ASME Y14.31:2008 pdf download

ASME Y14.31:2008 pdf download.Undimensioned Drawings
1 GENERAL
1.1 Scope
This Standard establishes the requirements for undi- mensioned drawings that graphically define items with true geometry view(s) and predominantly without the use of dimensions.
1.2 Drawing
Type Selection Considerations The acceptance zone for an undimensioned drawing is the uniform boundary along the true profile or line on the undimensioned drawing [see Fig. 1, illustration (a)]. The line on the undimensioned drawing located at true profile is not probable due to contributors such as graphical tolerance, reproduction tolerance, or skill of the user. These contributors can move the acceptance zone resulting in a relaxed acceptance [see Fig. 1, illustration (b)]. This relaxed acceptance makes the undi- mensioned drawing equivalent to a tolerant gage per ASME Y14.43, accepting most part features that are within tolerance, rejecting most part features not within tolerance, accepting a small percentage of borderline out-of-tolerance features, and rejecting a small percent- age of borderline within tolerance features. The effect of these contributors on item acceptance shall be consid- ered before selecting this drawing type.
1.3 Figures
The figures in this Standard are intended only as illustrations to aid the user in understanding the prac- tices described in the text. In some cases, figures show a level of detail as needed for emphasis; in other cases, figures were deliberately left incomplete to illustrate a concept or facet thereof. The presence or absence of figures has no bearing on the applicability of the stated requirement or practice.
1.4 Notes
Notes depicted in this Standard in capital letters reflect actual drawing entries. Notes in lower case letters are to be considered supporting data to the contents of this Standard and are, therefore, not intended for literal entry on drawings. 1.5 Units In the drawing examples, the U.S. Customary units are featured.
1.7.2 Bend Radius bend radius: the inside radius of a formed part. 1.7.3 Bend Tangent Line bend tangent line: the line at which the flat surface of a part becomes tangent to the radius of the bend (see Fig. 2). 1.7.4 Brake Process brake process: a method of forming in which the punch is brought down on a flat pattern that is laid on the die, bending the sheet metal up and around the surface of the punch. 1.7.5 Center Line of Bend (CLB) center line ofbend (CLB): a line half the distance between the bend tangents that indicates the straight line of con- tact where the brake press bar will strike the flat pattern to form the bend (see Fig. 3). 1.7.6 Common Reference common reference: a reference line provided for use as a guide in coordinating the alignment of an item across multiple views or drawing sheets. 1.7.7 Comparator Drawing comparator drawing: a drawing defining a 2D true profile, used for overlay validation viewing of items with a comparator checking machine. 1.7.8 Contour Definition Drawing contour definition drawing: a drawing containing the mathematical, numeric, or graphic definition required to locate and define a contoured surface, also known as loft drawing. 1.7.9 Dimensional Accuracy Points dimensional accuracy points: a set of points located in a rectangular pattern to establish a means of measuring horizontally, vertically, or diagonally across the drawing to validate dimensional accuracy. 1.7.10 Flange flange: the portion of the item being bent. 1.7.11 Form Block Line (FBL) form blockline(FBL): the line representingthe intersection of the projected surfaces of the tool used for forming (see Fig. 4). 1.7.12 Grid Lines grid lines: a pattern of perpendicular lines drawn to a precise scale across the face of the drawing to validate dimensional accuracy.