Introduction to Technical Drawing for Engineers and Technologists
- 2. Contents Drawing standards Engineering drawing Drawing sheet Scale Lettering Line types
- 3. Engineering Drawing The words of the language, as they are written or spoken, do not seem to play any role in my mechanism of thought. The psychical entities which seem to serve as elements in thought are certain signs and more or less clear images which can be “voluntarily” reproduced and combined--this combinatory play seems to be the essential feature in productive thought before there is any connection with logical construction in words or other kinds of signs which are communicated to others --Albert Einstein Contents
- 4. 1. Try to write a description of this object. 2. Test your written description by having someone attempt to make a sketch or visualize from your description. Effectiveness of Graphic Language The word language is inadequate for describing the size size, shape shape and features features completely as well as concisely. You can easily understand that …
- 5. Graphic Language in Engineering Drawing “Engineering drawing” or “blueprint” uses l lines ines to represent the features features of an object. Features of an object are surface surface (include plane plane) and edge edge. Surface Edge
- 6. A drawing can be created in 3 ways Ways to Create an Engineering Drawing 1. Freehand sketch 2. Using typical drawing instruments 3. Using a computer
- 7. Example Create a Drawing : Freehand sketch The lines are drawn using only pencil and erasers on a blank or grid paper. Pictorial sketch Orthographic sketch
- 8. Example Create a Drawing : Using instruments Drawing instruments are used to draw straight lines, circles, and curves concisely concisely and accurately accurately. Drawings are usually made to scale made to scale.
- 9. Example Create a Drawing : Using a computer Computer aided drafting (CAD) software is used. 2D drawing Solid modeling
- 10. Elements of a Drawing A clear and precise engineering drawing requires both graphics graphics and word word languages. Graphics language Describe a shape (mainly). Word language Describe an exact size, location and specification of the object.
- 11. Text on drawings : Example General notes Title block Dimensions & Notes
- 12. Knowledge and Skills Require Graphics language Word language Dimensions & Notes Visualization Visualization is the ability to mentally picture things that do not exists. Visualization Using line types Geometric construction Projection method Engineering Drawing Contents
- 13. Drawing Standard Drawing sheet Scale Lettering Line types Contents
- 14. Definition and Necessity Drawing standards are set of rules set of rules that govern how technical drawings are represented. Drawing standards are used so that drawings convey convey the same meaning the same meaning to everyone who reads them.
- 15. ISO International Standards Organization Standard Code ANSI American National Standard Institute USA JIS Japanese Industrial Standard Japan BS British Standard UK AS Australian Standard Australia Deutsches Institut für Normung DIN Germany Country Code Full name มอก./TIS สำนักงานมาตรฐานผลิตภัณฑ์อุตสาหกร Thailand
- 16. Examples of TIS Standard มอก. 210 2520 วิธีเขียนแบบทั่วไป : ทางเครื่องกล อก. 440 ล.1 2541 การเขียนแบบก่อสร้างเล่ม 1 ทั่วไป มอก. 446 ล.4 2532 ข้อแนะนำสำหรับการเขียน แผนภาพวงจรไฟฟ้า มอก. 1473 2540 การเขียนแบบเทคนิค การติดตั้ง สัญลักษณ์สำหรับระบบท่อของเหลว ระบบทำความร้อน การระบายอากาศ และระบบท่ออากาศ Code number Contents ที่มา : http://library.tisi.go.th/data/lib_resources/pdf/catalog-online49/tis/02_ICS.pdf
- 17. JIS Z 8311 Sizes and Format of Drawings Sizes and Format of Drawings JIS Z 8312 Line Conventions Line Conventions JIS Z 8313 Lettering Lettering JIS Z 8314 Scales Scales JIS Z 8315 Projection methods JIS Z 8316 Presentation of Views and Sections JIS Z 8317 Dimensioning Code number Contents Examples of JIS Standard
- 18. Drawing Standard Drawing Sheet Drawing standard Contents
- 19. Drawing Sheet : Standard size Trimmed paper of a size A0 ~ A4. Standard sheet size (JIS) A4 210 x 297 A3 297 x 420 A2 420 x 594 A1 594 x 841 A0 841 x 1189 A4 A3 A2 A1 A0 (Dimensions in millimeters)
- 20. Drawing space Drawing space Title block d d c c c Border lines 1. Type X (A0~A4) 2. Type Y (A4 only) Title block Sheet size c (min) d (min) A4 10 25 A3 10 25 A2 10 25 A1 20 25 A0 20 25 Drawing Sheet : Orientation & Margin
- 21. Drawing Standard Drawing Scale Drawing standard Contents
- 22. Drawing Scales : Definition Drawing Actual Length, size : Scale Scale is a ratio between the linear dimension of a drawn representation of an object and the actual object. 1 2
- 23. Designation of a scale consists of the word “SCALE” followed by the indication of its ratio, as follows SCALE 1:1 for full size SCALE X:1 (X > 1) for an enlargement enlargement scales SCALE 1:X (X > 1) for a reduction reduction scales Drawing Scales : Designation Drawing scale is commonly found in a title block.
- 24. Dimension numbers Dimension numbers shown in the drawing represent the “true size” of an object and they are independent of the drawing scale used. Drawing Scales : Notes
- 25. Standard reducing scales are 1:2, 1:5, 1:10, 1:20, 1:50, 1:100 Drawing Scales : Standard scale Standard enlarging scales are 2:1, 5:1, 10:1, 20:1, 50:1, 100:1
- 26. Drawing Standard Lettering Drawing standard Contents
- 27. - Size (or text height) - line thickness - Shape - Space between letters - Space between words Recommendation Legibility Legibility Uniformity Uniformity Text’s style on the drawing must have the following 2 properties Examples GOOD Not uniform in style. Not uniform in height. Not uniformly vertical. Not uniform in thickness of stroke. Inappropriate space between letters
- 28. Style (this course) Gothic vertical style. Begin the sentence, phrase or word with a capital letter. Text height 2~3 mm. Space between lines of text is about of text height. Height of the lower-case letter is about 2/3 of that of a capital letter.
- 29. Basic Strokes Straight Slanted Curved Horizontal 1 1 2 3 “I” letter “A” letter 1 2 3 4 5 6 “B” letter Examples
- 30. Suggested Strokes Sequence Straight line letters Curved line letters & Numerals Upper-case Letters & Numerals
- 32. I L T F E H Stroke Sequence : Upper-case Skip section
- 33. V X W Stroke Sequence : Upper-case Skip section
- 34. N M K Z Y A 4 Stroke Sequence : Upper-case Skip section
- 35. O Q C G Stroke Sequence : Upper-case Skip section
- 36. D U P B R J Stroke Sequence : Upper-case Skip section
- 37. 5 7 Stroke Sequence : Upper-case 1 2 Skip section
- 38. 6 8 9 0 S 3 Stroke Sequence : Upper-case Skip section
- 39. l i Stroke Sequence : Lower-case Skip section
- 40. v w x k z Stroke Sequence : Lower-case Skip section
- 41. j y f r t Stroke Sequence : Lower-case Skip section
- 42. c o a b d p q e Stroke Sequence : Lower-case Skip section
- 43. g n m h u s Stroke Sequence : Lower-case Skip section
- 44. DRAWING Word Composition Non-uniform spacing Uniform spacing DR A WING Space between the letters depends on the adjacent contour of the letters. Word having non-uniform spacing is more readable.
- 45. Word Composition Contour DRAWING Contour can be denoted as “straight”, “slant” and “curve”. Adjacent contour can be 1. straight-straight : II, IN, IM, IP etc. 2. straight-curve (or curve-straight) : IO, QR etc. 3. straight-slant (or slant-straight) : IV, IW etc. 4. curve-curve : OO, OG etc. 5. slant-curve (or curve-slant) : VO, WG, VC etc. 6. slant-slant : VW, VX etc. Spacing
- 46. Leave the space between words equal to the space requires for writing a letter “O”. Example Sentence Composition ALL DIMENSIONS ARE IN MILLIMETERS O O O O UNLESS OTHERWISE SPECIFIED. O
- 47. Drawing Standard Line Types Drawing standard Contents
- 48. Basic Line Types & Name according to application Continuous Dash Chain Style Thickness Thick Thin 1. Dimension line 2. Extension line 3. Leader line Center line Hidden line Visible line represent features that can be seen in the current view. represent features that can not be seen in the current view. represents symmetry, path of motion, centers of circles, axis of axisymmetrical parts indicate the sizes and location of features. 1. Visible line 3. Hidden line 4. Center line 2. Dimension line Extension line Leader line
- 49. Example Contents