ptc_casting tuto wf5

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Making

aPewter

Castin

g

Making a Pewter Casting Mould

Pro|ENGINEER Wildfire5

Schools & Schools Advance Edition


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Pro|ENGINEER Wildfire 5.0

Written byJ ohn E. Forth

Copyright 2010, DTE Consultancy

All rights reserved under copyright laws of theUnited Kingdom, United States and other

countries.PTC, the PTC Logo, Pro |ENGINEER,Pro|DESKTOP, Wildfire, Windchill, and allPTC product names and logos are trademarksor registered trademarks of PTC and/or itssubsidiaries in the United States and in othercountries.

Conditions of use Copying and use of these materials isauthorised only in the schools, colleges anduniversities of teachers who are authorised to

teach Pro |ENGINEER in the classroom.All other use is prohibited unless writtenpermission is obtained from the copyrightholder

Acknowledgements Flamefast Ltd

Feedback

[email protected]

In order to ensure these materials are of thehighest quality, users are asked to reporterrors to the author.

Suggestions for improvements and otheractivities would also be very welcome.

Product code WF5M-SE-L1-010-1.0

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mailto:[email protected]:[email protected]


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Table of Contents

Making a Pewter Casting Mould 1Table of Contents 3Introduction 4

Pre-requisites 4Abbreviations and terminology used within this tutorial 5Installation and setup 5Pro|ENGINEER functionality addressed in this tutorial. 6STEM subject concepts in this module 6Science concepts addressed in this tutorial 6D&T subject areas addressed in this tutorial 7Engineering areas addressed in this tutorial 7Maths areas addressed in this tutorial 7Module aims and objectives 7Aim: 7Learning objectives: 7

Background 8Creating the Mould 10

Task 1: Create the Basic Mould parts. 10Task 2: Assemble the mould parts. 12Task3: Create the item to be cast with its Sprue pin 14Task4: Creating the Sprue Pin 16Task 5: Creating the Mould cavity. a) Assembling the model to the Mould 19Task 5: Creating the Mould Cavity b) Using the model to subtract material. 21Task 6: Setting material properties for mass calculations. 24Task 7: Create files that can be taken to a CNC Router 26



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Teachers notes

Introduction

The health and safety problems associated with casting metals in schools has led tothe demise of this most valuable learning experience for pupils. Man has, since theBronze Age, been shaping metal by raising its temperature to melting point andpouring the resultant liquid into a shaped cavity called a mould.

Many schools have used aluminium as the metal of choice but even that has fallenfoul of the H&S hurdles and has all but disappeared from the curriculum. Howeverthere is light at the end of the tunnel in the form of specialist low temperature castingequipment using lead free pewter as the medium. This material melts at about 140degrees Celsius and in a controlled environment is quite safe for pupils to use from

Y7 upwards (S1 in Scotland).

This equipment is available from several suppliers including:-

Flamefast Ltd

Techsoft

Middlesex University Teaching Resources

The advantage of using pewter is that the moulds can be made from materials thatare readily available and easily machined on a CNC router in a school workshop.For one-off situations the mould can be made from J elutong or MDF.

This tutorial shows how a simple pendant, designed using Pro|ENGINEERWildfire5, can be used to model the part file from which the mould can be created.In principle you will create the pendant or other part to be cast, then use it to performa NOT intersection with the mould parts to produce the cavity. The mould parts canthen be exported as an stl file, machined on a CNC router and used to cast thefinished pendant.

Pre-requisites

Pro|ENGINEER Wildfire 5.0 Schools Editionor

Pro|ENGINEER Wildfire 5.0 Schools University Edition*

or

Pro|ENGINEER Wildfire 5.0 University Plus Edition

or

Pro|ENGINEER Wildfire 5.0 Student Edition

*There is a specific mould application within the Advanced Edition which can be used

to create much more comprehensive types of moulds where shrinkage and mould

http://www.flamefast.co.uk/http://www.flamefast.co.uk/http://www.techsoftuk.co.uk/http://www.mutr.co.uk/http://www.mutr.co.uk/http://www.mutr.co.uk/http://www.techsoftuk.co.uk/http://www.flamefast.co.uk/


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release functions apply. This tutorial is for the much simpler application found inlower secondary school syllabuses. The tutorial is written for teachers but can bemodified for pupil use.

This tutorial contains screen and menu images taken from the Schools Edition soUsers of other Pro|ENGINEER Editions may notice some slight differences.

This tutorial has also been based on the use of Pro|ENGINEER start parts &templates supplied as part of the PTC D&T programme. While this tutorial can beused with other Pro|ENGINEER start parts there may be changes required in termsof view orientation, datum plane and coordinate system references etc.

This tutorial requires some previous modelling experience in Pro|ENGINEER.

Pro|ENGINEER Wildfire requires the use of a 3 button mouse. If possible a mousewith a combined middle wheel & button can improve User interaction withPro|ENGINEER Wildfire.

Abbreviations and terminology used within this tutorial

Left-click Press and release the left-hand mouse button

Left-click-drag Press and hold-down the left-hand mouse button and move themouse

Right-click Press and release the right-hand mouse button

Middle-click Press and release the middle mouse button

Middle-drag Press and hold-down the middle mouse button and move themouse

Note: The word mould (E) is used in this tutorial but it is the same as mold (US)

Installation and setup

These Installation notes have been compiled based on a directory structure used aspart of the PTC D&T programme, the UK CAD in Schools initiative and the

deployment of Pro|ENGINEER. Users not part of this programme can still use thistutorial but may need to adapt either their Pro|ENGINEER configuration files or thedirectory structure used in the tutorial.

Please ensure you have the required materials (Pewter, J elutong or any hardwoodetc) in the material library folder within C:/Program File/Pro|ENGINEERWildfire4/pro-standards/material_database.

You should create a directory under their documents or network folder called PewterCasting. The part files mould1.prt, mould2.prt and mould_ass.asm together with thematerials file pewter.mtl can be placed in this folder for use during the tutorial and as

a common folder for all to use.



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Pro|ENGINEER functionality addressed in this tutorial.

Sketching

o 2D geometry creation & modification

Circles, Lines, Centrelines, Trimming. References

o Geometric & dimensional constraints

Weak, Strong & Locked dimensions

Linear and angular dimensional constraints

Equal radius and tangent geometric constraints

Creating additional Datum Planes

Modelling

o Revolve

o Extrude

o Parametric modifications

o Set Materials

o Export as a *.stl file for CNC machining

Assemblieso Assembly constraints

o Copying Assemblies

o Component Operation

o Hide/Unhide components

STEM subject concepts in this module

Science concepts addressed in this tutor ial Modelling

Communication

Handling data

Making things happen

Materials

Melting points

Relative Density (Specific Gravity)



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D&T subject areas addressed in this tutor ial

CAD

Mould making

Engineering areas addressed in this tutorial

Casting procedures

Maths areas addressed in this tutorial

Volumes

Shapes

Module aims and objectives

The aim of this tutorial is to learn how to use Pro|ENGINEER Wildfire4to create amould that can be used with Flamefast LT1 Low Temperature casting equipment tocreate a pewter casting.

Aim:

During this module you will learn..

To assemble different parts together.

Use the Component Operations feature to create a cavity in one partfrom a solid shape of another

Create stl files that can be used by CNC and RP equipment

Learning objectives:

By the end of this module you should:

Be aware of the relationship between a part and a mould

Understand the concept of logically operating on parametric solid objects to create newobjects.

Be able to create a mould from a modelled object so that a casting can be made.

Understand the relationship between 3D Solid modelling and CNC machining.



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Background

Low temperature casting equipmentis slowly finding its place in the CDT

curriculum of many secondaryschools. The equipment has amould capacity of 100mm X 100mmX 35mm however larger moulds canbe used if a more risky open heatingand ladle technique is employed.

This tutorial will make a mould forthe Flamefast LT1 equipment

This is the casting equipment and is very safe touse as the pupils do not come into contact withthe molten metal. The case is cooled and thefumes are vented away. The crucible will hold2.5kg of the lead free pewter which wouldprobably be sufficient to pour a class of 20making small jewellery items.

Two alloys are available a low temperature 138oC

and pewter proper which melts at 240o

CThe process starts with the construction of a splitmould, which is the subject of this tutorial. Themould is positioned in the holder and the metal ispoured by tilting the crucible using the sidehandle.

This is the split mould used tocreate the casting. The CAVITY willbe created using the design for themodel. The shape of the pouringhole or sprue will be added to themodel design and will, as a resultautomatically, create the pattern andthe cavity together.



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The creation of the model forcasting is not the function of thistutorial except to say that themaximum size cannot exceed thesafe maximum for the mould size of

this machine. The molten pewtermust not leak out therefore the itemto be cast must not come, at anypoint closer than 6mm from the sidefaces of the mould and 3mm fromthe front and back faces of themould. The Sketch opposite is theone used to create the two parts ofthe mould and the construction linesindicate the maximum buildenvelope for the item to be cast.



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Creating the Mould

Task 1: Create the Basic Mould parts.

Note: *This is assuming you have the Flamefast LT1 Low temperature castingequipment. If you have any other machine or are using a brazing hearth/ ladleapproach then vary the sizes accordingly. You can, as a teacher create thesemould parts and save them in a common folder so that pupils can accessthem and create their moulds as required. Alternatively you can allow pupils tocreate their own.

1. Open Pro |ENGINEER Wildfire5and create a working directorycalled Pewter_Mould

2. From the Pro|ENGINEERWildfire4top toolbar left-click

Create New File . In thedialogue box that appears enterMOULD1. Make sure that Partand Solid and the default settingsare selected.

3. Select Extrude and sketch ontothe FRONT datum plane.

4. Create the sketch as shownopposite*

5. Accept the sketch using the blue

tick .

6. In the dashboard set theextrude depth to 15mm andextrude BELOW the datumplane.

7. Left-Click the green tick toaccept the feature.

8. Save the part.

9. Select File > Save a Copy

10. Enter the new nameMOULD2.

11. Open the new file MOULD2



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12. Right-Click Extrude 1 and Left-ClickEdit Definit ion.

12. Right-Click Extrude 1 and Left-ClickEdit Definit ion.

13. Modify the direction of extrusion toAbove the Datum plane by Left-Clickon the arrow symbol and applychanges.

13. Modify the direction of extrusion toAbove the Datum plane by Left-Clickon the arrow symbol and applychanges.

ngWF5.doc of 2811

14. Regenerate the model15. Save the part.

You have now created the basic parts ofthe mould. You will now assemble themas if they were containing the item to becast.



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Task 2: Assemble the mould parts.

1. From the Pro|ENGINEERWildfire5 top toolbar Create

New File . In the dialoguebox that appears enterMOULD_ASS

Notice thatAssembly andDesign are selected.

2. Left-Click Assemble

.

3. Left-Click MOULD1 and

.

4. As this part is to be the anchor it can

be fixed in place. Left-Click the downarrow to the right of the field currentlyshowingAutomatic.

5. From the lst, left-click Fix

6. Accept the constraints by Left-Clickon the green tick .



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7. Left-Click Add

Component

7. Left-Click Add

Component

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8. Left-Click MOULD2 and

.

The second mould partwill now appear and youwill assemble this to thefirst part.

9. Left-Click the topsurface of Mould1 andthe bottom surface ofMould2 and ensure anAutomatic Mate hasoccurred

10. Left-Click the left side ofMould 1 and the Leftside of Mould2. Ensurethat an AutomaticCoincidentAl ign hasoccurred.

11. Left-Click the right sideof Mould1 and the rightside of Mould2.

Ensure that anAutomatic CoincidentAl ign has been created.

12. If, as is the case shownright the Align is offset,Left-Click the symbolshown and select the

top icon . This willforce a coincidentalignment.

The two parts are nowassembled

13. Save the assembly

(NOTE:This part of the tutorial can be missed if you are happy about creating simpleparts and assemblies. The files needed to create these parts are supplied with thetutorial. However these mould parts are specifically for the Flamefast LT1 systemand if you have any other system or are creating moulds for open use then you willneed to create your own parts with different sizes to facilitate this. Remember this

can be done by using Pro|ENGINEER Wildfire5

modification associativity. Make a



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copy of these files and Edit the sketches and extrusions to get the size mould youneed.)

Task3: Create the item to be cast with its Sprue pin

Since it is not the purpose of this tutorial

to create the actual item to be cast, therest of this tutorial will assume that asuitable model part has been created.

The only connection will be that the partmust be enclosed within the buildenvelope of the mould as explainedearlier.

This jewellery pendant will be used in therest of the tutorial and is shown right.(Thispart is included with the tutorial for use if required)

This is about 70mm in diameter and about 12mm deep at the deepest point. It wascreated using a Rotation, a Sweep Protrusion and various Sculpt elements fromthe Warp feature. The final clean engraving surface was achieved with an Extruderemoving material using a circular sketch on an appropriate datum plane.

1. Open the model to be used asthe part for casting.

2. Ensure that the Datum planes areon view. (Note that in theconstruction of this part it wasmade as symmetrical about theDatum Planes as possible, this willhelp with location later in theassembly and in the creation of aparting line plane.



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3. You are now to create two newdatum planes, one will be theparting line of the model and onewill determine the length of theSprue pin.

(Since the mould will be in two peach part will contain a portionthe finished casting. The shape ofthe model will determine where thisparting plane is to go. The partmust be designed so that it can beremoved from the mould once themetal has solidified and cold.)

In the e

artsof

xample right you can seethat the FRONT datum plane can

be used as the parting line, In myexample above a new one must becreated.

Example: A totally symmetrical object

There has to be a little bit of trial and error now depending on the shape and the way

4. With the Datum Planes

the model was created.

onat ashow, orientate the model so th

side view is presented. Use the

Named View List

5. Left-Click the Datum plane tool

6. Left-Click the plane from which you

s, as

ight.

need to offset the new plane.

7. Drag the new plane so that it iaccurately as possible, on thewidest part of the model. See r

8. Rename the Datum PlaneSPRUE_CENTRE

You now have to create the plane that will determine the length of the Sprue. Againlthis will be dependent on the shape and size of your model. Consider this, the mode

should, so far as is possible, be in the centre of the build envelope. If you can



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estimate a distance from that centre to the upper edge of the mould then this giyou the distance of offset for the new plane from the, in my case RIGHT datumplane.

ves

. Left-Click the Datum plane tool910. Left-Click the plane from which you

ry if

END

You now have the set-up as shown

need to offset the new plane.

11. Set the offset distance to yourestimated distance. (do not worthis is not accurate, changes canbe made once the item isassembled into the mould)

12. Rename the plane SPRUE_

right.

Now n create the Sprue Pin that will in turn create the hole into which thefrom

you cametal can be poured or, to use a casting term teemed. The term sprue comesthe method of producing sand casting whereby the tapered hole into which metal isteemed is created by ramming the sand around a tapered pin called a sprue pin. It istapered so that it can be withdrawn from the sand easily thus creating the cavity, italso means that there is a mass of metal acting as a reservoir and its mass pressesthe molten metal into the mould.

Task4: Creating the Sprue Pin

1. Left-Click Revolve

2. Define the Sketch usi gn the

e plane SPRUE_END

SPRUE_CENTRE datumplane

3. Add thas an additional reference.



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4. Sketch the rotation section ofthe Sprue pin as shownopposite. Its exact shape isnot critical but it must extendfrom the SPRUE_END plane

to intersect with the model sothat it can form a solid object.

4. Sketch the rotation section ofthe Sprue pin as shownopposite. Its exact shape isnot critical but it must extendfrom the SPRUE_END plane

to intersect with the model sothat it can form a solid object.

5. Dimension as shown howeveryou may have to vary thelower number depending uponthe shape of the model

5. Dimension as shown howeveryou may have to vary thelower number depending uponthe shape of the model

6. Accept the sketch,(Note theuse of the Filled Sketchdiagnostic to ensure that thereare no sketching problems)

6. Accept the sketch,(Note theuse of the Filled Sketchdiagnostic to ensure that thereare no sketching problems)

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7. Before accepting the rotationfeature, check that the spruepin intersects fully with themodel to allow the free flow ofcasting metal. Remember this

pin will form a cavity in themould through which themolten metal will flow.

8. Adjust the sketch until you arehappy, fillets can be addedlater to help with free flow ofmolten metal.



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Your Model should now looksomething like this.

The next stage is to assemble

the model within the mould andthen let the model carve outthe cavity for both itself and thesprue.

9. Save the model. (Dont worryabout the addition of the spruepin, this can be hidden so thatany rendered images areunaffected, see front cover)



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Task 5: Creating the Mould cavity. a) Assembling the model to the Mould

(This part of the tutorial could be given to pupils to create their own mould)

What you are about to do now is in two distinct parts.

Part A. Create a copy of the original mould you created

Part B Assemble the model into the mould in the correct position.

1. Open the assembly fileMOULD_ASS

2. File > Save a Copy

3. In the New Name box type in thenew name of the assembly. In mycase PENDANT1_MOULD

4. Left-Click OK .

A new dialogue box opens, in the leftcolumn is the original assembly andthe parts that make it up. In the rightis the new assembly. You now haveto create new parts from these.

5. Select the two mould parts in theleft hand column by Left-Click on

the icon.

6. Left-Click Generate New Names

7. Rename the two mould parts withunique names as shown opposite.

8. Left-Click OK .

What you have done now is tocreate a copy of the original mouldassembly and its parts. These cannow be modified without affectingthe originals. These can then beused to create more copies for othermoulds. If you look in the WorkingDirectory you will see the new filescreated.



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9. Close the original assembly andErase from the session.

10. Close any other open parts andErase from the session if youhave found that with a few partsopen the m/c has slowed down.

This will free up RAM and allow thePC to run more efficiently

11. Open the newly created copyassembly. In my casePENDANT1_MOULD.ass

12. Left-ClickAssembly .

13. Left-Click .part(where modelname is the name ofthe item you wish to cast)

Your screen should look something likethis. You are now going to assemble the

model into the mould. Make sure thedatum planes are visible.

14. Left-Click SPRUE_CENTRE datum plane onthe model and Left-Click TOP datum plane onthe MOULD. Ensure that a coincident Align iscreated. This ensures that the model iscentrally placed in relation to the thickness ofthe mould

15. Left-Click the RIGHT datum plane on themodel and then Left-Click the RIGHT datumplane on the mould. Ensure a coincident Alignis created. This centres the model in thewidth of the mould.

16. Left-Click the end of the Sprue pin that shouldbe sticking out of the top centre of the mould;Left-click the top surface of the mould. Ensurea coincident Align is created.

Note: You may need to assemble slightly differently if yourmodel demands it. The important thing is to keep the spruepin central between the two mould faces but not allow themodel outside the build envelope. If this happens, andassembly modifications fail, then return to the part and modifythe position of the Sprue pin there.

17. Save the assembly.



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You have now successfully placed the modelwithin the mould, to best see how it is placedchange the shade to Hidden Lines.

You have now successfully placed the modelwithin the mould, to best see how it is placedchange the shade to Hidden Lines.

18. Make any assembly adjustments now so thatthe model is exactly where you want it withinthe mould.

18. Make any assembly adjustments now so thatthe model is exactly where you want it withinthe mould.

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Task 5: Creating the Mould Cavity b) Using the model to subtract material.

The next part of the process is to create the cavity, first in the top part of the mould,in my case called PENDANT_MOULD1; then in the bottom part of the mould, in mycase called PENDANT_MOULD2. The description of the procedure is exactly thesame. You will merely be reminded to repeat the action as necessary.

1. From the Top Toolbar select Editand from the menu that appearsselectComponent Operations

2. In the Menu ManagerselectCutOut

You are now going to select twoparts; the first will be a part of themould from which material will beremoved or Cut Out. The secondwill be the part that will perform thecutting. You may find it easier toselect in the model tree rather thanon the assembly itself.

3. When you have selected Cut Outyou will see an instruction at the topof the screen

4. In the Model Tree select the top partof the mould, in my casePENDANT_MOULD1. It will displaya red outline in the graphics window

5. In the small box that now appears atthe top right of the screen Left-ClickOK.

6. You will now see another instructionat the top of the screen.



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7. Select the Model that is to bemoulded, in my case PENDANT

8. In the small box that now appears atthe top right of the screen Left-ClickOK.

9. In the box that now appears topright Left-Click Done

10. Back in the Menu ManagerLeft-Click Done/Return

11. If you now expand the model tree ofthe mould part, in my casePENDANT_MOULD1, you will see afeature called Cut Out id 154 this isthe shape of one half of the mould

12. Now repeat this operation but whenyou get to step 4 select the otherhalf of the mould

When you get to step 9 of thisyou may get a question.

13. Left-Click the Yes button at thebottom right hand end of thescreen to accept the default

14. Save the Assembly

Support associative placement for thefeature?

To see the finished Mould all you

need to do is Hide the model beingcast, in my case PENDANT.

15. To do this Right-Click on the partand select Hide. If you cannot see ahole where the model once was oronly half a hole then the ComponentOperation was not completedsuccessfully and will need to berepeated.



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To see the mould parts, use the defaultExploded View.

16. From the top toolbar menu select

View17. Select Explode and from the pop-

out menu select Explode View asshown on the right.

Check carefully to see that the sprue holeintersects the model cavity so that metalcan flow. If adjustments need to be madedo so in the model part.

The associativity ofPro|ENGINEERWildfire5will mean that any changes tothe part will be reflected in the assembly

so no re-assembly or recreating of thecavity will be necessary, all changes willhappen automatically.

Completed mould upper partTo revert to a closed view follow steps 16

and at 17 select Un-explode



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Task 6: Setting material properties for mass calculations.

The material supplied with the Flamefast Ltd LT1 equipment is a Tin/Bismuth eutecticalloy with a melting point of 138oC. This information is included in the material filepewter.mtl.

1. Open the model part, in my casePENDANT. Right-Click on the part in theModel Tree to do this from the assemblyand select Open.

2. To set material properties from the toptoolbar select Edit and from the dropdownmenu select Setup.

The Part Setup Menu Manager appears.

3. Select Material.

(Note: the material file pewter.mtl is includedwith the two mould parts in the Zip file with thistutorial. Copy this to the material_databaseFolder in the program location:-

C:/Program File/Pro|ENGINEER Wildfire4/pro-standards/material_database); this will make itavailable to all who use the program or you canplace it in the Working Directory and Browse tofind it when necessary. It could be placed in a

common folder for all pupils to find.

4. Left-Click on pewter.mtl and then thethree arrow icon which attaches this file tothe model.

5. Select OK and Done

6. To see the mass properties of themodel Left-ClickAnalysis from thetop menu; then select Model andMass properties from the pop-outmenu.



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7. A dialogue box opens and by Left-Click on the spectacles icon youcan see the mass properties of themodel. Select the green tick toclose.

8. The Centre of Gravity also appearsand if a balance weight is beingcast this can be most helpful.

Note: The information here can be ofuse when expressing the amount ofmaterial required in mass (grams) aswell as in volumetric terms. This is oftenthe case with plastic injection mouldingand small castings.

The ratio of surface area to volume isused to calculate cooling rates,information required by your sciencecolleagues



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4. Select File and Save a Copy

5. Select STL{*.stl}

6. In the New Name Box a copy

of the part name will appear.You can enter a new name forthe mould part if you wish, oryou can accept the defaultwhich will have the stl suffix toidentify it.

7. Left-Click OK

8. A Dialogue box appears in the top right ofthe screen. This allows you to set theresolution of the output file. I suggest thefollowing figures are put in to get the bestquality model.

Chord Height =0

Angle Control =1

Leave all of the other boxes default.

9. Left-Click . Notice that the systemmay modify the chord height.

10. Left-Click OK

11. Check in the Working Directory and you willsee the stl file created.

12. Repeat this action for the other half of themould

These two files can now be relayed to theCNC equipment using a USB memory stick.

Note: the same stl file can beused in rapid prototyping (RP)machines.

iDetails of suitable silicone mould making material from:-


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Mouldlife UK [email protected] Tele: +44(0)1638 750679

Mouldlife [email protected] Tele: +1 949 923 9583
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]

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