ME180_Lecture_14_Geometric_Tolerancing_2

ME180_Lecture_14_Geometric_Tolerancing_2 - Geometric...

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Unformatted text preview: Geometric Tolerancing II 1 Geometric Tolerancing Referred to as GD&T Geometric Dimensioning & Tolerancing Follows ANSI Y14.5M, 1982 standard Developed from 1973 standard which was a modification of MIL-STD-8 (1940's) 2 Feature Control Frame 3 GD&T Tolerance Zones 4 5 6 7 8 Geometric Characteristic Symbols Straightness Element of a surface or an axis is a straight line Specifies a tolerance zone within which the element of axis must lie Tolerance is applied in the view where the elements to be controlled are represented by a straight line 9 Straightness 10 Straightness 11 Geometric Characteristic Symbols Flatness Condition of a surface having all elements in one plane Flatness tolerance specifies a tolerance zone defined by two parallel planes within which the surface must lie 12 Flatness 13 Flatness 14 Geometric Characteristic Symbols Circularity (Roundness) Specifies a tolerance zone bounded by two concentric circles within which each circular element of the surface must lie 15 Geometric Characteristic Symbols Cylindricity Condition of a surface of revolution in which all points of the surface are equidistant from a common axis Applies simultaneously to both circular and longitudinal elements of the surface (the entire surface) 16 Geometric Characteristic Symbols Profile of a Line Specifies a uniform boundary along a true profile within which elements of the surface must lie Profile of a line is two-dimensional and applies in the view in which shown 17 Geometric Characteristic Symbols Profile of a Surface Specifies a uniform boundary along the true profile within which the elements of a surface must lie It is used to control form 18 19 Geometric Characteristic Symbols Angularity Condition of a surface or axis at a specified angle (other than 90) from a datum plane or axis 20 Geometric Characteristic Symbols Perpendicularity Condition of a surface, median plane, or axis at a right angle to the datum plane or axis 21 22 Geometric Characteristic Symbols Parallelism Condition of a surface equidistant at all points from a datum plane, or an axis equidistant along its length to a datum axis 23 Geometric Characteristic Symbols Concentricity Condition where the axes of all cross-sectional elements of a surface of revolution are common to the axis of a datum feature 24 Geometric Characteristic Symbols Circular Runout Provides control of circular elements of a surface The tolerance is applied independently at any circular measuring position as the part is rotated 360 25 Geometric Characteristic Symbols Total Runout Provides composite control of all surface elements The tolerance is applied simultaneously to all circular and profile measuring positions as the part is rotated 360 26 Datum Reference Plane Establishing Datums Datums indicate the origin of a dimensional relationship between a toleranced feature and a designated feature on a part Measurements originate from planes or axes simulated by usage of the 3 plane concept 27 Datum Feature Symbol 28 Degrees of Freedom 29 Datum Reference Frame 30 Establishing a Datum 31 32 Datum Planes 33 The Part Actually Produced 34 Datum Plane Ordering 35 Datum Plane Ordering 36 Datum Plane Ordering 37 Implied Datums 38 Establishing a Datum Axis 39 Establishing a Datum Axis 40 41 42 Gaging a Part 43 ...
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