MECH 313 Engineering Drawing & Design

1. MECH 313 Engineering Drawing & Design Time: Mondays 1:15 - 3:45 p.m. Venue: H-535 Coordinator: Dr. Suraj Joshi Prerequisite: MECH 211 Credits: 3 Lecture 1

2. Lecturer contact details Instructor: Dr. Suraj Joshi Office: Engineering and Visual Arts Building Room: EV – 2.255 (Second floor) Phone: 848-2424 (7019) Office Hours: M _ W _ _ 12:00 –13:00 e-mail: sjoshi@encs.concordia.ca Web site: http://users.encs.concordia.ca/~nrskumar

3. Outline of the course

4. This is course is not mainly about drawing, but more towards design Extension of Mech 211 which is primarily drawing Lectures – 2.5 hours each 12 Lectures of all - one is an introductory lecture Midterm test (in week 8) on Mar 2 (tentative) 8 Assignments 4 Quizzes Final exam About the course

5. 2.5 continuous teaching hours/ week on Mondays from 1:15 – 3:45 at H-535 12 lectures + Midterm + Final In addition, one will be a guest lecture on “Bearings” by SKF (tentative) Class logistics

6. Course Webpage • http://users.encs.concordia.ca/~nrskumar • Password “Mech313” • Password is case sensitive • do not type enter after the password, but press the submit button • Password for downloading the lecture notes is “student”

7. Text book and other reference • TEXTBOOK • Jensen. C, Jay D. Helsel, Dennis R. Short, ‘Engineering Drawing and Design’, Glencoe-McGraw-Hill, Sixth Edition, SI Metric, 1998 • REFERENCES • Giesecke F.E.et al. : Engineering Graphics, Prentice Hall 1998 • Bertoline, G. R., et al.: Technical Graphics Communication, Times Miror Higher Education Group Inc., 1995 • Luzzander, W. V.: Fundamentals of Engineering Drawing, Prentice-Hall, Ninth Edition, 1981

8. Attend classes and tutorials Start solving the assignments immediately after you receive it Quizzes will be ad-hoc and at best you will have a week’s notice Solutions to quizzes will be posted at appropriate times A little strategy - requirements

9. You will write the midterm test on Mar 2, 2009 (tentative) during the tutorial period Open book exam Duration of the test will be 2 hours Write the midterm test – this is a good measurement means for your performance Midterm Exam

10. The final exam will have number of multiple choice, short drawings and design questions similar to assignments. Open book test Duration of the test is 3 hours Write the final exam with the confidence that you will do very well Final Exam

11. Eight assignments that will require significant effort must be completed during the term The timetable of the assignments is given in the course webpage. No late submissions are accepted, regardless of the reason Submission of assignments “ONLY” in the tutorial period Assignments

12. There will be four quizzes in all during the term The quizzes will be 15 minutes, comprising 10 multiple choice questions or short calculations There will be no prior intimation of the dates (mostly a weeks notice) Attending classes regularly is the only way of not missing the quizzes Quizzes

13. There will be 2 hour tutorials on Mondays after the lecture There will be TA’s who will give more detailed design and drawing instructions One or two of the tutorials may be converted to Laboratory Attending tutorials is necessary as this will help in solving the assignments as well as prepare you for the exams The Tutorial

14. There will be a group design project of design problems Details will be given in one of the tutorials Formation of groups will be done subsequently within the tutorials as well The group will have to design and draw a mechanism based on the design constraints defined in the problem The Project

15. Grade composition: Assignments: 16% Project 4% Quizzes: 10% Midterm: 20% Final: 50% To pass the course you have to Pass the final Submit your assignments on or before due date Attend the midterm as well as quizzes and get good marks Grading Scheme

16. Theory of Shape Description Sections Contents of today's lecture

17. Theory of Shape Description

18. Different kind of representations Hidden lines Inclined surfaces and Circular features Oblique surfaces One and two view drawings Special views Conventional representation Intersections Foreshortened projection Outline

19. Orthographic Representation Types of Projection • Orthogonal Projection • Requires more than one view to describe an object • Pictorial representation • Isometric • Oblique • Perspective

20. Uses parallel orthogonal projection to represent an object Flat, two dimensional views Views are positioned on the page according to projection method An identifying symbol next to the title block indicates which representation method is used Orthographic Representation

21. Orthographic Representation Projection Method • First Angle Projection • Third Angle Projection • Reference arrows layout • Mirrored Orthographic Representation

22. Orthographic Representation Shape Description The observer views the object perpendicular to each of the six sides of the box. To project the orthographic views of the object, think of the object enclosed in a “glass box”.

23. Orthographic Representation Third angle projection • The object to be represented appears behind the coordinate viewing planes on which the object is orthogonally projected • Identifying symbol • The most commonly used method in the US and Canada

24. Orthographic Representation First angle projection • The object to be represented appears between the observer and the coordinate viewing planes on which the object is orthogonally projected • Identifying symbol • The most commonly used method in Europe and Asia

25. Orthographic Representation Reference arrows layout • Permits various views to be freely positioned • Used when it is advantageous not to position views according to strict pattern • No identifying symbol needed • Each view identified by a letter.

26. Orthographic Representation Location of points • Origin (0,0,0) can be any convenient place in drawing • The coordinates for HJKL are shown • X axis represents width • Y axis represents depth • Z axis represents height

27. Orthographic Representation Location of points • The coordinates of the points remain the same, regardless of the views they are shown • H is 0.0, 4.0, 8.0 • J is 0.0, 0.0, 6.5 • K is 4.0, 0.0, 6.5 • L is 4.0, 4.0, 8.0

28. Orthographic Representation Location of points – Pictorial Drawing • Pictorial drawing is also series of lines connecting points on space • 0,0,0 is the absolute co-ord origin of X,Y,Z • 12,0,0 means movement in X and not in Y, Z • Similarly for other points

29. Arrangement of Views Balancing drawing on paper • Drafter must anticipate space required • Draw the views so that they are balanced on the drawing paper • Avoid crowding or excessive space • See page 92 for details

30. Arrangement of Views Use of Miter Lines • 1. Given the TV & FV, project lines to the right of the TV • 2. Establish how far (from FV) the SV is to be drawn (D) • 3. Construct the miter line at 45° to the horizontal

31. Arrangement of Views Use of Miter Lines • 4. Drop vertical lines from where the horizontal lines of the TV intersect the miter line • 5. Project horizontal lines to the right of the FV • 6. Complete side view

32. Parallel surfaces appear parallel to the viewing plane, with and without hidden features It will appear as a surface in one view and lines in the other views Parallel surfaces • The length of the lines in other views are same as is in the surface view

33. Parallel surfaces that appear parallel to the viewing plane, with and without hidden features Inclined surfaces that appear inclined in one plane and parallel to the other two principal reference planes Oblique surfaces that appear inclined in all three reference planes Types of Flat Surfaces

34. Hidden surfaces and edges Hidden Lines • Consist of short, evenly spaced dashes • Represent edges that cannot be seen from outside • Lines must begin and end with a dash except when it will be seen as an extension of a visible line

35. Hidden surfaces and edges Application of hidden lines • Lines must begin and end with a dash except when it will be seen as an extension of a visible line • Dashes should join at corners • Arcs should start as dashes at tangent points

36. Inclined Surfaces • Inclined surfacesthat appear inclined in one plane and parallel to the other two principal reference planes • It is seen as a distorted surface in two views and appear as line in one view • A & B appear as shortened in TV & RSV, but the TL of the surface is seen as Lines in FV • True shape ?

37. Circular Features • Appear circular in only one view • No line shown, when curved surface joins flat surface • Hidden circles, shown as hidden lines • Use of centre lines

38. Circular Features Center line applications • Thin broken line (alternative long and short dashes) • To locate centre of circles or cylinders • Lines should project beyond the outline of the referred part • Point of intersection of centre lines must be lines

39. Oblique Surfaces • Oblique surfaces that appear inclined in all three reference planes • Not perpendicular to any principal plane • Appear as surface in all 3 views but never in true shape • How many Auxiliary Views are required to find the TS of oblique surface?

40. One and two view drawings View selection • Best describe the object to be shown • Minimum number of views to describe object • for simple parts, one or two views often enough • Avoid views with more hidden lines

41. One and two view drawings One View drawing • Third dim (thickness) expressed as note or symbols • Abbreviations such as HEX ACRFLT, DIA, or  • Square sections can be indicated by crossed lines on diagonal • Used even when the surface is parallel or inclined to the drawing plane

42. One and two view drawings Two View drawing • When cylindrical features have keyway, end view is required to shown them • Usually drafters use two views only to define a part • For cylindrical surfaces, if three views are drawn, any 2 of them will be identical

43. Special views Partial views • A symmetrical object can usually be adequately shown using a half view and symmetry symbol • For complex shapes, side views sometimes maybe sometimes partial

44. Special views Enlarged views • Required to show particular feature with greater details, in a complex drawing • Oriented in the same manner as in view • If rotated, must show details of angle, direction etc..

45. Special views Key Plan • Used primarily in structural drawings • Includes a small key plan using Bold lines to show relationship between structures on that sheet to the whole work

46. Conventional representation • Simplify representation of common features • Mainly for improving clarity and reducing drafting time • Clarity, more important than speed

47. Conventional breaks • Long simple parts (shafts, pipes etc) can be shown using conventional breaks • True length must be shown in dimension • Short breaks are free hand thick lines, while long breaks are thin line with some zig zags • Special break lines are used to show the shape of features

48. Materials of construction • Symbols are used in sectional views to indicate materials • Symbols for concrete, wood, and transparent materials may be used for outside views

49. Cylindrical intersections • Conventional representation for intersecting rectangular and circular contours • Intersecting rectangular and circular contours shown conventionally, unless large • Same convention can be used for two cylindrical intersections

50. Cylindrical intersections • Conventional representation of holes in cylinders