, text GDT2_22D, ANI: 3D cylindricity part with two tolerance zone circles, arrows, text, entire length in tolerance zone GDT2_22E, ANI: c.u. partial diameter of CYLINDRICITY IS VERY SIMILAR TO CIRCULARITY. BUT RATHER THAN CONTROLLING ONLY TWO-DIMENSIONAL CROSS-SECTIONS, CYLINDRICITY APPLIES THE TOLERANCE UNIFORMLY OVER THE ENTIRE THREE-

9 6/23/2016 Copyright 2016 Society of Manufacturing Engineers part GDT2_22F, ANI: c.u. partial diameter of part with 0.2 tolerance zone GDT2_19H, ANI: c.u. rough part diameter surface GDT2_19P, ANI: blurred blue background GDT2_22G, ANI: nest DIMENSIONAL FEATURE. THE TOLERANCE ZONE CONSISTS OF TWO IMAGINARY COAXIAL CYLINDERS, SEPARATED BY THE SPECIFIED TOLERANCE AMOUNT. THE DIAMETER OF THE PART FEATURE MAY RESIDE ANYWHERE WITHIN THE INDICATED SIZE TOLERANCE LIMITS, BUT THE CYLINDRICITY TOLERANCE REQUIRES THE DIAMETER TO THEN BE FAIRLY CONSISTENT OVER THE LENGTH OF THE PART. SCENE 23. GDT2_23A, SME4021, 05:07:14:00-05:07:42:00 zoom out, milling of a cylindrical shape GDT2_23B, SME4021, 05:44:29:00-05:45:05:00 alternate shot, milling of a cylindrical shape GDT2_23C, CGS: Circularity Straightness Taper GDT2_23D, SME4021, 05:22:46:00-05:22:56:00 machined blank with offset hole GDT2_23E, SME4021, 05:23:39:00-05:23:53:00 machined part with tapered offset hole CYLINDRICITY ALSO CONTROLS CIRCULARITY, STRAIGHTNESS, AND EVEN TAPER. AND THOUGH IT IS NOT A COMMONLY USED GD&T SYMBOL, CYLINDRICITY CAN BE HELPFUL WHEN MANUFACTURING PRECISION MACHINED PARTS WHERE A CYLINDRICAL SHAPE IS CRITICAL. SCENE 24. GDT2_11A, ANI: form tolerances isolated GDT2_11B, ANI: straightness icon GDT2_11C, ANI: flatness icon GDT2_11D, ANI: circularity icon GDT2_11E, ANI: cylindricity icon GDT2_11A, ANI: form tolerances isolated GDT2_24A, ANI: straightness print GDT2_24B, ANI: straightness print, highlight straightness symbol in FCF GDT2_24C, ANI: straightness print, highlight diameter tolerance in FCF & surface 01 GDT2_24D, ANI: straightness print, highlight diameter tolerance in FCF & surface 01, crossed out GDT2_24E, ANI: straightness print, highlight diameter tolerance in FCF & surface 03, crossed out GDT2_24F, ANI: straightness print, highlight diameter tolerance in FCF & surface 05, crossed out THE FOUR GD&T FORM SYMBOLS AS PRESENTED SO FAR ALL APPLY TO PART SURFACE TOLERANCES. BUT SOME FORM SYMBOLS CAN ALSO BE APPLIED TO AN ENTIRE FEATURE OF SIZE, AS IN THIS EXAMPLE. AS INDICATED, THE STRAIGHTNESS CALLOUT IN THIS FEATURE CONTROL FRAME IS NOT POINTING TO THE SURFACE OF THE SHAFT. BUT, RATHER TO THE AXIS OF THE SHAFT.

10 6/23/2016 Copyright 2016 Society of Manufacturing Engineers GDT2_24G, ANI: straightness print, highlight diameter tolerance in FCF & axis of cylinder SCENE 25. GDT2_24B, ANI: straightness print, highlight straightness symbol in FCF GDT2_25A, ANI: straightness print, highlight straightness symbol, diameter symbol in FCF GDT2_25B, ANI: straightness print, highlight straightness symbol, diameter symbol in FCF and axis of cylinder GDT2_25C, ANI: ANI: ANI: straightness print, highlight straightness symbol, diameter symbol in FCF, axis of cylinder, 0.1 tolerance GDT2_25D, ANI: straightness print, surface 02 along with surface diameters GDT2_25E, ANI: straightness print, surface 04 along with surface diameters GDT2_25F, ANI: straightness print, surface 06 along with surface diameters NOTICE THAT THE DIAMETER SYMBOL WITHIN THE FEATURE CONTROL FRAME INDICATES THE SHAPE OF THE TOLERANCE ZONE, WHICH IS TO BE A CYLINDER. THEREFORE, THE ENTIRE AXIS OF THE SHAFT MUST STAY WITHIN A CYLINDRICAL TOLERANCE ZONE DIAMETER OF 0.1 MILLIMETERS. ADDITIONALLY, THE SURFACE OF THE SHAFT MUST ALWAYS STAY WITHIN THE SPECIFIED DIAMETER TOLERANCE ON THE SIZE. SCENE 26. GDT2_24A, ANI: straightness print GDT2_25C, ANI: ANI: ANI: straightness print, highlight straightness symbol, diameter symbol in FCF, axis of cylinder, 0.1 tolerance GDT2_26A, ANI: pin on blue background GDT2_26B, ANI: pin with 13.0 cross section, 13.0 envelope GDT2_26C, ANI: pin with 13.0 cross section, 13.0 envelope, 0.1 tolerance zone GDT2_26D, ANI: pin with 13.0 cross section, 0.1 tolerance zone, 13.1 envelope GDT2_26E, ANI: bent pin with 13.1 cross section, 0.1 tolerance zone, 13.1 envelope USING GD&T IN THIS MANNER INTRODUCES TWO CONCEPTS THAT DON T APPLY TO SURFACES. FIRST, BECAUSE THE GD&T IS APPLIED TO A FEATURE OF SIZE, THE GEOMETRIC TOLERANCE ALLOWS THE PART TO DEVIATE BEYOND THE USUAL ENVELOPE CREATED BY THE SIZE TOLERANCE. IN OTHER WORDS, THERE IS AN ADDITIVE EFFECT THAT PERMITS THE PART TO BEND 0.1 MILLIMETER, CREATING A LARGER ENVELOPE OF 13.1 MILLIMETERS. THIS IS ALLOWED BECAUSE THE GD&T IS APPLIED TO A FEATURE OF SIZE. SCENE 27. GDT2_27A, ANI: straightness print without MMC modifier

11 6/23/2016 Copyright 2016 Society of Manufacturing Engineers GDT2_27B, ANI: straightness print, FCF GDT2_27C, ANI: straightness print, FCF, axis GDT2_27D, ANI: straightness print with MMC modifier, FCF, axis SECONDLY, BECAUSE STRAIGHTNESS IS BEING APPLIED TO A FEATURE OF SIZE, THE GEOMETRIC TOLERANCE CAN BE MADE INTO A VARIABLE TOLERANCE THAT CHANGES, DEPENDING ON THE CROSS-SECTIONAL SIZE OF THE PART. SCENE 28. GDT2_28A, ANI: straightness print with MMC modifier, nothing GDT2_28B, ANI: straightness print with MMC modifier, circled M GDT1_50A, CGS: Maximum Material Condition GDT2_28C, ANI: straightness print with MMC modifier, FCF GDT2_28D, ANI: straightness print with MMC modifier, FCF, 13.0 diameter GDT2_28E, ANI: straightness print with dimensions but no FCF, 13.0, top of screen GDT2_28F, ANI: straightness print with dimensions but no FCF, no highlights, with MMC table, top of screen GDT2_28G, ANI: MMC table, GDT2_28H, ANI: MMC table, 12.9 GDT2_28I, ANI: MMC table, GDT03D, light blueprint background NOTICE THE CIRCLED M SYMBOL IN THIS FEATURE CONTROL FRAME. IT STANDS FOR MAXIMUM MATERIAL CONDITION, SOMETIMES SHORTENED TO MMC, AND INDICATES THAT THE GIVEN STRAIGHTNESS TOLERANCE OF 0.1 MILLIMETERS APPLIES ONLY WHEN THE CROSS- SECTIONAL SIZE IS MADE TO THE MAXIMUM MATERIAL CONDITION, WHICH IS 13.0 MILLIMETERS. HOWEVER, IF THE PART IS MANUFACTURED AT ANOTHER CROSS-SECTIONAL SIZE, SUCH AS 12.9 MILLIMETERS, THEN THE STRAIGHTNESS TOLERANCE IS ALLOWED TO INCREASE BEYOND 0.1 TO 0.2 MILLIMETERS. SCENE 29. GDT2_29A, ANI: MMC table, 12.8 GDT2_29B, ANI: MMC table, GDT2_29C, ANI: MMC table, 12.7 GDT2_29D, ANI: MMC table, GDT2_29E, ANI: MMC table, 12.6 GDT2_29F, ANI: MMC table, GDT2_29G, ANI: straightness print with dimensions but no FCF, 12.6, top of screen GDT2_29H, ANI: LMC table, 12.6 GDT2_29I, ANI: LMC table, GDT2_29J, ANI: straightness print with THIS SAME TREND CONTINUES FOR ANY CROSS- SECTIONAL SIZE OF THE PART, WITHIN THE GIVEN SIZE LIMITS. THE EXTRA STRAIGHTNESS TOLERANCE, ABOVE AND BEYOND THE ORIGINAL 0.1 MILLIMETERS, IS CALLED A BONUS TOLERANCE. THERE IS A SIMILAR MODIFIER CALLED LEAST MATERIAL

12 6/23/2016 Copyright 2016 Society of Manufacturing Engineers dimensions but no FCF, no highlights, top of screen GDT2_29K, ANI: LMC table, 12.7 GDT2_29L, ANI: LMC table, GDT2_29M, ANI: LMC table, 12.8 GDT2_29N, ANI: LMC table, GDT2_29O, ANI: LMC table, 12.9 GDT2_29P, ANI: LMC table, GDT2_29Q, ANI: LMC table, 13.0 GDT2_29R, ANI: LMC table, GDT1_55B, ANI: LMC, circled L GDT1_55A, ANI: MMC, circled M GDT2_29S, ANI: entire MMC table, nothing, centered CONDITION, OR LMC, WHICH IS THE REVERSE OF THIS TREND. OF THE TWO MODIFIERS, MAXIMUM MATERIAL CONDITION IS MUCH MORE COMMON. SCENE 30. continue previous shot GDT2_30A, ANI: MMC table, GDT2_30B, ANI: MMC table, GDT2_30C, ANI: MMC table, GDT2_30D, ANI: MMC table, GDT2_30E, ANI: MMC table, GDT2_30F, ANI: MMC table, 04 & 05 GDT2_30G, ANI: MMC table, 03, 04 & 05 GDT2_30H, ANI: MMC table, 02, 03, 04 & 05 GDT2_30I, ANI: MMC table, all GDT2_30J, ANI: 13.1 Millimeters GDT2_30K, CGS: Virtual Condition NOTICE THAT THROUGHOUT THE TABLE, THE TOTAL OF THE SIZE AND THE ALLOWABLE STRAIGHTNESS VARIATION ALWAYS ADDS UP TO THE SAME NUMBER 13.1 MILLIMETERS. THIS IS THE PRIMARY REASON FOR THE BONUS TOLERANCE; THE SIZE AND THE GEOMETRIC TOLERANCE ARE VARIABLES, BUT THE OVERALL FIT OF THE PART, WHICH IS THE MAIN OBJECTIVE, IS ALWAYS PRESERVED. THIS OVERALL NUMBER OF 13.1 MILLIMETERS IS SOMETIMES CALLED THE VIRTUAL CONDITION. --- TOUCH BLACK --- SCENE 31. GDT2_31A, CGS: Datum GDT1_13D, ANI: round part on blue background GDT1_13E, ANI: round part with center datum point GDT1_13A, ANI: rectangular part on blue background GDT1_13B, ANI: rectangular part with datum A DATUM IS DEFINED AS A THEORETICALLY EXACT POINT, AXIS, PLANE, OR COMBINATION OF THESE ELEMENTS, WHICH THEN SERVES AS

13 6/23/2016 Copyright 2016 Society of Manufacturing Engineers hole axis GDT1_13C, rectangular part with datum plane GDT2_31B, SME4394, 04:02:42:00-04:03:05:00 fixturing of parts GDT2_31C, SME4394, 04:19:35:00-04:19:58:00 zoom out, machining of parts AN ORIGIN FOR A GEOMETRIC TOLERANCE. DATUMS ARE ONE OF THE MOST IMPORTANT ASPECTS OF THE GD&T SYSTEM SINCE MOST GD&T CONTROLS REQUIRE A DATUM REFERENCE TO ESTABLISH AN ORIGIN FOR THEIR MEASUREMENT. THIS ORIGIN IS OFTEN USED TO REPEATEDLY HOLD OTHER TOLERANCES IN THE SAME SET-UP. SCENE 32. GDT2_32A, SME4394, 04:32:02:00-04:32:35:00 zoom out, fixturing rectangular parts GDT2_32B, CGS: Datum Feature GDT2_32C, ANI: drawing with datum feature GDT2_32D, ANI: drawing with datum feature GDT2_32E, ANI: c.u., datum feature GDT2_32F, CGS: I, O, Q GDT2_32G, ANI: cross out GDT03D, light blueprint background HOWEVER, SINCE A TRUE DATUM IS DEFINED AS THEORETICALLY PERFECT, THE ACTUAL SURFACE OF A PART CANNOT SERVE AS THE TRUE DATUM. INSTEAD, A PART S ACTUAL SURFACE IS CALLED A DATUM FEATURE. IT IS IMPORTANT TO DISTINGUISH THE DIFFERENCE BETWEEN A DATUM AND A DATUM FEATURE: A DATUM IS THE PERFECT ZERO LINE OR PLANE, WHERE THE DATUM FEATURE IS THE SURFACE CONTACTED TO CREATE THE IMAGINARY, PERFECT DATUM. ON A DRAWING, A DATUM FEATURE IS SIGNIFIED USING A TRIANGLE SYMBOL ALONG WITH AN ALPHABETIC LETTER DESIGNATION. ANY LETTER MAY BE USED EXCEPT I, O, AND Q. SCENE 33. GDT2_33A, ANI: part drawing GDT2_33B, ANI: part drawing, datum A highlight GDT2_33C, ANI: part drawing with, datum A, parallelism tolerance highlight GDT2_33D, ANI: part drawing with, datum A, parallelism tolerance, top surface highlight IN THIS EXAMPLE, ONLY ONE DATUM IS NECESSARY. THE FEATURE CONTROL FRAME CALLS FOR A PARALLELISM TOLERANCE ON THE

14 6/23/2016 Copyright 2016 Society of Manufacturing Engineers GDT2_33E, ANI: part drawing with, datum A, parallelism tolerance, top surface FCF datum A highlight GDT2_33F, ANI: grey datum plane GDT2_33G, ANI: datum plane A GDT2_33H, ANI: datum plane A, part with datum feature A GDT2_33I, ANI: datum plane A, part with datum feature A, contact 01 GDT2_33J, ANI: datum plane A, part with datum feature A, contact 01, contact 02 GDT2_33K, ANI: datum plane A, part with datum feature A, contact 01, contact 02, contact 03 GDT2_33L, ANI: datum plane A, part with datum feature A, contact 01, contact 02, contact 03, tolerance lines GDT2_33M, ANI: datum plane A, part with datum feature A, contact 01, contact 02, contact 03, tolerance lines, tolerance text GDT2_33N, ANI: part drawing with flatness GDT2_33O, ANI: part drawing with flatness, flatness tolerance highlight GDT2_33P, ANI: part drawing with flatness, flatness tolerance, datum A surface highlight TOP SURFACE, WITH RESPECT TO DATUM A. HOWEVER, DATUM A IS NOT THE BOTTOM SURFACE. RECALL THAT A DATUM IS A PERFECTLY FLAT PLANE. THAT PERFECT DATUM IS TO BE ESTABLISHED FROM THE THREE HIGHEST POINTS ACROSS THE BOTTOM OF THE PART. EVERY POINT MAKING UP THE TOP OF THE PART MUST NOW BE PARALLEL TO DATUM A WITHIN A 0.2 MILLIMETER TOLERANCE ZONE. IT IS SOMETIMES ADVISABLE TO ALSO APPLY A FLATNESS TOLERANCE TO A SURFACE THAT WILL BE USED TO CREATE A PRIMARY DATUM, SO THAT THERE IS MORE STABILITY AND REPEATABILITY. SCENE 34. GDT2_33N, ANI: part drawing with flatness GDT2_34A, ANI: part drawing with flatness, parallelism tolerance highlight GDT2_34B, ANI: part drawing with flatness, parallelism tolerance, datum A highlight GDT2_34C, ANI: part drawing with 3 datums GDT2_34D, ANI: part drawing with 3 datums, position tolerance GDT2_34E, ANI: part drawing with 3 datums, position tolerance, datum A GDT2_34F, ANI: part drawing with 3 datums, position tolerance, datums A, B GDT2_34G, ANI: part drawing with 3 datums, position tolerance, datums A, B, C GDT2_34H, CGS: Datum Reference Frame GDT2_34I, ANI: part drawing with 3 datums, position tolerance, datums A, B, C - A plane GDT2_34J, ANI: part drawing with 3 datums, position tolerance, datums A, B, C A, B planes GDT2_34K, ANI: part drawing with 3 datums, position tolerance, datums A, B, C A, B, C planes PARALLELISM CAN REFERENCE ONE DATUM, BECAUSE THE OTHER DIRECTIONS OF SPACE ARE NOT RELEVANT TO THE PARALLEL REQUIREMENT. HOWEVER, GEOMETRIC TOLERANCES SUCH AS POSITION WILL OFTEN REFERENCE THREE DATUMS. THE THREE DATUMS CREATE THE DATUM REFERENCE FRAME, WHICH HELPS TO LOCK THE PART IN ALL THREE DIRECTIONS OF SPACE.

15 6/23/2016 Copyright 2016 Society of Manufacturing Engineers SCENE 35. continue previous shot GDT2_35A, ANI: 3-sided fixture GDT2_35B, ANI: part located in corner of fixture GDT2_35C, ANI: part isolated IN THIS EXAMPLE, THE THREE DATUM FEATURES ARE DESIGNED TO BE PART SURFACES THAT ARE AT 90 DEGREES FROM EACH OTHER. NOW, PICTURE THE PART PLACED ONTO A FIXTURE FOR INSPECTION. IF THE PART IS MADE PERFECTLY, THEN ALL THREE SURFACES WOULD BE FULLY FLUSH AGAINST THE FIXTURE SURFACES. SCENE 36. continue previous shot GDT2_35A, ANI: 3-sided fixture GDT2_36A, ANI: 3-sided fixture, datum A bottom of fixture GDT2_36B, CGS: Primary Datum GDT2_34A, ANI: part drawing with 3 datums GDT2_36C, ANI: part drawing with 3 datums, datum A GDT2_36D, ANI: part drawing with 3 datums, datum A, datum A plane GDT2_36E, ANI: 3-sided fixture, 3 points of contact GDT2_36F, ANI: 3-sided fixture, 3 points of contact, datum A plane BUT BECAUSE A PART CANNOT BE PERFECT, ONE OF THE THREE SURFACES MUST BE SPECIFIED TO BE HELD MOST FLUSH AGAINST THE FIXTURE. THIS IS KNOWN AS THE PRIMARY DATUM. THE PRIMARY DATUM IS INDICATED AS THE FIRST DATUM LISTED IN A FEATURE CONTROL FRAME IN THIS CASE, DATUM A. EVEN IF THIS SURFACE IS NOT PERFECTLY FLAT, IT MUST NATURALLY CONTACT A MINIMUM OF 3 POINTS IN ORDER TO ESTABLISH THAT FIRST DATUM. SCENE 37. GDT2_34C, ANI: part drawing with 3 datums GDT2_37A, ANI: part drawing with 3 datums, datum B GDT2_37B, ANI: part drawing with 3 datums, datum B, datum B plane GDT2_37C, CGS: Secondary Datum GDT2_36F, ANI: 3-sided fixture, 3 points of contact, datum A plane GDT2_37D, ANI: 3-sided fixture, 3 points of contact, datum A plane, datum B plane GDT2_37E, ANI: 3-sided fixture, 3 points of contact, datum A plane, datum B plane, THE SECOND LETTER INDICATED IN THE FEATURE CONTROL FRAME IS CALLED THE SECONDARY DATUM, AND THE PART SHOULD CONTACT THE FIXTURE ON THAT SURFACE AS BEST AS IT CAN, WITHOUT LIFTING OFF THE

16 6/23/2016 Copyright 2016 Society of Manufacturing Engineers points of contact PRIMARY DATUM. THUS, ONLY 2 POINTS OF CONTACT ARE REQUIRED TO ESTABLISH THIS SECONDARY DATUM. SCENE 38. GDT2_34A, ANI: part drawing with 3 datums GDT2_38A, ANI: part drawing with 3 datums, datum C GDT2_38B, ANI: part drawing with 3 datums, datum C, datum C plane GDT2_38C, CGS: Tertiary Datum GDT2_38D, ANI: 3-sided fixture, 3 points of contact, datum A plane, 2 points of contact, datum B plane, datum C plane GDT2_38E, ANI: 3-sided fixture, 3 points of contact, datum A plane, 2 points of contact, datum B plane, datum C plane, 1 point of contact GDT2_38F, ANI: part drawing with 3 datums GDT2_38G, ANI: part drawing with 3 datums, geometric tolerance GDT2_38H, ANI: part drawing with 3 datums, all datums GDT2_38I, ANI: 3-sided fixture, 3 points of contact, datum A plane GDT2_38J, ANI: 3-sided fixture, 3 points of contact, 2 points of contact, datum A, B planes GDT2_38K, ANI: 3-sided fixture, 3 points of contact, 2 points of contact, 1 point of contact, datum A, B, C planes IF A THIRD LETTER IS INDICATED IN THE FEATURE CONTROL FRAME, AS IN THIS EXAMPLE, IT S CALLED THE TERTIARY DATUM. THE PART SHOULD CONTACT THE FIXTURE ALONG THIS SURFACE WITH A MINIMUM OF ONE CONTACT POINT. THEREFORE, A GEOMETRIC TOLERANCE THAT REFERENCES 3 SURFACE DATUMS WILL BE FIXTURED SO THAT IT TOUCHES 3 POINTS, 2 POINTS, AND 1 ONE POINT ON THE RESPECTIVE DATUM FEATURES. SCENE 39. GDT2_39A, ANI: part drawing with 3 datums GDT2_39B, ANI: part drawing with 3 datums, datum A GDT2_39C, ANI: part drawing with 3 datums, datums A, B GDT2_39D, ANI: part drawing with 3 datums, datums A, B, C DATUMS SHOULD ALWAYS BE DISPLAYED IN ORDER OF IMPORTANCE LEFT TO RIGHT WITHIN THE FEATURE CONTROL FRAME, WITH THE DATUM REFERENCE SEQUENCE BASED ON THE FUNCTION OF THE PART OR ASSEMBLY. SCENE 40. GDT2_40A, SME2638, 01:04:37:00-01:05:15:00 zoom in, machining of base with holes MANY PARTS HAVE DATUMS THAT REQUIRE DIFFERENT DATUM FEATURES. SCENE 41. GDT2_41A, ANI: part drawing with 4 holes GDT2_41B, ANI: part drawing with 4 holes,

17 6/23/2016 Copyright 2016 Society of Manufacturing Engineers back of part GDT2_41C, ANI: part drawing with 4 holes, back of part, datum F GDT2_41D, ANI: part drawing with 4 holes, diameter of part GDT2_41E, ANI: part drawing with 4 holes, diameter of part, datum G GDT2_41F, ANI: part drawing with 4 holes, diameter axis, datum G FOR EXAMPLE, THE FUNCTION OF THIS PART REQUIRES THAT IT BE SEATED AGAINST IT S BACK FACE. FOR THAT REASON, THE BACK FACE WOULD BE CHOSEN AS THE PRIMARY DATUM FEATURE. THE FUNCTION MIGHT ALSO DICTATE THAT THE OUTSIDE DIAMETER BE CHOSEN AS THE SECONDARY DATUM FEATURE. IF THAT OUTSIDE DIAMETER IS HELD WITH A COLLET THAT CENTERS THE DISC, THE TRUE SECONDARY DATUM WILL BE THE AXIS DERIVED FROM THE OUTSIDE DIAMETER, AND THAT AXIS NOW LOCKS IN SEVERAL ADDITIONAL DEGREES OF FREEDOM. SCENE 42. continue previous shot GDT2_42A, ANI: part with 4 holes, rotating GDT2_41A, ANI: part drawing with 4 holes GDT2_42B, ANI: c.u. FCF GDT03C, dark blueprint background GDT2_42C, ANI: c.u. FCF, highlight datum F GDT2_42D, ANI: c.u. FCF, highlight datum F & datum G THE ONLY DEGREE OF FREEDOM THAT IS NOT CONSTRAINED IS THE ROTATION OF THE PART. SINCE ROTATION IS IRRELEVANT TO THE PART FUNCTION, A THIRD, TERTIARY DATUM IS NOT NEEDED FOR LOCATION. SCENE 43. GDT2_43A, ANI: part drawing with hole & slot GDT2_43B, ANI: part drawing with hole & slot GDT2_43C, ANI: part drawing with hole & slot, back face & datum A GDT2_43D, ANI: part drawing with hole & slot, back face & datum A, hole axis & datum B GDT2_43E, ANI: part drawing with hole & slot, back face & datum A, hole axis & datum B, slot & datum C GDT2_43F, ANI: part drawing with hole & slot, back face & datum A, hole axis & datum B, slot horizontal center plane & datum C ANOTHER COMMON DATUM SYSTEM IS ONE WHERE THE PART HOLE AND SLOT WORK TOGETHER TO LOCK THE PART IN PLACE. ONCE AGAIN, THE PRIMARY DATUM IS TAKEN FROM THE BACK FACE OF THE PART. THE SECONDARY DATUM IS THE AXIS OF THE CIRCULAR HOLE, AND THE SLOT COMES IN LAST AS A WAY TO CONTROL THE ROTATION OF THE PART. THEORETICALLY

18 6/23/2016 Copyright 2016 Society of Manufacturing Engineers SPEAKING, THE TERTIARY DATUM IS THE DERIVED HORIZONTAL CENTER PLANE OF THE SLOT. SCENE 44. continue previous shot GDT2_44A, ANI: part drawing with hole & slot, datum C GDT2_44B, ANI: part drawing with hole & slot, datum C, dimension arrow GDT2_44C, ANI: part drawing with hole & slot, datum C in different position GDT2_44D, ANI: part drawing with hole & slot, datum C in different position, top of slot IT SHOULD BE NOTED HERE THAT THE DATUM FEATURE SYMBOL FOR C IS IN LINE WITH THE DIMENSION ARROW. THIS IS IMPORTANT SINCE IT TIES THE DATUM WITH THE WIDTH OF THE SLOT, WHICH IS A FEATURE OF SIZE. IF THE DATUM FEATURE SYMBOL IS MOVED OVER SO THAT IT IS NOT IN LINE WITH THE DIMENSION ARROW, THEN THE DATUM WOULD BE A PLANE FORMED FROM ONLY THE TOP SURFACE OF THE SLOT. THIS COULD SIGNIFICANTLY CHANGE THE PART MEASUREMENTS. SCENE 45. GDT2_45A, ANI: part drawing with holes GDT2_45B, ANI: part drawing with holes, 01 hole GDT2_45C, ANI: part drawing with holes, 01, 02 hole GDT2_45D, ANI: part drawing with holes, 01, 02, 03 hole GDT2_45E, ANI: part drawing with holes, 01, 02, 03, 04 hole GDT2_45F, ANI: part drawing with all holes, datum B GDT2_45G, ANI: part drawing with all holes, datum B, A GDT2_45H, ANI: part drawing with all holes, datum B, A, tolerance IF A PART HAS A PATTERN OF FEATURES, SUCH AS THESE FOUR HOLES, THEN IT IS POSSIBLE TO ATTACH ONE DATUM FEATURE SYMBOL TO THAT PATTERN. THIS THEN TIES OTHER DIMENSIONS TO THE PATTERN. THIS IS USEFUL IF ALL HOLES ARE OF EQUAL IMPORTANCE, AND IT ELIMINATES THE NEED FOR A TERTIARY DATUM, SINCE DATUM A AND DATUM B LOCK THE PART IN ALL DIRECTIONS. THERE SHOULD BE A GEOMETRIC TOLERANCE CONTROLLING THE POSITION OF THE HOLES TO ONE ANOTHER, TO ENSURE A

19 6/23/2016 Copyright 2016 Society of Manufacturing Engineers REPEATABLE DATUM STRUCTURE. SCENE 46. GDT2_46A, ANI: cylindrical part with holes GDT2_46B, ANI: cylindrical part with holes, datum G highlight GDT2_46C, ANI: cylindrical part with holes, datum G, diameter highlight GDT2_46D, ANI: cylindrical part with holes, c.u. FCF, datum G highlight GDT2_46E, ANI: cylindrical part with holes, c.u. FCF, datum G, circled M highlight IF A DATUM IS DERIVED FROM A FEATURE OF SIZE, AS IN THIS EXAMPLE, IT IS SOMETIMES ADVISABLE TO USE A CIRCLED M MODIFIER AFTER THE DATUM LETTER. SCENE 47. GDT2_46A, ANI: cylindrical part with holes GDT2_47A, ANI: cylindrical part with holes, holes diameters & axes, 0.3-M GDT2_47B, ANI: cylindrical part with holes, holes diameters & axes, 0.3-M, feature size GDT2_47C, ANI: cylindrical part with holes, holes diameters & axes, 0.3-M, feature size, G datum, G-M, part diameter GDT2_47D, ANI: cylindrical part with holes, holes diameters & axes, 0.3-M, feature size, G datum, G-M, part diameter, GDT2_47E, CGS: Maximum Material Boundary WE ESTABLISHED EARLIER THAT THE MAXIMUM MATERIAL CONDITION MODIFIER PERMITS A TOLERANCE VALUE TO VARY, DEPENDING ON THE ACTUAL SIZE OF THE FEATURES BEING TOLERANCED. IN THIS CASE, THE M MODIFIER, WHEN APPLIED TO A DATUM, REFERS TO THE MAXIMUM MATERIAL BOUNDARY, OR MMB, OF THE DATUM FEATURE. SCENE 48. GDT2_48A, ANI: cylindrical part with holes, 0.3 & G in FCF, G datum GDT2_48B, ANI: cylindrical part with holes, 0.3 & G-M in FCF, G datum GDT2_48C, ANI: cylindrical part with holes, 0.3 & G-M in FCF, G datum, GDT03D, light blueprint background GDT2_48D, ANI: gage at 110.8, part at GDT2_48E, ANI: gage at 110.8, part at GDT2_48F, ANI: gage at 110.8, part at GDT2_48G, ANI: gage at 110.8, part at GDT2_48H, ANI: gage at 110.8, part at GDT2_48I, CGS: Datum Shift THIS M SYMBOL INDICATES THAT THE GIVEN TOLERANCE IS BASED ON THE DATUM AS TAKEN FROM THE WORST-CASE MAXIMUM, WHICH IN THIS CASE IS MILLIMETERS. IF THE ACTUAL DATUM FEATURE IS LESS THAN MAXIMUM, THEN THERE IS AN ALLOWABLE SHIFT IN THE DATUM, WHICH MAKES THE POSITION TOLERANCE ON THE PATTERN OF HOLES APPEAR LARGER. THIS EXTRA VARIABLE ON THE DATUM FEATURE IS CALLED DATUM

20 6/23/2016 Copyright 2016 Society of Manufacturing Engineers SHIFT. SCENE 49. continue previous shot GDT2_48G, ANI: gage at 110.8, part at GDT2_48F, ANI: gage at 110.8, part at GDT2_48E, ANI: gage at 110.8, part at GDT2_48D, ANI: gage at 110.8, part at MAXIMUM MATERIAL BOUNDARY DATUM SHIFT IS ONLY PERMITTED ON A FEATURE OF SIZE DATUM, NOT ON A SURFACE DATUM. SCENE 50. GDT2_50A, ANI: shaft drawing with multiple datum features GDT2_50B, ANI: shaft drawing with multiple datum features, datum C GDT2_50C, ANI: shaft drawing with multiple datum features, datum C & D GDT2_50D, ANI: shaft drawing with multiple datum features, datum C & D, FCF C-D IN THIS EXAMPLE, TWO DATUM FEATURES ARE IDENTIFIED ON THE DRAWING, BUT IN THE FEATURE CONTROL FRAME, THE TWO DATUM LETTERS ARE REFERENCED TOGETHER, WITH A HYPHEN BETWEEN THEM. SCENE 51. continue previous shot GDT2_51A, ANI: c.u. FCF with C-D GDT2_51B, ANI: shaft drawing with multiple datum features, datum C & D, FCF C-D, center axis WITH THE USE OF THE HYPHEN, THE FEATURE CONTROL FRAME INDICATES THAT THERE IS ONLY ONE THEORETICAL DATUM ON THE PART: THE SINGLE AXIS CREATED BY BOTH FEATURES TAKEN TOGETHER. IN OTHER WORDS, THERE IS ONLY ONE DATUM, BUT IT INCORPORATES MULTIPLE DATUM FEATURES. USING THE HYPHENATED DATUM FEATURES, NO ONE FEATURE TAKES PRECEDENCE OVER THE OTHER. THEY ALL FORM ONE THEORETICAL DATUM. SCENE 52. continue previous shot GDT2_52A, ANI: fixture with offset surfaces drawing GDT2_52B, ANI: fixture with offset surfaces drawing, FCF datums GDT2_52C, ANI: fixture with offset APPLICATION OF HYPHENATED DATUM FEATURES CAN BE USED NOT JUST FOR DIAMETERS, BUT

21 6/23/2016 Copyright 2016 Society of Manufacturing Engineers surfaces drawing, FCF datums, drawing datums GDT2_52D, ANI: fixture with offset surfaces drawing, FCF datums, drawing datums, surfaces ALSO FOR SURFACES, OR OTHER DATUM FEATURES THAT ARE TO ESTABLISH CONTROL IN THE SAME DIRECTION. SCENE 53. GDT2_53A, SME2758, 02:01:27:00-02:01:43:00 stamping of automotive quarter panel GDT2_53B, SME2758, 02:05:33:00-02:05:59:00 shearing of automotive quarter panel GDT2_53C, CGS: Datum Target MANY TIMES DATUM FEATURES ARE NEEDED ON PARTS WHERE THERE ARE NO FLAT SURFACES OR ANY OTHER FEATURE THAT MIGHT SERVE AS A GOOD PRIMARY DATUM FEATURE IN CASES LIKE THIS, GD&T UTILIZES A SPECIAL SYMBOL CALLED A DATUM TARGET. SCENE 54. GDT03D, light blueprint background GDT2_54A, ANI: empty datum target symbol GDT2_54B, ANI: datum target symbol with datum letter & number GDT2_54C, ANI: datum target symbol with datum letter & number, size THE SYMBOL FOR A DATUM TARGET IS A CIRCLE DIVIDED IN HALF. THE LOWER HALF OF THE CIRCLE CONTAINS THE DATUM LETTER AND THE TARGET NUMBER. THE UPPER HALF OF THE CIRCLE MAY CONTAIN A SIZE, IF THE DATUM TARGET DESIGNATES AN AREA. SCENE 55. GDT2_55A, ANI: datum target drawing GDT2_55B, ANI: datum target drawing, datum targets GDT2_55C, ANI: datum target drawing, datum targets, datum feature A GDT2_55D, ANI: datum target drawing, datum targets, datum feature A, areas of contact DATUM TARGETS ARE A WAY OF SUBDIVIDING A DATUM FEATURE INTO SPECIFIC POINTS, LINES, OR AREAS OF CONTACT. IN THIS WAY, ANY SURFACE, EVEN IF CURVED OR IRREGULAR, CAN STILL BE USED TO CREATE A PERFECT IMAGINARY PLANE. SCENE 56. GDT2_55A, ANI: datum target drawing GDT2_56A, ANI: datum target drawing, datum target A1 GDT2_56B, ANI: datum target drawing, datum target A2 GDT2_56C, ANI: datum target drawing, datum IF THREE DATUM TARGETS POINTS WERE IDENTIFIED, TOGETHER THEY WOULD FORM A

22 6/23/2016 Copyright 2016 Society of Manufacturing Engineers target A3 GDT2_56D, ANI: datum target drawing, datum targets, datum feature A, areas of contact SINGLE IMAGINARY PLANE, CALLED DATUM A. FROM DATUM A OTHER GEOMETRIC TOLERANCES CAN THEN BE REFERENCED AND OFFSET DIMENSIONS GIVEN. SCENE 57. GDT2_55A, ANI: datum target drawing GDT2_57A, ANI: c.u. FCF of datum target drawing, tolerance highlight GDT2_57B, ANI: c.u. FCF of datum target drawing, tolerance, datum A highlight GDT2_54B, ANI: datum target symbol with datum letter & number GDT03D, light blueprint background GDT2_57C, SME4254, 11:10:39:00-11:11:06:00 c.u. cmm inspection GDT2_55A, ANI: datum target drawing GDT2_57A, ANI: c.u. FCF of datum target drawing, tolerance highlight GDT2_57D, ANI: c.u. FCF of datum target drawing, tolerance, datum B highlight GDT2_57E, ANI: c.u. FCF of datum target drawing, tolerance, datum b & c highlight ANY FEATURE CONTROL FRAMES THAT REFERENCE DATUM A WILL NOW REFERENCE THE DATUM AS A FULL LETTER, ALTHOUGH THE ACTUAL INSPECTION FIXTURE OR CMM SIMULATION WILL SEE THE REAL CONTACT POINTS AS BEING DATUM TARGETS. TARGETS MAY ALSO BE CREATED FOR THE SECONDARY DATUM B AND THE TERTIARY DATUM C. --- FADE TO BLACK --- SCENE 58. GDT CRXM, credit music, up and under GDT CRX01, CGS: credit 01 white text, centered GDT EXM, extended motion background Produced By: Society of Manufacturing Engineers SCENE 59. continue motion background GDT CRX02, CGS: credit 02 white text, centered Producer/Director/Cameraman: Jerome T. Cook SCENE 60. continue motion background GDT CRX03, CGS: credit 03 white text, centered Written By: John-Paul Belanger, Geometric Learning Systems SCENE 61. continue motion background GDT CRX04, CGS: credit 04 white text, centered Technical & Editorial Consulting: Colin Parks John Stolter SCENE 62. continue motion background GDT CRX05, CGS: credit 05 Equipment Access Provided By:

23 6/23/2016 Copyright 2016 Society of Manufacturing Engineers white text, centered leave on-screen during credits 06 & 07 SCENE 63. continue motion background GDT CRX06, CGS: credit 06 white text, centered SCENE 64. continue motion background GDT CRX07, CGS: credit 07 white text, centered SCENE 65. continue motion background GDT CRX08, CGS: credit 08 white text, centered SCENE 66. continue motion background GDT CRX09, CGS: credit 09 white text, centered Bowden Manufacturing Jergens, Inc. The L.S. Starrett Company Master Precision Mold Technology PBC Linear Protomatic Rockford Toolcraft, Inc. Washtenaw Community College Production Assistance Provided By: Patrick Fitzpatrick, N-Code, Inc. Lance Rosol, Pixel Perfect Photography Graphics/Video Editing: Jerome T. Cook SCENE 67. continue motion background GDT ASME, CGS: ASME permission white text, centered on background SCENE 68. continue motion background GDT CRGT, CGS: Copyright text white text, centered on lower third Visuals & texts gratefully reprinted from ASME Y14.5M-1994 (R2004) and Y , by permission of the American Society of Mechanical Engineers. All rights reserved. Copyright 2016 Society of Manufacturing Engineers SCENE 69. GDT02A, SME logo open, with music