Lecture 05

1. Lecture 05 Sectional Views Engineering Graphics & 3-D Modeling

2. New Assignment: HW 05 • MGC: • Reading • Finish CH6 • HW 05: • Sketch section for 6.4 - j only on p. 244. • Sketch the necessary views for 6.5, p. 245 (no dimensions necessary) • Sketch the necessary views for 6.19, p. 247 (no dimensions necessary); include the (1) broken-out and both (2) revolved sections • Lab: • Start Term Project: Cab Roof & Cab, Seat & Engine Housing Engineering Graphics & 3-D Modeling

3. Sectional Views • Sectional views show hidden detail clearly - a very important method! • Cutting planes are depicted in an adjacent view as lines with perpendicular arrows showing the viewing direction for the section • Cutting plane lines are patterned, thick, dark: A A Engineering Graphics & 3-D Modeling

4. Types of Sections • Full Sections • fully cut with a single plane • Half Sections • cut to a center line with a single plane • Broken-out Sections • cut to a break line with a single plane • Revolved Sections • cut with a single plane, revolved in place • Removed Sections • cut with a single plane, removed from position • Offset Sections (usually prismatic parts) • cut using multiple, offset planes • Aligned Sections (usually rotational parts) • cutting plane is bent to pass through other features Engineering Graphics & 3-D Modeling

5. Full Section View Engineering Graphics & 3-D Modeling

6. Creating a Section View (Offset Section) Engineering Graphics & 3-D Modeling

7. Full & Partial Section Views Engineering Graphics & 3-D Modeling

8. Revolved Sections Engineering Graphics & 3-D Modeling

9. Keys in Drawing Sections • Visible lines behind the cutting plane are shown • Hidden lines are nottypically shown • Sectioned areas are cross-hatched and always bounded by visible lines, only • Within an individual part, all cross-hatch lines are parallel • Cross-hatch lines in adjacent parts run oblique (often perpendicular) to cross-hatch lines in other parts Engineering Graphics & 3-D Modeling

10. Cross-hatch Patterns • Differing materials may be shown with distinct cross-hatch patterns (Fig. 6.18 on p. 228) • Cross-hatch lines should be: • thin • dark • evenly spaced • complete* to, but not over, the visible lines * can use outline hatching for large areas • Draw cross-hatch lines at 45o unless nearly parallel to an edge or adjacent to other sectioned (cross-hatched) materials Engineering Graphics & 3-D Modeling

11. Std Material Cross-hatch Patterns Engineering Graphics & 3-D Modeling

12. Odd Details • Ribs (webs) and projecting lugs are not cross-hatched • Rotated / angled features that are off-plane with the cutting plane are shown sectioned as if they were aligned with the cutting plane (Fig. 6.39, p. 236; 6.40, p.237) • Some intersections (particularly small holes) are not shown as truly projected (Fig. 6.42, p. 238) • Isometric/Oblique cross-hatches are 60o, typically. Engineering Graphics & 3-D Modeling

13. Showing Ribs in Section Views Engineering Graphics & 3-D Modeling

14. Conventional Break Lines • Short break lines are thick, dark, solid, rough • Round Solid • drawn as a gap and an ‘s-break’ on each end • Round Tube • unsectioned - hollow s-break • sectioned - similar to regular sectioning, with a regular, rough break line • Rectangular • Metal - use a regular, rough break line • Wood - exaggerate break line to look sharp, jagged, splintered Engineering Graphics & 3-D Modeling