lab manual preparation

8/13/2019 Lab Manual Preparation

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Thalambur,Chennai-603103

DEPARTMENT OF MECHANICAL ENGINEERING

ME 2155 COMPUTER AIDED DRAFTING AND MODELING LABORATORY MANUAL

NAME :

REG NO. :

YEAR :

BRANCH :

BATCH :


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INDEX

EX.NO DATE EXPERIMENT NAME MARKS SIGNATURE


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INTRODUCTION TO AUTOCAD

DRAWING AND MODIFYING OBJECTS

AutoCAD is drafting/modeling software used all over the world by almostall manufacturing companies. It is variable software which can be used in allengineering divisions. It is a drafting version popularly known to everyoneassociated with mechanical engineering. The AutoCAD drawing enables thedesigner to communicate his ideas to the outside of department easily.

Conversion of AutoCAD files to other software is also using drawingexchange formula. In the lesson, commands and procedures for drawing andmodifying the objects are explored.

START AND SAVE A DRAWING

When you start a drawing, you specify the type of units and other settings you canalso choose how to save your files, including saving back up files. The settings youselect, English a metric determines default values used for many system variablesof controlling text dimensions, grid, snap and default line type and hatch patternlife. ENGLISH - Creates a new drawing based on Imperial Measurement System.The drawing is based on cad.dwt template.

METRICCreates a new drawing based on metric measurement. The drawing is based onocadiso.dwt template. Save drawing files for later use.

CONTROL THE VIEWSYou can magnify the details in your drawing for a closer view or shift the view to adifferent part of the drawing. If you can save the view by name, you can restorethem later.

UNITSEvery object is measured in units. In AutoCAD we can determine the value of theunits before we draw.

LIMITS

The drawing limits are two-dimensional points in the world coordinate thatrepresent a lower-left limit and an upper right limit. You cannot impose limits onthe Z direction.


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ABSOLUTE COORDINATE SYSTEMIn Absolute Coordinate System, the dimensions X and Y of a point is specified with reference to the origin (0, 0).

RELATIVE COORDINATE SYSTEMIn Relative Coordinate System, the dimensions X and Y of a point are specifiedwith respect to the last entered point (i.e.) the last enter point is taken as origin.

POLAR COORDINATE SYSTEMIn Polar Coordinate System, the dimensions of a point are specified by using adistance and angle with reference to the previous point. Angles are measured inanticlockwise direction, taking 0 degrees towards right.

LINE

Line command allows you to create a line where the end points are specified bytwo dimensional or three dimensional coordinates.

POLYLINEPLINE command allows you to draw line and arc segments, but from start to end,it is treated as a sing object. With PLINE command, you can draw objects evenwith line width.

ARCThe ARC command allows you to create an arc segment. There are differentmethods of creating an arc. The different methods of creating an arc are:1) 3 Points2) Centre, Start, Radius3) Start, Centre, End 4) Start, Centre, Angle5) Start, Centre, Length6) Start, End, Angle7) Start, End, Direction8) Start, End, Radius

CIRCLEThe CIRCLE command allows you to create a circle. There are four differentmethods for drawing circles. They are:Centre, Radius/Centre, Diameter 3 Points (3P), 2 Points (2P)Tangent, Tangent, Radius (ttr)


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POLYGONPolygon command creates a regular polygon. You must specify the number of sides of the polygon and whether it is Inscribed or Circumscribed polygon. Now,specify the centre and radius of the polygon circle.

OSNAPOsnaps allow you to snap onto a specific object location when you are picking a

point. For example, using Osnaps you can accurately pick the end point of a line or the center of a circle.

ERASEThis command is used for deleting unwanted objects. You must select the object to

be erased.

COPYThe copy command is used for making copies of selected objects. The object to becopied must be selected and the base point must be specified and the copy can bedragged and placed at the required position.

MOVEThis command is used for moving selected objects. The object to be moved must

be selected and its base point must be specified then we can drag it to the requiredlocation.

ROTATEThis command is used for rotating selected objects. To rotate an object, first selectit and specify a base point. Now enter an angle value or specify a second point torotate the object.Entering a positive angle value rotates the objects counterclockwise or clockwise,depending on the Direction Contorl Control setting and Drawing Units dialog box.The plane of rotation and the direction of the zero angle depend on the orientationof the user coordinate system.

MIRRORThe MIRROR command is used for creating mirror images of selected objects.You must first select the object to be mirrored and then specify the axis alongwhich it is mirrored, to create an mirror image of the selected object. This is a veryuseful command for drawing symmetrical objects about a particular axis.


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OFFSETOffset an object to create a new object whose shape parallels the shape of theoriginal object. Offsetting a circle or an arc creates a larger or smaller circle or arc,depending on which side you specify for the offset.

POLAR ARRAYThis command creates an array of the selected object around a centre point. Youmust specify the centre point of the array, the total number of items and the angleto fill for creating a polar array.

RECTANGULAR ARRAYThis command creates an array of the selected objects defined by the number ofrows and columns and the offset between them.

EXTENDThe EXTEND command elongates the selected objects to a specified boundary.

TRIMThe TRIM command trims off an object using cutting edges defined by other objects. Here the user is required to select object(s) to define cutting edge(s) thenselect the object to be trimmed; the selected side of the object is removed based onthe side of selection of the object to be trimmed relative to the cutting edge.

BREAKThe BREAK command is used to remove only parts of an object. You must specifythe first and second points between which the object must be deleted.

FILLETFILLET rounds of the edges of two arcs, circles, elliptical arcs, lines, polylines,rays, splines or xlines with an arc of a specified radius. Rounds along the edgescannot be created with zero radius.

CHAMFER

CHAMFER command draws a line at the corner between two selected lines. If thelines do not intersect, it extends the lines. If they intersect, the lines extending

beyond the chamfer line can be trimmed or left as it is, by the trim mode.

LENGTHENThe LENGTHEN command is used to increase/decrease the length of AutoCADobjects.


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DIVIDEThis command places evenly spaced point objects or blocks along the length or

perimeter of an object. You can select only one entity at a time to be divided. Theentities that can be selected are: line, arc, circle, polyline and spline.

ZOOM ALLThis zoom to display the entire drawing in the current viewport. The display showsall the entities even if the drawing extends outside the drawing limits.

ZOOM WINDOWZOOM WINDOW commands to display an area specified by two diagonallyopposite corner points of a rectangle window.

ZOOM EXTENTS

This zoom to display the drawing extents. If the drawings are small in the existinglimits, then there is an enlarging effect on the screen. If the drawing occupy thecomplete area of the limits, then there are many not be much difference betweenZOOM ALL and ZOOM EXTENTS.

DIMLINEARThis command specifies the linear distance between two selected points.

DIMALIGNEDThis command is used for specifying the linear distance (exact dimensional value)

between two points which are inclined at an angle.

DIMANGULARThis command is used for obtaining the angle two selected points. The threetypes are:1) Arc Selection2) Circle Selection3) Line Selection4) Three Point Selection

DIMRADIUSThis command gives the value of radius of the specified circle, arc or fillet. Aradial dimension consists of a radius dimension line with an arrowhead at the arcor circle end.


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DIMCENTERThis command marks the centre point of the selected arc or circle. The center markcannot be updated, so set the required style before executing this command.

LINETYPELINETYPE greatly improves the readability of technical drawings. You can makeimportant features stand out with bold line weights.

LAYERLayer is an organizing tool. Layers are like one, where you can keep various typesof information. Its always a good idea to keep notes and reference symbols abouteach element of the drawing as well as drawing dimensions on a new layer.

DISTANCE

This command lists the distance between the selected points and also lists out theangle in current plane and 3D angle from the current plane, based on the directionof picking the two points. It also lists the projected lengths on the three axes called the delta length.

TEXTTEXT command creates text objects with specified height and orientation. Textobjects can be created with a variety of character patterns call style. This commandallows you to type a single line or multiple lines of text.

MTEXTMTEXT creates paragraph that fit within a nonprinting text boundary. The userspecified text boundary determines the width of the paragraph and the justificationof the text within the paragraph. Each multiline text object is a single object,regardless of the number of lines it contains.

HATCHHatches are shaded pattern which generally represent cross-section of a mechanicalcomponent. Using BHATCH command the required area, type of hatch, hatch

angle and scale can be specified.

PROPERTIESThe PROPERTIES command displays the Properties palette. The Properties paletteis the main method for viewing and modifying the properties of AutoCAD objects.


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VPORTSViewports are areas that display different views of your model. As you work on theModel tab, you can split the drawing area into one or more adjacent rectangularviews known as model space viewports . In large or complex drawings, displayingdifferent views reduces the time needed to zoom or pan in a single view. Also,errors you might miss in one view may be apparent in the others.

EXTRUDESolids can be created by extruding selected objects. Use the EXTRUDE commandto create a solid or surface from a common profile of an object

REVOLVEREVOLVE command can create a solid or surface by revolving open or closedobjects about an axis. The revolved objects define the profile of the solid or

surface.

PYRAMIDThis command can create a solid pyramid. The number of sides for a pyramid,from 3 to 32, can be defined. The axis endpoint defines the length and orientationof the pyramid.

CREATE LAYOUTSA layout stimulates a sheet of paper and provides a predictable plotting setup for alayout, you can create and position view post objects and you can add a title blockor other objects geometry.

PLOT DRAWINGSOnce you have completed a drawing you can plot the drawing on paper or create afile for use with another application. In either case, you select the plot settings.


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TITLE BLOCK


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Aim :

To draw a title block with necessary text and projection symbol on A4 size sheet of

210 X 297 mm using AutoCAD.

Software Used:

AutoCAD 2011

Commands Used:

Procedure:

Result:

Thus the title block with necessary text and projection symbol of a title block onA4 sheet was drawn using AutoCAD.

Ex. no:TITLE BLOCK WITH NECESSARY TEXT AND

PROJECTION SYMBOLDate:


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Aim :

To study the capabilities of softwares for drafting and modeling coordinatesystems. (Absolute & Relative).

Software Used :

AutoCAD 2011

Commands Used:

Procedure:

Result:

The capabilities of software for drafting and modeling were studied and the shapeslike square, pentagon and hexagon was drawn using Absolute and Relativecoordinate system.

Ex. no:ABSOLUTE AND RELATIVE COORDINATE SYSTEM

Date:


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Aim:

To create the plan of given residential building using Auto CAD software.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:

The plan of the given residential building is drawn using Auto CAD.

Ex. no:PLAN OF RESIDENTIAL BUILDING

Date:


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PROJECTIONS AND SECTIONS OF SOLIDS

1. Draw the projections of a hexagonal prism of base side 20mm and axis

length 50mm when its rests on the ground on one of the edges of the base and the

axis inclined at 35 o to the ground and parallel to the VP.

2. A square pyramid of base side 30mm and height 50mm rests on the ground

on one its base edges such that its axis is inclined at 45 o to the ground and parallel

to VP. Draw its projections.

3. A Pentagonal prism, side of base 25mm and axis 50mm long, rests with one

of its shorter edges on HP. Such that the base containing that edge makes an angle

of 30 o to HP, and its axis is parallel to VP. Draw its projections.


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Aim:

To draw front and top view of given simple solids (prisms and pyramids) usingAuto CAD software.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:The front and top views of the given simple solids (prisms and pyramids) aredrawn using Auto CAD.

Ex. no:PROJECTION & SECTION OF SIMPLE SOLIDS

Date:


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ORTHOGRAPHIC VIEWS OF SOLIDS


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Aim:

To draw the orthographic views from the given pictorial views using AutoCAD software.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:The orthographic views of the given solids are drawn using Auto CAD.

Ex. no:ORTHOGRAPHIC VIEWS OF SOLIDS

Date:


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ISOMETRIC VIEWS OF OBJECTS


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Aim:

To draw the isometric view of given simple solids and objects using AutoCAD software.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:

The Isometric view of the given simple solids and objects are drawn usingAuto CAD.

Ex. no:ISOMETRIC VIEWS OF OBJECTS

Date:


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SIMPLE TRUSSES


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Aim:

To draw simple trusses using Auto CAD software.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:Thus the simple trusses are drawn using Auto CAD .

Ex. no:SIMPLE TRUSSES

Date:


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Aim: To draw the given 2d machine components by using Auto CAD.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:

Thus the given 2d machine components are drawn and saved.

Ex. no:2D DRAWING - MACHINE COMPONENTS

Date:


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Aim:

To create a special curves like B-spline or Cubic spline using Auto CAD software.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:

The special curves like B-spline or Cubic Spline are drawn using Auto CAD.

Ex. no:SPECIAL CURVES

Date:


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POLAR TRACKING METHOD


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Aim:

To draw a given diagram using polar tracking method by using Auto CAD.

Software Used:

Auto CAD 2008

Commands Used:

Procedure:

Result:

Thus the given polar tracking diagram drawn and successfully saved.

Ex. no:POLAR TRACKING METHOD

Date:

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