1、 FECDS C-4 Engineering CAD slight violation of scale in such cases is acceptable. For illustration, see Standard D1 (ASME Y14.52009, Paragraph 1.7.1.2). 3.2 UNIFORMITY AND THICKNESS OF LINE 3.2.1 It is essential that uniformity of line thickness and style be maintained throughout the drawing. The wi
2、dths of line recommended are: THIN 0.3 and THICK 0.5. In specific applications 0.7 may be used. 3.3 BROKEN LINES (DASHED AND CHAIN LINES) 3.3.1 The lengths of the dashes and spaces of broken lines must be generally as shown in Figure C4.1 but may be varied according to the overall length of the line
3、. The proportions must be consistent over the length of any one line. 3.4 CENTER LINES 3.4.1 Extend only a short distance beyond the feature unless required for dimensioning or any other purposes. 3.5 GRID LINES AND CIRCLES 3.5.1 Grid lines are lines which serve as an accurate foundation for both la
4、yout and detail drafting. They are normally spaced 100 apart and terminated by minimum 15 diameter circles. See Figure C4.3. 3.6 PROJECTION LINES 3.6.1 Are used to refer to a point or line on a drawing to which a dimension applies. Where projection lines are extensions of lines of the outline they s
5、hould start just clear of the outline and extend slightly beyond the dimension line as shown in Figure C4.5. Where projection lines refer to points on surfaces, or to points of intersection, they should touch or pass through the points as shown in Figure C4.2 and Figure C4.6. For clarity the points
6、may be emphasized by small circles. Return to TOC ENGINEERING CAD & DRAFTING STANDARDS 3.7 CUTTING PLANE LINES 3.7.1 Used to indicate the location of cutting planes for sectional views. See Figure C4.2. For application see Standard C6, Sectioning. 3.8 LEADER LINES 3.8.1 Leader lines are preferably s
7、traight ruled thin lines and are used to direct notes, dimensions, symbols or part numbers to features or other items on the drawing. See Figure C4.2. A leader is normally composed of a short horizontal line at the note end, an inclined line extending to the feature and an arrowhead touching the fea
8、ture. 3.9 LEADER APPLICATIONS 3.9.1 A leader must originate at the beginning or end of the note, extending from the center of the letter height. See Figure C4.11. The horizontal portion must never be used to underline the note. A leader should be short, must not cross other leaders, and where severa
9、l are in a group and adjacent, must be drawn parallel. Leaders must not, however, be parallel to the adjacent dimension, section or projection lines. 3.9.2 Leaders drawn to symmetrical features must be in line with the center of the feature and the arrowhead shall terminate exactly on the line which
10、 represents the profile of the feature. See Figure C4.7. 3.10 LEADER ANGLES 3.10.1 The angle between the horizontal and the inclined portion of the leader must be not less than 20 degrees. The angle between the object and any leader must not be less than 20 degrees. This applies also to the angle be
11、tween the inclined portion of the leader and any line to which it points. See Figure C4.8. 3.11 BENT LEADERS 3.11.1 Although oblique portions of a leader are made preferably without bends, it may include a single bend where justified, as in a group of leaders. See Figure C4.9. Bends must be made as
12、angles, however, rather than arcs. 3.12 CURVED LEADERS 3.12.1 Curved leaders must be used only for the purpose of enclosing a portion of the view. See Figure C4.10. 3.13 MULTIPLE LEADERS 3.13.1 Multiple leaders may be used where required. See Figure C4.11. 3.14 HATCHING LINES (SECTION LINES) 3.14.1
13、Thin continuous lines to indicate the cut surface of an object in a sectional view. See Figure C4.2. For application see Standard C6, Sectioning. 3.15 REPETITIVE INFORMATION Original Issue: 19960419 Copyright, Ford Motor Company. Latest Re-issue: 20090630C42 Printed copies are uncontrolled.Return to
14、 TOC ENGINEERING CAD & DRAFTING STANDARDS 3.15.1 Repeated illustrations of identical features may be avoided by drawing one and indicating the positions of the others by their center lines. See Figure C4.4. Figure C4.1 Original Issue: 19960419 Copyright, Ford Motor Company. Latest Re-issue: 20090630
15、C43 Printed copies are uncontrolled.Return to TOC ENGINEERING CAD & DRAFTING STANDARDS Figure C4.2 Original Issue: 19960419 Copyright, Ford Motor Company. Latest Re-issue: 20090630C44 Printed copies are uncontrolled.Return to TOC ENGINEERING CAD & DRAFTING STANDARDS Original Issue: 19960419 Copyrigh
16、t, Ford Motor Company. Latest Re-issue: 20090630C45 Printed copies are uncontrolled.Return to TOC ENGINEERING CAD & DRAFTING STANDARDS Original Issue: 19960419 Copyright, Ford Motor Company. Latest Re-issue: 20090630C46 Printed copies are uncontrolled.Original Issue: 19960419 Copyright, Ford Motor Company. Latest Re-issue: 20090630C47 Printed copies are uncontrolled.ENGINEERING CAD & DRAFTING STANDARDS Return to TOC 4 SPECIFICATIONS (Reserved) 5 ADDENDUM (Reserved)
