7 65 What are the LIMITS? What happens if you go out of that zone? Any speed in between the limits is within the acceptable range or zone.SPEED LIMIT6540MINIMUMUPPER LIMITMAX.MIN.LOWER LIMITWhat happens if you go out of that zone?
8 What is the TOLERANCE?The difference between the upper and lower limit equals the Tolerance zone.65 UPPER LIMIT-40 LOWER LIMIT25 = TOLERANCE ZONESPEED LIMIT6540MINIMUM25Tolerance = is the total amount that a dimension is permitted to vary.
9 What are the LIMITS? 12 .7 5 12.50 + 0.25 12 .25 SPECIFIED DIMENSION TOLERANCELIMITS
10 MMC & LMC MAXIMUM MATERIAL CONDITION AND LEAST MATERIAL CONDITION
11 What is the difference between these two glazed doughnuts? Both of these doughnuts cost 90 cents. Which one is the best buy? Why?Which one was made with the most or maximum amount of dough?MMMC = Maximum Material ConditionLMC = Least Material ConditionL
12 MMAXIMUM MATERIAL CONDITION (MMC) =IS WHERE A FEATURE CONTAINS THE MAXIMUM AMOUNT OF MATERIAL PERMITTED WITHIN THE STATED LIMITS.(SEE BOOK EXAMPLE 1-8 & 1-9)1 . 751 . 73nLook at the limits of the O.D. and the I.D. of the washer. Which ones represent the washer at MMC?0. 750. 73n
13 n n 1 . 75 MMC OF THE O.D. 1 . 73 0. 75 0. 73 MMC OF THE I.D. M MAXIMUM MATERIAL CONDITION (MMC) =IS WHERE A FEATURE CONTAINS THE MAXIMUM AMOUNT OF MATERIAL PERMITTED WITHIN THE STATED LIMITS.(SEE BOOK EXAMPLE 1-8 & 1-9)1 . 751 . 73MMC OF THE O.D.n0. 750. 73nMMC OF THE I.D.
14 LLEAST MATERIAL CONDITION (LMC) =IS WHERE A FEATURE CONTAINS THE LEAST AMOUNT OFMATERIAL PERMITTED WITHIN THE STATED LIMITS.(SEE EXAMPLE 1-10, 1-11)1 . 751 . 73nLook at the limits of the O.D. and the I.D. of the washer. Which ones represent the washer at LMC?0. 750. 73n
15 n n 1 . 75 LMC OF THE O.D. 1 . 73 0. 75 LMC OF THE I.D. 0. 73 L LEAST MATERIAL CONDITION (LMC) =IS WHERE A FEATURE CONTAINS THE LEAST AMOUNT OFMATERIAL PERMITTED WITHIN THE STATED LIMITS.(SEE EXAMPLE 1-10, 1-11)1 . 751 . 73nLMC OF THE O.D.0. 750. 73LMC OF THE I.D.n
16 n n 1 . 75 MMC OF THE O.D. 1 . 73 0. 75 0. 73 MMC OF THE I.D. M MAXIMUM MATERIAL CONDITION (MMC) =IS WHERE A FEATURE CONTAINS THE MAXIMUM AMOUNT OF MATERIAL PERMITTED WITHIN THE STATED LIMITS.(SEE BOOK EXAMPLE 1-8 & 1-9)1 . 751 . 73MMC OF THE O.D.n0. 750. 73nMMC OF THE I.D.
17 RFSSometimes a geometric tolerance will be applied to a dimension at its MMC or it LMC.However………..REGARDLESS OF FEATURE SIZE (RFS) = IS THE TERM USED WHEN A GEOMETRIC TOLERANCE OR DATUM APPLIES AT ANY INCREMENT OF SIZE WITHIN ITS UPPER OR LOWER LIMIT. (SEE EXAMPLE 4-7)
18 Review IT IS A GLOBAL STANDARD FOR DIMENSIONING AND TOLERANCING. 1. What does ASME Y stand for? IT IS A GLOBAL STANDARD FOR DIMENSIONING AND TOLERANCING.2. What is tolerance?IT IS THE TOTAL AMOUNT THAT A DIMENSION IS PERMITTED TO VARY. 3. What are limits? ARE THE LARGEST AND SMALLEST (THE MAXIMUM AND MINIMUM) NUMERICAL VALUE THAT A FEATURES DIMENSIONS CAN BE.4. How do they differ? TOLERANCE IS THE DIFFERENCE BETWEEN A DIMENSIONS UPPER AND LOWER LIMITS.5. What is meant by Maximum Material Condition?IS WHERE A FEATURE CONTAINS THE MAXIMUM AMOUNT OF MATERIAL PERMITTED WITHIN THE STATED LIMITS.6. What is meant by Least Material Condition?IS WHERE A FEATURE CONTAINS THE LEAST AMOUNT OFMATERIAL PERMITTED WITHIN THE STATED LIMITS. 7. What is meant by RFS?REGARDLESS OF FEATURE SIZE
31 Datum Placement on Drawings BCDATUM FEATURE SYMBOLS ARE PLACED ON THE EDGE VIEW OR ON EXTENSION LINES.THE ORDER IN WHICH THE DATUM REFERENCE LETTERS ARE PLACED IN THE FEATURE CONTROL FRAME SIGNIFY THEIR IMPORTANCE. THIS IS CALLED THE ORDER OF PRECEDENCE.
32 Datum Axis Placement on Drawings .25BDATUM AXIS
33 Datum Axis Placement on Drawings ON THE OUTSIDE SURFACE (THE EDGE) OF A CYLINDRICAL FEATURE.ON THE LEADER LINE SHOULDERTHE SYMBOL CAN ALSO BE PLACED ON THE EXTENSION LINE.
34 Datum Axis Placement on Drawings THE DATUM SYMBOL CAN ALSO BE ATTACHED TO THE FEATURE CONTROL FRAME.
35 Datum Target Placement on Drawings At times only a small area on a surface will be used as a datum.To identify these areas a Datum Target Symbol is used.12XDATUM TARGET SYMBOL =ARE USED TO DESIGNATE POINTS OR A SPECIFIC SURFACE AREA. THEY ARE USED WHEN IT MAY NOT BE POSSIBLE TO ESTABLISH AN ENTIRE SURFACE AS A DATUM.(SEE EXAMPLE 3-12 PAGE 71)
38 Review Edge view Extension lines Leader line shoulder 1. Define Datum? Are planes, surfaces, points, lines or axes from which measurements are made. They identify surfaces or axes that are important to the function of the design.2. Describe the Datum Feature symbol?3. List three areas where datum symbols should be placed?Edge viewExtension linesLeader line shoulderFeature control frameA
39 Review (cont.)4. When are Datum Target Symbols used? They are used to designate points or a specific surface area. They are used when it may not be possible to establish an entire surface as a datum.5. Describe the Datum Target symbol?
53 Flatness a Form Tolerance A condition of a surface where all of the elements are in one plane.The problem is….
54 ….can any surface be made perfectly flat? So the designer must establish a range or zone of allowable variation. The form tolerance ‘Flatness’ is used to control the amount of variation on a flat surface.
55 Unlike straightness which controls the form of an object… flatness is used to control only a surface.
57 Circularity a Form Tolerance What kind of ride would you get if the wheels on you car were ‘out-of-round’?Is it possible to make a wheel that is perfectly round?How do you control the amount of allowable variation?
58 Circularity a Form Tolerance Circularity is established by two concentric circles created by a cross-section thru a rod or the center of a sphere.0.25The problem is….
63 ObjectivesIdentify orientation tolerance symbols, explain their purpose, and apply them to a drawing.ParallelismPerpendicularityAngularity
64 What are Orientation Tolerances? Orientation Tolerances control the relationship of features to one another. One or more datum features shall be referenced.These Orientation Tolerances are total, meaning that all elements of a related surface or axis fall within the specified tolerance zone.
65 Parallelism an Orientation Tolerance Parallelism is a condition of a surface or center plane equidistant from a datum plane or axis.Parallelism an Orientation Tolerance
66 Parallelism an Orientation Tolerance NOTICE THAT A DATUM IS REFERENCEDA
67 Perpendicularity is a condition of a surface, center or axis at a right angle (90 degrees) to a datum plane or axis.
68 PERPENDICULARITY an Orientation Tolerance .312AA
69 PERPENDICULARITY an Orientation Tolerance .312AA.312 WIDE TOLERANCE ZONE
70 ANGULARITY is a condition of a surface, center plane or axis at any specified angle from a datum plane or axis.
79 WHAT IS THE MEANING OF THE FEATURE CONTROL FRAME SHOWN BELOW? IT MEANS = THE IDENTIFIED HOLE IS TO BE POSITIONED WITHIN A 0.5 DIAMETER OF ITS TRUE (EXACT) POSITION, AT ITS MAXIMUM MATERIAL CONDITION.THE HOLE WILL BE PERPENDICULAR TO DATUM-A, AND LOCATED FROM DATUM-B AND DATUM-C.
81 Concentricity Tolerance is used to establish a relationship between the axes of two or more cylindrical features of an object.When two or more cylindrical features share the same axis, they are said to be coaxial.
87 GDT Placement Problem 1Instructions: Ortho sketch, model and detail the Tool Post. Add the required GDT shown below.Top surface is to be a primary datumTop surface to be smooth within .002Rear surface is to be a secondary datumRight-side surface is to be a tertiary datum.625 Dia hole in top to be positioned within .002.625 Dia hole in base to parallel to .625 Dia. at top within .002
88 GDT Placement Problem 2Instructions: Ortho sketch model and detail the Frame Guide. Add the required GDT shown below.Bottom surface is to be a primary datumRight-side surface is to be a secondary datumFront surface is to be a tertiary datumThe two 10 Dia holes in top to be positioned within .01, at maximum material conditionThe right-side surface is to be at right angles with the base within .02
89 GDT Placement Problem 3Instructions: Model and detail the Roller Stud and add the required GDT shown below.Axis of the – Dia is to be a primary datumThe – Dia to be on the same center as the – Dia within .01The – Dia to be straight within .01, at maximum material condition
90 GDT Placement Problem 4Instructions: Model and detail the Center Bushing and add the required GDT shown below.Axis of the Dia hole is to be a primary datumBottom surface is to be a secondary datumBottom surface is to be flat within .0021.372 Dia hole is to be 90 degrees to the bottom surface within .005 at LMC.Upper Dia surface to be parallel to the bottom within .005.The three .375 Dia holes are to be positioned within .001 at MMC.