Model Documentation

1. Model Documentation

2. Working Drawing • Documentation • Once a design has been researched and approved, the part is sent to be prototyped or manufactured. Appropriate documentation is needed to communicate the idea to everyone in the company. This is the most difficult, time consuming, yet the most important part of engineering communication. These documentation are called working drawings.

3. What are Working Drawings? • Working drawings are a complete set of documents that specify how an object will be manufactured and assembled. Each set should include: • Part Drawings • Assembly Drawings • Parts List • Any Special Specifications or Instructions.

4. Working Drawings • Elements of Working Drawings • Drawing Layout • Drawing Views • Dimensioning • Annotations • Multiple Features

5. Drawing Layout • Elements of Drawing Layout • Sheet Styles and Sizes • Borders • Title Block • Scale • Revision Block

6. Sheet Styles • Drawing Sheets are laid out with a border, title block and can be customized for a company or project.

7. Sheet Sizes • Inch • Sizes are based upon standard letter head paper sizes, starting with an 8.5 x 11 sheet (A size), then each size after that doubles. • Metric • These are based on the A0 size, having an area of 1 square meter and a length to width ratio of 1: 2

8. Sheet Sizes International Organization of Standards ISO

9. Sheet Sizes American National Standards Institute ANSI

10. Borders • A border acts as a frame for drawings. Large drawings are broken into zones for locating information on a drawing. These are numbered horizontally and lettered vertically. Letters are upper case and originate in the lower right hand corner.

11. Border Example Zone Letters Numbers

12. Title Block • A box found in the lower right hand corner of a drawing. • It contains pertinent information on the part • Drawing Number • Scale • Material • Title or Description • Company • Tolerances

13. Title Blocks Zoning is used to find specific locations on the drawing. Usually shown in numbers and letters. General notes and information. Located here you will see information on, fillet and rounds, tolerances, and other general information that would take up too much space on the drawing if repeated on every feature. Title of the project. As opposed to a specific part. Remember working drawings are made of many different types of drawings and there are usually more than one sheet that goes with a design. ANSI Large style title block. All title blocks should include the following information. Name of person who checked the drawing. Just like first drafts of papers written in English class, drawings go through many revisions. Scale of the part is important so the person being communicated to can get an idea of what the part looks like. Another person will check the drawing and approve the part for manufacture. Size of sheet. Very valuable when printing. Company name. Many times companies will create their own borders and their logo will appear also. Name of person who did the drawing. Specific part name in relationship to the total design. Documentation of how many times the drawing has been changed.

14. Scale • When objects can be drawn using the actual dimensions, it is referred to as full scale or 1:1. Some objects are drawn larger than actual size, so one can clearly see details and dimensions these can be as large as 10:1. • Scale is represented as an equation. The left side is the drawing size and the right side represents the part.

15. Scale The bolt is drawn five times larger than actual size Scale 5:1

16. Revision Block A revision block is a documentation of all the changes that have occurred on the drawing.

17. Revision Block Description of the revision made. Date when drawing was revised. Who revised the drawing. Number of revision.

18. Drawing Views • For clear and accurate dimensioning and specification of a part the drawing may need a variety of views. • The five basic views are: • Orthographic • Isometric • Section • Auxiliary • Assembly

19. Orthographic (Multiview Drawings) Orthographic Projection is also known as a Multiview drawing. Orthographic projection is a way to project a view based on a line of sight that is perpendicular to that view. There are six views to any object as shown in the next slide.

20. Orthographic (Multiview Drawings) The arrows represent the line of sight associated with each view.

21. Orthographic Principal Views Note how the views are oriented. Each view is adjacent to the other as if they were unfolded from a 3D shape. Front, Top and Right views are used most often. You can see how other views resemble these three except they are not as clear due to hidden lines.

22. Orthographic Angle of Projection The example you have just seen is shown in the third angle of projection. This is the standard in the United States and Canada. The rest of the world draws in the first angle of projection. The following slides will show how the views are derived and what they look like.

23. Orthographic 1st Angle Projection Views are projected onto planes that exist on the opposite face of the view you want to display. The arrows show the direction of the projection. ISO Symbol

24. Orthographic 3rd Angle Projection Views are projected onto planes that exist on the face of that view. Arrows show the direction of the projection ISO Symbol

25. Orthographic View Selection • Steps in selecting the front view. • Most natural position or use. • Shows best shape and characteristic contours. • Longest dimensions. • Fewest hidden lines. • Most stable and natural position. • Relationship of other views. • Most contours • Longest side • Least hidden lines • Best natural position

26. Orthographic View Selection Most natural position. Longest Dimension Best shape description. No hidden lines.

27. OrthographicView Selection Numbers • A decision must be made in accordance to how many views are needed on a drawing. Generally, three views are needed and, in some cases, only one or two.

28. Orthographic Example 2 Orthographic views are used instead of three.

29. Orthographic Example 3 View Orthographic Drawing Dimensions to show size and shape. Title Block gives general information about the part.

30. Placing and Locating Orthographic Views • Which orthographic views you need are based on the same rules we had in the sketching unit. • Steps in selecting the front. • Most natural position or use. • Shows best shape and characteristic contours. • Longest dimensions. • Fewest hidden lines. • Most stable and natural position. • Relationship of other views • Most contours. • Longest side. • Least hidden lines. • Best natural position.

31. Placing and Locating Orthographic Views Parts are evenly spaced. Enough white space is left for dimensioning. Third angle projection is used. (We live in North America.)

32. Isometric Views • An isometricview is a pictorial view inserted in an orthographic drawing. • An Isometric, meaning equal measure, is created by rotating the object at equal angles to the projection plane in order to appear inclined and to show three faces.

33. Width and depth lines are drawn at 30 degrees from the horizon line. Isometric Note one pictorial view shows height width and depth.

34. Isometric Views Isometric View

35. Section Views • When a part has a lot of interior details, hidden lines can make the part hard to understand and dimension. To see the interior of these parts, we cut some of the part away. This allows for details to be seen clearly, as well as, giving us alternative locations to properly dimension the part.

36. Sectional Views • Types of Sectional Views • Half • Full • Offset • Removed • Revolved • Broken-out • Aligned

37. In a half section, one quarter of the part is cut away. This is done with symmetrical parts where you would like to show the outside, as well as, the inside details. Half Section Notice how the cutting plane line runs through the center of the part and there is no arrow head.

38. Full Section A full section is a view that shows what the object looks like if it were cut in half. A cutting plane line is used to indicate how the front view was cut. It is also labeled in case another section is necessary. The arrows should point in the line of sight as you are looking straight on at the section. Section lines called Hatch lines are used to show where the part is solid. This helps to see the detail that would be normally blocked and only shown as hidden lines.

39. Offset Section Interior features not in line with each other can be shown in an offset section view. Note how the cutting plane line changes and follows the center of each feature.

40. Revolved Sections • Used when an object has a constant shape throughout the length that cannot be illustrated in an external view. • The section is revolved 90 degrees. It may be represented one of two ways, either broken away or not.

41. Not Broken Away Revolved Section Section is revolved 90 degrees

42. Broken Away Revolved Section Section is revolved 90 degrees and broken away from part

43. Broken-out Section Views • A small portion of an object may be broken away to clarify an interior surface or feature. No cutting plane line is used.

44. Broken-out Section View Section exposes the interior surfaces

45. Removed Sections • A cutting plane is placed through the part where the section is taken. The removed sections are not aligned with the view. Placement is in the surrounding area.

46. Sections are not aligned with the view. Removed Sections

47. Aligned Section Views • A true projection of a part with inclined ribs, spokes, and arms will be foreshortened. An aligned section view is recommended to acquire accurate dimensions of the part. The cutting plane is bent at an angle as it passes through the object. The section view is then projected 90 degrees from the cutting plane and is in alignment to the original view.

48. View is projected 90 degrees from the cutting plane and is in alignment to the original view. Cutting plane is bent at an angle Aligned Section Views

49. Auxiliary View • To accurately view the true dimensions of an inclined surface, one must create a view at 90 degrees from that inclined face. This is referred to as anAuxiliary View. This allows us to view the surface in its true size and shape.

50. To obtain this view the auxiliary must be drawn from the view that allows the line of sight to be perpendicular to the desired feature. Line of sight. Primary Auxiliary View In order to see a feature in it’s true size and shape, we must look at it straight on or perpendicular to the plane in which the feature exists. Note that in this view (the auxiliary view) the slotted hole is true size and shape. Many times a feature on a part cannot be seen in true size and shape. When this is the case we use an auxiliary view.