ASME Y14.41-2019 pdf download

ASME Y14.41-2019 pdf download.Digital Product Definition Data Practices.
Identification of Datum Features The following subparagraphs describe requirements for identification of datum features and attachment or placementofdatumfeaturesymbolsonannotatedmodels. (a) Identification of Datum Features. Figure 11-2 demonstrates symbol attachmentmethods for identifying the datum features. The datum feature symbol should be attached to the surface representing the datum feature. Single extension lines of feature outlines should not be used for attachment ofdatum feature symbols. Particular requirements and the preferred methods governing each ofthe four fundamental datum feature types are given in the following subparagraphs. (1) Identification ofa Planar Surface Datum Feature. The datum feature symbol is placed on an annotation plane perpendicular to the surface. See datum A in Figure 11-2, illustration (a). (2) Identification of a Spherical Surface Datum Feature. The datum feature symbol is attached as shown to the size limits imposed upon the feature. See datum F in Figure 11-2, illustration (a). (3) Identification of a Cylindrical Surface Datum Feature. The datum feature symbol is attached as shown to the size limits imposed upon the feature. See datum B in Figure 11-2, illustration (a). (4) Identification ofa Set ofTwo Opposed, Parallel Planes (a Width). dimensionandextensionlinesareplacedonanannotation plane perpendicular to the width centerplane. The size limits shall be organized and displayed similarly as shown. See datum C and datum E in Figure 11-2, illustra- tion (a). (5) Identification ofLimited Area Application. When the surface containing a datum feature also contains an area of limited application of a geometric tolerance, the limited area of application is represented on the model geometry using supplemental geometry. See Figure 11-3. (6) The datum feature symbol mayalso be placed on thehorizontalportionofaleaderlinethatisdirectedtothe appropriate surface. See Figures 11-5 and 12-25.
A Pattern ofFeatures Establishing a Datum Axis. When a pattern of features of size is used to establish a datum axis, the involved features and any applied toler- ance forthese features shall be organized as an associated group. See Figure 11-7. (b) Two Coaxial Cylinders Establishing a Single Datum Axis. When two coaxial and cylindrical datum features are used to establish a single, common datum axis, the involved features and any applied tolerance for these features shall be organized as an associated group. See Figure 11-8. (c) Coplanar Surfaces Establishing a Datum Plane. When two or more coplanar surface features are used to establish a datum plane, the involved model surfaces and anyapplied tolerance forthese surfaces shall be orga- nized as an associated group. See Figure 11-9. When an intervening feature separates the surfaces being toler- anced, the profile tolerance shall be attached to one of the surfaces but not both. See Figure 11-10. 11.3 DRAWING GRAPHIC SHEET REQUIREMENTS Datum features in axonometric views shall be indicated as follows: (a) Datum Reference Frame and Coordinate System Correspondence. The corresponding coordinate system shall be displayed in each axonometric view in which a datum reference frame is cited. (b) Identification of Datum Features in Axonometric Views. The following subparagraphs describe require- ments for identification ofdatum features in axonometric views: (1) The datum feature symbol should be attached to the model geometry surface representing the datum feature. A single extension line of a feature outline should not be used for attachment of datum feature symbols in an axonometric view. (2) Datum feature symbols may be attached to the dimension for features ofsize when the feature is used to define a datum. See Figure 11-2. (c) V-Type Equalizers Using Axonometric Views. V-type equalizers shall use the display presentation method of Figure 11-11, illustration (a). The V-type equalizers shall be represented by supplemental geomThe feature control frame shall be placed on an annota- tion plane parallel to, perpendicular to, or coincidentwith the surface to which itapplies. See Figure 12-1. Table 12-1 lists the form tolerances with the type of attachment method used. (a) Flatness, Limited Area Application. A limited area of application shall be represented on the model geometry using supplemental geometry. The leader directed from the flatness feature control frame shall be attached within the represented area. See Figure 11-3. (b) Circularity Applied to a Sphere, Cylinder, Cone, or a Surface ofRevolution. The feature control frame shall be placed on an annotation plane perpendicular to the feature’s axis ofrevolution, or containing the centerpoint of a sphere. See Figure 12-2. (c) Straightness Applied to the Line Elements ofa Cylin- dricalorConicalSurface. Thefeaturecontrolframeshallbe placed on an annotation plane containing the axis of the feature surface. See Figure 12-6.The feature control frame shall be placed on an annota- tion plane parallel to, perpendicular to, or coincidentwith the surface to which itapplies. See Figure 12-1. Table 12-1 lists the form tolerances with the type of attachment method used. (a) Flatness, Limited Area Application. A limited area of application shall be represented on the model geometry using supplemental geometry. The leader directed from the flatness feature control frame shall be attached within the represented area. See Figure 11-3. (b) Circularity Applied to a Sphere, Cylinder, Cone, or a Surface ofRevolution. The feature control frame shall be placed on an annotation plane perpendicular to the feature’s axis ofrevolution, or containing the centerpoint of a sphere. See Figure 12-2. (c) Straightness Applied to the Line Elements ofa Cylin- dricalorConicalSurface.