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8 Working Drawings in AutoCAD

Most engineering designs consist of more than a single part. Usually there area several or many parts that must fit and work together. When we are creating thedrawings of a design, we must create dimensioned drawings of each part so that they

can be manufactured correctly and we must also show how the parts fit together sothey can be assembled correctly.The drawing of a single part is called a detailed drawing. It contains one or

more orthographic views of the object, dimensions and possibly sectional andisometric views. In essence, a detailed drawing may contain all of the elements wehave been studying this semester. An example of a detailed drawing is shown below.

The drawing above shows two parts. Each part is shown in two different

views, a front and a top view using a third angle projection. This is a detaileddrawing of the two parts. It contains sufficient information to build the parts. It doesnot tell us how to assemble the parts. That is shown in the drawing below.

Bill of materials

Balloonsnumberingthe parts

Explodedassemblyview

Assembledview

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Note: The assembly views in the drawing above are shown asisometric or pictorial views. This is usually not done inAutoCAD drawings. AutoCAD assembly views are usuallyorthographic because of the difficulty in drawing pictorialviews.

The Bill of Materials (BOM) lists all of the parts needed to make the machine.Each part is numbered in the BOM and the same number is used in the balloons thatpoint to each part. The bill of materials lists the part number, the name of the part,and the material from which the part is made.

Both exploded and unexploded assembly views are shown in this particularexample but if the assembly can be fully explained with a single view, then only oneview need be shown. The view may be similar to one of the ones in the drawingabove or it may be a sectional view. Sectional assembly views are especially useful ifsome parts are inside of housings or are concealed from view.

A set of working drawings consists of a detailed drawing for each part thatmust be manufactured and sufficient assembly drawings to explain how the parts areassembled.

Detailed Drawings

The first step in creating a set of working drawings is to create the detaileddrawings showing each part. Here you usually show a front view and possibly otherviews (top view, right side view, left side view, etc.) if they are required to fullydescribe the geometry. Sectional views and isometric views may also be included ifthe geometry is not easily understood from the orthographic projections. Dimensionsare included on these drawings so the part can be manufactured correctly. The titleblock on the drawing should contain the name of the part and this should be the samename used in the Bill of Materials.

After the detailed views are drawn, you can create the assembly drawings.

These drawings are created by combining views from the detailed drawings to showhow the parts are assembled. The process involves several simple steps.

1. First you need to create the assembly drawing. You can do this by opening theStandard_A4 drawing sheet (You may have named it differently.) Once it isopen, remember to use Save as to save the drawing under a different name.I usually use the abbreviation _ASM as the last characters in the file nameso that I will know that this is an assembly drawing.

2. Open the detailed drawing to show the view of the part you want to insert intothe assembly drawing.

3. Turn off all layers that are not needed in the view so that what is left can beeasily selected. Dimensions and projection lines are not usually shown inassembly drawings so these layers should be turned off.

4. Select the view you want to copy to the assembly drawing by dragging a boxaround it with the mouse. Move the mouse to a location to the left and abovethe view and click. Next, move the mouse to a location to the right and belowthe view and click again. AutoCAD will select all of the objects in the view.

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5. Hold down the CTRL key and press the C key. This will copy everything youhave selected to the program clipboard.

6. Next, you switch from the detailed drawing to the assembly drawing you arecreating. You can do this by clicking on the big red A in the upper rightcorner and select the assembly drawing in the list of open files.

7. Paste the view from the detailed drawing into the assembly drawing byholding down the CTRL key and pressing the V key. Use the mouse to movethe view to a convenient location then click to complete the copy.

8. Repeat this process for all of the parts in the assembly. When you havefinished, you should have a drawing containing copies of all of the parts in theassembly. The figure below shows a bracket that is used to bolt two platestogether. We will use this as an example.

Building the Assembly

After the parts have beencopied to the assembly drawing, wecan arrange them so that they areoriented correctly. We start byconnecting Parts 4 and 5. Use theMOVE command to move Part 4 so

that points A and B are at thesame location. Point A is located atthe intersection of the centerline andthe bottom of Part 4 and point B islocated at the intersection of thecenterline and the top of Part 5.

AutoCAD Selects Lines

1 Click here with mouse

2 Click here with mouse

1 2

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4

5

A

B

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MOVE

Sel ect obj ects: w {Part 4 wil l be selected with a window}

Speci f y f i rst cor ner : {Click above and to the left of Part 4}

Speci f y opposi t e cor ner: {Click below and t the right of Part 4}

Sel ect obj ects: {Press enter the selection is complete}

Speci f y base poi nt {Click on Point A at the intersection of the holecenterline and the bottom of Part 4}

Speci f y second poi nt {Click on Point B at the intersection of the holecenterline and the top of Part 5

The resulting placement isshown in the figure on the right.

Next we will align point Cwith point D. Point C is located atthe intersection of the centerline withthe right side of Part 1. Point D islocated at the intersection of thecenterline and the left side of Part 4 asshown in the figure on the right. Hereagain, use theMOVE command tomove Part 1 into the correct location.

C

D

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Speci f y base poi nt : mid {enter mid and select point 1}

Speci f y second poi nt : {let OSNAP find the intersection of the top of thehole and the centerline point 2}

When you have finished, your drawing should resemble the one shown above

on the right.

Next copy the nut, rotate it -90degrees, and place it on the bolt as shown inthe figure at the right. You can use the COPY,ROTATE, andMOVE commands just as youdid for the bolt. The resulting drawing isshown on the right.

Some of the interior lines of the bolt, should be changed to hidden lines. Youcan make these changes with the CHANGE command.

CHANGE

{Select the lines that should be changed to the hidden layer}

Sel ect obj ect s: 1 f oundSel ect obj ect s: 1 f ound, 2 t ot alSel ect obj ect s: 1 f ound, 3 t ot al

Sel ect obj ects: {press enter}Speci f y change poi nt or

[ Propert i es] ] : P {we are changing the properties}Enter pr opert y t o change

[ Col or / El ev/ LAyer / LType/ : LA {we want to change the layer}Enter new l ayer name : hiddenEnter pr opert y t o change

[ Col or / El ev/ LAyer / LType/ : {press enter}

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2

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The bolt with hidden lines withcorrect hidden lines is shown on theright.

Continuing moving and

rotating parts until the parts are fullyassembled and your drawing looks likethe one on the right.

These lineswere changedto HIDDEN

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Creating Balloons

Next, we need to create theballoons that identify parts. Balloonsare called leaders in AutoCAD and wemust first define balloon style leaders

before we can draw them. Start bytyping:

mleaderstyle

This produces the dialog box on theright. Click on the New button tocreate a new leader style.

1. Enter Balloons forthe name of the newleader style we are

creating.

2. Mark theAnnotative check

box.

3. Click on Continue.

Next we define how the newmultileader will look in the dialog boxshown on the right.

1. Click on the Content tab2. Select Block for the

multileader type

3. Select Circle for the sourceblock

4. Select the Leader Structuretab

Click on New

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The settings in the LeaderStructure tab are:

1. Mark the Maximum leaderpoint check box.

2. Set the number to 23. Mark the Second segmentangle check box4. Set the angle to 05. Mark Automatically include

landing6. Mark Set landing distance7. Set the landing distance to 1.5 or what seems reasonable. This is a personal

preference.8. Mark Annotative9. Click OK

In the Multileader StyleManager dialog box:

1. Make sure Balloons ishighlighted.

2. Click on Set Current3. Click on Close

Now you are ready to draw the leaders. Change the layer to Dimensionlayer and create the balloons by clicking on:

1. Click on the Annotate tab at the top of the window2. Click on the Multileader icon in the annotate ribbon at the top of the

window.3. Click at a point on a part where

you want the leader to start4. Click where you want the

balloon to be placed5. Enter the number of the part.

Repeat the process above untilall of the parts have been numbered.When you have finished, your drawingshould look like the one on the right.The numbers may appear a little small

but they are annotative and will havean appropriate size on the drawingsheet.

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2

3

1

2

3

3

4

4

5

9

1 2

3 4

5

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Placing on the Sheet

Next we will place the drawing on the sheet. We do this using the sametechnique we have used before. Click on:

1. Click on the Layout1 tab at the bottom of the window.

2. Double click in the drawing area to activate the viewport.3. Enter the commandzoom all4. Use the mouse to drag the drawing to the correct location. Size the drawing

by scrolling the wheel on the mouse.5. If the arrowheads are too small, correct their size by modifying the

Multileader style. Use the Leader Format tab to change the size of thearrowheads.

The drawing should be locatedas shown in the figure on the right.The assembly is placed on the left sideof the drawing sheet to leave room forthe bill of materials.

Bill of Materials

Next we will create the bill of materials (BOM). The bill of materials is atable that lists:

1. The part number2. The part name3. The number of parts required for the complete assembly

4. The material from which the part is made. The material is not listed forpurchased parts such as bolts, nuts, etc.

You can create the table with the TABLE command or you can just draw it. It isfrequently simpler to just draw it and that is what we are going to do. We will use theOFFSET command to create this table.

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OFFSET

Speci f y of f set di st ance: 10 {Distance between lines}

Sel ect obj ect t o of f set : {Click on the top border line}Speci f y poi nt on si de t o of f setor [ Exi t / Mul t i pl e/ Undo] :M {Enter M to create multiple offsets using

the 5mm offset distance}Speci f y poi nt on si de t o of f set : {Click below the top border line 6 times

until all of the lines have been created}Speci f y poi nt on si de t o of f set :Speci f y poi nt on si de t o of f set :Speci f y poi nt on si de t o of f set :Speci f y poi nt on si de t o of f set :Speci f y poi nt on si de t o of f set :

Speci f y poi nt on si de t o of f set or [ Exi t / Undo] : {Press enter twice toexit}

Next we create vertical lines byoffsetting the right border line. Createlines at 20, 35, 65, and 85 from theright border. After you have created

the vertical lines, use the TRIMcommand to trim the lines to form atable. The results are shown on theright.

Next, use theMTEXT command to fillin the table. You mayneed to set the size of text

used in the table. Do thisby clicking on:

1. Click on theAnnotate tab.

2. Click on the Textarrow

3. Check theAnnotative box

4. Set the text height to 55. Click on Apply then Close

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Finally, fill in the table as shown below.