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ME- 102 - Engineering Drawing

LAB MANUAL

DEPARTMENT OF ELECTRICAL ENGINEERING,

FAST-NU, Chiniot Faisalabad Campus

Created By: Engr. Ameer Hamza Approved by HOD Signature: ______________

List of Equipment Sr. No. Description 1 Personal Computer 2 Auto CAD 2016 Software

Details of Obtained Marks Experiment No. LLO1 LLO2 LLO3 Total 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Total Obtained Marks Teacher Signature and Date

Experiment # 1: Demonstrate Co-ordinate System types and apply basic drawing commands to visualize 2D drawing. Apparatus:

• Personal Computer
• Auto CAD software

Objectives: The objectives of this lab are as follows:

• To have basic overview of auto cad interface.
• To learn various co-ordinates systems used in auto cad.
• To learn basic drawing commands. The X,Y co-ordinate system Everything that you draw in AutoCAD is exact. It will be more accurate than you will ever need it to be. All objects drawn on the screen are placed there based on a simple X,Y co-ordinate system. In AutoCAD this is known as the World Co-ordinate System (WCS). You must understand this to know how to put things where you want them. (3-D work has an added axis, the Z-axis, but this is not covered in this lesson.) Below is a diagram showing you how this system works. In order to work effectively with AutoCAD, you have to work with this system. Until you are comfortable and familiar with it, learning AutoCAD will be more of a chore. My experience in teaching is that the better a student is with co-ordinates, the better CAD drafts person they are. Working AutoCAD uses points to determine where an object is located. There is an origin where it begins counting from. This point is (0,0). Every object is located in relation to the origin. If you were to draw a line straight out to the right from the origin, this would be considered the positive X-axis. If you were to draw a line straight up, this would be the positive Y-axis. The picture above shows a point located at (9,6). This means that the point is 9 units over in the X-axis and 6 units up in the Y-axis. When you are working with points, X always comes first. The other point shown is (-10,- 5). This means that the point is 10 units in the negative X-axis (left) and 5 units in the negative Y- axis (down). A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Move your cursor over the picture above and you will see line drawn from the absolute points of (-10,-5) to (9,6).

Most of the time you will not have an indication of where the origin is. You may need to draw a line from the endpoint of an existing line. To do this you use relative points. These work the same way, but you have to add the @ symbol (shift+2) to tell AutoCAD that this next point is relative from the last point entered. Its a simple system, but mastering it is the key to working with AutoCAD and is explained below. Angular Measurement AutoCAD measures angles in a particular way also. When drawing lines at an angle, you have to begin measuring the angle from 0 degrees, which is at the 3 o'clock position. If you drew a line at 90 degrees, it would go straight up. The example above (when you move your mouse over it) shows a line drawn at +300 degrees, or - 60 degrees. You might not always have an obvious reference point for 0 degrees. Look at the figure below. In this example, you are given information about the lines, but not the angle AutoCAD needs to draw the line from the start point. What you are given though, is (a) the knowledge that 0° is at the 3 o'clock position (b) the knowledge that 180° is at the 9 o'clock position and (c) the angle between 180° and the line you want to draw is 150°. With this information, you can figure out what angle you need. Here is a fool-proof way of getting the angle you need: 1.) Start at the 0° position and measure counter-clockwise (+) to 180°.

• Select Draw > Line from the pull-down menu. All three approaches will do the same thing: prepare AutoCAD to draw a line where you tell it. AutoCAD is a popular program because it can be customized to suit an individual's needs. The toolbars are a good example of this. You can have the toolbars you use most often on the screen all the time. You can easily make them go away so that you have more drawing space. You can also customize them so you have the most common commands on one toolbar. For example, the dimensioning toolbar is one that you will not want taking up space on your screen while drawing, but is very handy when you're dimensioning your drawing. The AutoCAD Screen Move your cursor around the image above to find the names of various areas of the screen. ▪ Application Button - This button displays commands for printing, saving, drawing utilities and other non-drawing tool. ▪ Quick Access Toolbar - This is for quick access to common commands like New, Open, Save, Plot ▪ Filename - The name of the current file you are working on. ▪ Search Bar - Search for text in your drawing or search the help files. ▪ Ribbon - The Ribbon has most of the commands/tools that you will use while you are working. ▪ Tabs - A series of Tabs make up the Ribbon (Home, Insert, Manage, etc) and organize the Tools into common groups. ▪ Panels - Contain a group of tools ▪ Tools - These are the icon that start the commands you use to draw, modify, etc.

▪ Tool Tip - If you hover your mouse over a tool, a tool tip will appear to give your more information. Hold it longer for more info. ▪ Drawing Space - These is where you draw your designs. ▪ Command line - When you type a command, you will see it here. AutoCAD uses this space to 'prompt' you for information. It will give you a lot of information and tell you where you are in the command. Watch this line while learning. ▪ Status bar - This allows to see and change different modes of drawing such as Ortho, Osnaps, Grid, Otrack, etc. You can right click this area to toggle between icons and text for this area Introduction to Drawing and Modify Commands AutoCAD allows you to have access to a large number of commands. The general rule is that you will use 20% of the commands 80% of the time. We will start by introducing you to the most common drawing commands. When you combine these with the basic modify commands, you will be able to make elaborate drawings quite quickly. The important thing to remember is that AutoCAD will expect you give it information in a very particular order. The most frustrating thing when you begin using this program is that you will try to do something, but AutoCAD will 'not work'. In most cases, it means that you are trying to input information at the wrong time. This is why it is very important to be in the habit of looking at the command line. The command line tells you what information AutoCAD requires to continue. Your first drawing assignment will be to use the drawing commands in conjunction with the co- ordinate system defined above. This is a basic assignment, but it is very important to understand how to give the program accurate information. You will use the following commands: Command Keystroke Icon Location Result Line Line / L Home > LIne Draw a straight line segment from one point to the next Circle Circle / C Home> Circle

Center, Radius Draws a circle based on a center point and radius. Erase Erase / E Modify

Erase Erases an object. Undo

U /

CTRL+Z

Quick Access Toolbar> Undo Undoes the last command.

Select the "acad.dwt" template file and press the Open button to continue to the drawing screen. Once there, type in Z E this will zoom into to the extents of the drawing area and make it easier to see what you are drawing (NOTE: nothing will appear to happen). For all lessons on this level, make sure that you do not have Dynamic Input turned on. You can check this on the status bar. Make sure (the DYN button) isn't depressed. Your status bar buttons (bottom of the screen) should like the image above with 3 icon pressed (in blue). Start the LINE command (as explained in the table above) and draw a line from 1,2 to 3,2 to 3,4 to 1,4 Press enter after each point. (*Remember to watch the command line as you do this.) For the last line, you can either type in 1,2 or C to close the line back to the first point you entered. You have just drawn a 2" square using absolute co-ordinates. Your command history (F2 key) should look like this: Command: L LINE Specify first point: 1, Specify next point or [Undo]: 3, Specify next point or [Undo]: 3, Specify next point or [Close/Undo]: 1, Specify next point or [Close/Undo]: 1,

Specify next point or [Close/Undo]: If you make a mistake, you can use the undo icon, press U or press CTRL+Z. You can also use the ERASE command to get rid of lines you don't want. Next draw a similar box using relative co-ordinates. Start the LINE command and begin at point 4.5,2. From there draw a line two units to the right by typing @2,0 (this means 2 units in the X direction, 0 units in the Y direction based on the last point you entered). Next type @0,2 then @- 2,0 then @0,- 2 to finish the box. (Remember to press enter after each point.) Now erase the last box you just drew. Start the ERASE command and then select the lines you want to erase. Then press . Now redraw the box for more practice! Draw a third box using polar co-ordinate input. Start the LINE command and begin at point 8,2 then enter. Type @1<45 to draw the first line. Next enter @1<135 then @1<225 then @1<315 (or C to close). What you have just done is drawn a line 1 unit long at 45o, then another at 135o^ and so on. Do the angles you entered make sense to you? If not, review it. Start the CIRCLE command and add a circle that has a center point at 7,6 with a radius of .75 (Watch the command line for instructions). To finish the drawing, try putting a 10"x7" border around the page starting at 0,0 using the any of the methods shown above (relative, absolute or polar). Tasks

Experiment # 2 : Demonstrate the 2D modifying commands to trace given tasks in 2D view using Auto CAD. Apparatus:

• Personal Computer
• Auto CAD software

Lab Objectives: The objectives of this lab are as follows:

• To learn drawing commands of Poly Line and Rectangle
• To learn various modifying commands such as Trim, Extend, Offset
• To learn how to determine specific point on object using Object Snaps The previous lesson dealt with drawing commands. This lesson will introduce some common modifying commands. In AutoCAD, you may actually use modifying commands more often than drawing commands. Now that you know the basics, here's some more commands to add to your collection. Three commands, Trim, Extend and Offset are used standard AutoCAD work. Command Keystroke Icon Location Result Rectangle RECTANGLE / REC H ome > Draw

Rectangle Draws a rectangle after you enter one corner and then the second. Trim TRIM / TR Home > Modify

Trim Trims objects to a selected cutting edge. Extend EXTEND / EX Home > Modify

Extend Extends objects to a selected boundary edge. Offset OFFSET / O Home > Modify Offset Offsets an object (parallel) by a set distance. Object Snaps OSNAP / OS / F3 CLICK Tools > Object Snap Settings Brings up the OSNAP dialog box. Assignment #2 - Modifying Commands The purpose of this assignment is to use the commands learned in the previous lesson and learn some new ones. Once again, do not worry about title blocks, text or dimensions, draw only objects. Draw a LINE from 1,2 to 3,2 to 3,4 to 1,4 (*Remember to watch the command line as you do this.) For the last line's endpoint , you can either type in 1,2 or C to close the line back to the first point you entered. These are absolute coordinates. Make sure you understand what the points your just entered represent. Draw the next square using the RECTANGLE command. A rectangle is created by specifying 2 points to represent the opposite corners. Enter the first point as 4.5,2 and then make the opposite corner 2 inches over and 2 inches up @2,2 using relative coordinates. This is much faster and also makes the square one object and not 4 separate lines.

ERASE the rectangle. You will see that all of it is gone with one pick. Redraw it and continue. For the 3rd square, draw a 1.5 x 1.5 unit square using any of the methods you know. The bottom left corner must be a 8,2. Draw a line from 2,5 to 2,6.5 Draw another line from 1,6 to 3,6 You should now have two perpendicular lines. What you want to do is trim off the top of the vertical line and create a T. Start the TRIM command. It will first ask for a cutting edge. Select the horizontal line and press . It will now ask for the object to be trimmed. Select the vertical line anywhere above the horizontal (cutting) line and press to finish the command. This is what you saw on the command line: Command: TR TRIM Current settings: Projection=UCS, Edge=None Select cutting edges ... Select objects: 1 found Select objects: Select object to trim or shift-select to extend or

ICON SETTING ICON SETTING Endpoint Insertion Point Midpoint Perpendicular Center Tangent Node Nearest Quadrant Apparent Intersection Intersection Parallel Extension M2P Midpoint between 2 points Intersection - snaps to the point where two object cross - INT Extension - Snaps to the phantom extension of an arc or line - EXT

Insertion - snaps to the insertion point of an object (such as a block or text) - INS Perpendicular - will snap so that the result is perpendicular to line selected - PER Tangent - snaps to create a line tangent to a circle or arc - TAN Nearest - will find the closest point an object and snap to that point - NEA Parallel - Snaps parallel to a specified line - PAR M2P - This isn't technically an 'Object Snap' as you are not snapping to specific point on an object, but it allows you to select 2 points and it will calculate the midpoint between those 2 points. This is a very handy option to have. Note: Beside each checkbox is a symbol. That symbol will show up on the screen when you have found a valid snap point. (An endpoint will show a small square). If you select the "Options" button, you can change the aperture size and the color of the Osnaps. Depending upon the background you are drawing on, this may be needed. a. Check off the boxes as shown in the dialog box above (Object Snaps On, Endpoint, Midpoint, Center) and press OK. b. Begin the LINE command. Move your cursor around the screen and you'll see that as you get close to an object, it will 'snap' to one of the points that you had checked off in the dialog box. Place your cursor on the circle (not the middle of the circle) until you see a small purple circle appear at its center. Left-click to make this the start point of the line. Move the cursor towards the middle of the vertical line until you see a small triangle appear. (Remember this is the symbol for 'midpoint'). When you see it left-click to accept this as your endpoint. Press to end the line command. c. Save your drawing.