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Wind sculpture Pro|ENGINEER - Wildfire 3.0 Schools Edition and Schools Advanced Edition

W3-SE-L1-002-1.4

Pro|ENGINEER Wildfire 3 Wind sculpture

PTC – www.ptc.com 2 of 54

Written by Tim Brotherhood

These materials are © 2006, 2007 Parametric Technology Corporation (PTC)

All rights reserved under copyright laws of the United Kingdom, United States and other countries.

PTC, the PTC Logo, Pro|ENGINEER, Pro|DESKTOP, Wildfire, Windchill, and all PTC product names and logos are trademarks or registered trademarks of PTC and/or its subsidiaries in the United States and in other countries.

Conditions of use Copying and use of these materials is authorised only in the schools colleges and universities of teachers who are authorised to teach Pro|ENGINEER in the classroom.

All other use is prohibited unless written permission is obtained from the copyright holder.

Acknowledgements PTC - Mike Brown, Mark Fischer Proofing and comments – John Forth, John Myerson, Andrew Dissington D&T Association – Richard Green and Kate Lamping Trialing materials – UK Pilot schools & Support centres

Feedback

[email protected]

In order to ensure these materials are of the highest quality, users are asked to report errors to the author.

Suggestions for improvements and other activities would also be very welcome.

Product code W3-SE-L1-002-1.4



Contents Wind sculpture ................................................................................................. 1

Pro|ENGINEER - Wildfire 3.0 Schools Edition and Schools Advanced Edition1

Contents .......................................................................................................... 3

Module Outline................................................................................................. 5

Module objectives.......................................................................................... 5

Background...................................................................................................... 6

Session one - Product analysis and design ............................................................ 7

Session two – Cam mechanism assembly ............................................................. 8

Session three – Assembly of parts - CAD .............................................................. 9

Task one - Getting started................................................................................ 9

Task two - Adding a component..................................................................... 12

Task three - Assembling components............................................................... 15

Task four - Kinematic movement ..................................................................... 19

Task five - Assemble fan components .............................................................. 20

Task six - Assemble follower .......................................................................... 24

What have you learned? .............................................................................. 27

Session four – Other cam shapes ...................................................................... 27

Session five – Cam connection and kinematics.................................................... 28

Task one - Cam connection ........................................................................... 29

Task two - Test the mechanism ....................................................................... 33


Session six – New CAD part............................................................................. 35

Task one - Starting a new design.................................................................... 35

Task two - Sketching a profile ........................................................................ 39


Session seven – Own design - workshop ............................................................ 46

Session eight – Own CAD design...................................................................... 47

Session nine – Final assembly - CAD.................................................................. 48

Task one - Getting started.............................................................................. 48

Task two - Adding a component..................................................................... 49

What have you learned this session................................................................ 51



Session ten – Final assembly and testing – workshop ........................................... 51

Session eleven – Consolidation and extension..................................................... 52

Session twelve – Student presentations ............................................................... 52

Module review ............................................................................................ 53

Extension activities .......................................................................................... 54



Module Outline

Within the context of a wind operated sculpture, this material teaches you how to use Pro|ENGINEER to assemble components with constraints and mechanical connections. The finished model can be operated kinematically by dragging on screen.

With basic hand tools and brazing/welding equipment the design could easily be manufactured using sheet metal and used outdoors.

Module objectives

By the end of this module you should:

Be aware:

• physical and virtual 3D modelling techniques

• simple cam mechanisms and toys that use them

• the concepts of 3D parametric solid modelling using Pro|ENGINEER

• the kinematic simulation capabilities of Pro|ENGINEER

Understand:

• the principles of 3D parametric solid modelling and mechanical simulation using Pro|ENGINEER

• how 3D solid modelling software be used to refine designs including parts, assemblies and mechanisms.

• the concepts behind simple cam mechanisms

Be able to:

• use simple workshop techniques to assemble parts into a working mechanism

• use Pro|ENGINEER to assemble parts into a working mechanism

• use Pro|ENGINEER to create a new component using sketching and extrude



Background

Wind vanes have been used over the centuries to show people which direction the wind is coming from.

Before radio and television weather forecasts this was very important for anyone working outside.

Image courtesy Paul Margetts. http://www.forging-ahead.co.uk/weather1.htm

Designs for wind vanes have developed over the years and now come in a bewildering range of shapes and sizes.


This one was designed and manufactured by Paul Margetts based on ideas from children in a Staffordshire, UK primary school.




Sample files

You will need a set of sample files to carry out this activity. Your teacher will show you how to copy these into your working area.

Session one - Product analysis and design

Focus

This session introduces the challenge and involves you in product analysis of automata and toys from a variety of sources including toy stores, and promotional items from burger outlets, etc.

For homework you are asked to generate ideas for your model that will sit on top of the cam mechanism.

Learning objectives


Be aware of:

• the range of mechanical toys available.

Understand:

• the mechanical principles used in toys to create movement.

Be able to:

• evaluate existing products to identify the mechanism and how this is used to create movement in the design.

• suggest alternative designs they could make in school.

Homework

Carry out investigations of black box mechanisms using Pro|DESKTOP. Your teacher will provide 3D models, guidance and worksheets. These can also be downloaded from Teachernet at:

http://www.teachernet.gov.uk/supportpack/module.aspx?t=2&s=5&m=21377&n=285749&b=482575



Session two – Cam mechanism assembly

Focus

This session introduces the challenge and involves you in product analysis of automata and toys from a variety of sources including toy stores, and promotional items from burger outlets, etc.

For homework you are asked to generate ideas for your model that will sit on top of the cam mechanism.

Useful web sites

Useful resources for this activity include:

Technology Student www.technologystudent.com Theory and design

Focus on mechanical toys

www.focuseducational.co.uk Theory, design and ideas

Cabaret mechanical theatre

www.cabaret.co.uk Examples and ideas

Flying pig! http://www.flying-pig.co.uk/ Examples and ideas

Learning objectives

By the end of this session students should:

Be aware of:

• the range of mechanical toys available.

Understand:

• the mechanical principles used in toys to create movement.

Be able to:

• evaluate existing products to identify the mechanism and how this is used to create movement in the design.

• suggest alternative designs they could make in school.



Session three – Assembly of parts - CAD

Aim

During this session you will learn how to use Pro|ENGINEER to assemble the parts for a wind operated mechanism.

Learning objectives

By the end of the session you should:

Be aware of

• overall concepts and brief history of CADCAM.

• how 3D parametric solid modelling software can create multi-part assemblies

Understand

• the procedures necessary for assembly in Pro|ENGINEER

• how using 3D modelling software can help designers and engineers try out ideas and refine the detailed design of products

Be able to

• assemble components using insert, mate and align constraints in Pro|ENGINEER.

• Create mechanical connections including pin, slider and cam

Task one - Getting started

1. Start the Pro|ENGINEER program.

The Pro|ENGINEER screen

As you work through this tutorial you will soon become familiar with the Pro|ENGINEER screen, menus, dashboard and dialog windows.

It is worth having the Pro|ENGINEER Quick Reference Card available as a reminder of the key functions, toolbars and techniques.



Note: In Pro|DESKTOP the left panel is usually referred to as the ‘Browser’ window. Pro|ENGINEER uses this term for the embedded web browser. For this reason the left panel in Pro|ENGINEER is called the ‘Navigator’ window. It can present several different views

Folder Navigator

Model tree Navigator

The other two tabs will not be used in this tutorial.

Tip: Don’t be tempted to maximise the Pro|ENGINEER window. There should be a gap down the right hand side of the window where dialogs will appear.

Set working directory

Pro|ENGINEER designs are made p of many different files including configurations, parts, assemblies, drawings and the results of analyses and simulations. To help manage all these different files you need to tell Pro|ENGINEER where existing files for a project are stored. Any new files will then be saved automatically in the Working Directory.



2. The Navigator window on the left of the screen should be displaying folders.

3. Browse to the folder you will be saving your work in and where the sample files have been saved. Your teacher will tell you where this is.

4. Right click over the folder and from the floating menu select Set Working Directory.

Opening a file

5. In the Navigator – folder view window select the folder where the sample files are stored for this tutorial.

The browser window will display a list of files.

6. Locate and click on the file named WIND_SCULPTURE.ASM

The model will preview in the top of the browser window

7. Click on , the Open File… button.

The browser window will close and the assembly will appear in the graphics window. On your screen you may see a clutter of brown lines. These are datum planes and datum axes and the display of these can be toggled on/off.

8. In the main toolbar find the datum

tools then click on each one until the model is clearly visible.



Task two - Adding a component

To get you started, the assembly has all the components needed with the exception of a base. This will be added first.

1. In the Feature Creation toolbar on the right of the screen there are two tools for assembly.

2. Click on , the Add Component tool.

The Open dialog will display the files contained in the ‘default’ directory set earlier.

3. Select the file named base.prt then

click on .

The base component will appear coloured yellow in the graphics window and the assembly Dashboard will open at the bottom of the screen.



The dashboard is unique to Pro|ENGINEER and a very clever way of organising options in a logical way that would require complex menus or dialogs.

This dashboard is waiting for you to tell Pro|ENGINEER where the base component should be placed. You will use fix which anchors the component at the current position.

4. In the dashboard, open the list that currently shows Automatic and select Fix.

5. The status line in the dashboard will now report - STATUS: Fully Constrained.

6. In the dashboard click on to complete placement of the base.

The dashboard will close.

The rest of the components now need assembling to the base but first some background information.

Parent child relationships

Model tree

Look at the model tree in the navigator window. Each entry represents an element of the model

• Assembly

• Datum plane

• Coordinate system

• Sub-assembly

• Part

The concept of parent child relationships is fundamental to Pro|ENGINEER. Almost every action relies on previous actions. This may be drawing geometry, features or components. A good example is a rounded edge. The edge came before the round and the round relies on the edge existing.

If the feature that created the edge is deleted the round will also be deleted.



The model display lists datum planes, features, parts, etc in the order they were created. Shortly you will assemble parts to the BASE and to do this it must be at the top of the list of components in the model tree. In this way it can be the ‘parent’ to the other parts.

Reordering the model tree

7. Drag the BASE component above FRAME_ASSY.ASM in the model tree.

8. The model tree should now look like this.

Packaged parts

Look down the list of components in the model tree and you should notice that, with the exception of the BASE.PRT each component has a very small square before the name. This shows the part is packaged meaning it has been placed loosely in position but has few or no assembly constraints applied to it.

The BASE.PRT is not packaged because a moment ago you fixed it in position making it fully constrained so it cannot move within the assembly.

Soon you will be shown how to add assembly constraints to link the packaged parts together.

Selecting objects

Selection is a two step process and like Pro|DESKTOP this uses light blue to pre-highlight and red to show an object has been selected.

Unlike its younger brother, Pro|ENGINEER doesn’t have different selection tools. Instead ‘filters’ can be used to make selection easier. This is particularly important on complex models. For simple models like this we can rely on Pro|ENGINEER’s default

‘Smart’ filter shown at the bottom of the screen.



9. Move the mouse cursor over the follower.

The edges will pre-highlight a cyan colour (light blue).

If you do not move the mouse for a few seconds the name of the part appears as a pop-up note.

10. When the cyan pre-highlight is visible, click with the left mouse button.

The edges will turn red showing the component has been selected.

11. Click on a blank area of the screen to de-select the follower.

Task three - Assembling components

Look at the bottom of the Pro|ENGINEER screen. You should see a few lines of text.

This is called the Prompt Area and it is very important to keep an eye on it because Pro|ENGINEER will report errors here and tell you what it expects you to do next in any command.

Assemble frame to base

Unlike Pro|DESKTOP, when using Pro|ENGINEER you need to begin the assembly process before selecting surfaces.

Connecting the frame to the base will use two constraints; insert and mate.



Surfaces for Insert constraint Surfaces for Mate constraint

1. The navigator window should be displaying the model tree.

2. Move the mouse over the sub-assembly FRAME_ASSY.ASM and right mouse click.

3. From the floating menu select Edit Definition.

4. The Component Placement dashboard will appear along the bottom of the screen.

The prompt area at the bottom of the screen is asking you to select any reference for auto type constraining.

5. Click on the Placement tab to roll-up the panel.

This is where your assembly constraints will be stored as you make selections in the graphics window.

6. Move the mouse over the spindle on the base and select the outer cylindrical surface.

The edges will turn red to show it has been selected and the word Automatic appears in the graphics window.



7. In the dashboard, look at the Placement panel. It will now show the selected surface.

Selection filter

8. Move the mouse over the tube at the bottom of the FRAME.

9. The outer surface of the tube will pre-highlight. We could make this concentric with the spindle but instead use this opportunity to learn how to select awkward geometry.

10. Roll (Do not click!) the mouse wheel to zoom in on the spindle and tube.

11. With the mouse over the middle of the tube, right mouse click and the pre-highlight should change to show the internal surface of the tube.

This is one method to ‘filter’ the surface you wish to select.

12. Left click and the spindle and tube will be centred and the Automatic label changes to Insert.

You have created your first assembly constraint. Pro|ENGINEER chose an Insert constraint for you, based on your selection of two cylindrical surfaces.

The Placement panel now shows an insert constraint and beneath, the start of another (automatic).

13. If yours does not, click on New Constraint in the Placement panel.



14. In the Main toolbar, locate the Model Display

tools and click on , the Hidden Line tool.

15. Select the top of the spindle on the base.

16. Move the mouse just below the joint in the tubes of the FRAME and right click several times until the surface shown here in cyan (light blue) is pre-highlighted then click to select the surface.

A Mate constraint will be created with the two surfaces touching or ‘coincident’.

Look at the Placement panel and you will see the new Mate constraint listed.

17. Make sure there is no tick in the Allow Assumptions option!

The two constraints have centred the spindle and tube and mated the top of the spindle with the bottom of the hole in the tube. This will allow the frame to rotate on the spindle.



18. Click on , in the dashboard to finish assembly of the frame.

19. In the Main toolbar click on , to display the model with Shading.

The frame should now be assembled onto the base and ready to turn.

Task four - Kinematic movement

Kinematic - The branch of mechanics that studies the motion of a body or a system of bodies without consideration given to its mass or the forces acting on it. www.dictionary.com

There are two ways to move objects on screen. One uses the Drag (glove) tool and the other uses keyboard/ mouse buttons.

Method one - Drag tool

Now for the exciting bit!

1. Click on , the Drag… tool.

2. Click on one of the edges on the tail of the frame.

3. A small diamond symbol appears at the location where you clicked.

4. Click and hold the left mouse button and drag to rotate the handle.

The mechanism should ‘operate’ on screen. This is called Kinematic movement.

In the top right corner of the computer screen is the Drag dialog.

5. To finish dragging, click on

in the the Drag… dialog.



Method two - Keyboard/ mouse buttons

6. Hold down the Ctrl + Alt keys on the keyboard, move the mouse over a component then click and hold the left mouse button to drag the component.

Task five - Assemble fan components

The fan blades, hub, spindle and cam are a sub-assembly with one entry in the model tree. The next step will insert the spindle into the horizontal tube.

Changing the view

1. Hold down the middle mouse button and drag the model to change the viewpoint.

2. Roll the mouse wheel to zoom in until the graphics screen looks similar to this.

3. In the Navigator window, model tree view, move the mouse over the FAN_SPINDLE.ASM and hold down the right mouse button.

4. From the floating menu, select Edit Definition.

The Assembly Dashboard will open.

The prompt area at the bottom of the screen tells you Pro|ENGINEER is waiting for you to select a reference.



In this case it will be a surface on one of the components.

5. Select the cylindrical surface of the fan spindle.

6. Now select the horizontal hole inside the frame.

The screen label on the fan spindle will report an Insert constraint.

7. Make sure the Status line in the dashboard shows Partially Constrained.

This is all we need on this component.

8. Click on , to close the assembly dashboard.

Assemble long spacer tube

To stop the fan spindle from sliding through the tube, two spacer tubes will be added.

The 75 mm long spacer tube is a single component and can be selected in the graphics window.

9. Move the mouse over the long spacer in the graphics window and left click to select it.

10. Hold down the right mouse button to open a floating menu.


The assembly dashboard will open.

12. Click to select the outside surface of the Cam Spindle.

13. Select the internal surface of the long spacer tube.

The Insert constraint is complete and the tube will be centred on the spindle.



Mate spacer to hub

Remember you can move components by holding down the Ctrl+Alt keys and dragging with the mouse buttons.

14. Select the rear face of the fan hub.

15. Rotate the view to see the end of the long tube spacer facing the fan.

16. Select the front face of the tube spacer.

The surfaces should move to be coincident.

More likely, Pro|ENGINEER will offer an Offset mate due to the distance between the two surfaces.

Tip: If you want a coincident constraint move the parts close together before selecting the surfaces.

Changing the mate to coincident.

17. In the dashboard, roll-up the Placement panel.

18. Change the Offset option to Coincident.

19. The spacer will move flush against the rear face of the fan hub.



Mate spacer to frame

20. Click to select the rear surface of the long tube spacer.

21. Change the view until you can select the front face of the frame.

22. If necessary, open the Placement panel in the dashboard and change the Offset to Coincident.

23. Make sure the Status in the Dashboard reports Partially Constrained.

24. Click on to close the assembly dashboard.

The fan spindle will move into position in the frame.

In practice another spacer would be needed between the cam and frame.

25. Follow the same procedure from step 9 in this section to assemble the small spacer with an insert and only one mate.

Note: Pro|ENGINEER uses middle mouse click to complete an action. If your dashboard or dialog closes unexpectedly this is probably the cause.

If you need to re-open the assembly dashboard;

26. Move the mouse into the Navigator window over the component you were assembling.

27. Hold down the right mouse button and, from the floating menu, select Edit Definition.



Task six - Assemble follower

The follower will be assembled to slide up and down through the tube in the frame. This uses two constraints, an insert to centre the follower in the frame and a mate constraint to prevent rotation.

The mate constraint will reference datum planes in the frame and follower rather than surfaces on those solids.

1. Move the mouse pointer over the follower and click to select.

2. Hold down the right mouse button.


The assembly dashboard will open.



4. Use these keyboard/ mouse buttons to position the follower the right way up and adjacent to its final position.

5. Select the outer cylindrical surface of the follower

6. Select the internal surface of the hole through the frame.

7. An Insert constraint will have been added to the Placement list.

Mate datum planes

To stop the cam rotating we will mate datum planes.

8. In the main toolbar, click on , to make datum planes visible.

9. Zoom in on the area shown here.

10. Select the FRONT datum plane in the follower.



The next selection is the Front datum plane in the frame but this may be difficult because of the tangle of datum planes.

Datum planes can also be selected in the Navigator window from the model tree.

11. In the Navigator window click on the small + next to the FRAME_ASSY.ASM to expand the next level.

12. Click on the + next to the FRAME.PRT entry.

13. Underneath the FRAME.PRT entry, click to select the FRONT datum plane entry.

The datum plane will appear selected in the graphics window.

A Mate Angle constraint might be offered. If this is the case;

14. In the dashboard, open the Placement panel.

15. Change the Offset value to Coincident.

16. Make sure dashboard Status reports partially constrained.

17. Click on to close the assembly dashboard.



18. Hold down the CTRL + ALT keys and drag the follower until there is a small gap between it and the cam.

Saving your work

19. Open the File pull-down text menu.

20. Select Save

21. Click on .

22. Close Pro|ENGINEER and log-off your computer.

What have you learned?

By the end of this session you should now:

Be aware of

• overall concepts and brief history of CADCAM.

• how 3D parametric solid modelling software can create multi-part assemblies

Understand

• the procedures necessary for assembly in Pro|ENGINEER

• how using 3D modelling software can help designers and engineers try out ideas and refine the detailed design of products

Be able to

• assemble components using insert, mate and align constraints in Pro|ENGINEER.

• Create mechanical connections including pin, slider and cam

Session four – Other cam shapes Using physical models, you will explore the movement created by a range of different cam shapes. Using this analysis you will decide which shape of cam will provide the most appropriate movement for your design.



Learning objectives:


Be aware:

• how shaped cams create movement in a follower.

Understand:

• the relationship between the cam shape and follower movement.

Be able to:

• choose a cam shape that will create the most appropriate movement for your design

Homework

You will need the answer/marking sheet for Homework 2.

Using the mechanism drawing template as a starting point, draw your design.

Session five – Cam connection and kinematics

Aim:

This session will teach you about mechanical connections in 3D computer models and how to add a cam connection to your Pro|ENGINEER assembly. You will then be able to test it kinematically on screen.


By the end of the session you should:

Be aware of

• mechanical connections and how they differ from assembly constraints

• kinematic motion simulation in Pro|ENGINEER and how it is used to test and demonstrate mechanisms.

Understand

• the concepts behind mechanical connections including, types of connection and degrees of freedom each affords.

• the concepts behind kinematic motion, in particular the lack of physical properties including collision detection, forces, inertia, friction, etc.

Be able to



• add a cam mechanical connection using Pro|ENGINEER.

• operate their mechanism kinematically on screen.

Task one - Cam connection

Pro|ENGINEER can simulate a number of different mechanical connections including cam-followers.

The next section shows you how to:

• Switch to the Mechanism module

• Start a new cam-follower connection

• Select the cam surfaces

• Select the follower surface

• Complete the connection.

You will then be able to kinematically ‘test’ the mechanism.

Set working directory

1. Start Pro|ENGINEER.


3. Browse to the folder you saved your work in. Your teacher will tell you where this is.


5. Open your Wind sculpture assembly from the last session.



The cam connection is part of a different module in Pro|ENGINEER called Mechanism.

6. Open the Applications pull-down text menu and select Mechanism.

The navigator menu will now display different information in the model tree and, on the right of the screen, the mechanism toolbar replaces the creation toolbar.

7. In the Mechanism toolbar click on , the Define Cam-Follower connection tool.

A Cam-Follower Connection Definition window will open.

8. Click to activate the Autoselect option. This will try to predict the surfaces you select.

Selection filter

Along the bottom of the screen is the selection filter set by default to All.

9. Change the selection filter to Surface.

10. Click on one of the curved surfaces that make up the outside of the cam.

The Autoselect option, ticked earlier, predicts you want to use connected surfaces and offers the entire outer surface of the cam.



The full surface of the cam should be selected.

11. In the small Select window click to confirm the selection.

A series of cyan lines shows the surface defined for this part of the cam connection.

The other part of the cam is the bottom of the follower and will be selected next.

12. Click on the Cam2 tab.

The Autoselect option is not needed as the bottom of the follower is made up of only one surface.

13. Rotate the model using the middle mouse button and zoom in using the mouse wheel until you can see the bottom surface of the follower.

For the next selection you may need to use the right click query to ‘find’ the correct surface.

14. Select the bottom end of the Follower shown here outlined in red.



15. Click in the small Select window to confirm the surface.

For the purposes of our simple cam mechanism the definition is now complete

16. Before closing the Cam-follower Connection Definition window have a look at the Properties tab.

There are options to add friction to the cam connection and define whether the follower can lift-off the surface of the cam.

17. Click to close the definition window.

The follower will now move to touch the cam surface and the model will show the Cam-Follower connections.

The Cam connection will now be visible on the model in the graphics window as a series of cyan lines and the definition will be listed in the model tree in the Navigator window.

The cyan lines around the cam and follower show the surfaces used to create the cam connections but there is a new coloured symbol to show the Cam-Follower connection.

Close the Mechanism module

You will now return to the standard Pro|ENGINEER programme.

18. In the Applications pull-down text menu select Standard.



The cam connection symbols disappear and the Mechanism toolbar on the right of the screen is replaced with the Feature Creation toolbar.

Background

Most car engines use springs to hold the follower against the cam but still valves can bounce at high revs limiting how fast the engine can rotate.

Ducati, manufacturer of large capacity motorcycles, uses cams to close the valves instead of springs and their engines have a higher rev-limit as a result.

www.ducati.com

Task two - Test the mechanism

Now for the exciting bit!

1. Click on , the Drag… tool.

2. Click on one of the edges on the handle of the model.

A small diamond symbol appears at the location where you clicked.



3. Click and hold the left mouse button and drag to rotate the handle.

The mechanism should ‘operate’ on screen. This is called Kinematic movement.

4. To finish dragging, click on in the Drag dailog.

Save the assembly

5. Save your work.

6. Close down Pro|ENGINEER and log-off your computer.

Kinematic - The branch of mechanics that studies the motion of a body or a system of bodies without consideration given to its mass or the forces acting on it. www.dictionary.com


Having reached the end of this session you should now:

Be aware of

• mechanical connections and how they differ from assembly constraints


Understand

• the concepts behind mechanical connections including, types of connection and degrees of freedom each affords.


Be able to



• add a cam mechanical connection using Pro|ENGINEER.

• operate your mechanism kinematically on screen.

Session six – New CAD part

Aim:

In the next hour you learn how to create a new component from scratch by drawing a profile and extruding it to create a solid shape.



Be aware of:

• features and how they build to create simple engineering components.

Understand:

• the concepts behind sketching and sketch based features in Pro|ENGINEER.

Be able to:

• use Pro|ENGINEER to create an extrusion feature using an internal sketch.

• use sketching and editing tools to create a valid profile suitable for extrusion.

Task one - Starting a new design

Although it is possible to create a new part ‘In Context’ like Pro|DESKTOP, for this exercise we will create a new component separate to the assembly.


2. In the Windows toolbar across the top of the screen click on the File pull-down menu.

3. Click on New…

4. Part is already selected

5. Type in a name for the new part.

6. Click on



Graphics window

7. In the Main toolbar – Datum Display, make sure the workplanes button is selected.

A new design opens on screen in Pro|ENGINEER.

In the Graphics window are three default Datum Planes named Top, Right and Front.

8. If these are not visible click on , the Datum Planes on/off button.

The Navigator window

On the left hand side of the window is the Navigator panel (referred to as the Browser in Pro|DESKTOP). Currently this lists the three default datum planes in the design.

By default there are no sketches on any of the datum planes. This is because sketches can be created in isolation (external) or as part of a 3D feature (internal).

First a short description about datum planes and sketches

Datum planes and sketches

A datum plane can have several sketches. The datum plane is like the glass panel on an overhead projector and sketches are the transparencies (plastic sheets) you write on. For complex diagrams teachers overlay several transparencies, gradually building up the image.

Pro|ENGINEER can have multiple sketches on each datum plane

Transparencies = sketches

Glass panel = datum plane



Internal v external sketches

Sketches are most often used to define the geometry for 3D features. Pro|ENGINEER can use sketches created internal or external to the feature. External sketches can be used for more than one feature but internal sketches are checked for validity, an important advantage for inexperienced users.

Internal sketch External sketch

When internal sketches are used the model tree is more compact so for most purposes internal sketches are preferred.

Extrude + new internal sketch

9. In the Main toolbar click on , the Extrude tool.

The extrude dashboard will open along the bottom of the screen.

Pro|ENGINEER is waiting for you to choose an existing sketch or create a new internal sketch. You will create a new one.

10. In a blank area of the design window hold down the right mouse button and, from the floating menu, select Define internal sketch…



A sketch dialog window will open.

11. In the Graphics window select the Front datum plane.

The FRONT datum plane will be entered as the Plane for sketching.

Pro|ENGINEER automatically populates the options.

12. Click on the button to close the Sketch dialog.

The design window will be re-oriented with the sketch plane perpendicular to the screen

The rectangle represents the FRONT datum plane where the sketch has been created.

The vertical and horizontal dotted lines are references from the other two datum planes. These can be used to ‘reference’ geometry.

Sketch

This is the shape we will show you how to draw.

To simplify the screen the display of datum planes has been turned off.

The toolbar on the right of the screen has changed to the Sketcher toolbar.



Task two - Sketching a profile

Centrelines and geometric constraints

When sketching lines, Pro|ENGINEER tries to predict and apply geometric constraints as you work. For example, if you draw a line almost the same length as one that already exists, Pro|ENGINEER will offer to constrain them to be equal in length.

In this section you will begin to create the geometry for the head shape.

1. In the Sketcher toolbar on the right of the screen activate , the Create Circle… tool.

2. Move the mouse over where the horizontal and vertical lines cross in the middle of the screen.

You should see a red symbol like this . If you click when the symbol is showing, Pro|ENGINEER will constrain or link the centre of the circle to the reference lines.

3. When the constraint symbol is showing click to locate the centre of the circle.

4. Move the mouse a short distance and a circle will appear. Click to complete drawing the circle.

5. Middle mouse button to finish with the circle tool.

Pro|ENGINEER will create a circle with a ‘weak’ dimension. Unlike Pro|DESKTOP, Pro|ENGINEER automatically creates dimensional constraints. These are weak and coloured grey until you change them when they become ‘strong’ dimensional constraints.

6. In the Sketcher toolbar , the Select items tool should be active.

7. Double click on the weak dimension to open it.

8. Change the value to 80 mm.

9. Press the Enter key on the keyboard.

10. You will probably have to zoom now the circle is much smaller.



11. The dimension is still selected hence the red colour.

12. Click on a blank area of the graphics window to remove the highlight and you will see it is now coloured orange to show it is now a ‘Strong’ dimensional constraint.

Another way to change a weak dimension to strong is to right click over a selected dimension and, from the floating menu, select Strong.

Construction lines

Two horizontal centre lines will be created to locate the eyes and ears.

13. In the sketcher toolbar, click on the small triangle next to , the Create 2 Point lines tool.

14. In the fly-out menu select , the Create 2 Point Centerlines tool.

15. Click on the left of the circle at X1 about a third of the way up the top half of the circle.

Move the mouse across to the right of the graphics window and you should see a red H symbol. This shows Pro|ENGINEER will create a horizontal geometric constraint.

16. Click at X2 to complete the horizontal line.

17. In the Sketcher toolbar click on , to activate the Select Items tool.

18. Double click on the weak vertical dimension.

19. Change the value to 20 mm then press the Enter key on the keyboard.

The dimension is now strong, i.e. controls the distance between the two lines.

X1 X2



20. Use the same technique to create another horizontal construction line 30 mm above the centre of the circle.

Drawing the nose and eyes

21. Select the Create Circle… tool.

22. Draw a circle for the nose, concentric to the existing circle.

23. Use , the Select Items tool to change the size to 15 mm.

24. The eyes will be centred on the lower of the two centre lines drawn earlier

25. Activate the Create Circle… tool.

26. Click and hold down the left mouse button at X1 to start drawing the circle.

27. Drag the circle out and when you see the R1 constraint appear release the mouse button.

This circle is geometrically constrained to be equal in size to the nose circle.

X1



28. Draw the second eye in the same way.

For clarity we have hidden the dimensional constraints to emphasise the three circles geometrically constrained to be equal in radius

Drawing the ears

29. Use the Create Circle… tool to draw a circle centred on the intersection shown in the diagram on the right.

30. Use the Create Circle… tool to draw a second circle centred on the other intersection and equal radius to the circle just drawn.

Trimming lines

The trim tool , is slightly different to the one in Pro|DESKTOP. It can trim lines you select like Pro|DESKTOP or you can draw a freehand line intersecting with several line segments at once.



31. In the Sketcher toolbar activate , the Dynamically Trim… tool

32. Click and hold down the left mouse button and draw the freehand line shown on the right.

33. When the mouse button is released the lines highlighted in red will be deleted.

34. Using the same trim tool move the mouse over the line shown on the right pre-highlighted cyan.

35. Click the mouse button to delete the pre-highlighted line.

36. Use the trim tool to remove unwanted lines on the other ear.

Drawing the mouth

The mouth will be drawn using , the Create a Spline Curve tool.

37. In the Sketcher toolbar activate , the Create a Spline Curve tool.

38. Left click to locate the first point on the spline.

39. Left click to locate the second point on the spline

40. Left click to locate the third and last point on the spline.

41. Middle click to finish the spline.



42. Draw another spline, shown here highlighted in red, to complete the mouth

The finished sketch with dimensional constraints visible should look like this.

Notice how cluttered the sketch is.

The face shape is now complete but the sketch must be closed before creating an extrusion.

43. In the Sketcher toolbar click on , the Continue… button.

The sketcher will close and constraints will be hidden.

The design window will display a preview of the extrusion.

44. In the Main toolbar click on , the Saved Views tool and select Trimetric.

The sketch will rotate to a slanting position.

Note: Trimetric view is only available if the school templates have been installed.



The Sketcher toolbar has been replaced by the Feature Creation toolbar and the dashboard at the bottom of the screen is active.

Complete the extrude

45. If necessary roll the mouse wheel to zoom.

The extrusion length can be set to 2(mm) in one of two ways.

Either or

46. Drag the handle in the design window

47. Change the number in the dashboard.

48. In the dashboard, click on the small triangular arrow to the left of the distance field.

49. From the fly out menu select , the symmetrical option.

50. Click on , the green tick in the dashboard to complete the extrusion.

51. Save your model and close Pro|ENGINEER.




Having completed this session you should:

Be aware of:

• features and how they build to create simple engineering components.

Understand:

• the concepts behind sketching and sketch based features in Pro|ENGINEER.

Be able to:

• use Pro|ENGINEER to create an extrusion feature using an internal sketch.

• use sketching and editing tools to create a valid profile suitable for extrusion.

Session seven – Own design - workshop Here you will have the opportunity to turn your paper ideas into a real component to go on the top of the mechanism. This should synthesise your research, ideas and investigations into mechanisms.



Be aware of:

• the range of factors that must come together to create a successful cam operated automata

• health and safety procedures when working in a manufacturing environment.

• manual and computer controlled techniques for manufacturing parts.

• safe working practices in practical areas.

Understand:

• how to turn a paper design into a real component suitable for adding to the cam mechanism.

• the concepts behind computer controlled manufacture.

• the need to carry out and implement risk assessments when working with tools and machinery.

Be able to:

• work safely in a manufacturing environment.

• use machines and hand tools to create a component based on their design ideas.



• assemble and link their own parts to the cam mechanism.

• test and evaluate a mechanism and make adjustments to optimise operation.

Session eight – Own CAD design You now have the introductory skills necessary to create shapes that will extrude to make solid shapes.



Be aware:

• how new parts are created from scratch.

Understand:

• the concepts behind part creation including internal sketches

Be able to:

• create a ‘valid’ sketch for extrusion

• create a successful extrusion from their sketch.

Using Pro|ENGINEER create a virtual model of the design you have developed to go on top of the cam mechanism.

Where to get help?

Use the previous section of this tutorial as a guide and if you have difficulty ask your teacher or the student CADCAM mentor for their help.



Session nine – Final assembly - CAD

Aim:

In this session you will assemble your part onto the cam mechanism. The movement can then be simulated on screen using kinematic motion.


By the end of this session you should:

Be aware of:


Understand:


Be able to:

• demonstrate capability in assembling components using Pro|ENGINEER.

• apply prior learning by adding their component to the wind sculpture.


Task one - Getting started



3. Browse to the folder you saved your work in. Your teacher will tell you where this is.


5. Open the Wind sculpture assembly you completed in a previous last session.



Task two - Adding a component

1. In the Feature Creation toolbar on

the right of the screen click on , the Add Component tool.

2. Locate the head design you created in the last session.

3. Click on .

4. Hold down the Ctrl+Alt keys and use the mouse buttons to manoeuvre the head close to the top of the follower spindle.

The assembly dashboard opens at the bottom of the screen.

5. Make the datum planes visible

6. Add an Align constraint between these workplanes.

Right datum plane on the face part.

Front datum plane on the Follower part.



Selection filter

For the next section you may need to use the right mouse click ‘filter until the surface you need is pre-highlighted then left click to select.

7. Use the methods you used before to create a Mate constraint between these surfaces.

8. Finally, create a constraint between these surfaces.

Pro|ENGINEER will offer a Tangent.

9. Click on to finish assembling the head.

Kinematic motion

10. In the Main toolbar

select , the Drag… tool.

11. Click and drag on part of the mechanism to ‘operate’ the wind sculpture.



What have you learned this session

Having completed this session you should:

Be aware of:


Understand:


Be able to:

• demonstrate capability in assembling components using Pro|ENGINEER.

• apply prior learning by adding their component to the wind sculpture.


Session ten – Final assembly and testing – workshop During this session you will assemble your part onto the cam mechanism. You can then test the operation before making any adjustments to make the final design operate efficiently.


By the end of this module students should:

Be aware of:

• assembly techniques, the need for adjustments to ensure efficient operation and techniques that can improve how mechanisms work.

Understand:

• what to look for when testing a mechanism and the range of changes that can be made including; alignment, lubrication, clearance, etc.

Be able to:

• test and fettle their mechanism.



Session eleven – Consolidation and extension Sketcher is a key technique in Pro|ENGINEER so this session gives students the chance to experiment creating one or more alternative components. More capable students may create a sub-assembly made up of several parts. Students are also expected to collate evidence of their work into an e-folio record.



Be aware:

• of design alternatives for part creation.

Understand:

• the key procedures in creating a new component and adding it to an assembly or replacing an existing component.

Be able to:

• create a simple component/assembly and add/replace it in an assembly.

Homework

Students complete e-folio for presentation in final module.

This completes the CAD sessions for this module

Session twelve – Student presentations

Focus:

Students will have the opportunity to present their work using presentation software and a digital projector.


By the end of this module students should:

Be aware of:

• the concepts involved in presenting to peers.

Understand:



• the key procedures in creating an electronic presentation.

• the techniques of creating an electronic presentation.

Be able to:

• capture screen activity and insert this into presentation software.

• format their presentation to tell the story of their design development.

Module review

Over the last few sessions you have learned many new things including:

Be aware of:

• physical and virtual 3D modelling techniques

• simple cam mechanisms and toys that use them

• the concepts of 3D parametric solid modelling using Pro|ENGINEER

• the kinematic simulation capabilities of Pro|ENGINEER

Understand:

• the principles of 3D parametric solid modelling and mechanical simulation using Pro|ENGINEER

• how 3D solid modelling software be used to refine designs including parts, assemblies and mechanisms.

• the concepts behind simple cam mechanisms

Be able to:

• use simple workshop techniques to assemble parts into a working mechanism

• use Pro|ENGINEER to assemble parts into a working mechanism

• use Pro|ENGINEER to create a new component using sketching and extrude

To become confident creating mechanical assemblies and recording movies of systems you will need to practice these techniques.



Extension activities

Design Challenges

• Create an animation of the assembly using a servo motor to operate the mechanism and record a video of the wind sculpture ‘in action’

• Create a rendered image of the

• Reverse engineer simple office/ household mechanical products such as a cork screw, whisk, staplers, hole punches, etc as virtual mechanisms and create movies to demonstrate their operation.

• Design and model a can crusher to help save space when recycling drink cans. Produce a movie to show users how the can crusher operates.

Pro|ENGINEER tutorials

The Mechanism module in Pro|ENGINEER is very powerful and contains servo motors to ‘power’ mechanisms to create convincing animations and videos. The animation module explains how to do this and is just one of many addition curriculum modules for Pro|ENGINEER.

Technique Tutorial

Mechanism Animation Animation

Part modelling Sports drink bottle

Rendering CO2 Dragster

Engineering drawing Sports drink bottle/Periscope

Mechanism dynamics Rolling ball roller-coaster

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