TA 101: Technical Arts 2015-16 II Dr. Prishati Raychowdhury Department of Civil Engineering IIT Kanpur Office: FB 330; Phone: 6692 E-mail: prishati@iitk.ac.in

Lecture 11 Sectional Views

What is Sectioning? Cutting an object

Need for sectioning A B C B C A Section @ AA Section @ BB Section @ CC

Need for sectioning

Need for sectioning

Sectional Views A view of an object when it is ‘sectioned’ or ‘cut’ by an imaginary plane to reveal interior details of the object Sectional view is usually (but, not always) parallel to one of the principal orthographic planes e.g. frontal, top, or profile A sectional view must indicate which portions of the object are solid and which are spaces

Cutting Plane An imaginary plane that cuts the object Generally indicated in an adjacent view with a line and two arrows Generally named by letters : AA, BB etc A

Full Section Cutting plane passes completely through the object One cutting plane, it need not be straight

Half section Half sections are used for symmetrical objects in which one half is shown in section and other half in regular exterior Advantage: showing both interior and exterior in one view

Rotated/ Revolved Section Cut section rotated by 90o

Auxiliary Section

Drawing Sectional Views Visible edges shown in Main part hatched with 45o lines (2H)

Drawing Sectional Views Different parts are hatched at 30o, 60o, etc

Material Specific Hatching

Parts NOT Hatched Spokes Ribs Standard components like nuts, bolts, shafts, pins etc

Parts NOT Hatched Spokes are not hatched: to distinguish between Fig A and Fig B Solid wheel Wheel with spokes

Parts NOT Hatched Ribs not sectioned: otherwise they give the impression of a solid part

Parts NOT Hatched Ribs not sectioned in longitudinal section (along axis)

Parts NOT Hatched Ribs are hatched in transverse section (although this section is rarely taken)

Hidden Lines Hidden lines are not shown in sectional views (unless absolutely necessary) Section B is preferred over A

Important Note Sections are to be used only if some new information is revealed Use half section only if full section will not reveal any new information Sections should be hatched appropriately NO HIDDEN lines are to be shown in sections

Example: sectional view

Assembly Drawings A system (machine/house/computer, etc.) consists of many parts joined together in relation to each other A total drawing will be made up of Assembly, sub-assembly and part drawings A drawing may be viewed for a particular purpose: manufacturer, customer, information

Sectional Assemblies Single lug chain

Sequence of manufacture Step 1

Sequence of manufacture Step 2

Sequence of manufacture Step 3

Sequence of manufacture Step 4

Concept Top view

Concept Importance of Sectional view Know the fitting among the parts

Concept Importance of Sectional view Understand the alignment among the parts

Rules for Assembly Drawings Understand the function as a whole Understand the function of each part Decide the number of views required Estimate the size of each view Put the overall major dimensions only Don’t show hidden lines if it can be avoided Label parts with leader lines and numbers in circles Sections only if required

Example Bell Roller Support

Example Bell Roller Support…

Example Bell Roller Support…

Copper Rotor Motor Source: www.multivu.com

Thank you.. Next Day: AutoCAD