Fundamentals for building Drawing

Transcription

1 Fundamentals for building Drawing

2 What is Drawing Introduction Knowledge of preparing and understanding drawing will prove to be an invaluable aid while performing their jobs effectively, efficiently. All concerned have to understand the basics of this graphical language of engineers. Drawing is a pictorial presentation of anything, It s a means of communication because with the help of drawing, one can communicate the ideas to others. Sometimes, thousand of words can not able to express the ideas, but with the help of drawing, one can communicate most complicated problems also.

3 An Engineering Drawing is a type of technical drawing, used to fully and clearly define the requirements for engineered items, and is usually created in accordance with standardized conventions for layout, nomenclature, interpretation, appearance (such as typefaces and line styles), size, etc. Purpose of Drawing To capture all the geometric features of a product or a component accurately and unambiguously to convey all the required information that will allow a user to understand that component. A technical drawing is a form of graphic communication. This type of drawing is used in the transforming of an idea into physical form. The process of creating a technical drawing is called drafting or technical drawing. Different kinds of drawing are prepared for different purposes like Layout of plans, Drawings for approval of authority, Working and detailed drawings for estimates and construction

4 Drawings Convey the following critical information Geometry Dimension Material Finishes

5 Geometry Shape of the object; Represented as views; how the object will look Side view Top view Front view

6 Dimensions the size of the object is captured in accepted units

7 Material represents what the item is made of.

8 Finish specifies the surface quality of the item, functional or cosmetic. For example, a mass-marketed product usually requires a much higher surface quality than, say, a component that goes inside industrial machinery. Tolerances the allowable variations for each dimension

9 What we Draw? Layout of plans Submission drawing Working and detailed drawings for estimates construction For the contractor to execute the building How to Draw? By graphical language of lines, projections, projectors Orthographic and pictorial drawing

10 Why we Draw? For approval of client For approval of sanctioning authority Working and detailed drawings for estimates For the contractor to execute the building

11 CODE OF PRACTICE (IS-962,1989) Size of drawing papers Layout of drawing Conventional representation Size of letters and numerals on drawing Graphic symbols and abbreviation

12 SIZE OF DRAWING SHEET

13 ISO A Drawing Sizes (mm) Trimmed size Untrimmed size A5 148 x x 240 A4 210 X x 330 A3 297 X x 450 A2 420 X x 625 A1 594 X x 880 A0 841 X x 1230

14 Layout of Drawing Border line are drawing all round the drawing sheet leaving margin of 10 mm 25 mm to 30 mm on left side for filing

15 Title Block LOCATION RIGHT HAND SIDE BOTTOM CORNER

16 SCALE OF DRAWING (FOR PLAN,ELEVATION AND SECTION) 1: 100 1:200 DETAILED DRAWING 1:20 OR 1: 10

17 Lettering and Dimensioning LETTER SHOULD BE OF UNIFORM SIZE 1. MAIN TITLE AND DRAWING NO 6,8,10 and12 mm 2. SUBTITLE AND HEADINGS 3,4,5 and 6 mm 3.NOTES, LEGENDS, SCHEDULE, MATERIAL AND DIMENSIONS 2,3,4 and 6 mm

18 PROJECTION SYSTEMS

19 PROJECTION SYSTEMS Orthographic Projection Isometric Projection Perspective Oblique Projection

20 Orthographic projection: Orthographic comes from the Greek word for "straight writing (or drawing)." This projection shows the object as it looks from the front, right, left, top, bottom, or back, and are typically positioned relative to each other according to the rules of either first-angle or third-angle projection.

21 First Angle Projection 3D object is projected into 2D "paper". An object is placed in first quadrant. Object lies between observer and plane of projection The top view is under the front view the right view is at the left of the front view.

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23 Third Angle Projection An object is placed in third quadrant. The plane of projection lies between object and observer Plan is above the elevation The left view is placed on the left the right view on right side

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25 Combination of First and Third Angle Projection Building drawing, we use combination of first and third angle projection Plan is below the elevation In relation to elevation, end view are so placed that they are in third angle projection Left view on left and right view on right side

26 ELE B ELEVATION ELE A B PLAN A

27 ELEVATION SEC A SEC B KEY PLAN SITE PLAN Name of drawing Schedule Area Table B PLAN A PLAN Details of owner/ar chitect/e ngineer

28 LINE STYLES AND TYPES visible are continuous lines used to depict edges directly visible from a particular angle. hidden are short-dashed lines that may be used to represent edges that are not directly visible. center are alternately long- and short-dashed lines that may be used to represent the axes of circular features. cutting plane are thin, medium-dashed lines, or thick alternately long- and double short-dashed that may be used to define sections for section views. section are thin lines in a pattern (pattern determined by the material being "cut" or "sectioned") used to indicate surfaces in section views resulting from "cutting." Section lines are commonly referred to as "cross-hatching."

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30 Type A lines show the outline of the feature of an object. They are the thickest lines on a drawing and done with a pencil softer than HB. Type B lines are dimension lines and are used for dimensioning, projecting, extending, or leaders. A harder pencil should be used, such as a 2H. Type C lines are used for breaks when the whole object is not shown. They are freehand drawn and only for short breaks. 2H pencil Type D lines are similar to Type C, except they are zigzagged and only for longer breaks. 2H pencil Type E lines indicate hidden outlines of internal features of an object. They are dotted lines. 2H pencil Type F lines are Type F[typo] lines, except they are used for drawings in electrotechnology. 2H pencil Type G lines are used for centre lines. They are dotted lines, but a long line of 10 20mm, then a gap, then a small line of 2mm. 2H pencil Type H lines are the same as Type G, except that every second long line is thicker. They indicate the cutting plane of an object. 2H pencil Type K lines indicate the alternate positions of an object and the line taken by that object. They are drawn with a long line of 10 20mm, then a small gap, then a small line of 2mm, then a gap, then another small line. 2H pencil.

31 Symbols Scale are in constant use on small scale drawing It is considered that time can be saved and confusion can be avoided. It also save the space in drawing. Abbreviation Abbreviation are generally used in drawing for sake of clarity. A systematic notation of architectural and building terms is necessary for uniformity and avoiding confusion and ambiguity. Scale used to prepare submission and working drawings is 1: 200, 1:100, 1:50.

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