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ISO128 Engineering Drawing Essentials Further Reference Download your copy of ISO 128/129 from: http://www.ihserc.com/cgi-bin/ihslogin Accessible by PolyU staffs and students on campus only Relative position of views First angle projection Third angle projection
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ISO128 Engineering Drawing Essentials
Further Reference • Download your copy of ISO 128/129 from: • http://www.ihserc.com/cgi-bin/ihslogin • Accessible by PolyU staffs and students on campus only
Relative position of views First angle projection Third angle projection
The use of reference arrows permits the various views to be freely positioned Each view shall be identified by a capital letter and a reference arrow The identifying capital letters shall be placed immediately below or above the relevant views Overriding Default View Positions
Direction of viewing different from those of standard projection method View cannot be placed in its correct position Partial views may be used may be used where complete views would not improve the information to be given Special Views
Choice of Views • Principle view: • Most informative • Functioning position • Main position of manufacturing or mounting • Other views: • As few as possible • As few sections as possible • Avoid the need of hidden outlines and edges • Avoid unnecessary repetition of details
Section Views • The object is imagined to be cut by a plane & the portion nearer to observer is removed. • The interior is exposed & shown in continuous lines • Hatching is applied at the plane of cutting The object is cut with the front part removed
Section Views • Use a thin chain line w/ thick continuous lines at both ends to represent the imaginary cutting plane • Label the sectional view • Draw cutting line on a view adjacent to the sectional view • Add label & viewing direction • Since sectional cutting is imaginary, all other views remain uncut Normal top & side views, plus a sectional front view SECTION A_A
Imaginary intersection lines such as fillets or rounded corners may be indicated in a view by means of continuous thin lines not touching the outlines Simplified representations of true intersection lines may be applied provide that they do not affect the comprehensibility of the drawing True and Imaginary intersections
The use of colours on technical drawings is not recommended All object made of transparent material should be drawn as non-transparent Colour and texture specified in separate document Texture and Materials