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CBB 1052

Engineering Graphics

AUTOCAD 2005

Students’ Manual

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1. Exercise 01 By the end of this session, student should be able to:

Create drawing by using different method from AUTOCAD Apply different coordinate systems in drawing Type words in AUTOCAD drawing

Draw the following object based on all THREE (3) coordinate systems.

From Pt. 1 To Pt. 2 To Pt. 3 To Pt. 4 To Pt. 5

0, 0 3, 0 4.5, 1.4 4.5, 3.4 Close

Point Absolute Coordinate

0, 0 @3, 0 @1.5, 1.4 @0, 2 Close

Relative Coordinate

0, 0 @3<0 @2<43 @2<90 Close

Polar Coordinate

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2. Exercise 02

By the end of this session, student should be able to: Produce drawing by applying knowledge on snap, grid, ortho and polar status Produce dimensions on drawing

- Linear,angular, aligned, ordinate Create polyline and hatched drawing

Create the above drawing

1. Switch on Snap and Grid 2. Snap and Grid spacing can be specified from Drafting Setting toolbar

- Tools>Drafting Setting - Specifying smaller of x-space and y-space on grid will allow the grid spacing becomes

closer - Specifying smaller values on x-space and y-space on snap will allow the cursor snaps at a

shorter distance 3. For horizontal and vertical lines click on ORTHO

- Example: Command: l LINE Specify first point: <Ortho on> <Snap on> <Grid on> Specify next point or [Undo]: @0,0.5

4. For slanting lines, click on POLAR - Example:

Specify next point or [Close/Undo]: <Polar on> @1.7<30 5. Dimensioning

- Dimensioning by using pull down menu or toolbar

- Click on the toolbar and choose the intended dimension - Example:

Linear dimension

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6. Change the colour of the dimension text using layer manager - Command: Layer or Pulldown-menu: Format>Layer

- click for new Layer and define the specification to the layers - Basic information to know about the layer properties manager

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Name Define the name of the layer

On/Off Ensure layer is active or inactive

Freeze Freeze or unfreeze the layer

Color To define the colour for the defined layer

Linetype To define the layer type eg continuous, hidden, centreline etc.

- Follow the setting as above - The outcome will be as follows:

- Select dimension layer - Redo the dimension as shown below:

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Now, having the object ready, locate coordinate on specific point 1. Use dor command or dimordinate - Example

Command: dor DIMORDINATE Specify feature location: (select the point on screen)

- Press Enter

- If extend the line on x-axis, x-coordinate will be given, if otherwise, y coordinate will be given

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Now, instead of using command line to produce the object, use polyline, known as PLINE (Remember: Change the layer to initial black colour) 1. Enter pline in the command

Command: pline Specify start point: (point at any point on the screen) Current line-width is 0.0000

Specify next point or [Arc/Halfwidth/Length/Undo/Width]: @0,0.5 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: @-0.5,0 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:@1.7<30 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: @1.7<330 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: @-0.5,0 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: @0,-0.5 Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: close

2. Now, click the object and compare between two of them. What can you see?

A line is selected on pline represented the whole object while a line selected on using line command will only represent one single line

3. Now, try to use explode Command: explode Select objects: 1 found (select on the polyline’s object) Enter

4. Try to click on the object again,

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5. Now the polyline is exploded into single separated lines 6. Next, to create polyline again,

Command: pedit Select polyline or [Multiple]: (Select any line on previous exploded polyline) Object selected is not a polyline Do you want to turn it into one? <Y> Y Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: Join Select objects: 1 found (Select all the lines previously exploded) Select objects: 1 found, 2 total Select objects: 1 found, 3 total Select objects: 1 found, 4 total Select objects: 1 found, 5 total Select objects: 1 found, 6 total Select objects: 1 found, 7 total Select objects: Enter 6 segments added to polyline Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: Enter

7. Now, click again on the polyline’s object and see the difference To create hatched boundary (purpose for sectional view), do as follows: 1. Use bhatch command

Command: bhatch 2. A window will pop-up as follows

3. Leave the pattern and swatch as it is

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4. Click Pick Points button - In the command area, you can see an instruction: Select internal point:

5. Select the internal point of the object as follows:

6. Click the mouse until the dotted lines appear and enter 7. Click OK on the pop-up windows 8. Object will appear as follows:

9. To fill in the object with colours, change the PATTERN and SWATCH on pop-up windows of

bhatch command

10. Pick points and the object will appear as follows:

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3. Exercise 03

By the end of this lecture, student should be able to Explain what is geometric drawing Draw circles at different conditions required Produce polygons on drawing Array object in polar or rectangular way Modify drawing by using chamfer and fillet method

OFFSET COMMAND

1. Construct a circle with diameter of 1 2. Our objective is to offset the circle with another bigger circle at a distance from its

circumference of 1 unit

Command: offset @ select Specify offset distance or [Through] <Through>: 1 Select object to offset or <exit>: (pick the circle from the screen)

Specify point on side to offset: (Select the any point outer part of the circle)

3. Finally,

4. Further offset the circles to construct bigger circle at equidistance length of gap

Select object to offset or <exit>

:

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5. Select the outer circle, and again Specify point on side to offset: (Select the any point outer part of the circle)

6. Now, instead of specifying the point outside/ outer part of the circle, try to specify inside the

circle, what can u see? CONSTRUCTING CIRCLES (2P)

1. Suppose that you have two circles as follows, and you wanted to produce another circle in between these two circles

2. Use 2P command

Command: c CIRCLE Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 2p Specify first end point of circle's diameter: tan to

Specify second end point of circle's diameter: tan to

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3. Now see, the results

CONSTRUCTING CIRCLES (3P)

1. Suppose that you have three circles as follows and you wanted to create another circle touching all these three circles

2. Use 2P command

Command: c CIRCLE Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 2p Specify first end point of circle's diameter: tan to

Repeat the same procedure for every other circle

3. Now, you can see the results

CONSTRUCTING CIRCLES (TTR)

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1. Imagine you have these two lines connected to each other

2. You wanted to locate a circle in between these two lines, which has radius of 0.5 3. Use TTR command

Command: c CIRCLE Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: ttr Specify point on object for first tangent of circle: (Select the first line and left click) Specify point on object for second tangent of circle: (Select the second line and left click)

Specify radius of circle <1.0625>: 0.5

4. Now you see the circle

TRIM THE OBJECT

1. Suppose you have two circles with two lines connecting together

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2. Use TRIM command

Command: trim Current settings: Projection=UCS, Edge=None Select cutting edges ... Select objects: 1 found Select objects: 1 found, 2 total Select objects: 1 found, 3 total Select objects: 1 found, 4 total

Select objects: ENTER

Select object to trim or shift-select to extend or [Project/Edge/Undo]: (Click the bigger circle arc internally) Select object to trim or shift-select to extend or [Project/Edge/Undo]: (Click the smaller circle arc internally) Select object to trim or shift-select to extend or [Project/Edge/Undo]: Enter

3. Results as follows:

Select all the lines and

circles on the object!!

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Trim another object

(HINT: Click on all of the lines and circle, and click one by one to eliminate the unwanted lines and arc)

Further exercise Having these three circles, try to produce this object

Hint:

1. Construct bigger circle which governs all these three circles using 3P command 2. Give offset command to the circle of R0.5 so that it will produce another circle with a radius of 0.25 3. Use TRIM command and select all the objects. Eliminate where necessary

CONSTRUCT POLYGON

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1. Suppose that you wanted to draw a hexagon 2. Use command polygon

Command: polygon Command: polygon Enter number of sides <4>: 6 (for hexagon) Specify center of polygon or [Edge]: Enter an option [Inscribed in circle/Circumscribed about circle] <I>: Specify radius of circle: 5

3. The results as follows

4. What’s the different between inscribed in circle/circumscribed about circle?

ARRAY

1. Suppose that there is a object that needs repetition in a systematic arrangement 2. Use array command

Rectangular Array Command: array (array popup window will appear) Select rectangular array Specify number of rows for the object to be repeated Specify number of columns for the object to be repeated

If let say there are 4 x 4, suppose the 16 similar objects will appear on a specific arrangement

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Now, select objects (pick button Select Objects) Enter Click OK

You will get this

What are row offset and column offset made for? If you notice from the above arrangement, the gap from the similar point either horizontally or vertically is the same i.e. at 4 unit distance. This is similar as the above array popup window showing that the offset on both row and column are set at 4.

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Polar Array

Command: array Now on the popup window, select polar array You have this object

Your aim is to array the hexagon around the circle

Select centre point by clicking the button next to X and Y coordinate – Select the center of the circle Method: Select total number of items & angle to fill Select the number of items to be appeared around the circle Select the angle to fill Select the object i.e. the hexagon Now the results as follows:

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There are 16 objects appeared as required, filling 360 degrees of the circle

CHAMFER AND FILLET CHAMFER 1. Suppose you have this object

2. You want it to be like this

3. Chamfer command Command: chamfer

(TRIM mode) Current chamfer Dist1 = 0.0000, Dist2 = 0.0000 Select first line or [Polyline/Distance/Angle/Trim/Method/mUltiple]: Distance Specify first chamfer distance <0.0000>: 5 Specify second chamfer distance <5.0000>: Enter Select first line or [Polyline/Distance/Angle/Trim/Method/mUltiple]: Pick line on A Select second line: Pick line on B

4. At this moment, you’ll see this object appeared

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5. Now, proceed with other sides by using the same method as above FILLET

1. Suppose you have the same object

2. Now, use fillet command

Command: fillet Current settings: Mode = TRIM, Radius = 0.0000 Select first object or [Polyline/Radius/Trim/mUltiple]: radius Specify fillet radius <0.0000>: 5 Select first object or [Polyline/Radius/Trim/mUltiple]: pick A Select second object: pick B

3. The results as follows:

4. Now, proceed with other sides as well and try to get this object

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4. Exercise 04

By the end of this lecture, student should be able to: Use modify command e.g. mirror, rotate, scale, stretch, break, move and copy Produce machinery drawing

MIRROR

Create the above drawing

7. Draw the first line HINT (Use FILLET, specify radius at 1.5)

8. Draw a constructing line at the end of both points (any distance) at angle of 45 degree each.

9. Use Mirror command

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Command: mirror Select objects: 1 found Select objects: 1 found, 2 total Select objects: 1 found, 3 total Select objects: 1 found, 4 total Select objects: 1 found, 5 total Select objects: ENTER

Specify first point on mirror line

Specify second point on mirror line

Delete source objects? [Yes/No] <N>: N ENTER

10. Repeat the same procedure again

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Command: mirror Select objects: 1 found Select objects: 1 found, 2 total Select objects: 1 found, 3 total Select objects: 1 found, 4 total Select objects: 1 found, 5 total Select objects: 1 found, 6 total Select objects: 1 found, 7 total Select objects: 1 found, 8 total Select objects: 1 found, 9 total Select objects: 1 found, 10 total Select objects: ENTER

Specify first point on mirror line

Specify second point on mirror line

Delete source objects? [Yes/No] <N>: N ENTER

11. Delete the construction line where necessary 12. Object ready

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ROTATE

1. Having the previous object ready, use rotate command to rotate them at 45 degree

Command: rotate Current positive angle in UCS: ANGDIR=counterclockwise ANGBASE=0 Select objects: Specify opposite corner: 22 found Select objects: ENTER

Specify base point: (point at any edge)

Specify rotation angle or [Reference]: 45 ENTER

2. Now the results as follows:

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SCALE 1. Suppose that the object to be scaled down to half than the original object 2. Having the object ready, use scale command

Command: scale Select objects: Specify opposite corner: 22 found Select objects: ENTER Specify base point: (pick any point)

Specify scale factor or [Reference]: 0.5 3. The results as follows:

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OTHER COMMANDS Command Function

Stretch To stretch line/circle Hint: For easier operation, click on the specific line required, then click at the end point which needs stretching. The colour will change from blue to red

Then, bring that point to further stretch them and click on the specific location you wish for extension.

Break To break a line into two separate lines

Hint: Use command BREAK and follow the instruction in command window

Move and Copy To relocate or to copy the object Use command MOVE and COPY

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EXERCISE

Draw the above object

‘Grip’ the base and then stretch.

A tooth.

Draw a rectangle (width=1, height=2)

Stretch the base by 0.5 unit each to the left and right.

The final object (a gear’s tooth) on the most right.

Explode the stretched rectangle.

Extend these two lines

Erase the base line.

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The discs (circles) may be added by using the offset command.

Trim the teeth around the circle with R5.0.

Array (Polar)

Angle to fill = 360

# of items = 14

Note: %%p = ±