Engraving) SG

CADComputer Aided DesignspectraCAD/Engraver

Student Activities Book

CADComputer Aided DesignspectraCAD/Engraver

Student Activities Book

© 1997 Light Machines Corporation Manchester, NH, U.S.A. July, 1997and Intelitek 34-7792-0000

© 1997 Light Machines CorporationAll Rights Reserved.

The information contained in this guide was accurate at the time of its printing. Light Machines Corpora-tion and Intelitek reserve the right to change specifications and operational performance of its productswithout notice. Any changes or corrections to the information contained in this publication will be incor-porated in future issues.

This publication (34-7792-0000, July, 1997) corresponds to the spectraCAD Engraver software program.

Printed in U.S.A.

spectraCAM� and spectraCAD� are trademarks of Light Machines Corporation.

All other register marks or trademarks are of their respective holders.

Teklink Activities Book i Computer Aided Design

Table of Contents

Activity 1 Getting Started

Objectives ............................................................................................................1-1

Skills .....................................................................................................................1-1

Materials...............................................................................................................1-1

Overview What is CAD? .....................................................................................1-2

Procedures ............................................................................................................1-4

Activity 2 Using spectraCAD

Objectives ............................................................................................................2-1

Skills .....................................................................................................................2-1

Materials...............................................................................................................2-1

Overview In this Section......................................................................................2-2

Using Coordinate Systems .............................................................................2-2

Cartesian Coordinate System .........................................................................2-2

Polar Coordinate System................................................................................2-4

Selecting and Cancelling Commands ............................................................2-5

Picking Points ................................................................................................2-7

Selecting and Deselecting Entities .................................................................2-8

Getting Help ..................................................................................................2-10

Activity 3 Managing Files

Objectives ............................................................................................................3-1

Skills .....................................................................................................................3-1

Materials...............................................................................................................3-1

Overview Managing spectraCAD Files ...............................................................3-2

Procedures ............................................................................................................3-2

Teklink Activites Book ii Computer Aided Design

Activity 4 Creating the LMC Project

Objectives ............................................................................................................4-1

Skills .....................................................................................................................4-1

Materials...............................................................................................................4-1

Overview ..............................................................................................................4-2

Procedures ............................................................................................................4-3

Activity 5 Drawing the M

Objectives ............................................................................................................5-1

Skills .....................................................................................................................5-1

Materials...............................................................................................................5-1

Overview ..............................................................................................................5-2

Procedures ............................................................................................................5-2

Activity 6 Drawing the C

Objectives ............................................................................................................6-1

Skills .....................................................................................................................6-1

Materials...............................................................................................................6-1

Overview ..............................................................................................................6-2

Procedures ............................................................................................................6-2

Activity 7 Speaker Design Project

Objectives ............................................................................................................7-1

Skills .....................................................................................................................7-1

Materials...............................................................................................................7-1

Overview ..............................................................................................................7-2

Procedures ............................................................................................................7-3

Activity 8 Creating the Speaker Cone

Objectives ............................................................................................................8-1

Skills .....................................................................................................................8-1

Materials...............................................................................................................8-1

Overview ..............................................................................................................8-2

Procedures ............................................................................................................8-2

Teklink Activities Book iii Computer Aided Design

Activity 9 Completing the Project

Objectives ............................................................................................................9-1

Skills .....................................................................................................................9-1

Materials...............................................................................................................9-1

Overview ..............................................................................................................9-2

Procedures ............................................................................................................9-2

Activity 10 spectraCAD Engraver

Objectives ...........................................................................................................10-1

Skills ....................................................................................................................10-1

Materials..............................................................................................................10-1

Overview Engraving Text ...................................................................................10-2

Procedures ...........................................................................................................10-2

Activity 11 Generating an NC File

Objectives ...........................................................................................................11-1

Skills ....................................................................................................................11-1

Materials..............................................................................................................11-1

Overview Generating the NC file .......................................................................11-2

Procedures ...........................................................................................................11-2

Activity 12 NC Files and Coding

Objectives ...........................................................................................................12-1

Skills ....................................................................................................................12-1

Materials..............................................................................................................12-1

Overview .............................................................................................................12-2

Procedures ...........................................................................................................12-2

What is NC Programming? .................................................................................12-3

Elements of a Part Program ................................................................................12-4

Teklink Activites Book iv Computer Aided Design

Activity 13 Pocketing

Objectives ...........................................................................................................13-1

Skills ....................................................................................................................13-1

Materials..............................................................................................................13-1

Overview .............................................................................................................13-2

Procedures ...........................................................................................................13-3

Activity 14 Pocket Toolpaths and spectraCAM

Objectives ...........................................................................................................14-1

Skills ....................................................................................................................14-1

Materials..............................................................................................................14-1

Overview .............................................................................................................14-2

Procedures ...........................................................................................................14-2

Academics CAM and spectraCAM ....................................................................14-7

Activity 15 Conclusion

Objectives ...........................................................................................................15-1

Skills ....................................................................................................................15-1

Materials..............................................................................................................15-1

Overview .............................................................................................................15-2

Teklink Activities Book v Computer Aided Design

About the Teklink Activities BookThe Teklink Activities Book is a lab manual which contains 15 Activities, each ofwhich can be completed in one 45-minute lab session.

Each activity begins with several lists:

w Objectives are the goals students will achieve.

w SCANS Skills are the competencies students will develop.

w Materials are the specific items needed for each activity.

The Overview section introduces the students to the subjects which will be explored ineach activity.

The Procedures contain series of Tasks, or operations. The first time an operation is tobe performed, instructions are given in a tutorial manner. In subsequent tasks studentsshould be able to perform these operations without guidance.

Questions and tables for entering lab results appear within the tasks. Questions for dis-cussion and review conclude each activity. All questions and tables are printed on a setof Worksheets supplied with this book. Students should record their answers on theworksheets, or as directed by the instructor.

In teklinks which include hardware (e.g., vise, tooling), students will be directed to per-form inventory and safety checks at the beginning of every working session, and to shutdown the system properly at the end of each activity.

In teklinks which utilize software, it is assumed that students are familiar with the PCand are comfortable working in the Windows/DOS operating environment. However,instructions for operating the software are explicit and can be performed by novices.

Teklink Activites Book vi Computer Aided Design

Teklink Activities Book 1-1 Computer Aided Design

Activity 1

Getting StartedBefore you begin this activity, take the Pre-Test. The purpose of the pre-test is to measure yourknowledge and skills with CAD. You are not graded and can not fail this test. When you finishthe test, hand it in to your instructor. Then you can begin this activity.

Objectives

This activity describes the basics of working with spectraCAD. By reading this section,you will learn:

u How to start and exit spectraCAD.

u The parts of the spectraCAD screen.

u The spectraCAD coordinate systems and types.

u How to select a command.

u How to pick a point.

u How to select an entity.

u How to get help.

Skills

In this activity you will develop the following skills:

w Technology: Learn the components of a Design program

w Systems: Utilize a computer system

w Resources: Manage time, manage programs

w Interpersonal: Participate as a member of a work team

w Information: Absorb/evaluate information

w Basic: Reading and writing

w Thinking: Learning

w Personal: Responsibility and self-management

Materials

In this activity you will need the following materials:

w Computer with the spectraCAD Engraver software installed

w Worksheets for Activity One

Teklink Activites Book 1-2 Computer Aided Design

Overview What is CAD?

Computer-Aided Design, or CAD, is a way to draw complex shapes easily and accu-rately using a computer. Once you create a CAD drawing, you can use it in a CAM(Computer-Aided Manufacturing) program, like spectraCAM. CAM turns your draw-ing into tool paths that the Computer Numeric Control (CNC) machine can use to cut apart. The figure below illustrates the computer-aided design, manufacturing, and con-trol process.

Following are definitions of the CAD terms frequently used in this manual. You shouldunderstand them before you use spectraCAD.

Coordinates - The coordinates of a point are a pair of numbers that describe its lo-cation in the drawing. This location is relative to the origin, or center, of atwo-dimensional coordinate system. We will learn more about coordinatesystems in another activity.

spectraCADCAD Program

spectraCAMCAM Program

Machining CenterControl Program

CAD CAM CNC

Origin(0,0)

Y-axis(+)

(+)

(-)

(-)

X-axis

3

3 Point(X=3,Y=3)


DXF - The drawing interchange file, or DXF, is a standard file format used bymany CAD and CAM programs. spectraCAD reads and saves drawings inthis file format.

Entity - An entity is an object which you draw, modify, and place to create a draw-ing. Points, lines, arcs, circles, text blocks, rectangles, and polylines are allentities.

Grid - The Grid is the rectangular array of dots in the spectraCAD Drawing Area.The grid helps you create accurate freehand drawings.

Layer - A layer is like a transparent sheet on which you draw entities. You canview just one layer, or a few layers together, or all the layers at once. Wewill cover layers in more depth in a later activity.

Grid Points

Drawing Area

Layer 2

Layer 1

Layer 3


View - The view is the position and size of the Drawing Area in relation to thedrawing. Drawings can be larger than the spectraCAD Drawing Area. Tosee different parts of a large drawing, you can change the view. You canalso magnify the view, to make the drawing look larger or smaller.

Drawing Area

Procedures

Task 1-1 Starting spectraCAD

To start the Control Program:

w Power up the computer.

From Windows 95:

w When the Windows desktop appears, select Start from the Task Bar.

w From the Start menu, select Programs and then the CADEng folder.

w In that folder, select spectraCAD Engraver

After you start spectraCAD, you can use the New command under the File Menu tocreate a drawing based on a template other than DEFAULT.


Task 1-2 Exploring the spectraCAD Screen

This section explains the components that make up the spectraCAD screen. They aredescribed in order from the top to the bottom of the screen. As you read through thissection, move the mouse over the commands and buttons and select them.

Cursor

Drawing Area

Status Bar

a tool bar

Layer Display BoxLayers Button

Type ButtonCoordinate Display Box

Title BarMenu Bar

Tool Bar

Coordinate Type Button

Stock Outline

Title Bar

The Title Bar shows the application name, “spectraCAD” and the name of the currentdrawing. If the drawing has not been assigned a name, the word “untitled” appears onthe Title Bar.

Menu Bar

The Menu Bar contains the spectraCAD pull-down menus. Click on each menu to seethe list of items.


Tool Bar

The Tool Bar contains buttons that correspond to frequently-used commands. Clickingone of these buttons is equivalent to selecting the command from a menu. The Tool Barcan be visible or hidden.

Coordinate Type Button

The Coordinate Type button sets the type of coordinates shown in the Coordinate Dis-play box, either absolute, relative, or polar. Clicking the button changes the type of co-ordinates displayed.

Coordinate Display Box

The Coordinate Display box shows the current position of the cursor in the DrawingArea. The position is given in the type of coordinates (absolute, relative, or polar) set bythe Coordinate Type button.

Type Button

Clicking the Type button brings up various dialog boxes in which you can enter coordi-nates, distances, factors, and dimensions during certain Draw and Modify operations.

Layers Button

Clicking the Layers button brings up a dialog box in which you can change layer prop-erties.

Layer Display Box

The Layer Display box shows the name and color of a drawing layer. The layer dis-played depends on which entities are selected. Clicking the down arrow brings up a listof all the layers in the drawing. You can use this list to change the current layer and tomove entities between layers.

Drawing Area

The Drawing Area is where you view and draw entities.

Import

Copy to Clipboard

New

Open

Save

Print

About spectraCAD

Show Grid

Show End Points

Show Text

Pan

Redraw

Grid Snap

Ortho Lock

Move

Delete

CopyContext Help


Tool Bars

The Tool Bars contain buttons that correspond to spectraCAD menu commands. Youcan make the Tool Bars visible or hidden individually, and you can move and resizeTool Bars.

The five Tool Bars are Modify, Draw, View, Tool, and Snap (see next page). Each onecontains buttons associated with commands in one spectraCAD pull-down menu.

Status Bar

The Status Bar displays useful information while you work in spectraCAD.

Cursor

The cursor is the point-and-click device, which you control with the mouse. You canselect entities, select commands, and pick points with the cursor.

When it is within the Drawing Area, the cursor can have two parts: the crosshairs andthe entity box. Crosshairs are horizontal and vertical lines that intersect at the preciselocation of the cursor. The entity box is centered around this intersection point.

The look of the crosshairs and entity box change depending on the operation you areperforming:

1. When you are in idle mode (when no operations are being performed), thecrosshairs and entity box are shown.

2. When you are selecting an entity, only the entity box is shown.

3. When you are picking a point without entity snaps, just the crosshairs areshown.

4. When you are picking a point with entity snaps, the crosshairs and snap box areshown.


Task 1-2 Review Questions

Q What is CAD?

Q What is a .dxf file?

Q How many layers can you view at once?

Q What does the Status Bar do?

Task 1-3 System Shut Down

To exit spectraCAD, select Exit from the File menu, or press Alt+F4. If there are un-saved changes to the current drawing, the dialog box appears.

u Click Yes to save the changes and exit.

u Click No to ignore the changes and exit.

u Click Cancel to cancel the Exit command and return to spectraCAD.

w Return all materials to their proper place at your lab station.

w Select shut down from the start Menu on the computer.

w Shut the computer off.

Teklink Activities Book 2-1 Computer Aided Drafting

Activity 2

Using spectraCAD

Objectives

In this Activity you will learn the following:

w Types of Coordinate Systems

w Commands and Command selection

w How to select the entities in a drawing

w How to get help within the spectraCAD software

Skills


w Technology: Understanding of design technology

w Systems: Selecting operations in the spectraCAD system, manipulating theComputer system

w Resources: Manage time, manage programs


w Information: Evaluate information




Materials



w Worksheets for Activity Two

Teklink Activites Book 2-2 Computer Aided Drafting

Overview In this Section

This activity covers some basic information on how a CAD system works and how youwork within the system. The different types of coordinate systems are explained, givingyou an understanding of entity location in a CAD drawing. Menu commands and differ-ent ways of selecting commands are covered so that you can use the tools in an efficientmanner. These things may seem boring or repetitive now, but they are a necessary stepin coming to learn to use CAD. These steps will also allow you to become a better userand designer in the CAD system.

Procedures Using Coordinate Systems

spectraCAD has two coordinate systems, Cartesian and Polar. These two-dimensionalsystems describe the location of every point in the drawing with a pair of numbers,called coordinates. These coordinates are given in relation to the origin, or center, ofthe coordinate system.

Using the Cartesian and Polar coordinate systems, you can specify three types of coor-dinates: Absolute, Relative, and Polar.

Cartesian Coordinate System

The Cartesian coordinate system describes the location of a point by its horizontal andvertical distance from the origin. Horizontal distance, X, is measured along the X-axis,and vertical distance, Y, is measured along the Y-axis.

Using the Cartesian coordinate system, you can specify either the Absolute or Relativecoordinates of a point.

Absolute Coordinates

Absolute coordinates are the horizontal (X) and vertical (Y) distances of a point fromthe origin. The origin is fixed at the center of the drawing. The coordinates of the originare written (0,0), and the coordinates of all other points are written (X,Y). For example,the point 2 units to the right of and 3 units above (0,0) has Absolute coordinates (2,3).

Select one of the following methods to use Absolute coordinates:

u Click the Coordinate Type button until it says “Abs.”

u Select Coordinates from the Draw Menu, then from the submenu, select Abso-lute. The Coordinate Display box now shows the Absolute coordinates of thecursor.


X-axis

Y-axis

(-7.5,8)

(-5,-1.5)

(2,3)

(9,-5)

(+)(-)

(+)

(-)

(0,0) origin

Relative Coordinates

Relative coordinates are the horizontal (dX) and vertical (dY) distances of the pointfrom the origin. The origin is the last point you picked. The coordinates of the originare written r(0,0), and the coordinates of all other points are written r(dX,dY). For ex-ample, the point 2 units to the right of and 3 units above the last point you picked hasRelative coordinates r(2,3).

Select one of the following methods to use Relative coordinates:

u Click the Coordinate Type button until it says “Rel.”

u Select Coordinates from the Draw Menu, then from the submenu, select Rela-tive. The Coordinate Display box now shows the Relative coordinates of thecursor. The coordinates are relative to the last point you picked. If there is nolast point pick, the coordinates are relative to the center of the drawing.

r(-6,-2.5)

r(-8.5,7)

r(1,2)

Y-axis

X-axis

r(8,-6)

(+)(-)

(-)

(+)

r(0,0) last point picked


Polar Coordinate System

The polar coordinate system describes the location of a point by its radius and angle (indegrees) from the origin. A point due east of the origin is at 0°, and angles increasecounterclockwise, as shown in the figure below. Using the polar coordinate system, youcan specify the Polar coordinates of a point.

p(6,30)

300°

135°

30°p(4,135)

p(8,300)

p(0,0) last pointpicked

Polar coordinates are the radius and angle of the point from the origin, which is the lastpoint you picked. The coordinates of the origin are written p(0,0), and the coordinatesof all other points are written p(radius,angle). For example, the point 6 units away and30° from the last point you picked has Polar coordinates p(6,30).

Select one of the following methods to use Polar coordinates:

u Click the Coordinate Type button until it says “Polar.”

Angle measurementconvention

90

270

315

0180

135

225

45

u Select Coordinates from the Draw Menu, then from the submenu,select Polar. The Coordinate Display box now shows the Polar coordinates ofthe cursor. The coordinates are relative to the last point you picked. If there isno last point pick, the coordinates are relative to the center of the drawing.


Task 2-1 Coordinate Systems

Q What is the Cartesian Coordinate system?

Q What is the Polar Coordinate System based on?

Q What is an Absolute coordinate?

Q Are Polar coordinates relative or absolute?

Selecting and Cancelling Commands

There are many methods of selecting and cancelling commands. You can use themouse, or one of the keyboard methods. In the following tasks you will experiment witheach method so you can determine which is easiest for you.

Task 2-2 Start spectraCAD



From Windows 95:





Task 2-3 Using the Keyboard to Select Commands

You can select commands with the keyboard in two ways: by using the pull-downmenus or by using hot keys.

Select a pull-down menu command with the keyboard:

1. Press Alt and the first letter of the menu name. For example, press Alt+V to pulldown the View menu. The pull-down menu appears.

2. Choose the desired command using one of the two following methods:

w Press the up and down arrow keys to highlight the command, then press En-ter to select it.

w Press the underlined letter of the command. Press I to select Zoom In.

3. Some menu commands have one or more key designations next to them; theseare the hot keys. Pressing the hot keys selects the corresponding command.Learning the hot keys is a great way to become an efficient spectraCAD user.

To select a command using hot keys, press the hot key(s) for the desired com-mand. Press Ctrl +R to redraw the drawing area.

Task 2-4 Using the Mouse to Select Commands

You can select spectraCAD commands with the left mouse button. Using the left mousebutton, you can select a command from the pull-down menus or click a Tool Bar orTool bar button.

Using the Left Mouse Button

Select the File pull-down menu command with the mouse:

1. In the Menu Bar, click with the left mouse button the File menu name. The pull-down menu appears.

2. Click with the left mouse button on New.

3. A new file is opened.

To select a command using the Tool Bar or Tool Bars, click with the left mouse buttonon the button associated with the desired command.


Picking Points

You will often pick points when using Draw, Modify, and View commands. For in-stance, you pick the center of a circle in Circle; you pick a rotation base point in Rotate;and you pick the corners of a box in Zoom Box.

When spectraCAD prompts you to pick a point, you can either click in the DrawingArea or use the Enter Point dialog box. This guide uses the phrase “Pick the [kind of]point” to mean “Pick the point by clicking in the Drawing Area or by using the EnterPoint dialog box.”

Clicking in the Drawing Area is quick, but it can be hard to pick a point accurately. Theaccuracy of a drawing is very important when you want to machine a part in a CAMprogram, or when parts from different drawings must fit together precisely. To drawand modify entities accurately, use the Enter Point dialog box instead of clicking in theDrawing Area.

Task 2-5 Clicking in the Drawing Area

1. Move the cursor until the coordinates (1.5, 1.0) are shown in the CoordinateDisplay box.

2. Click to pick the point.

Task 2-6 Using the Enter Point Dialog Box

1. Do either one of the following:

u Click the Type button.

u Select Type from the Tools Menu.

The Enter Point dialog box appears.

2. Select Absolute as the coordinate type. You have a choice of Absolute, Rela-tive, or Polar, but for this exercise, choose Absolute.

u Absolute coordinates (see next page) specify the X and Y distances of thepoint from the center of the drawing at (0,0).

u Relative coordinates specify the dX and dY distances of the point from thelast point you picked in that operation.

u Polar coordinates specify the radius and angle (in degrees) of the point fromthe last point you picked in that operation.


3. Type the coordinates X = 1.5, Y = 1.0.

4. Click OK or press Enter.

Task 2-7 Questions

Q What are two ways to select commands in spectraCAD?

Q What is the most accurate way to pick a point?

Selecting and Deselecting Entities

After you draw an entity, you may need to modify it, get information about it, or use itto draw other entities. To perform any of these tasks you must select, or activate, theentity. Selected entities temporarily appear dashed. You can select one or more entitiesat a time.

Task 2-8 Using the Entity Box

You can use the entity box to select or deselect one or more entities.

Select one entity:

1. Before you can select an entity, you will have to draw one.

2. Select Rectangle from the Draw Menu.

3. Click the cursor on any point in the drawing area.

4. Move the cursor down and to your right and draw a small rectangle.

5. Click the mouse again to complete the rectangle.

6. Repeat steps 3-5 to draw another small rectangle. Press escape to end the rect-angle operation.

7. Move the cursor until a part of the first rectangle is inside the entity box.

8. Click to select that entity. The entity appears dashed instead of solid, indicatingthat it is selected. Note that all the entities that are inside or cross the entity boxwhen you click will be selected.


Select an additional entity:

1. Move the cursor until part of another entity is inside the entity box.

2. Hold Shift and click to select that entity. Both entities now appear dashed.

You may do this for as many entities as you want.

Deselect one entity:

1. Move the cursor until part of a selected entity is within the entity box.

2. Hold Shift and click to deselect that entity. The entity you clicked on now ap-pears solid, indicating that it is deselected.

Task 2-9 Using a Selection Box

You can drag a selection box around entities to easily select or deselect many entities atonce. When you use this method to select entities, the selection is direction-sensitive; thatis, there is a difference in selection depending on whether you drag the mouse from left toright, or from right to left.

If the selection box is dragged left to right, all entities completely enclosed by the boxare selected. If the selection box is dragged right to left, all entities that are within orcross the box are selected. It does not matter whether you draw a selection box top tobottom or bottom to top.

1. Click and hold the mouse button with the cursor above and to the left of theboxes.

2. Drag the cursor and the selection box around the two boxes and then release themouse button. Both boxes will appear dashed.


Using Select All

You can select all the visible entities in your drawing us-ing the Select All command from the Edit Menu. Someoperations prompt you to select one or more entities tomodify; you can use Select All only with these opera-tions.

Getting Help

When you are first learning to use spectraCAD, there are avariety of ways you can get help. In addition to reading the manual, you can usespectraCAD's on-line help features.

Using the Status Bar

The Status Bar displays brief descriptions of the menu commands once you highlightthem with a mouse. After you select a command, the Status Bar prompts you for input.

The Status Bar helps you remember what each menu command does and which actionsto perform. Using the Status Bar is one of the best ways to learn spectraCAD quickly.

Using the Tool Bar

If you place the cursor over a Tool Bar button (without clicking it), a balloon appearsnear the cursor. The balloon shows the name of that button. Use the balloons to helpyou remember what the Tool Bar buttons do.

Using On-line Help

The on-line Help utility gives you detailed help withspectraCAD while you work. You can start Helpand browse through Help topics, or you can viewthe Help topic related an operation, dialog box,command, or Tool Bar or Tool bar button.

To learn how to use Help on-line, select Using Help from the Help Menu. The Helputility starts, and the How to Use Help screen opens. Simply follow the directions.

To start the Help utility, select Index from the Help menu. The spectraCAD Help utilitystarts. The Contents screen is displayed. Select the topic with which you require help.


While performing an operation, select Help from the Help Menu, or press F1. The Helputility starts, and the Help topic related to the current operation is displayed.

Click the Help button in any dialog box that includes the button. The Help utility starts,and the Help topic related to the current dialog box is displayed.

To get help on a menu command, a Tool Bar, or tool bar button, click on the ContextHelp button on the toolbar, or press Shift+F1. When the Help cursor appears, use it toopen a pull-down menu, and select a command, or to click on a Tool Bar or tool barbutton. The Help utility starts, and the Help topic is displayed.

Task 2-10 Questions

Q If you drag a selection box from right to left across your drawing, which entitesare selected?

Q What are 3 ways to get help in spectraCAD?

Q If you have 3 entities selected, how can you deselect one?







w Select shut down from the start Menu on the computer.




Activity 3

Managing Files

Objectives

In this Activity you will learn to:

u Create, open, and save spectraCAD drawings

u Import DXF files

u Print spectraCAD drawings

Skills

In this Activity you will develop the following skills:

w Technology: Learn basic CAD functions

w Systems: Use computer filing systems

w Resources: Manage time, manage computer programs






Materials

In this Activity you will need the following materials:


w Worksheets for Activity Three


Overview Managing spectraCAD Files

File management is an important aspect of using any computer program, andspectraCAD is no different. Creating new drawings, saving new files, importing otherdrawings into your present one, improving on existing designs, printing, storing and up-dating information are all part of the file management activity.

In this activity you will learn how to use the spectraCAD program to do all of thesethings, as well as polish your keyboard and mouse skills.

Procedures

Task 3-1 Starting spectraCAD



From Windows 95:





Task 3-2 Creating a New Drawing

Use the New command under the File Menu to create a new drawing. A newspectraCAD drawing is based on a template, or pattern. When you start spectraCAD itcreates a new drawing based on the default spectraCAD template, called DEFAULT.Your new drawings can be based on any available template.

You can create a new drawing any time after you have started spectraCAD, but you canonly have one drawing open at a time. If you have changed the current drawing,spectraCAD asks you to save the changes before it creates a new drawing.

Create a new drawing:

1. Click the New button on the Toolbar, select New fromthe File Menu, or press Ctrl +N.

2. If there are unsaved changes to a current drawing, a dia-log box appears. Choose whether or not to save thechanges:

w Click Yes to save the changes and create a newdrawing

w Click No to discard the changes and create a newdrawing

w Click Cancel to close the New dialog box withoutcreating a new drawing or saving the changes.

A new blank drawing appears. The Title Bar displays the name“Untitled,” indicating that this is a new drawing.

Task 3-3 Save Your New Drawing

Use the Save and Save As commands under the File Menu to save the current drawingto a DXF file. Saving your drawings preserves your work for later use in spectraCADor spectraCAM. You should also save frequently as you work, to ensure that all yourchanges are recorded.

If the current drawing has been saved previously to a DXFfile, selecting Save saves the changes to the same file. If thecurrent drawing is new (and still has the name “Untitled”), se-lecting Save brings up the Save As dialog box, in which youname, choose a location for, and save the new drawing. Alsouse Save As if you wish to rename or relocate the currentdrawing (whether or not you have changed it).

1. Click the Save button on the Toolbar, select Savefrom the File Menu, or press Ctrl +S.


Since this is a new drawing, the Save As dialog box appears. It displays thename and location of the current DXF file.

2. In the Drives field, scroll through the list, then click on the drive where youwish to locate the file. If you have your own directory on the hard drive, selectthe drive where it is located. If you are saving to a disk, select the floppy driveand install your disk.

3. In the Directories field, scroll through the list and highlight the directory whereyou wish to locate the file. Press Enter or double-click on the directory to select it.

4. In the File Name field, type “NEW” as the file name.

5. Click OK or press Enter. The current drawing is saved NEW.DXF in the loca-tion that you specified.


Task 3-4 Open an Existing Drawing

Use the Open command under the File Menu to open an exist-ing drawing. An existing drawing is one that was previouslysaved to a DXF file (using spectraCAD or another CAD pro-gram). For instance, you can open a drawing you created andsaved yesterday, so you can modify those entities and drawnew ones.

You can open an existing drawing any time after you havestarted spectraCAD, but you can only have one drawing openat a time. If you have changed the current drawing,spectraCAD asks you to save the changes before it opens an-other drawing.

Open an Existing Drawing:

1. Click the Open button on the Toolbar, select Open from the File Menu, orpress Ctrl +O. The File Open dialog box appears.

2. In the Drives field, scroll through the list and click on the C drive.

3. In the Directories list box, scroll through the list and highlight the directorywhere the desired file is located. In this exercise it will be the Data directory inthe CADEng folder.

4. In the Files list box, highlight the CAD.dxf file, or type the file name into theFile Name field.


5. Click the Preview button to display the preview area of the Open dialog box.Preview allows you to view the selected file and obtain information about it.Clicking Preview again hides the preview area of the dialog box.

6. Click OK or press Enter. If there are unsaved changes to the current drawing,the following dialog box appears.

7. Choose whether or not to save the changes:

w Click Yes to save the changes and open the drawing

w Click No to discard the changes and open the drawing

w Click Cancel to close the Open dialog box without opening a drawing or sav-ing the changes

The selected drawing is opened. The Title Bar displays the name of the drawing.

Task 3-5 Opening a Recently Used Drawing:

spectraCAD keeps track of the last four drawings youopened, making it easier for you to return to a file you wereworking on. These recent drawings appear in the File Menuas file 1 (most recent) through file 4 (fourth-most recent).

To open a recent drawing, click the mouse on the File menu,and select the number (1, 2, 3, 4) of the file you want.

The drawing you selected opens. If there are unsaved changesto the current drawing, spectraCAD will ask you to savethem before it opens the file.


Task 3-6 Import a DXF File

As you become more experienced working with spectraCAD,you may want to incorporate some of your other drawingsinto newer ones. Rather than repeating all the drawing steps,you can import the drawing into your current work. Using theImport command under the File Menu will place all of the en-tities from a DXF file into the current drawing. This operationis useful for merging two spectraCAD drawings, or for placingany DXF file into your spectraCAD drawing.

1. Be sure you have your NEW.DXF file open. Click theImport button on the Toolbar or select Import fromthe File Menu. The Import File dialog box appears.

2. In the Drives field, scroll through the list, then click on the drive where thePocket.DXF file is located.

3. In the Directories field, scroll through the list and double-click the directorywhere the Pocket.DXF file is located.

4. In the list of files, highlight Pocket.DXF, or type the file name into the FileName field.

5. Click the Preview button to display the preview area of the Open dialog box.Preview allows you to view the selected file and obtain information about it.Clicking Preview again hides the preview area of the dialog box.

6. Click OK or press Enter. The entities in the file you selected are placed in thecurrent drawing. New layers are created, if necessary, and the imported entitiesare selected, as set by the current Preferences.


Task 3-7 Printing a Drawing

Next, we will print your NEW.dxf drawing. You can print the current contents of theDrawing Area to any printer supported by Windows. First we will preview the file to beprinted, and then print it.

Preview the Drawing:

Previewing the drawing allows you to see what it will looklike before you print it. This is helpful when managing a largenumber of files. Rather than printing files to see what theywere, and tying up the printer, you can simply look at a pre-view to determine whether that file was what you were look-ing for.

1. Select Print Preview from the File Menu. The Pre-view window appears.

2. You may:

w Click Print to print the page, if desired.

w Click Zoom In to magnify the page, then click Zoom Out to see the wholepage again.

w Click Close to close the Preview window.

To alter the page, you can change the print settings again, change the contents of theDrawing Area, or both.


Print the Drawing:

1. Click the Print button on the Toolbar, select Printfrom the File Menu, or press Ctrl +P. The Print dialogbox appears.

2. Select a Printer . The Windows default printer is cur-rently selected.

3. Select the Copies settings (the number of copies andwhether or not the copies are collated).

4. Select a Print Range, All pages, pages From and To,or a Selected page.

5. Click OK to print.

See your printer manual or Windows documentation for more information on installingand using printers with Windows.


Task 3-8 Discussion and Review

Q Why is it so important to save your work at regular intervals?

Q What is the quickest way to open an existing drawing that you recently used?







w Select Shut Down from the Start menu on the computer.



Activity 4

Creating the LMC Project

Objectives


w How to draw text using the CAD tools

w How to draw a rectangle

Skills

In this Activity you will develop the following skills:

w Technology: CAD layout and design tools

w Systems: Utilize a complex design system

w Resources: Manage time


w Information: Evaluate and use important information

w Basic: Reading, writing, and measurement



Materials

In this Activity you will need the following materials:


w Worksheets for Activity Four


Overview

In this activity you will begin the design process of your first part. During this and thenext two activities, you will draw the part shown below. It includes a material outline,an inner boundary, and three islands. The islands form the letters L, M, and C.

If you machined this part using a CAM program, the inner boundary and the islandswould be cut from a block of material. These activities will teach you some of the basicand a few advanced spectraCAD operations

From the previous activities, you should know:

u How to select a command from the pull-down menus, the Tool Bar, or the ToolBoxes.

u How to select an entity with the cursor and with a selection box.

u How to pick a point by clicking in the Drawing Area or by using the Enter Pointdialog box.

u How to use Absolute and Relative coordinates.

u The parts of the spectraCAD screen.


Procedures

Task 4-1 Start spectraCAD and Create a New Drawing

Before you begin drawing, you have to start spectraCAD and create a new drawing.The new drawing will based on a special pattern, or template.

The first step is to start spectraCAD from the Programs group on the Windows 95 StartMenu. To start the Control Program:


From Windows 95:




spectraCAD will open a new drawing, based on a template. The Title Bar displays thedrawing name, “Untitled,” meaning this is a new drawing.

w The material outline should be visible in the Drawing Area. If the outline is notvisible, select the Show/Stock command from the View Menu.


Draw the Inner Boundary

The next step is to draw the inner boundary. This boundary forms a margin between thematerial outline and the material that will be machined. The inner boundary is 0.25"from the material outline on all sides, and has rounded corners of radius 0.125".

There are many ways to draw the inner boundary. In this example, you will use the ma-terial outline to create the inner boundary.

By completing this step, you will learn:

u How to offset and fillet entities

u How to save a new drawing

Task 4-2 Offset the Rectangle

First, offset the rectangle that represents the material outline to create the inner bound-ary. In this example, you will offset the rectangle toward its center, so the offset issmaller than the original rectangle. The offset distance will be 0.25", so that the offset isseparated from the rectangle by 0.25" on all sides.

1. Select Offset from the Modify Menu.

2. Select the rectangle as the entity to offset. Once selected, the rectangle appearsdashed, and the offset appears. Moving the cursor changes the size of the offset.

3. Set the offset distance: Click the Type button. The Enter Offset Distance dialogbox appears.

Enter .25 as the offset value, then click OK or press Enter.


4. Click inside the rectangle to select the offset side. The offset appears inside therectangle.

5. Press Escape to end the Offset operation.

Side 1

Side 4

Side 2

Side 3

Material outline

Task 4-3 Fillet the Corners

Next, fillet the corners of the inner boundary. This makes the corners rounded. The filletradius is the radius of the arc in the corner; a smaller radius creates a tighter corner.

1. Select Fillet from the Modify Menu.

2. Set the fillet radius: click the Type button, and the Enter New Fillet Radius dia-log box appears.

Type .125, then click OK or press Enter.


3. Select Side 1 as the first fillet entity.

4. Select Side 2 as the second fillet entity.

2

1TheresultingFillet arc

Click Side 1

Click Side 2

Sides 1 and 2 now have a fillet arc connecting them. The radius of the fillet is0.125".

5. Repeat Steps C and D to fillet the other three corners in the same way. You donot need to set the fillet radius again.

6. Press Escape to end the Fillet operation. The inner boundary is now complete.

The Drawing Area after Step 2.2

Inner boundary


Task 4-4 Save the Drawing

Finally, save your drawing. You should save your drawings frequently, so you don'tlose your work.

1. Click the Save button on the toolbar, select Save from the File Menu, or pressCtrl +S. The File Save As dialog box appears.

2. If you are saving your work to a directory on the hard drive, locate that direc-tory now. If you are saving to a floppy, select the floppy drive (usually A), andinsert your disk.

3. Type the name, LMC.dxf, into the File Name field.



Draw the “L” Island

The L, M, and C are called “islands” because the material surrounding them is ma-chined, but the material inside them is not. They will appear raised on the machinedpart, just as islands are raised above the ocean's surface. Note that the islands areshaped like letters of the alphabet, but they are not text blocks.

In this step you will draw the “L” island. There are many ways to draw this island. Inthis example, you will draw continuous lines.


u How to draw continuous lines

u How to use the Grid snap and change Grid spacing

u How draw with Relative coordinates

Task 4-5 Change Grid Constraints and Coordinate System

First, change Grid Spacing so the Grid points are 0.0625" apart, then enable Grid Snap.Grid spacing ensures that the drawn lines have the correct lengths. Enabling Grid Snapforces the cursor to “snap” to the Grid points, which makes it easier to draw freehand.

1. Select Setup from the Snap Menu. The Setup Snaps dialog box appears.

2. In the Constraints area, click the Grid checkbox so it contains an “x.”

3. Enter .0625 in the Grid Spacing field.


Now you can only pick Grid points to draw the “L” island, and the Grid points are0.0625" apart.


Task 4-6 Switch to the Relative Coordinate System

Now change the coordinate type to Relative, so that each point will be measured fromthe last point you picked. This makes it easy to draw horizontal and vertical lines ofspecified lengths.

Click the Coordinate Type button until it displays “Rel.”

Relative coordinates are now shown in the Coordinate Display box.

Task 4-7 Draw Six Continuous Lines

Draw the six lines that form the “L” island. They are called continuous lines because theend point of one is the start point of the next.

1. Select Line from the Draw Menu.

2. Move the cursor until the Coordinate Display box says r(.375, .5625). Click topick the start point of Line 1.

Start Point for Line 1,End Point for Line 6

End Point Line 1,Start Point Line 2





3. Move the cursor up to r(0.0, 0.875). Click to pick the end point of Line 1. Line1 appears.

4. Move the cursor right to r(0.25, 0.0). Click to pick the end point of Line 2.Line 2 appears.

5. Move the cursor down to r(0.0, -0.625). Click to pick the end point of Line 3.Line 3 appears.




8. Move the cursor left to r(-0.5, 0.0). Click to pick the end point of Line 6. Line6 appears.

9. Press Escape to end the Line operation. The “L” island is now complete.


Finally, save your drawing to preserve the changes made in this activity.

Click the Save button on the toolbar, select Save from the File Menu, or press Ctrl +S.


Q What are continuous lines?

Q When you fillet a corner, what are you doing?

Q What key do you use to end most CAD operations?

Q Why is it a good idea to save your work on a regular basis?









The Drawing Area after completingthe "L".


Activity 5

Drawing the M

Objectives

In this Activity you will accomplish the following:

w Continue your product design

w Learn to use basic and advanced CAD design tools

Skills


w Technology: CAD layout and design tools

w Systems: Utilize a complex design system



w Information: Study and use important information




Materials



w Worksheets for Activity Five


Overview

In this step you will draw the “M” island. There are many ways to draw the M. Youcould just draw continuous lines. But because it is symmetrical, it is easier to draw theleft half and then mirror those lines to create the right half.


u How to mirror entities

u How to snap to end points

Procedures

Task 5-1 Start spectraCAD and Open the LMC file

The first step is to start spectraCAD from the Programs group on the Windows 95 StartMenu:


From Windows 95:




w When spectraCAD is running, select Open from the file menu and open theLMC.dxf file you created in the last activity.


Task 5-2 Draw Six Continuous Lines

Before you begin this task, check to see that the coordinates box is set to “Relative.” Ifit is set to Absolute or Polar, you will have to change it back to relative. You can dothis by clicking the mouse on the box until it says “Rel”.

The first step is to draw six continuous lines to form the left half of the “M” island.Drawing these lines is similar to drawing the continuous lines of the “L” island. How-ever, this time we will use a different method to pick the start point.

1. Select Line from the Draw Menu.

2. Pick the start point of Line 1. Click the Type button. The Enter Point dialogbox appears.

Enter 1.5 for X and 0.8125 for Y, then click OK or press Enter.

3. Move the cursor up and to the left until the Coordinate Display box reads r(-0.25,0.3125). Click to pick the end point of Line 1. Line 1 appears.


5. Move the cursor left to r(-0.25, 0.0). Click to pick the end point of Line 3.Line 3 appears.

6. Move the cursor up to r(0.0, 0.875). Click to pick the end point of Line 4. Line4 appears.

Start Point for Line 1






End Point Line 6

Drawing the left half of the “M” island



8. Move the cursor down and to the right to r(0.25, -0.3125). Click to pick theend point of Line 6. Line 6 appears.

9. Press Escape to end the Line operation. The left half of the “M” island is com-plete, and should look similar to the one pictured below.


Task 5-3 Mirror the Lines

Next, mirror the lines to create the right half of the “M” island. Mirroring creates a re-flected image of the selected lines.

To form the mirror line, you will use the End Point snap. Using this snap makes it mucheasier to pick an end point of an existing entity. Here, you will snap to the end points ofLines 1 and 6 to form the mirror line. This ensures that the right half of the “M” islandis properly connected to the left half.

1. Click the Mirror button on the Modify Toolbar, or select Mirror from theModify Menu.

2. Pick a point above and to the left of the existing half of the “M” island. This isthe first corner of a selection box.

3. Drag the cursor down and to the right, until the existing half of the “M” island iscompletely inside the selection box, then click to pick the second corner of theselection box. Lines 1 to 6 should be selected. If they are not, or if other entitiesare also selected, cancel the operation and repeat Steps a, b, and c.

4. Press Enter to end the selection process.

5. Click the End Point button on the Snap Toolbar, select End Point from theSnap Menu, or press F2.

6. Click the cursor on the end point of Line 6 to pick the first point of the mirrorline. A mirror image of the existing half appears. Moving the cursor moves theimage.


8. Click the cursor on the start point of Line 1 to pick the second point of the mir-ror line. The right half of the M, a mirror image of the left half, is drawn, and theM is complete.

Click on theend point ofLine 6.

Click on thestart point ofLine 1.

The completed mirrorimage.



Finally, save the drawing again. If you make a mistake in Step 5, you can still recoverthe work you have done to this point.

Click the Save button on the Toolbar, select Save from the File Menu, or press Ctrl +S.

The drawing is saved with the changes made in Step 4.

The Drawing Area after Step 4


Q Why is it more efficient to mirror an entity rather than try to draw it?

Q What would have been the result if you had not checked the coordinate type boxand it had been set to Absolute?










Activity 6

Drawing the C

Objectives


u How to draw an arc

u How to copy, trim, and extend entities

u How to enlarge part of a drawing and restore the previous view

Skills


w Technology: Develop a working knowledge of CAD design tools

w Systems: Utilize a computer file system, and a CAD system


w Interpersonal: Participate as a member of a work team and provide assistance tomembers of your own and other teams


w Basic: Reading, writing, measurement



Materials



w Worksheets for Activity Six


Overview

In this step you will draw the “C” island. Again, there are many ways to draw this is-land. In this example, you will draw two lines and two arcs, then trim them so theyshare end points.


u How to draw an arc

u How to copy, trim, and extend entities

u How to enlarge part of a drawing and restore the previous view

Procedures



From Windows 95:




w When spectraCAD is running, select Open from the file menu and open yourLMC.dxf file.


Task 6-2 Draw Line 1

Again, before you begin, check that your coordinate system type is set to “Relative.” Ifit is not, click on the button with your mouse until relative is selected.

Draw Line 1 of the “C” island, the vertical line at the top of the “C.” You will then useLine 1 to create Line 2 in the next step.

1. Click the Line button on the Draw Toolbar, or select Line from the DrawMenu.

2. Pick the start point of Line 1. Click the Type button. The Enter Point dialogbox appears.

Enter 2.625 for the X Coordinate value and 1.4375 for the Y Coordinate value,then click OK or press Enter.

3. Drag the cursor down to r(0.0, -0.25) and click to pick the end point of Line 1.Line 1 appears.

4. Press Escape to end the Line operation.

Line 1


Task 6-3 Copy Line 1

Next, copy Line 1 to create Line 2. Since the lines are the same length and have thesame orientation (both are vertical), it is easier to copy the existing line than to draw an-other one. Also, since you know where Line 2 should be, you will use the End Pointsnap to position it accurately.

1. Click the Copy button from the Toolbar, or select Copy from the Modify Menu.

2. Select Line 1, then press Enter to end the selection process.


4. Click on the start point of Line 1 to pick the reference point of the copy.

5. Drag the cursor until the Coordinate Display box reads r(0.0, -0.625), then clickto select the new base point of the copy. Line 2 appears directly below Line 1.

6. Press Escape to end the Copy operation.

Click the startpoint of Line1.

Drag copy ofLine 1 to newbase point andclick.

There are nowtwo lines.

Line 1

Line2


Task 6-4 Draw Arc 1

Now draw the small arc of the “C” island. You will use End Point snap to make surethat the arc is connected properly to Lines 1 and 2.

1. Click the Radius Arc button on the Draw Toolbar, or select Radius Arc fromthe Draw Menu.


3. Click the end point of Line 1 to pick the start point of Arc 1.


5. Click the start point of Line 2 to select the end point of Arc 1.

6. Move the cursor to r(-0.25, 0.0625) and click to set the radius of Arc 1.

7. Press Escape to end the Radius Arc operation. Arc 1 appears, connected toLine 1 and Line 2.

1) Click theend point ofLine 1.

Drawing Arc 1

2) Click thestart point ofLine 2.

3) Click to setthe radius orArc 1.

The completedArc.


Task 6-5 Offset Arc 1 to Create Arc 2

Next, offset Arc 1 to create Arc 2. Offsetting an arc is similar to offsetting a rectangle,as you did when you created the inner boundary. In this example, you will offset Arc 1away from its center point, so the offset has a larger radius. The difference in radii isequal to the offset distance, which you set in Task 4-2 to be 0.25".

1. Click the Offset button on the Modify Toolbar, or select Offset from theModify Menu.

2. Select Arc 1 as the entity to offset. The offset appears when you move the cur-sor to the outside of Arc 1.

3. Click on any point toward the outside (to the left) of Arc 1, to select the offsetside. Arc 2 appears. It has the same center point as Arc 1, and a radius 0.25"larger than Arc 1.

4. Press Escape to end the Offset operation.

The Drawing Area after Step 5.4Arc 2


Task 6-6 Zoom in on the Drawing

Next, zoom in on the drawing, so that you have a close-up view of Line 1 and Arc 2.This will make it easier to trim those entities so they share an end point.

1. Click the Zoom Box button on the Display Toolbar, or select Zoom Box fromthe View Menu.

2. Click on a point above and to the left of Line 1 and Arc 2 as the first corner ofthe zoom box. Drag the mouse to a point below and to the left of Line 1 andArc 2 and click. This is the second corner of the zoom box. The view becomes aclose-up of the area in which you will be working.

Zooming in on the drawing.

Drag a zoom box around the area you wish to magnify.

Click firstpoint.

Click secondpoint.

Task 6-7 Disable Grid Snap

You do not need to snap to Grid points to trim and extend entities. This will make iteasier to move the cursor when you are zoomed in on the drawing.

Select Grid from the Snap Menu. Grid snap is disabled. You can move the cursor any-where in the drawing.


Task 6-8 Extend Line 1 to Arc 2

Extend Line 1 so that it meets Arc 2. Arc 2 is the boundary. Extending Line 1 makes ita bit longer, and will allow you to trim Arc 2 in the next step.

1. Click the Trim/Ext button on the Modify Toolbar, or select Trim/Extend fromthe Modify Menu.

2. Select Arc 2 as the boundary.

3. Select Line 1 as the entity to extend. Line 1 now starts on Arc 2.

The Drawing Area after Task 6-8

Line 1 extended to Arc 2

Task 6-9 Trim Arc 2 to Line 1

Next, trim Arc 2 to Line 1. Line 1 is now the boundary. Arc 2 will become a bit shorter,so that it starts at Line 1. This ensures that the two entities share an end point. This is im-portant when you use your drawing in a CAM program.


2. Select Line 1 as the boundary.

3. Select the outer portion of Arc 2 (to the right of Line 1) as the entity to trim.The outer portion is deleted. Arc 2 is trimmed to Line 1, and the two entitiesshare an end point.

If you pick the inner portion by mistake, select Undo from the Edit Menu andrepeat the task.


Task 6-10 Zoom in on the Drawing

Change the view to a close-up of the ends of Line 2 and Arc 2. This will help you trimand extend these entities more easily. You will go back to the previous view of thedrawing (which shows all entities), then use a zoom box to enlarge the desired area.

1. Click the Zoom Previous button on the Display Toolbar, or select Zoom Previ-ous from the View Menu. The entire drawing is now within the Drawing Area.

2. Click the Zoom Box button on the Display Toolbar, or select Zoom Box fromthe View Menu.

3. Click on a point above and to the left of Line 2 and Arc 2 as the first corner ofthe zoom box. Drag the mouse to a point below and to the left of Line 1 andArc 2 and click. This is the second corner of the zoom box. The view becomes aclose-up of the area in which you will be working.


Arc 2

Line 2


Arc 2 trimmed to Line1


Task 6-11 Extend Line 2 to Arc 2

Extend Line 2 so that it meets Arc 2. Arc 2 is the boundary. This is similar to Task 6-8.


2. Select Arc 2 as the boundary.

3. Select Line 2 as the entity to extend. Line 2 now starts on Arc 2.


Arc 2 trimmed to Line 2


Line 2, extended to Arc 2

Task 6-12 Trim Arc 2 to Line 2

Now trim Arc to Line 2. Line 2 is now the boundary. This is similar to Task 6-9.


2. Select Line 2 as the boundary.

3. Select the outer portion of Arc 2 (to the right of Line 2) as the entity to trim.The outer portion is deleted. Arc 2 is trimmed to Line 2, and the two entitiesshare an end point.


Task 6-13 View the Entire Drawing

Next, view the whole drawing to make sure it is complete and accurate.

Click the Zoom All button on the Display Toolbar, or select Zoom All from the ViewMenu. The entire drawing is now displayed in the Drawing Area.

The complete part drawing.


Finally, save your drawing. This preserves the last changes you made.


Congratulations! Your first part drawing is complete!

Now, you can open another drawing, create a new drawing, or exit spectraCAD (by se-lecting Open, New, or Exit from the File Menu, respectively).

Task 6-15 Review and Discussion

Q In Task 6-3, why was it better to copy line 1 to create line 2, rather than justtrying to draw a second line?

Q What are the three points you need to draw a radius arc?

Q When would you disable Grid Snap? Enable Grid Snap?

Q When you are trimming a line, what side of the boundary do you click on, theside you want to save or the side you want to trim?







w Return all materials to their proper place at your lab Station.




Activity 7

Speaker Design Project

Objectives


w Begin a new design project

w Learn about polylines

w Use basic and advanced CAD operations

Skills










Materials



w Worksheets for Activity Seven


Overview

In the next few activities you will be creating a second dxf file, pictured below. You willbe using some other operations in the CAD system, such as layering, rotating, and mov-ing entities. When you complete this module, not only will you have a good understand-ing of how to use a CAD system, but you will also have a few design projects underyour belt to bring to the CAM module, and eventually run on a milling machine.

This series of activities requires you to use your imagination a bit. Imagine you areworking for a design firm and a client has asked your company to design a new audiospeaker for a computer multimedia system. The speaker must be small, no larger thanthree inches tall, two inches wide, and one and a half inches deep. In the first step of thedesign process, you use spectraCAD to create a drawing of the speaker that will meetall of the design specifications. spectraCAD allows you draw your part and makechanges quickly and easily as you develop your part. Your finished CAD drawing willlook like the drawing below.

Speaker Cone(Inner Circle)

Speaker Cone(Outer Circle)

Contour Boundary

On/Off Switch

Volume Knob

Nameplate

Material Outline


Procedures



From Windows 95:






w Select Open from the File menu. When the list of templates (*.dxf, *.dxt) isshown, click on the 3x2.dxt file. This will open a 3”x2” template, which is thesize of the speaker stock.


Task 7-2 Set the Grid Spacing

Before we begin drawing, the grid spacing must be set to 0.0625 inches.

1. Select Setup from the Snaps menu.

2. In the dialog box that appears, set the grid spacing to 0.0625.

3. Make sure there is a check in the Grid Constraints box.

4. Click on Okay to close the box.

Task 7-3 Draw the Contour Boundary

The design for the speaker calls for a contoured edge with rounded corners for an aes-thetically pleasing shape. The contour boundary creates the raised face of the speaker.

There are many ways to draw the contour boundary. In this lesson, use the Draw Rect-angle feature to create the contour boundary. Then fillet the rectangle to give it therounded corners.

Use the Rectangle command under the Draw Menu to draw a closed rectangularpolyline between two corner points.

A polyline is a series of two or more connected lines or arcs which are treated as oneentity. Closed polylines have the same start and end point, while open polylines havedifferent start and end points. The only polyline you can draw in spectraCAD is a rect-angle (though spectraCAD supports polylines created in other CAD programs). Theend points of closed polylines are invisible in spectraCAD.


1. Click the Rectangle button on the Draw Toolbar or select Rectangle from theDraw Menu.

2. Move the pointer to point (0.125, 1.875) and click to establish the start point ofthe rectangle.

3. Move the pointer down to point (2.875, 0.125) and click to establish the endpoint of the rectangle. As you move the mouse, notice that spectraCAD displaysthe rectangle dimensions on the screen. These are not the coordinates you need.Be sure to look in the Coordinate Display Box for the end point coordinates.

4. Press Esc on your keyboard to end the Draw Rectangle operation. When youcomplete this step, your drawing should look like the one below.


You should save your drawings frequently, so you don't lose your work.

1. Click the Save button on the toolbar, select Save from the File Menu, or pressCtrl +S. Because this is a new file, the File Save As dialog box appears.


3. Type the name, SPKR.dxf, into the File Name field.



Task 7-5 Fillet the Corners

Use the Fillet command under the Modify Menu to create a rounded corner betweentwo entities. The rounded corner is called a fillet arc, and its radius is the fillet ra-dius. If the current fillet radius is too large for the fillet entities, the operation will fail.

We will use the Fillet command on the contour boundary to create the rounded cornersof the speaker enclosure’s front panel.

1. Select the Fillet button from the Modify Toolbar, or from the Modify menu.

2. Click the Type button.

The Enter New Fillet Radius dialog box appears.

3. Enter .25 in the Radius field. Click on OK or press Enter.

4. Select Line 1 as the first fillet entity.

5. Select Line 2 as the second fillet entity.

spectraCAD draws the fillet arc connecting Lines 1 and 2.

6. Repeat this procedure for the remaining three corners of the rectangle.


Save the Drawing

Click the Save button on the toolbar, select Save from the File Menu, or press Ctrl +S.


Q What is a closed polyline?

Q What is an open polyline?

Q If the fillet radius is too large for the fillet entities, what happens?

Q What is the rounded corner between two entities called?

Q If you chose two entities to fillet, and entered a fillet radius of zero, what kindof corner would result?

7. Press Esc on your keyboard to end the Fillet operation.

When you complete this step, your drawing should look like the one below.











Activity 8

Creating the Speaker Cone

Objectives


w Three methods of drawing circles

w How to place an entity on another Layer

Skills










Materials



w Worksheets for Activity Eight


Overview

In this activity, you will continue working with the SPKR.dxf file. You will create thespeaker cone and what would be a pocket in a CAM operation. You will use bothmethods of drawing a circle, and place the inner circle on a second layer. Then you willdraw the volume knob.

Your company’s speaker cone manufacturer makes a speaker with a 0.6875” radius.This size should work very well with the compact speaker design. You will have to cre-ate the speaker cone in your drawing.

Procedures



From Windows 95:




w When the program is up and running, open the SPKR.DXF file.


Task 8-2 Draw the Outer Circle of the Speaker Cone

You can use either the Circle command under the Draw Menu, or the Circle button onthe Draw Toolbar to draw a circle with a specified center point and radius.

1. Click the Circle button on the Draw Toolbar, or select Circle from the DrawMenu.

2. Select the centerpoint for the circle. Move the cursor to the point 2.0625, 1.0and click. A circle appears, centered at the point you picked.

3. The circle’s radius is displayed in the Drawing Area as you draw. Move the cur-sor to set the radius at 0.6875”, and click to set the circle size.

This is one method of drawing a circle. We will use another method for the In-ner Circle of the speaker cone.


Task 8-3 Draw the Inner Circle

Because the inner circle is smaller, we will use a different method to create it.


2. Select the centerpoint for the circle. Click on the type button. The Enter Pointdialog box appears.

3. Enter the coordinates X=2.0625, Y=1.0.

If you put the cursor on the drawing area, a circle will appear with the radiusdisplayed.

4. Select the Type button. The Enter Circle Radius dialog box appears.

5. Enter a radius of 0.25”.

6. The inner circle appears in the drawing area.

7. Press Escape to end the Circle operation.

Save The Drawing

Click the Save button on the Toolbar, select Save from the File Menu, or pressCtrl +S.


Task 8-3 Draw the Volume Control Knob

The specifications for this new speaker call for a volume knob that is small enough to fitinto the design, but large enough to be functional. Your company has managed to findan acceptable knob with a radius of 0.198” from one of your vendors.

We will use another method of drawing a circle, which is actually a combination of thefirst two.


2. Select the centerpoint for the circle. Move the cursor to the point 0.4375, 0.5and click.

3. Select the Type button. The Enter Circle Radius dialog box appears.

4. Enter a radius of 0.198”.

5. The volume knob circle appears in the drawing area.

6. Press Escape to end the Circle operation.

7. Click the Save button on the Toolbar, select Save from the File Menu, or pressCtrl +S.

When complete this step, your drawing should look similar to the one here.


Task 8-4 Layering

Using layers is an easy way to keep your spectraCAD drawings organized. When youplace entities on separate layers, you can choose to see only one layer, a few layers atonce, or all the layers in the drawing. This flexibility in viewing layers makes drawingand modifying entities easier, especially when your drawing is complicated. The abilityto view one layer at a time is the principal reason to use layers.

There are many ways you can organize entities on different layers. You might want toorganize entities by:

Type: Points on one layer, text on a second, other geometry on a third.

Color: Entities on layer #1 are yellow, those on layer #2 are green, etc.

Tool path: Entities on each layer form a separate tool path in a CAM program.

Use these suggestions, or create your own ways to organize your drawings with layers.

There are a few things to remember when using layers in your drawings.

1. All entities on the same layer are the same color. Changing the layer colorchanges the color of all entities on the same layer.

2. All entities on the same layer have the same visibility. Making the layer invisiblemakes all the entities on that layer invisible.

3. You cannot group entities that are on different layers.

Of course, you do not have to use layers in your drawings. Every drawing has at leastone layer. You can place every entity on one layer, if you wish.

We will put the speaker cone on a separate layer. Since the cone is recessed in thespeaker, it makes sense to have it on its own layer.

The first step is to create a second layer. We have been working on the default layer,Layer 0. We need to create Layer 1 to put the speaker cone on. Use the Layers com-mand under the Edit Menu to add a layer to the drawing.


1. Click the Layers button, or select Layers from the Edit Menu. The Edit Layersdialog box appears.

2. Click the Add button. A new untitled layer appears on the list, with black as thedefault color.

3. Name the new layer “Layer_1”. Highlight Untitled if it is not already high-lighted, and type in Layer_1.

4. Select medium blue as the color for the new layer.

5. Make sure there is a check in the Visible box for Layer 1.

6. Press Enter or click OK to accept the changes.

The layer that was highlighted when you closed the Edit Layers dialog box be-comes the current layer.

Task 8-5 Move the Speaker Cone to the New Layer

Use the Change Layer command under the Modify Menu to move one or more entitiesto another layer. But before you move an entity to another layer, you must determinewhich layer the entity is currently on by using one of the following methods:

u While in idle mode, click on an entity with the right mouse button; the context-sensitive menu displays the layer name.

u While in idle mode, select an entity; the layer name is shown in the Layer Dis-play box.

u Select Query from the Tools Menu, then select an entity or its group. The Querydialog box appears, and displays the entity's layer.


The speaker cone should be on Layer 0. To move the speaker cone to Layer 1:

1. Select Change Layer from the Modify Menu.

2. Select the circles of the speaker cone. Holding the shift key down while clickingon the entities allows you to select more than one entity. Press Enter when fin-ished. The Select Layer dialog box appears.

3. Highlight the layer where you want to move the speaker cone.

4. Click Change or press Enter. The speaker cone moves to the new layer. Thespeaker cone circles change to medium blue. If the new layer is invisible, the en-tities become invisible.

There is also a shortcut to move entites between layers.

1. Select the entities to move.

2. Click the arrow in the Layer Display box.

3. Scroll through the list and highlight a new layer. The selected entities are movedto the new layer.

You can use whichever method you want to move the speaker cone.




Q What are two reasons for using layers in a drawing?

Q What would have happened to the Speaker Cone when we moved it to Layer 1if we had not selected the “Visible” box in the Add Layer Dialog Box?

Q How could this have been fixed?











Activity 9

Completing the Project

Objectives


w How to Explode text

w How to Rotate entities

w How to Move entities

Skills










Materials



w Worksheets for Activity Nine


Overview

In this activity you will complete your speaker prototype by adding the on/off switch,the nameplate and the text. Some of the operations you will be performing include ex-ploding and rotating the text, and zooming in on specific areas of the drawing.

Procedures



From Windows 95:




w When the program is up and running, open the SPKR.DXF file.


Task 9-2 Draw the On/Off Switch

Just like the volume control knob, the on off switch must be small but functional. Drawthe switch as a rectangle. Creating this small component requires precision, so we willspecify coordinates rather than drawing freehand.

1. Select Rectangle from the Draw Toolbar or from the Draw Menu.

2. Click on the Type button. The Enter Point dialog box appears.

3. Enter the starting corner point for the rectangle (X=0.341, Y=1.692). Click onOK or press Enter.

4. Click the Type button again. The Enter Rectangle Dimensions dialog box appears.

5. Enter the following dimensions for the rectangle (X=0.191, Y=-0.381). Noticethe negative Y value. A negative value is used so that spectraCAD draws therectangle correctly, going down on the Y axis away from the starting point.Click on OK or press Enter.


Task 9-3 Draw the Nameplate

The nameplate for the speaker enclosure includes the company’s initials engraved intoan island. To create the nameplate, first draw the rectangle, then add and rotate the text.Because you are still in Rectangle operation, you do not need to select Rectangle fromthe Draw menu.

1. Click the Type button. The Enter Point dialog box appears.

spectraCAD draws the on/off switch. When you complete this step, your draw-ing should look similar to the one shown here.


2. Enter the starting corner point for the rectangle (X=0.774, Y=1.634).

3. Click the Type button again. The Enter Rectangle Dimensions dialog box appears.

4. Enter the dimensions for the rectangle (width=0.439, height=-1.257). Click onOK or press Enter.

spectraCAD draws the nameplate rectangle.

5. Press Esc on your keyboard to end the Draw Rectangle operation.

Task 9-4 Add the Text

The next step is to add the company’s initials to the nameplate.

1. Select Text from the Draw menu.

The Enter Text dialog box appears.

2. Enter ITK, with 2 spaces between each letter, in the Text field. Click on OK.

3. Click on a point at the top of the nameplate rectangle as the text insertion point.You will rotate and move the text shortly, so the text insertion point is not criti-cal for this task.

4. As soon as you move the cursor, the text will appear in the drawing area. Movethe cursor to the Type button and select it.


The Enter Text Height dialog box appears.

5. Enter 0.2 as the text height. Click on OK or press Enter.

spectraCAD draws the text with the height you specified in the dialog box.

Save the Drawing


Task 9-5 Move the Text

Use the Move command under the Modify Menu to change the location of entities inthe drawing.

Entities are moved with respect to a reference point and a new base point. These pointscan be anywhere in the drawing. The relation of the these points determines the direc-tion and distance that the selected entities move.

Deselecting the Grid Snap will make it easier for you to select the text in the next fewsteps. In order to move and explode the text, you will have to select all of the line seg-ments that make up the text.

1. Select Grid from the Snap menu to turn off the snap to grid feature.

2. Zoom in on the drawing by 20%. Click on the Zoom In button on the Toolbar,select Zoom In from the View menu, or press the Ctrl and Plus (+) keys on thekeyboard, twice, to increase the view by 20%.

3. Select Move from the Modify menu, or from the Modify Toolbar.

4. Select the ITK text. Press Enter when you are finished.

5. Press Enter again to select the geometric center of the text. A dashed image ofthe text appears.

6. Click the Type button. The Enter Point dialog box appears.


7. Enter an X value of 0.969 and a Y value of 1.000. Click on OK or press Enter.

spectraCAD moves the text block to the new location.

8. Select Zoom All to view the entire drawing again.


Task 9-6 Explode the Text

Use the Explode command under the Modify Menu to break, or explode, a polyline ora text block into lines and arcs. Exploding a polyline is the only way you can modify itssegments individually or move them to separate layers.

Text is exploded into lines only. Exploding text is the only way you can modify the linesindividually, or engrave text using a CAM program.

Exploded lines and arcs are placed on the same layer as the original entity.

1. Click the Explode button on the Modify Tool Bar, or select Explode from theModify Menu.

2. Select the ITK text to explode. The text is broken into lines and arcs.

When you complete this step, your picture should look like the one below.

Task 9-7 Rotate the Text

Use the Rotate command under the Modify Menu to change the orientation of one ormore entities.

Entities are rotated about a rotation base point, which can be anywhere in the drawing.By picking the entity's center point as the rotation base point, you just rotate the entity.Its angle changes, but its center point does not move.

By picking any other point as the rotation base point, you rotate and move the entity.The angle of the entity changes, and its center point rotates about the rotation base point.

The rotation angle is the angle by which the entity rotates about the rotation base point.


1. Click the Rotate button on the Modify Tool Bar, or select Rotate from theModify Menu.

2. Select the ITK text to rotate. You need to select each entity of the ITK textblock individually by holding down the Shift key while clicking on the entities.Press Enter when finished.

3. Pressing Enter again picks the geometric center of the text as the rotation basepoint.

An image of the selected entities appears. Moving the cursor rotates the imageabout the rotation base point. The Status Bar displays the current rotation angle.

4. Click on the Type button.

The Enter Rotation Angle dialog box appears.

5. Enter -90 as the rotation angle. Click on OK.

spectraCAD rotates the text -90 degrees.

When you have completed this step, your completed spectraCAD drawing should looklike the one below.

Save the Drawing




Q Entities are moved with respect to what two points?

Q Why do you have to explode text in spectraCAD?

Q What is the advantage of picking an entity's center point as the rotation basepoint?

Q What is a rotation angle?










Activity 10

spectraCAD Engraver

Objectives


w Edit and define the Engraver stock, tooling, and material

w Select a post processor

w Add text and select a font style

w Insert the text into the drawing

Skills





w Interpersonal: Participate as a member of a work team and provide assistanceto members of your own and other teams





Materials



w Worksheets for Activity Ten


Overview Engraving Text

In this section we will be using the Engraver feature of spectraCAD. You will be pro-ducing a nameplate using this program. The difference between the spectraCAD En-graver and a plain CAD program is that the Engraver allows you to not only producethe drawing for the product, but to also create the NC code that the milling machinereads to cut the final product.

Engraving is a simpler version of Milling. It uses the same machine, tools, and codes,but does not include some of the more advanced operations. Engraving usually uses ahigher spindle speed, a lower cutting force, and shallower cuts resulting in less materialbeing removed from the workpiece. Most engraving is done as outlines of drawings, oras text.

The first step is, as always, to start spectraCAD Engraver, and create a new file. Oncewe have done that we can begin the process of designing your nameplate.

Procedures

Task 10-1 Start spectraCAD Engraver

Before you begin drawing, you have to start spectraCAD and create a new drawing.Start the Control Program:


From Windows 95:







Create the Engraver File and Set Parameters

In previous CAD exercises, you have opened a new file, started drawing, and thensaved it under a new name. In those cases, the default stock size was fine. However, thenameplate stock as a different size and shape. We must create the new stock size beforebeginning so that the drawing is accurate.

Task 10-2 Open the Engraving Setup Screen

1. Click the Setup button on the Engrave Tool Bar, or select Engraving Setupfrom the Engraving Menu.

2. The six Engraving Setup panels appear. These panels allow you to create or editsettings for materials, tools, and files that are used by the program when an en-graving NC file is generated.

Task 10-3 Select the Material

1. Select the Edit Material Panel, if it is not already selected.

The Edit Material Panel provides you with a means of selecting a material type.When you select a material from the list of materials, default cutting speed val-ues are displayed for High Speed Steel and Carbide tools. The Advance PerTooth default value is also displayed.

2. Since the nameplate stock is made of plastic, and there is no plastic listed in theMaterials list, we will have to create it. Start by highlighting Machinable Wax inthe library list.

3. Click the New button. “Undefined Material” appears in the library list and theName field.


4. Type “Plastic” over “Undefined Material” in the Name field.

5. The values for plastic are the same as machinable wax, so you do not have tochange the cutting speed or the advance per tooth values.

Task 10-4 Define the Tool

Before you can engrave, you must define the tool you wish to use. You may use one ofthe existing tools from the Tool Library list, or you can create a new tool for your pur-poses. For this project we will be using an 1/8” End Mill. Although this tool is alreadydefined in the library, we will create another one to understand the steps involved.

1. Click on the Tool Library tab. The Tool Library Panel appears.

2. In the Tool Library scroll box, scroll down to Tool 2, which is undefined at thispoint. Highlight Tool 2 by clicking on it with your mouse.

3. In the Tool Type pull-down list, select End Mill.

4. Enter "End Mill" in the Description box.

5. Enter 0.125 in the Diameter box.

6. Click on the Apply button. You have just defined a new tool in the library. Nowwhenever you need an 1/8" HSS end mill, it will be there.

7. Click on OK to exit the Tool Library.


Task 10-5 Select the Post Processor

The post processor file allows spectraCAD Engraver to generate NC code for differentmachines. Since different machines have different operating parameters, it is importantto match the right files with the right machines. For example, the maximum spindlespeed on a Light Machines VMC-5000 (post file plm5000.PST) is much higher than thespindle speed on a spectraLIGHT (post file SPECTRA.PST), as is the travel distance oneach of the 3 axes. Details such as these can be very important in the code generation.

To select a post processor file:

1. Select the Post Processor tab. The Post Processor list appears.

2. Click on the SPECTRA.PST post processor file in the Posts list.


Task 10-6 Change the Stock Dimensions

Since our nameplate stock is different than the default stock size, we will have tochange the stock dimensions.

1. Click on the Stock Size tab.

2. Enter the following values in the X, Y, and Z Dimension fields:X: 8”Y: 1.5”Z: 0.0625”

The default origin of the stock is X0Y0Z0, the top, front, left corner of thestock. That will not change in this exercise.

3. Click on OK to accept all the changes you have made to the Engraver file. Thedialog box will disappear, and the stock outline will change on the drawing area.

4. Select Zoom All from the View Menu to see the entire stock outline.


Task 10-7 Draw the Text

Now that you have the file set up you can create the text to engrave. For this project,you will use your name as the text. You can use your first name, last name, or both. Theonly limitation is that it must fit on the 8 inch long stock.

1. Click the Text button on the Draw Tool Bar, or select the Text command fromthe Draw Menu. The Enter Text dialog box appears.

2. Enter the text in the Enter Text dialog box.

3. If you wish to use a font other than the default font, click the Font button andselect a new font. The font is the way the letters are written. They can be fancyor plain. The CAD Engraver Font dialog box appears.

By default, the font is a simple stroke font; the letters are made up of singularcenterlines, not outlines. You can engrave outline fonts by selecting the TrueType button. If you choose an outline font, the final product will only have theoutline of the letters engraved.


Select a font, if desired, then click on OK . The Enter Text dialog box reappears.Click on the OK button to return to the Drawing Area.

4. Click on the Type button. The Enter Coordinates box appears.

5. Enter the point 0.25, 0.25 in the box and click on OK. This is the insertion pointfor the lower left corner of the text.

6. Click on the Type button again. Enter 1 for the text height, and click OK. Thetext appears in the drawing area on the nameplate.

Your drawing should resemble the one shown below.


Task 10-8 Save the File

Finally, save your drawing. You should save your drawings frequently, so you don'tlose your work.

1. Click the Save button on the toolbar, select Save from the File Menu, or pressCtrl +S. The File Save As dialog box appears.


3. Type the name, Name.dxf, into the File Name field.



Q What is Engraving?

Q What is the difference between spectraCAD Engraver and a plain CAD program?

Q What do the Engraving Setup panels allow you to do?

Q What is the purpose of the post processor file?











Activity 11

Generating an NC File

Objectives


w Select geometry to be engraved

w Set cutting parameters

w Review the engraving Job Summary

w Generate the NC file to be used by the mill to engrave the name plate

Skills










Materials



w Worksheets for Activity Eleven


Overview Generating the NC file

Now that you have created the text and laid out the parameters for your nameplate, youhave to generate the NC code the milling machine will read when it cuts the nameplate.There are another series of steps to prepare for this operation. The spectraCAD pro-gram will walk you through them, but the first step is to select the Engrave Command.

When you select the Engrave command from the Engraving Menu, the first of a seriesof several dialog boxes appears. These dialog boxes guide you through the process ofgenerating an NC part program for engraving. The dialog boxes appear in the followingorder:

u Select Geometry

u Select Cutting Parameters

u Engraving Job Summary

u Generate NC File

Procedures


Start the Control Program:


From Windows 95:




w When spectraCAD is up and running, open your Name.dxf file.


Task 11-2 Select the Geometry

Select the Engrave command from the Engraving Menu. The Select Geometry dialogbox appears as the first in the series. This box allows you to select and name the text inthe current drawing for engraving.

1. Click on the Toolpath Name box. Naming the toolpath is for reference only. Ifyou were engraving text and a small graphic, for example, you might name thetoolpaths Text, and Graphic.

The text is selected as one entity, so we will call the toolpath Toolpath #1.

2. Choose a geometry selection method. If there were multiple entities in yourdrawing, you could select them separately, and give each a name.

Use the Mouse to Select allows you to manually pick out particular geometries.

Select All Geometry and Text selects every entity in the drawing.

Select remaining Geometry and Text selects any entities that remainunselected.

Click on Select All Geometry and Text.

3. Click on the Do Selection button.

4. Click the Next button.


Task 11-3 Select the Cutting Parameters

The next box to appear is the Select Cutting Parameters dialog box. Here you enter theparameters for the cutting method, the feed rate and the spindle speed.

Cutting Method

u Final Depth is the finished depth of the engraving. Enter -0.020 for the finaldepth.

u Depth Increment is the depth of each step required to reach the final depth.Because the plastic you are cutting is soft, the full cut can be made in a singlepass. If you were engraving a harder material, such as steel, multiple passeswould be necessary to reach the desired depth. In that case a depth incrementwould be necessary.

Enter 0.020 for the Depth Increment.

u Rapid Height is the height to which the cutting tool moves just prior to a rapidtraverse motion. If you were engraving on a surface that had been machined todifferent heights and contours, it would be necessary to raise the tool up abovethe highest level on the workpiece before moving the tool. This would avoid atool crash, which could damage the tool, the workpiece, or the machine.

Since you are engraving on a flat surface, a safe height here is 0.7.

u Top of Stock Z is the location of the stock surface on the Z axis, usually a valueof zero.


u When Finish Pass is selected (a check mark appears) the machine will performa finish pass after the engraving is complete. This is not usually necessary in en-graving, unless you are roughing out the engraving first and want to make a fi-nal pass to smooth out any rough areas. Leave this box unchecked.

u The Tool box is used to select a cutting tool from the tool library. Tool #1, the1/8” end mill (0.125”), should be selected. If it is not, select it now.

Feeds and Speeds

These values are automatically set by the program, based on the information about thestock and the cutting tool. You should not have to change any of these values. Readthrough the following explanations before continuing.

Select the Next button when you have finished specifying the Cutting Parameters.

u The Feed Rate is the speed at which the cutting tool moves into the workpiece.The feed rate is based on the type of cutting tool being used and the stock mate-rial being cut.

u The Spindle Speed is the rate at which the spindle turns, measured in RPM.The spindle speed depends on the post processor selected during EngravingSetup. If you enter a speed that is too high or too low, an error message appearsinforming you of the correct speed range.

u The Plunge Rate is the speed at which the tool plunges into the workpiece.

u When checked, the Automatic setting automatically calculates the feed rate andspindle speed based on the tool, material and post processor selected during En-graving Setup.

u The Material is selected during Engraving Setup.

u Acc#1 and Acc#2 to turn outputs on and off (a checkmark appears). These areused when the NC program is used with robotics.

u The current measurement mode is displayed underneath Acc#2.


Task 11-4 View the Engraving Job Summary

The Job Summary dialog box allows you to view and verify all the information aboutyour toolpaths before it creates the NC code.

Select Toolpath #1 (if it is not already selected) and view the assigned parameters.

If you were generating multiple toolpaths, clicking on the New button would bring youback to the Select Geometry dialog box where you can name a new tool path, and beginassigning new parameters.

Click on the Next button to continue.


Task 11-5 Generate NC File

The final dialog box is used to create an NC part program file based on the geometryand parameters you set up in the previous dialog boxes.

1. Your file name, Name.NC, should be displayed in the NC Output File window.

2. Enter the name that is being engraved in the Job Description field.

3. Verify that the post processor file displayed in the Machine field is the correctone.

4. Click on the Finish button to select the location for the Name.NC file. Youshould save the file to your directory on the hard drive or to a floppy disk.

5. Click on Save, or press Enter on the keyboard. The program will generate theNC file and exit the dialog box.



Q Why would you need to set a Rapid Height?

Q What happens if a spindle speed that is too high or low is selected?










Activity 12

NC Files and Coding

Objectives


w View your own NC file

w Define NC code

w Understand how NC code works

w Learn how to read NC code

Skills










Materials



w Worksheets for Activity Twelve


Overview

In the last activity, you generated an NC file based on your nameplate CAD drawing. Inthis activity you will look at that file, and learn more about what makes up an NC file,what NC coding is, and how it works. By the time you complete this activity, some ofwhat you see in your Name.NC file may actually make sense to you.

Procedures


Start the Control Program:


From Windows 95:




Task 12-2 View the NC Part Program

Once an NC part program has been generated, you can view it by selecting the ViewNC File command from the Engraving Menu.

Included at the beginning of the program file are comments that reflect the engravingsetup data, such as the machining center (the post processor used), the selected tool andmaterial, the material size and origin, and the unit of measure used for the project. Youwill also notice that the description you entered in Task 11-5 is at the top of the file.


As you read through the information in the rest of this activity, refer back to your fileto see the blocks of code and different commands that make up an NC program.

What is NC Programming?

Before a part is machined, every step in the machining process must be described in apart program . The program, or list of instructions, is written in a language that can beunderstood by many CNC machine tools. The language is called the EIA RS-274Dstandard format, or G&M code programming.

In this module, you will learn how to write NC words using EIA RS-274D codes, andhow to combine the codes to form an NC part program.

This is a typical block of NC code.

N5G90G01X2Y3Z2

These are the individual NC words that make up the block.

N5 G90 G01 X2 Y3 Z2


Elements of a Part Program

Part programs use two types of instructions: those that define the tool path (such as Xand Y axis coordinates), and those that specify machine operations (such as turning thespindle on or off).

An NC part program is made up of blocks (lines) of code. Each code block contains astring of words. An NC word is made up of an alphabetic character (the address char-acter) and a number (the parameter). For example, the coordinate X2 has the addresscharacter “X” and the parameter “2.”

The address characters you will use for your NC part programs are N, G, X, Y, Z, I, J,K, F, S, T, M, and the semicolon (;).

The character “N” is used in words that number the blocks of code in your program.For instance, the first block in a program begins with the word N0. The next block be-gins with N1. The next blocks are N2, N3, N4 and so on. The N word is always the firstword in each block.

The character “G” is used to create preparatory codes. Preparatory codes tell the ma-chining center what kind of cut to make and which programming mode to use. G wordsare always written before any instructions that tell the machining center to move the tool.

The character “X” is used to tell the tool where to move to (absolute) or how far tomove (incremental) on the X axis. If you are working in absolute programming mode,the word X2 tells the Machining Center to move the tool to the coordinate X2. In incre-mental programming mode, the tool would move 2 units from its current position.

The character “Y” is used to tell the tool where to move to (absolute) or how far tomove (incremental) on the Y axis.

The character “Z” is used to tell the tool where to move to (absolute) or how far tomove (incremental) on the Z axis.

I , J and K words tell the tool the X, Y and Z coordinates of the center point of an arc(for circular interpolation). In absolute programming, I words represent the X coordi-nate, J words represent the Y coordinate and the K words represent the Z coordinate.In incremental programming, the I, J and K words specify the distance from the startpoint to the center point of the arc.

The character “F” is used in words that tell the tool what feed rate to use to move thetool into the workpiece. The parameter represents the rate of speed in inches perminute. For instance, the word F2 means to move the tool into the workpiece at a rateof two inches per minute.


The character “S” is used in words to specify spindle rotation speed. The parameter de-fines the speed at which the spindle rotates in revolutions per minute (RPM).

The character “T” is used in words that define the tool, if more than one tool is used.The parameter in the T word is the number assigned to the tool. For instance, tool #1(T1) can be an 1/8" end mill, while tool #2 (T2) is a 1/4" end mill.

The character “S” is used in words to represent miscellaneous machine operations.These operations vary from turning the spindle on and off (M03 and M05), to repeatingthe NC program (M47).

A semicolon ( ; ), or comment code, allows you to attach comments, or reminders, toeach block of code. These reminders usually contain information about the words in theblock. For instance, the comment in this block N2M03;TURN SPINDLE ON tells you ex-actly what the function of the block is. Any characters that appear after a comment codeare not acted upon by the Machining Center.

Here is another example:

N5G90G01X2Y3F2; GO TO START POINT AT 2 IPM

Any text following the semicolon is a comment, and has to be on the same line as thesemicolon.

Some NC words are used more often in part programs than others. Here are some ofthe more common NC words you should know. The G codes are broken into severalgroups.

G CODES

G00 Rapid Traverse: Move rapidly to the indicated position. Rapid traverse mo-tion does not necessarily mean the tool moves in a straight line.

G01 Linear Interpolation: Move in straight lines.

G02 Circular Interpolation, Clockwise: Move the tool in an arc in a clockwisedirection.

G03 Circular Interpolation, Counterclockwise: Move the tool in an arc in acounterclockwise direction.

G04 Dwell (wait): A timed pause equalling the feed rate value in seconds.

G05 Pause: Pause until the Return key is pressed. You can also use M00.

G90 Absolute Coordinates: Move the tool to the place in the program definedby X, Y or Z.

G91 Incremental Coordinates: Move the tool the distance defined by X, Y andZ in the program.


M CODES

M00 Pause: Pause until the Return key is pressed. You can also use G05.

M02 End of Program: This is the last instruction in the program.

M03 Spindle On: Turns on spindle motor.

M05 Spindle Off: Turns off spindle motor.

M06 Tool Change: Pauses all operations, turns off spindle, retracts spindle fortool change.

M47 Rewind: Repeats the program. If rewind is used, you must place a G05 orM00 pause at the beginning of the program.

New Terms

Address Character - An alphabetic character representing a command in an NCword.

EIA RS-274D Standard Format - A standard for NC programming established in1979 by the Electronics Industries Association, also called G&M code program-ming.

Block - A word or group of words making up one line of an NC program.

Code - In NC programming, the same as a word, typically used for G and M words,also a general term for a set of programming instructions.

Parameter - Numbers that describe movement or distance, and are used with an ad-dress character command in an NC word.

Part Program - A list of numerically coded instructions.

Preparatory Code - NC words (G address character plus a parameter) that tell themachine tool what type of interpolation and programming mode to use.

Word - The combination of an address character (the command) and a parameter (thedistance or movement).


Task 12-3 Questions

Use the Activity 12 Worksheet and answer the following questions.

1. What is a part program?

2. What are the two parts of an NC word?

3. Here are some new terms you learned in this module. Write a brief definition ofeach term.

Code-

Address Character-

Word-

EIA RS-274D Standard Format-

Parameter-

Block-

Preparatory Code-

4. Match the NC words in the first column to their correct meaning in the secondcolumn.

_____M02 a. Move the tool to 2.5 on the X axis (absolute)

_____G90 b. Move the tool to .25 on the Z axis (absolute)

_____T1 c. Move the tool rapidly to the indicated position

_____J.5 d. Make the center point of the arc .15 on the X axis

_____G00 e. Use clockwise circular interpolation

_____X2.5 f. End of program

_____N12 g. Turn off the spindle motor

____G02 h. Make the center point of the arc .5 on the Y axis

_____F1 i. Use incremental coordinates

_____Z.25 j. Use absolute coordinates

_____I.15 k. Move the tool at a feed rate of one inch per minute

_____M05 l. This is the block marked number twelve

_____G91 m. Use tool #1



Q Does the code in the program make more sense to you than it did before?

Q Pick out specific blocks of instruction, such as starting and stopping the spindle.

Q What is the programmed feed rate? Spindle speed?










Activity 13

Pocketing

Objectives


w Draw and create pockets for two entities

w Use the Measure function

w Use the Offset function

Skills










Materials



w Worksheets for Activity Thirteen


Overview

This Activity is the final project the spectraCAM Activity Guide. During this projectyou will create a pocketing operation for the Engraver program. When you are done,your NC program will cut two pockets in a 3x2 workpiece. Pocketing operations re-move all the material within a closed boundary defined by CAD geometry. Geometry isclosed if the start point and end point connect to form a completed path, such as a rect-angle or circle.

By using the Offset and Engrave functions you will create toolpaths manually. Thetoolpaths are the motions the mill makes to remove material from a workpiece during amilling operation. The manual creation of the toolpaths will give you an idea of whatCAM (Computer Assisted Manufacturing) does automatically.

Below is a picture of the dxf file you will create.


Procedures



From Windows 95:






The stock outline shown may be the nameplate stock you used in the previous activity.You may want to change tis for this project.

1. Select Engraving Setup from the Engrave Menu, or click on the EngravingSetup button on the toolbar.

2. When the dialog box appears, select the Stock Size Tab, and set the size toX=3, Y=2, and Z=1.5.

3. Click on OK to accept the changes.

4. When the drawing area reappears, select Zoom All from the view menu to get abetter view of the drawing area.

Task 13-2 Draw the Rectangle

Before you begin drawing, verify that the coordinate system is set to Absolute. If it isnot, click on the Coordinate Type button until Absolute is selected.

1. Click on the Rectangle button on the toolbar, or select Rectangle from theDraw menu.

2. Start the rectangle at the point 0.250,0.50. Move the cursor to the point2.50,1.50 and click to complete the rectangle.

3. Press Escape to end the rectangle operation.


Task 13-3 Rotate the Rectangle

1. Select Rotate from the Modify menu, or click the Rotate button on the toolbar.

2. Select the rectangle as the entity to rotate and press enter.

3. Select the point (0.25,0.625) as the rotation base point.

4. Click on the Type button to set the rotation angle.

5. Enter 15 degrees as the angle, and click OK.

6. The rectangle rotates 15 degrees.

Task 13-4 Draw the Circle

1. Click on the Circle button on the toolbar, or select Circle from the Draw menu.

2. Click on the Type button, and enter the points (2.375, .625).

3. Click on the Type button again to set the radius, and enter .375.

4. The circle appears at the bottom right corner of the drawing.


Task 13-5 Save your Drawing

1. Click the Save button on the toolbar, select Save from the File Menu, or pressCtrl +S. Because this is a new file, the File Save As dialog box appears.


3. Type the name, Pockets.dxf, into the File Name field.


Task 13-6 Toolpaths, Geometry, and Offsets

When you are designing a part, you design it to be a specific size. The geometry of thedrawing is the outer boundary, and is not part of a toolpath. In order to preserve the ge-ometry as the outer boundary, we must create toolpaths within the geometry. Thetoolpaths must be offset from the outer boundary, and from each other. The offset valuewill be a fraction of the width of the cutting tool used.

In spectraCAD Engraver, the toolpaths are always the centerline of the cutting tool.

Q If we are cutting a centerline toolpath, what value of the tool will be our offsetvalue?

Q We will be using a 0.125” end mill for this project. What is the actual offsetvalue we will use when creating the toolpaths?


Task 13-7 Offset the Entities

The next step is to generate what will become the toolpaths for the pocket operation.Because we want to remove all the material within each entity, the toolpaths must beclose together. The easiest way to do this is by offsetting each entity towards the center.The offset value will be the radius of the cutter, to ensure that no material is missed.

1. Click the Offset button on the Modify Toolbar, or select Offset from theModify Menu.

2. Select the Type button to set the offset distance. The Enter Offset Distance boxappears.

3. The cutter we are using is an 0.125” end mill, so we need to enter an offsetvalue equal to the cutter radius. This will cause an overlap on each cut of.0625”, and remove all the necessary material. Enter an offset value of .0625”,and press OK .

4. Select the rectangle as the first entity to offset.

5. Click the mouse inside the rectangle as the offset side.

6. A new rectangle appears inside the original, offset by .0625”.

7. Select the rectangle you just created as the next entity to be offset, and click in-side it.

8. Repeat this operation until you can not create another offset inside the rect-angle.

9. Select the circle as the next entity to offset.

10. Repeat steps 5-8 until you can not create another offset inside the circle.

11. Press Escape to end the offset operation.

12. Save your file.



Q What is Pocketing?

Q What is a toolpath?


To exit spectraCAD, select Exit from the File menu, or press Alt+F4 . If there are un-saved changes to the current drawing, the dialog box appears.









Activity 14

Pocket Toolpaths and spectraCAM

Objectives

In this activity you will accomplish the following:

w Generate Toolpaths for a pocketing operation

w Set up spectraCAD Engraver to generate an NC file

w Learn how spectraCAM automates toolpath generation

Skills










Materials



w Worksheets for Activity Fourteen


Overview

In this activity, you will set up spectraCAD Engraver to generate the toolpaths and theNC file that the mill will use to cut the pockets. Once you have done that, you will viewthe NC file, and identify the beginning of the toolpaths. Then, when all your hard workis done, you will learn about how CAM can generate all those tool paths automatically.

Procedures



From Windows 95:




w When spectraCAD Engraver is up and running, open your pockets.dxf file.

Task 14-2 Engraving Setup

Before you can generate the toolpaths and NC file, you will need to verify settings inthe Engraving Setup screens.

1. Select Engraving Setup from the Engrave Menu, or click on the EngravingSetup button on the toolbar.

2. When the dialog box appears, select the Edit Materials tab.

3. Select machinable wax as the current material.


4. Click on the Tool Library tab. Verify that Tool 1 is an .125” end mill.

5. Click on the Post Processor tab. Select SPECTRA.PST as the post processor file.

6. Click on the Stock size tab, and verify that you are machining a 3”x2”x1.5”workpiece. This setting should not have changed since it was set in activity 13.

7. Select OK to save settings, and exit the dialog.

Task 14-3 Create Toolpaths and Generate NC Code

1. Select Engrave from the Engrave menu.

2. The select Geometry window appears.

3. Choose “Use mouse to select geometry” and click on the Do it Now button.


4. In the Drawing Area, use the mouse to select the first offset rectangle asToolpath #1. Remember, do not select the outer geometry of the rectangle asthe first toolpath. Press the Enter button on the keyboard or click the rightmouse button.

5. When the Select Geometry window reappears, click on Next.

6. In the Select Cutting Parameters window, set the following parameters:

Final depth -0.1Depth Increment .05Rapid Height .7Top of stock Z 0

7. The Tool should be Tool #1. All other settings should match those shown here.


9. Toolpath 2 should be highlighted. Follow steps 3-8 and repeat until all toolpathsare assigned a separate number.

Again, remember not to select the outer geometry of the circle as a tool path!

There should be 8 different toolpaths when completed. When you have all 8toolpaths set up, click the next button.

10. The generate NC File window appears. If you wish, enter a message in the de-scription field, and click on Finish.

8. Click on the Next button, and in the Engraving Job summary, Toolpath #1should be highlighted. Click on New, and return to the Select Geometry screen.


Task 14-5 View the NC File

1. From the same Engraving Menu, select View NC File. The Pocket.NC file ap-pears on the screen.

2. Based on what you have learned about NC files, you should be able to answerthe following questions.

Q What line is the header for Toolpath #1 on?

Q On line N12, what are the plunge depth, and the feed rate?

Q What are the X and Y coordinates for the start point of Toolpath #2?

When you have finished the questions close the Pocket.NC file.










Academics CAM and spectraCAM

The generation of NC code with the CAD Engraver program is a simple form of CAM(Computer Aided Manufacturing). More sophisticated programs exist to make the jobof the design engineer easier. For example, spectraCAM would take the outside borderof a pocket and automatically generate the pocketing toolpaths using the correct offsetfor the tool diameter. You would have to provide some of the same information thatyou gave the Engraver program, such as tool type, material type, feed rates, spindlespeeds, and cut depths. spectraCAM then creates the NC program necessary to cut apocket from your workpiece.

It is not limited just to pocketing operations. CAM provides all the necessary tools tomove your design from the drawing board into the machining stage, and is a necessarystep for anyone making complex parts on a mill.



Activity 15

Conclusion

Objectives

In this activity you will accomplish the following:

w Measure your knowledge of CAD and spectraCAD Engraver

w Complete the Post Test

Skills

In this activity you will exercise the following skills:









Materials


w spectraCAD Engraver Post Test

w Answer Sheet fot the test


Overview

This activity concludes the spectraCAD Engraver module. The test you will now takewill measure your knowledge and skills with CAD and spectraCAD Engraver.

Take the test according to your teachers instructions. Allow 30 minutes for the test.When you have completed the test, return it to your instructor.

Date post:	24-Apr-2015
Category:	Documents
Upload:	jason-douglas
View:	145 times
Download:	21 times

Engraving) SG

Documents