Engineering Graphics Basics Effectiveness of Graphics Language 1

Engineering Graphics- Basics

Effectiveness of Graphics Language 1. Try to write a description of this object. 2. Test your written description by having someone attempt to make a sketch from your description. You can easily understand that … *1 The word languages are inadequate for describing the size, shape and features completely as well as concisely.

Freehand drawing The lines are sketched without using instruments other than pencils and erasers. Example

Drawing by use of Instruments are used to draw straight lines, circles, and curves concisely and accurately. Thus, the drawings are usually made to scale. Example

Drawing by use of Computer The drawings are usually made by commercial software such as Auto. CAD, solid works etc. Example

Engineering Drawing *2

Elements of Engineering Drawing Engineering drawing are made up of graphics language and word language. Graphics language Describe a shape (mainly). Word language Describe size, location and specification of the object.

Basic Knowledge for Drafting Word language Graphics language Line types Projection method Geometric construction Lettering

Drawing Standard *2

DEFINITION §Standards are set of rules that govern how technical drawings are represented. § Drawing standards are used so that drawings convey the same meaning to everyone who reads them.

Standard Code Full name Country Code USA ANSI American National Standard Institute Japan JIS Japanese Industrial Standard UK BS British Standard Australia AS Australian Standard Germany DIN Deutsches Institut für Normung ISO International Standards Organization

Drawing Sheet Trimmed paper of a size A 0 ~ A 4. Standard sheet size (JIS) A 4 A 3 A 2 A 1 A 0 210 x 297 x 420 x 594 x 841 x 1189 (Dimensions are in millimeters) A 4 A 3 A 2 A 1 A 0

Drawing Scales • Definition: • Scale is define as ratio of linear dimensions of an element of an object represented in the original drawing to the linear dimension of the same element of the object by itself. Designation of a scale consists of the word “SCALE” followed by the indication of its ratio, as follow SCALE 1: 1 for full size scales SCALE X: 1 for enlargement scales SCALE 1: X for reduction scales

Basic Line Types *5

Meaning of Lines Visible lines : represent features that can be seen in the current view Hidden lines : represent features that can not be seen in the current view Center line : represents symmetry, path of motion, centers of circles, axis of symmetrical parts Dimension and Extension lines indicate the sizes and location of features on a drawing

Example : Line conventions in engineering drawing

Traditional Drawing Tools

DRAWING TOOLS *4 *3 1. T-Square 2. Triangles

DRAWING TOOLS 2 H or HB for thick line 4 H for thin line 3. Adhesive Tape 4. Pencils

DRAWING TOOLS 5. Sandpaper 6. Compass

DRAWING TOOLS 7. Pencil Eraser 8. Erasing Shield

DRAWING TOOLS 9. Circle Template 10. Tissue paper

DRAWING TOOLS 11. Sharpener 12. Clean paper

Lettering

Lettering Standard ANSI Standard This course Use a Gothic text style, Use only a vertical Gothic either inclined or vertical. text style. Use all capital letters. Use both capital and lower-case letters. Use 3 mm for most Same. For letters in title text height. block it is recommend to use 5~8 mm text height Space between lines N/A. of text is at least 1/3 Follows ANSI rule. of text height.

Stroke Sequence I L E H T F

Stroke Sequence V X W

N Y Stroke Sequence Z M K A 4

Stroke Sequence O Q C G

D R Stroke Sequence U P B J 1 2

Stroke Sequence 5 7

Stroke Sequence S 0 8 9 3 6

Stroke Sequence l i

Stroke Sequence w x v z k

Stroke Sequence y f j r t

Stroke Sequence o a c b d e p q

Stroke Sequence n m g u s h

Example : Good and Poor Lettering GOOD Not uniform in style. Not uniform in height. Not uniformly vertical or inclined. Not uniform in thickness of stroke. Area between letters not uniform. Area between words not uniform.

Sentence Composition Leave the space between words equal to the space requires for writing a letter “O”. Example ALL ODIMENSIONS OARE OIN MILLIMETERS OUNLESS OTHERWISE O SPECIFIED.

References- IMAGE 1. http: //www. bibliocad. com/library/piston_63810 2. http: //www. dreamstime. com/royalty-free-stock-photoengineering-drawing-equipment-image 19335615 3. http: //trade. indiamart. com/details. mp? offer=4715409313 4. http: //en. wikipedia. org/wiki/Set_square 5. http: //nptel. ac. in/courses/112103019/3 6. http: //grafoindia. com/drawinginstruments. html • http: //www. engineering 108. com/pages/Engineering_graphics_tutorials_free_download. html

References- Contents • http: //www. engineering 108. com/pages/Engin eering_graphics/Engineering_graphics_tutoria ls_free_download. html • A text book of engineering graphics- Prof. P. J SHAH • Engineering Drawing-N. D. Bhatt • Engineering Drawing-P. S. Gill

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