Catia Functional Design

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Functional Design��

Copyright DASSAULT SYSTEMES 1

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Functional Design

DS Solutions TrainingFoils

Version 5 Release 18September 2007

EDU_SOL_EN_FID_AF_V5R18

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About this courseObjectives of the courseUpon Completion of this course you will be able to use the Functional Molded Part workbench of CATIA V5 to create Styled Plastic and Packaging molded parts.

Targeted audienceAE with styling project background�

PrerequisitesStudents attending this course should have knowledge of CATIA V5 Fundamentals and Functional Molded Part

1 Day

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Table of Contents (1/5)

Methodology Guide Introduction 8A New Technology 9Practice Process FMP 11Benefits of Functional Modeling: An Illustration 12Changing Conventional Practices 13

Improving the Performance 14Performance Strategies 15Options and Settings 16Dummy Cavity / Core 17

Data Structure 19Design Order Reminder 20Managing Design Specifications (Design inputs) 21Functional Set 22Sketches: Update Cycle and Associativity in FMP 23Sketches: Solid Selection Possibilities for FMP 24Introduction to the External Shape Methodology 25Characteristics of the External Shape 26External Shape Vs Push, Pull, Fitting 27

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External Shape versus Part Design Union Trim 28Applying the External Shape Methodology 29Part Structure and Multi-bodies 33Order Independence and Modifiers 34Functional Set and Modifiers 38Rerouting Fillets and Drafts 39

Shell Management 40Managing Design Specifications (Shell Properties) 41The Shell in Functional Modeling 42Solving the Shellable Feature-Error 45Isolated Core Vs Select Core 46Creating Basic Features using Surfaces 47Thin Part in Functional Modeling 48Features Defining or Impacting the Shell 50

Design in Context 51Design in Context: Introduction 52Features Belonging to the Design in Context Category 53Envelope Body 54

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Examples of Envelope Body 55Using Envelope Body Methodology 57Envelope Body Methodology: First Method 58Envelope Body Methodology: Second Method 62

Design for Manufacturing 64Design for Manufacturing: Introduction 65Applying Draft using Tools 66Walls with Different Drafts 68Generating Different Drafts Between Faces 70Walls with Different Drafts Between Faces (R16) 71Drafts on Faces generated by Push or External Shape 75Functional Draft with Tangent Continuity 76Removing Undercuts using an Envelope Body 79Local Thickness 80

Tips for Reference 82Extend Internal Features Outside the Core 83Volume Creation From a Surface 86Use Joined Surface for Cut 87

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Use Up to Plane/Surface Limit or Cut Feature 88Parting Radius in the Draft Properties Definition 89Possible Ribs Creation 91

Defining Mold Models 92Mold Model Example 93How to Extract the Core as it is in the Part Model 94How to Extract the Cavity as it is in the Part Model 95How to Define the Core and Cavity for Milling 96How to Define the Model for EDM Tools 98How to Define the Model for Fixed Inserts 100How to Insert the Shrinkage 101Simulating Results of the Models Defined for Molding 102

Creating and Using Powercopies 103What is a PowerCopy? 104Recommended Structure For a PowerCopy 105Reusing Existing Part Design Templates 106How to Use PowerCopy 107Additional Information 109

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To Sum Up 112

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Methodology Guide IntroductionIn this lesson, you will be introduced to the Functional Modeling approach.

1. Methodology Guide Introduction

2. Improving the Performance3. Data Structure4. Shell Management5. Design in Context6. Design for Manufacturing7. Tips for Reference8. Define Mold Models9. Creating and Using

Powercopies

• Topics covered in this course:

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A New Technology (1/2)In Functional Modeling, the persistent behavior guarantees that the resulting geometry is always coherent with the design intent, therefore enabling design changes at any moment, while reducing the possibility of errors. The interactivity is also significantly simplified.

The first implementation of the Functional Modeling technology is incorporated in the Functional Molded Part (FMP) workbench of CATIA V5. FMP provides a set of high level dedicated functional features. As dedicated functional specifications are embedded in the features, the number of user interactions while designing plastic or molded parts are reduced .

Design Intent: Rib has to be typically applied inside the shelled body

Behavior: The part of the rib that goes outside the ‘Shelled’ body gets automatically trimmed.

User interaction Saved: Trimming of Rib sketch to the Shell.

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A New Technology (2/2)

Design Intent: Ribs are to be drafted by some angle to provide a relief when the component is ejected out of the mold.

Behavior: The Rib feature can apply a draft to the rib walls. This draft is intrinsic to the feature.

User interaction Saved: Manual application of draft after the creation of Rib.

FMP is new Functional Modeling extension option available from CATIA V5 R15. This extension includes functionality allowing automatic extraction of the Core, Cavity. Some functional volumes can also be extracted to change their behavior. For example, a volume used for cutout can be extracted as a solid to create the EDM tool.

This integration provides molded part designers with a comprehensive solution covering the entire creation process.

Volume used to make this cutout can be directly extracted to form the Electrode for EDM

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Surfaces from styling office

Practice Process FMP

Basic features: Functional feature

Dress up: Knowledge Advisor

Context

Draft AnalysisRib,

Rest, Pocket, Grill,

Push, Pull, Fit, (External shape option)

Fillet, Draft

Protected, Add, External, Core (inner shape), Internal

Rule, Check

Core & Cavity extraction

Mold ToolingDesign

Shell properties Draft properties

ConceptualDetail

Mold

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Benefits of Functional Modeling: An Illustration

Functional Modeling (Tree structure <R16)

Part Design

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Changing Conventional Practices

Moving from any history based system, such as Part Design (PDG), to an efficient implementation of the Functional Modeling (FMP) concepts requires a change of conventional practices and thinking, for example:

Think functional and not geometrical & sequential.The designer is free to create features instead of concentrating on sequential modeling. The skeleton approach is highly recommended for FMP (as it is already for PDG).Functional Modeling is order independent. However the creation of some features will always require a logical sequence (see also Order Independent and Modifiers).

Ask yourself Why you need to obtain a specific geometrical result.Use protected features instead of Pockets to remove material

Functional Modeling should provide on average a 30% to 50% increase in productivity compared to any PDG methodology, when correctly applied.

However this performance increase cannot be obtained everywhere.Performance control is different than with PDG, due to the different methods for computing the geometry. Check ‘Performances’ chapter for details.

Functional Modeling increases productivity:

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Improving the PerformanceIn this lesson, you will learn some strategies for improving the performance while working on the functional designs.



Powercopies


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Performance Strategies

While working on very large models, the update time can take over one minute and decrease the productivity.

Simple design strategies can maintain a reasonable update time, even if the model is complex.

Options & Settings

Dummy Shell/Cavity methods

Design organization: multi-bodies approach (cf. Data structure – External Shape methodology)

The following methodologies / tips, help to increase performance:

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Options and Settings

Use ‘Isolated’ rather than ‘Interconnected core’for the shellable features (where applicable):

‘Isolated core’ means only the current shellable feature is used to compute the shells, which is much faster.

The Manual Update mode should always be used. Using Manual Update, it becomes possible to run the update after a series of features have been defined.As most Input/validity errors (e.g. non-closed profiles..) can be detected during the feature definition itself, it is not necessary to run the update to check if the inputs were correct.

Manual / Auto Update icon in the Tools toolbar allows to switch the Update Option directly without going through the menu Tools/Options

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Dummy Cavity / Core (1/2)

> 1min < 15s

Updatetime

Complex Core & cavity With dummy cavity

ComplexCore & cavity

with dummycavity

The most costly features to update are usually the core and cavity styling surfaces which define a complex shell. But a designer seldom needs to see the cavity side when designing features that only affect the core (like ribs, bosses) and vice-versa.

Therefore it is very efficient to use simpler ‘dummy’ core or cavity when concentrating on the design of exterior or interior features respectively.

Cav

ityS

ide

Cor

eS

ide

Same coreDummy Shellable

Original Shellable

Dummy Cavity

When working on the interior (core side):Create a new ‘Shellable Feature’with the same core surface but a simpler cavity side

Advantages:The update time can be dramatically reduced. For an Industrial Example with approximately 60 features, update time reduces to 1/8th.

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Dummy Cavity / Core (2/2)

Deactivate Shell Properties

DummyCore

When working on the exterior (cavity side), you can select a simple Core Surface using the Dummy Core methodology.

If the core is ‘interconnected’ or ‘isolated core’, simply deactivating the ‘shell properties’ can also help us save the update time. It is almost similar to the ‘Dummy Core’ methodology as there would not be any shelled volume.

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Powercopies


Data StructureIn this lesson, you will learn to manage the design inputs and external shape characteristics.

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Design Order Reminder

= =

In Functional Design, you need not care about creation order of functional features. Each feature is independent. However, to clarify your design intend, you can:

Reorder your features (this does not affect the end result)Regroup your features in Functional Sets.

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The first step in Functional Design is to create a new Part. Hybrid Mode is notrecommended as the Bodies created with Hybrid Design mode cannot contain any Solid Functional Set.

For construction elements, you can create a Geometrical Set to group the sketches, surfaces etc of the functional features.

Wireframe references like planes, axes can be kept in a different Geometrical Set.

Managing Design Specifications (Design inputs)

Disable hybrid design Construction Elements and Wireframe References

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Functional Set is a organization feature similar to geometrical set :

It defines a group of functional featuresIt can contains functional features and also sketches, wireframe or surface featuresA functional set can be the ‘In Work Object’. New functional and wireframe features can be directly created in it.Features displacement between and inside functional sets is possible

The Functional Set feature provides a full capability to organize and manage the specification tree in order to group features by function and to capture design intents in a better way.

Functional Set

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Sketches: Update Cycle and Associativity in FMP

Sketcher tool in CATIA is compatible with Part Design as well as FMP. A good practice suggests not making constructions based on faces or edges, using Functional modeling or Part Design. However, sometime it’s unavoidable because the workaround may be too complex for getting the same type of associativity.

FMP is conceptually Order Independent so reuse of feature geometry to create a new geometry should be avoided.

With Part Design, you design in sequence, so it does not matter if you create a constraint with a previous feature. With FMP, as the Features are order independent (parallel contribution), you should not use them to constraint new ones.In other words, the FMP process follows the behavior rules and not the order sequence, therefore a face or an edge might not become available for other constructions.

RecommendationsUse geometries / sketches based on independent references construction elements (also called Skeleton or Framework). However in FMP, some selection on existing solid are allowed and can be managed easily if you limit this usage inside separated bodies.

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Self Feature Edge

Self Feature Vertex

Cross Vertex

Cross Edge

Sketches: Solid Selection Possibilities for FMP

FMP allows to create small sequences of features dependencies:Sketch support can be created on planar faces of existing function

Sketch constraints can be positioned on those type of solid geometry: self feature edge, self feature vertex as shown in the image below.

However, FMP Functional Modeler, will detect an ‘Update Cycle’ and will display the following warning in all the other cases. For example. Cross edge, Cross vertex, faces as shown below.

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Introduction to the External Shape Methodology

The External Shape Methodology consists in structuring bodies for establishing the differentiation of features before or after the Shell, providing an environment similar to the Part Design, with the possibility of inserting features before or after the shell.Points to note about the External Shape Methodology:

The ‘External Shape’ is an option available in all the Shape Features and also in the Remove and Intersect Feature Modifiers.It allows defining the basic volume of the feature (adding the desired behavior).It can be used for reusing existing shapes created with:

� Functional Molded Part or Part Design bodies, � Closed ‘Join Surfaces’, or surface closable by planes in its extremities.

In other words, the external shape is considered as a solid body whatever be the type of external shape you select. The type of external shape you select could be defined using FMP, PDG or GSD, IMA, etc.

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Characteristics of the External Shape

You can use the ‘External Shape’ option in the following cases:

Warning: Take care to put 0mm in the solid functional set that define the External shape body (in order to have a solid, not a shell)

Partitioning of a functional body into ‘functional cells’ for better management of complex bodies.Reuse of older models that are based on Part Design (legacy data)Transformation of surfacic shapes or imported parts into Functional BodiesImproving performances (The body which is selected as external shape is not impacted by the update of the main feature in which the body is selected as an external shape)Controlling better the model robustness (The model can be updated step by step using local update)

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External Shape Vs Push, Pull, Fitting

The results of using ‘External Shape’ are compared with the results of using Push, Pull and Fitting:

If you create a ‘Shellable Feature’ with wall direction as - ‘Outside’, the result is similar to Pull operation. Optionally, ‘Pull’ can generate a ‘Protected Volume’.

Using a Protected feature based on an external shape is identical to using Fitting feature.

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Assume that several faces of a solid body have been selected to perform the ‘Union Trim’operation and now this solid body is likely to be replaced by a different solid. In such case, CATIA will ask the designer to select new faces belonging to the replaced solid body. This behavior is quite annoying because the removed faces are difficult to locate because the solid is actually in another part. There is also the risk of forgetting some faces due to which the result of the trim could be wrong.

External Shape Vs Part Design Union Trim

The results achieved using external shape are compared with the results of Part Design Union Trim:

The External or Internal feature based on an external shape can be compared to the Union trim PDG operation. In FMP the shape trim is automatically performed, whereas while using the Union Trim some face(s) have to be selected manually.

The benefit of FMP is that it increases the robustness while replacing the external shape by a new one because there is no reroute operation to be perform. This is particularly valuable for ‘design in context’, where the external shape is coming from an external part definition which the current designer cannot control.

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Applying the External Shape Methodology (1/4)

Part Design (PDG) Functional Modeling (FMP)

Open Part : External_shape_methodology.CATPart

You will study Functional Modeling using the External Shape methodology in comparison with the traditional (historical) approach.

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Traditional (PDG) Functional Modeling (FMP)

The order of design features of the part using Part Design is given below:

The sketch of the pad.4 forming the rib is constrained to boundries of the part.

The Shellable Body in the Functional Modeling Body is equivalent in sequence to the Shell in the Part Design Body. I.e. the two fillets, are both propagated into the Shell irrespective of if they are from FMP or PDG,

Identical

Identical


Pad.1Pad.2EdgeFillet.1Edge Fillet.2Shell.1Pad.4

The order of design features of the part using FMP is given below:

Added Prism.1Added Prism.2EdgeFillet.1 (FMP Edge fillet)EdgeFillet.4 (using Part DesignA new Body called ‘Functional Modeling Body’A Shellable Body in the ‘Functional Modeling Body’ created using the ‘External Shape’ body for Shape definition (Shell thickness is specified)Rib (with its profile NOT constrained)

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Now the shape has to be extended with a Pad or a Prism according to the yellow profile.

Define in work the last feature before the Shell

Traditional (PDG)

Add a pad and two fillets

Define in Work the External Shape body

External Shape

Identical

Identical


Functional Modeling (FMP)

Inserted an Added Prism and two fillets

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The design shall be extended with a Pad or a Prism according to the yellow profile.

Traditional (PDG)

Make the Part Design Body as the In Work Object.

Edit the Sketch for changing the constraint and getting the desired result

Identical


Functional Modeling (FMP)

Make the Functional Modeling Body as the In Work Object.

The Rib did not occoupy the extended shape.

The shell is automatically updated and the fillets get propageted into the shell.

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Part Structure and Multi-bodies

When designing a complex part with a single functional body, the tree might become very long and difficult to understand. Therefore it is necessary to divide it into several bodies according to the structure below.

The Main Functional Body gathers the Functional Specification, GSD features and to produce the resulting geometry

All these Functional Bodies gather the geometry of specific functions (Ribs, Bosses, etc.) This geometry is used in Main Functional body as External Shape.

Master Sketches

Reference Planes

Bosses

Fixtures

Main Ribs

Cross Ribs

Holes

Main Shape

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Order Independence and Modifiers (1/4)

In the Functional Modeling concept, the behavior is embedded into features. This allows generation of geometries resulting from self-standing ‘Functional Features’ which maintain the required associativity. So the result is independent of generation order of the ‘Functional Features’

Whereas in all the history based systems, (Part Design for example), the geometry generated by a feature and all the required associativity is always derived using the existing geometry which is already generated. Therefore the result is dependent on the generation order of the geometry.

= =

Basic and Functional Features

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However, the desired geometry cannot always be generated using ONLY the ‘Functional Features’ because they do not include all the options necessary for generating any geometry.

Functional Features + Feature Modifiers + Dressup

= Desired Geometry

To enable the generation of a complex geometry associated to a single behavior (a single functional feature), “(Functional) Feature Modifiers” and Functional Dressup features are available in FMP. These modifiers can change a geometry created by Functional Feature’s while maintaining the Functional Feature behavior.

As the ‘Feature Modifiers’ and ‘Dressup Features’ do not carry a behavior in themselves, they are “sequence dependent’.

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So sometimes they have to be “reordered” for getting the desired results (i.e. when several fillets are modifying the same functional feature). For such purpose, you can use deactivate command as shown in the example below.

Initial design

Open Part : Order_independent_and_modifiers.CATPart

Deactivated Edge Fillets

New Edge Fillet added

1. Deactivate all the modifiers that are children of the feature to be modified.

2. Insert the required Edgefillet feature (Radius = 10mm)

3. Reactivate the 2 features.

Position in the tree does not reflect the sequence of fillet creation see next page.

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Edgefillet.4 is inserted before the other fillets as you can see using the parent children command. Like in GSD, there is no “Define in work object” for a feature in FMP, however, the ‘Autosort command’ helps to quickly sort the tree according the modifier relations.

EdgeFillet.4 is now sorted according the modification relations which is not the creation order

Edgefillet.4 was created in the tree after the existing fillets (last position)

Edgefillet.4EdgeFillet.2 is rolling on Edgefillet.4So, it is computed after EdgeFillet.4

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Functional Set and Modifiers

A Functional Set can be used to logically group the local modifiers. Autosort command can help to quickly reorder the tree according the modifier relations.

Contextual menu helps to Activate/deactivate Show/hide the components put in the functional set

Using ‘Insert’ menu, you can create a new Functional set, then use the command ‘Change the Functional Set’ to move the features.

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Rerouting Fillets and Drafts

When the system detects a need for rerouting features, the current Functional Modelling implementation cannot display the situation required for identifying the reroute path (i.e the edge to reroute a fillet)(unlike in Part Design). In other words, the Solid Functionnal Set cannot display any geometry if some features are in Error.

A bypass for the above problem exists in R16:Deactivate the entity (and all its children) to be rerouted: the display is updatedEdit the Entity to be rerouted for applying the appropriate selectionReactivate the entity to be rerouted

Since R17, you can use the ‘Display only parents’ command while editing Features in Error (the feature and all its children will be deactivated) so that you will be able to see the current geometry along with the parents of the feature in error.

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Shell ManagementIn this lesson, you will learn important methodologies for managing Shell properties and specifications.



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Managing Design Specifications (Shell Properties)

Shell Properties feature:

Adjacent Tangent Faces will be removed.

If you try to remove a lateral face.

Lateral face removed

Opening created using a Core or

Protected feature

Lateral faces can be removed using Core or Protected feature

Preferred methodology:

Shell thickness is a property of the functional body: removed faces can be specified at any stage of the design because of the order independent nature of Functional Modeling.Avoid removing lateral faces if you intend to add fillet on the feature. The removed faces could be extended by tangency and give unexpected result after a design change.

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The Shell in Functional Modeling (1/3)

In FMP, the Core of a shelled body is automatically generated taking into consideration, the effect of Basic Features, Functional Features and Feature Modifiers.However, sometimes the functionality of automatic core generation may not be successful due to complex geometry. In such cases, FMP allows you to define the desired ‘Type of Core’ for the ‘Shellable Feature’.

Interconnect Core (default)Creates the Core automatically.Generates the Core by offsetting the resulting external shape (sum of all Shellable), according to the wall thickness defined in the Shell Properties.

Three Types of Cores can be selected for a Shellable Feature

Interconnected Core

Interconnected Core

Interconnected Core

An interconnected core of a Shellable Feature is the one which flows into the interconnected core of an adjacent Shellable Feature.

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Isolated CoreIt offsets the faces added in the shape only for the feature in consideration. Consequently the complete body Core is the aggregation (sum) of the automaticallygenerated Core and the isolated ones. This is faster than the Interconnect Core.It allows you to define a wall thickness for the Shellable Shapes different than the one defined in the shell properties.The only difference in the result as compared to the Interconnect Core is the possibility to generate lumps when one or more elements of the profiles supporting different features have a distance less than the wall thickness.

In the above example, the core of Shellable Prism.1 is isolated. So the core does not flow from ShellablePrism.1 to Shellable Prism.2.

However the core of Shellable Prism.2 flows into Shellable Prism.3 because they both are interconnected.

Interconnected Core

Interconnected Core

Isolated Core

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Select CoreThe Select Core options allows you to define the Shellable Shape based on an existing core geometry. The existing core geometry can be a Solid Body or a closed surface. It is particularly useful when the external shape is not offsettable and/or when a variable wall thickness is desired. It also facilitates continious variation in wall thickness.

Selected Core

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Solving the Shellable Feature-Error

Select the Core tab, select the feature that cannot be shelled with others, and switch from Interconnected to Isolated core.

For the feature that cannot be shelled at all, Extract or create a surfacic Body and then select this Body as the new core.

2

Edit the shell properties1

Depending upon the geometry, sometimes the body may not be ‘shellable’. In such cases you can solve the ‘Shellable Feature’- error if any.

3

2

31

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Isolated Core Vs Select Core

Isolated Core: Use this option in the following cases:When it’s already known that the shell thickness generation will be in error.For editing the Shellable Features, changing core type from Interconnected to Isolate Core, for fixing a shell thickness generation error.When a different thickness than the Body thickness is required for the Shellable feature.When the required Core shall be a multi volume (disconnected volumes).To improve performances by simplifying the Core calculation

Select Core: Use this option in the following cases:

To define the Shellable Shape based on an existing core geometry i.e. when different wall thickness required. When it is required by manufacturing needs.For improving the performances

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Creating Basic Features using Surfaces

Close surface created in GSD

Functional Solid after removing the top face

In order to create the shell when external part is defined with a closed surface, you need to follow the steps given below:

Create the outer surface using GSD, FreeStyle, Imagine & ShapeUse the Shellable command with External Shape for Shape Definition; select the surface Use the Shell properties command for defining the wall thickness and to remove the face(s), if required

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Thin Part in Functional Modeling (1/2)

Cavity Selected Body Core Selected Body

Shellable Prism from Surface Up to XY Plane

In the Shell Property: Remove bottom + lateral faces

In order to keep the benefits of the FMP behaviors, thin Parts have to be created using at least one Core area. Four methodologies are possible to create a Core volume from a non-closed Surface:

Shellable Prism from Surface Up to Plane

Closed with GSD features (refer to the Car Audio exercise)

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Thin Part in Functional Modeling (2/2)

The methodology to be selected is depending of the Parting Curve or Surface needed.

Added Thick Surface Core Prism Feature

Prism with Length Cut modifier with Surface Design as Input

Prism Up to Surface/Length and optionally Cut modifier from a user define Sketch(refer to the Power tool exercise)

Added Thick Surface + Core Prism Feature

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Features Defining or Impacting the Shell

Do not select existing solid geometry but specify features according the function that is requested on your part

Any feature generating a protected (Hole) or internal volume

Pattern of Shellable features

Remove with Wall Thickness

Cut

Pull

Push

Reinforcement

Rest

Boss

Cutout

Pocket

Core Volume

Internal Volume

Shell Property

Shellable Feature

IconName of Feature

As a reminder, here are all features that you can use to modify shell according to your needs:

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Design in ContextIn this lesson you will learn some tips for designing in context using FMP features.



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Design in Context: Introduction

Design-in-Context is the terminology used for designing parts based on geometry of other parts in the product.

The Functional Modeling offers the ‘External Shape’ options in Functional Features and also in Feature Modifiers. Using this option, an external body can be used to design the part. Any change in the external body automatically propagates into the design part. No user interaction or reordering is required for the propagation of such changes.

While using the concept of ‘Design in context’, you should think of the most appropriate feature to be used. For example, when a part has to be modified for fitting an external component in it, you should use the geometry of the external component as the ‘Tool’ for the ‘Push’ or ‘Fitting’ feature. This recommendation may generate a complex geometry but at the same time, it will significantly increase the model robustness and allow automatic change propagation.

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Based on BodiesPush

Pull

Fitting

All the Basic Features, using body as an External Shape

Based on Surfaces:Cut

All the Basic and Functional Features, using a Surface in the limit(s), a Thick Surface or a surface as an External Shape

Based on SketchesPocket

Rest

Cutout

All the Basic Features based on sketches.

Features Belonging to the Design in Context Category

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Behavior Extraction

Part.1Part.2 Envelope BodyPart.2 Part 1 modified by Part.2

Envelope Body Tool

Core Extraction

Cavity Extraction

Volume Extraction

Envelope Body

The Designing-in-context features based on bodies are very powerful and can provide very significant results quite easily. However, the shape of a design part which is modified using the geometry of an external part may not always be the exactly desired shape.In such cases, an “Envelope Body ” should be defined and used in the Design-in-Context features.

The Envelope body can be considered as a body derived from another body (the main body), according to some rules. FMP Functional Extraction commands allow you to build the desired envelope body.

With FM1, the only way for building the Envelope Body is to Copy/Paste the main body, then change the shell thickness to zero and delete the features that are not required. In addition to this, some features might be edited for removing the unnecessary behaviors (mainly fillets), changing limits, etc. till the desired shape, is obtained.However it should be noted that this method is not fully associative, unless specifically fully built with parameters. The ‘Paste’ operation of a functional feature is supported only as “Specified in the Part Document”, therefore the full associativity is not maintained. While using the FMP Behavior Extraction, full associativity is possible.

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Coupling Example: If the Coupling shown in the image below has to be supported by a series of ribs of a molded part, its full definition will not be directly useful in a Fitting.However its envelope body can do the job perfectly. Its envelope body can be offset and used for a Fitting feature and later the ribs can created and limited to the envelope body. The draft can also be imparted to the ribs.

Examples of Envelope Body (1/2)

It adds the required functional gaps.It takes care of manufacturing details.It improves performance and robustness.

Example: Use of envelope in a coupling

Following are the advantages of this methodology

Model Used: Coupling.CATPart

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Examples of Envelope Body (2/2)

Draft / fillets added on the envelop

Resulting geometry on the part

Conceptual definition made directly from the part

Battery Housing Example:

Complex geometry is generated for defining a battery housing, using the Battery envelope shown below.

This geometry is generated by a Pull feature (using the envelope of the battery) and a Protected Volume, for limiting the Pull extension.

Now due to manufacturing constraints, if it is required that the faces of the battery housing should have more draft, the required modifications can be directly done on the envelope body of the battery.

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Using Envelope Body Methodology

Part-1Part-2

You will now see the use of Extraction Behavior in the ‘Envelope Body’ methodology.

Let’s assume that we have to modify Part-1, to fit Part-2 in it. Currently, Part-1 is shelled and Part-2 is not shelled.

By using the Envelope Body concept, we can get the desired result even after shelling Part-2. To achieve this, we have to use a New Body, the ‘Envelope Body’ in Part-2, which will act as the tool for the Push operation.

If you Push Part-2 into Part-1, keeping a larger and constant wall thickness, here is the result.

Now if you shell Part-2, the end result is not the desired one.

Push Part-2 into Part-1

Part-1Desired Result

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Using Envelope Body Methodology: First Method (1/4)

Open Product : Envelope_Body.CATProduct

Part-1

Let’s assume that the Part-2 is not a simple model, but has the shape, generated with a cutout.

Part-2 ( With Cutout)Desired Result

Part-2 (Simple)

The result, without using the Envelope Body concept, is not the expected one.

Undesired Result

Push Part-2 into Part-1

The adjoining image, shows the result of using the Envelope Bodyconcept. In this case, the cavity of Part2 has been extracted and its Protected Behavior is changed to ‘Added’ behavior and then used for the Push operation.

Simply by changing the ‘Protected Behavior’ to ‘Added Behavior’ cannot always give you the desired result. As you can see the above image, it is still not the desired result because the Cutout has affected Part-1 which is not expected.

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So, in this case we need to exclude the ‘Cutout’ while extracting the cavity for Part-2 so that the Envelope Body which is generated gives the desired result when used with the Push operation.

Part-1Desired Result

Part-2

Envelope Body of Part-2

Envelope Body excluding Cutout

Push operation using Envelope Body

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Now to create a cut in Part-1 (as shown in image1), if you use behavior extraction of a cutout of Part-2, it would generate a wall (as shown in image2) below which is not desired.

Now Let’s assume that Part-2 is modified with a Shellable Prism with fillet in the side and bottom

Automatically Part-1 is updated as below, where we can see the fillet in the side and bottom effect from the Push, including maintaining the wall thickness constant too.

Now we can realize that an ‘Envelope body’ can be a body derived from other part excluding some features. You can also change the behavior of the extracted envelope body.

Desired Result Part-1

Image1 Image2

The desired result can be obtained by extracting the ‘Volume’ of the cutout of Part-2 using the ‘Volumes Extraction’ command, and then using this ‘Volume’ as the ‘Tool’ body to create a ‘Protected Feature’ in Part-1.

Desired Result Part-2

Modified with a Prism and Fillets

Part-1 gets updatedPart-1 automatically gets updated with the fillets and the Shellable Prism and the wall thickness is also maintained constant.

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The right theoretical solution requires changing the fillet profile from an arc to a conic, for supporting the change in the clearance. This theoretical solution is not implemented yet.

A workaround consists in defining the envelope body and the relative push using another method, which is more generic.

Let us now assume that Part-2 has to be in contact with Part-1 at its bottom faces and there should be a larger clearance between the side faces of the two parts as shown.

Part-1

Part-2But there is a problem: the clearance on the side of the Shellable prism update is equal to the clearance in its bottom face, which is not as intended.

For this, in the advanced tab of Push command, the side faces are selected as ‘Other Clearance Faces’ and a clearance value is specified.

But the problems is that the clearance gets propagated to the bottom faces because the faces are tangent due to the fillets.

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Using Envelope Body Methodology: Second Method (1/2)

The result of Part-1 is as shown above because only one feature has been extracted. Unlike in method 1, both the Shellable Prisms and all other features which had contributed to the cavity extraction have not shown their effect in the result. However the circular protected volume which was a different feature, has shown its effect in the result.

Here, for the second method, we will start from the end result of first method.

Create a New Body and rename it as Tool-2Extract the behavior of the second ‘Shellable Prism’ with the fillet in the bottom and change its behavior to ‘Added’.Edit ‘Push’ in Part-1 and select the new Tool-2 and reset all the clearances to 0.

Different Clearance

Result Part-1

Now we will generate the required clearances in the Tool-2, using the following method:Offset the ‘Added Behavior Extraction’ (offset all the faces as the push does). Cut the Offset feature with a plane positioned at the desired clearance distance from the bottom face (to do so, it is better to define a plane offset from the bottom face of the Shellable Prism and then cut the Offset feature using this plane as cutting element. The differences in clearances are shown in the adjoining image.

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If a sharp edge as shown is not acceptable, for any manufacturing reason,

a functional fillet can be added on the corresponding sharp edge of the Tool-2.

Using Envelope Body Methodology: Second Method (2/2)

This methodology is to be used when no sharp edge in the push result is desirable (irrespective of the clearance needs).

Unlike method one, we need to repeat this operation for all the Part-2 features which would be contributing to the ‘Push’ definition.

For removing the sharp edge, a functional fillet can also be inserted in Tool-2.

The result of ‘Push’ operation with difference in clearance on bottom and side faces is shown in the adjoining image.

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Design for ManufacturingIn this lesson, you will learn tips and recommendations for designing the parts from manufacturing feasibility point of view. You will also learn specific methods of extracting Core, Cavity and other EDM inserts.



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Design for Manufacturing: Introduction

You can also use ‘Power Copy’ to define advanced functions.

Use the Part Design Draft only when none of the above method is applicable.Even in this case it is possible to build a very robust model, if only one feature is involved or all the involved features have the same behavior. The following workaround can be used: (this workaround is also valid for the fillets):

Copy the Features that require the draft, (including any existing ‘Draft Properties’) and Paste them into a ‘New body’If the behavior of the features is different, change it to ‘Added’ or ‘Cavity’ as required.Apply the required Draft, according to the above methods. Include ‘Part Design Draft’ if necessary.Delete the copied features from the Part bodyMake the Part body as the ‘In Work’ object.Create ‘Basic Feature’ using the new body, and apply the desired behavior.

The Draft Properties feature allows to specify the draft even before creating the features, thus enabling a draft orthogonal to the Function direction too. In molding, this capability is useful for predefining specific pulling directions for different sliders of the mold tooling.As far as possible you should use the Drafts and Fillets which are intrinsic to the Functional Features to improve the design stability and to make the specification tree look more simple.

You should use the ‘Functional Draft’ when the draft cannot be inserted directly in the Features.

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Applying Draft using Tools (1/2)

Using the ‘Envelope Body’, you will see how drafts can be applied easily:

If Part-1 requires a different draft than Part-2, due to material difference, the draft can be applied to the envelope body, to maintaining full associativity. If you apply draft on the faces of Part-1, it would decrease its robustness.

With Envelope Body Definition - method two (only R16) following steps should be followed:

Make ‘Tool-2’ as the ‘In Work’ object.Deactivate the functional edge fillets, if anyCreate two functional drafts selecting the side faces and the neutral elements.Reactivate the edge fillets, if any.Update Part-1, ( End result is shown in the adjoining image)

Side Faces

Applying Draft

If draft is applied to Part-2, Part-1 automatically gets updated. The Push feature propagates the draft to Part-1.

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Applying Draft using Tools (2/2)

Any modification in the shape of Part-2 gets automatically propagated to Part-1.

This methodology can also allow you to build drafts in opposite directions (but in this case Part-1 cannot be manufactured).

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Case 2: If Part-1 requires a fillet in the internal faces generated by the push, and also requires a different draft as compared to the faces of Part-1, you have to generate an additional tool body because the draft modifier cannot be added after a fillet resulting from the offset operation.

Case 1: If Part-2 has no fillet in the bottom part and no fillet is required in the push result, You can use the Draft modifiers, and draft the internal faces generated by the Push, (where a different draft angle between the internal and external faces is required).

Constant Wall Thickness cannot be maintained in this case, different solutions possible, according to the requirements

Walls with Different Drafts (1/2)

In a new body, create an Added Feature using extracted body from Part-2. (This new body will be used for the Push operation)Offset the new body imparting the required clearances.Draft the required faces.Fillet the required edges using functional fillets.

The additional tool body can be generated in the following way.

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Walls with Different Drafts (2/2)

Now you can use the newly created body as a tool for the fitting operation.

Using this newly created body as an external shape, create a Push operation.With this approach the Push in Part-1 can be converted in a Fitting, since the result is the same (all faces are generated by the envelope body)

This approach allows managing three different drafts:one in Part-2one on the external facesone on the internal faces

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Generating Different Drafts between Faces

If the result of ‘Push’ operation should have a fillet in the bottom of the part (due to manufacturing reasons or due to design requirements), the desired result can be obtained using the following process:

Now you can use the method specified in the previous slide to get the desired result.

Create a new body Tool-3, extract the required features from Part-2 excluding the fillets which are tangent to the faces to be drafted.

If the fillets are internal to the features, remove them from the features and create explicit functional fillets. This will help us extract a Functional Feature excluding the fillet.

Build a new body (Tool-4), and extract features from Tool-3 without the fillet.

Part-2

Part-1

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Part-2Part-1

Walls with Different Drafts between Faces: R16 – (1/4)

Part-2 has already been drafted.Part-2 is filleted around the area to be supported.Part-1 requires a different draft on its internal and external walls which shall be generated for supporting Part-1.The draft on the external wall of Part-1 should be different from the draft applied to Part-2.The housing of Part-2 shall have a clearance on all the lateral walls, where as the supporting wall shall allow the two parts to be in contact (OR – The lateral and supporting walls should have different clearance values)

The two parts are already positioned. Part-1 has some faces removed, for making the following steps easier to understand.

We’ll define two tool bodies, one for the external part (Tool-Ext) and one for the internal part (Tool-Int)Tool-Ext will define the support for external walls, including the clearances, drafts and fillets.Tool-Int will define the support for internal walls, with its drafts and fillets

If the result of ‘Push’ operation should have a fillet in the bottom of the part (due to manufacturing reasons or due to design requirements), the desired result can be obtained using the following process:

The design requirement is that Part-1 is to be modified for housing (supporting / fitting) Part-2

Conditions as follows:

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Walls with Different Drafts Between Faces: R16 – (2/4)

Definition of Tool-Ext:

If there exists any fillet in Part-2 which is internal to a feature and which is around the area tobe supported, remove it from the feature and add a Functional Fillet at that location.In Tool-E:

Using the ‘Behavior Extraction’ tool, extract the Feature of Part-2 which contributes to the lateral faces which are to be supported by Part-1. Change the extracted behavior of the feature to ‘Added’Offset the Behavior Extraction, according to the larger clearance(Clearance required at the lateral walls)The offset will result in addition of material in all directions, and the amount of material added on the bottom face is not as desired. So Cut the result of offset at the bottom using a plane. The plane used to define the bottom clearance should be defined by offsetting the bottom face of Part-2.Apply a Functional Draft on the lateral faces for providing the required draft for the external walls.Add a Functional Fillet on the bottom face edge which is generated by the cut. Radius of the fillet should be equal to the ‘bottom-fillet of Part-2’ + ‘the lateral clearance’.

Cut Draft Edge Fillet

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Definition of Tool-Int:

Using the ‘Behavior Extraction’ tool, extract the Feature of Part-2 which contributes to the lateral faces that are to be supported by Part-1. Change the extracted behavior of the feature to ‘Added’Offset the Behavior Extraction, according to the larger clearance(Clearance required at the lateral walls)Cut off the Offset for defining the supporting wall thickness. Use a plane to cut the offset. It is recommended to define a plane at distance = wall thickness + bottom clearance.Apply a Functional Draft on the lateral faces for providing the required draft for the internal walls.Add a Functional Fillet on the bottom face edge which is generated by the cut. Radius of the fillet should be equal to the ‘bottom-fillet of Part-2’ + ‘the lateral clearance’ or larger.

Offset and Cut Draft Edge Fillet

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Let us modify Part-1 housing (supporting) Part-2:

Use the ‘Fitting’ command and select ‘Tool-Ext’ as the ‘Tool Body’ for the Fitting command. (Push is not used because performance of ‘Fitting’ is better than ‘Push’). Create an ‘Internal Feature’ and select ‘Tool-Int’ as an ‘External Shape’ for the Internal Feature.

Result obtained is shown in the above image. The result satisfies all the needs and all the conditions, and also provides larger model robustness.

Fitting

Shellable Prism

Internal Body

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Drafts on Faces generated by Push or External Shape

The push, with clearance, generates the expected result, impacting the bottom part only. But the draft analysis shows an undercut on the faces, generated by the Push. This undercut has to be eliminated.

Tool Body

The problem here is that we need to modify the blue part (already divided) to adapt it to the orange part, keeping some clearance. Both parts are designed completely with FM1. In this example, the complete real life part has not been shown for confidentiality purpose.

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Functional Draft with Tangent Continuity (1/3)

The faces to be drafted are identified and shown below. The Part Design or Functional Draft cannot be applied to draft this configuration of geometry. So the part should be simplified by removing the fillets. The draft can be applied after removing the fillets which can be later rerouter and fixed.

Fillet to be removed

Faces to be drafted

Applying the draft intrensic to the features of the part, applies draft on all the faces. It does not take into account the faces generated by the push operation.

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Deactivating all the fillets, the part becomes as shown in the adjoining image.For the ‘Neutral Element’, a surface can be built using the profile which has been used to generate the basic shape.

A Functional Draft can be created by selecting one of the faces to be drafted, and the Neutral element above.

The orange part was completely built using Functional Modeling.An instance of it can be obtained in the following three ways:- With Relational Design (Cut & Paste) (the result is not fully

associative)- With the Extractioin Behavior (FMP) (the result is fully

associative)- With the Design Collaboration (CD1) (the result is fully

associative)

All Fillets Deactivated

The surface which will act as the neutral element

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Activating all the remaining fillets, the desired draft result is obtained. Faces are drafted and the tangent continuity is maintained . The result of the push now shows the appropriate drafts. From the draft analysis, you can notice that there is no undercut.

After applying the draft, the fillets have to be rerouted. At the bottom of the faces which are drafted, new edges are developed as a result of draft. These edges may generate some discontinuity which has to be fixed.Analyzing the edge shown in the first image below, a tangent discontinuity larger than the one allowed by the fillet is shown.

Adding a Function Fillet on the edge causing the discontinuity, the problem is fixed, as shown in the second image above.

Edge causing a Tangent Discontinuity

Edge causing a Tangent Discontinuity is filleted.

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Removing Undercuts using an Envelope Body

Create a new body and add the component body in it. Offset this body with a larger clearance.Thicken the required faces for adding material.To have different offset values at bottom and lateral faces, cut the faces of this new tool body using planes.Build a plane passing through the two lines. One of the line should be along the pulling direction through the vertex and the other line should be the component edge.Cut the added material with this plane, with an offset equal to the clearance desired on this faceApply a Part Design draft angle on the face which has resulted from the cut operation recently. Use this body as a tool in a push operation (without clearance) for obtaining the desired result.

A push operation may sometimes generate an undercut. The image below shows a simplified representation of such case. To remove such undercut, you can use the following process:

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Local Thickness (1/2)

Following are the ways to locally change the thickness of a wall:

Selection of a face of the SolidPros : It provides direct and easy access to elements that are to be modifiedCons: The design may not be robust in case of change of the solid.

Add new specifications (new features or modifiers)Pros: Specifications can be easily managed.

Wall thickness can also be changed using one of the following methods:

By assigning different shell thickness using the Advanced tab in the Shell Properties dialog box.By assigning different thickness using Functional Feature (‘Core Feature’, or ‘Thickness Feature )By using – [ Volume Feature + Thicksurface-Option]: This thickness of a face can be modified using the ‘Thick Surface’ option as shown below.

Pros: As this method is based on functional feature and functional need, it is more robust.Cons: If a face has participated in more than one feature, the functional feature (used to modify thickness) has to be applied to each feature in which the face has participated, deactivating the other ones.

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Local Thickness (2/2)

By using the appropriate Shape Prism and selecting the face to be thickened. This method provides a result which is different than the Thick Surface command.

Pros: As this method is based on functional feature and functional need, it is more robust. The ‘Protected’ and ‘Remove’ Feature can also be used to reduce the thickness.Cons: If a face has participated in more than one feature, the functional feature (used to modify thickness) has to be applied to each feature in which the face has participated, deactivating the other ones.

Using the ‘Dress-up Feature’ ‘Thickness’ of (Part Design) you can modify the thickness of a selected face of the functional solid. For the ‘Thickness’ feature, positive value can be used to increase thickness and negative value to reduce the thickness.

Pros: It is very easy to use this method. It is good for last minute adjustments of local thickness (i.e after flow analysis). Cons: This method does not follow the functional approach. And can be deployed only after the final result of the functional solid.

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Tips for ReferenceIn this lesson, you will learn various tips, which will be useful during the general use of FMP workbench.



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Extend Internal Features Outside the Core (1/3)

The following explanation provides tips to extend the ribs across the shell volume as shown in the image below.

The simple way to get the desired result is to use the option Extention Type = ‘Across Removed Faces’ but it has several draw-backs like the rib extends sometimes may produce and undesired result if the rib sketchs are not constrained to the edges of the part. Such constraining may also create update cycles.

The above image-1 shows a volume which is cut by a surface. The magenta colored faces are the faces that are removed using Shell Properties command. Image-2 shows the desired result.

image-1 Image-2

Undesired result got by using the option Extension Type = ‘Across Removed Faces’

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In this way you can extend the internal / rib feature outside the default shell volume by eventually extending the shell volume using ‘Core Feature’.

Another possible way is:� Create a ‘Rib’ / Internal feature as usual (No extension)� Extend the internal shell volume using ‘Core Feature’ as shown above.

Rib Feature maintains the rib inside the shell volume. Core feature extends the shell volume and the rib propagates into the extended shell volume.

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A third methodology consists of dividing the basic shape instead of cutting:

Define the basic shape upto the level of the extension required

Instead of cutting the shape with the surface, or a plane, or removing a face, divide the basic shape with the surface or plane.For Undivided Volumes Field in the Divide Feature dialog box, the ‘Core’ option. Keep only the desired side of the ‘Divide’ feature.

Apply the rib in the divided body.

The rib is properly generated, even if the profile extends beyond the shape

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Volume Creation from a Surface

If the surface cannot be closed by a plane, close it (using GSD Fill), create the volume.

Volume of any behavior can be created from a solid body. However it can also be create from a surface if the surface openings can be closed by planar faces.

Surface opening that can be closed by a planar surface

Shellable volume created using the Surface.

After removing a face

Surface opening that cannot be closed using a planar surface

Close it using GSD ‘Fill’, join if required.

And then create the Volume.

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Use Joined Surface for Cut

For using surfaces for cutting or trimming Functional Body, the surfaces should be joined.

Use joined surface to cut the ‘Functional Solid’.

If you use Cut feature to trim the Functional Body using a surface, the surface you use should be joined.

Use GSD Join feature to join the surfaces.

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Use Up to Plane/Surface Limit or Cut Feature

Basic Features and many Functional Features support the ‘Up to a Plane’ or a ‘Surface’option, including an optional offset, as limit. These limiting options are useful when you want to limit the ‘Shellable Features’ to pre-designed styling surfaces.“Up to” Pros:

Up to surface is valuable when the targeted surface is used as limiting reference. Very large scope of industrial features can be created related to only one reference surface (for example - Flange, engraving or local thickness change etc). Up-to-Surface makes a Functional Volume or Feature generating directly the desired geometry. This simplifies the specification tree.

The result of ‘Cut Feature Modifier’ is mostly similar to the ‘Up to Surface Option’. Optionally it can generate a ‘Functional Fillet’ at the intersection of the surface and shape it cuts. It also provides the facility of different wall thickness.“Cut” Pros:

‘Cut’ allows cutting the same feature by multiple surfaces.Using the Cut Feature provides a more understandable specification tree (the used cutting element exists in the specification tree). The Cut is suggested to be used for modifying the features in one go, when the limiting surfaces are not available up front. The Cut also allows to manage different design shape configuration by using several cut features for different configurations and keeping only one of these activated at a time.

Warning: Avoid using “Up to” with a ‘Face’ belonging to the current functional solid unlike you do in PartDesign because this creates a link between feature and creates a history/ dependency relation. It is recommended that you create a reference element (plane, surface) and then create all your features based on the reference elements. Using this method, you will also be able to manage design change using a simple ‘Replace’ command. The reference elements can be easily located as compared to an internal face of a solid.

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Parting Radius in the Draft Properties Definition (1/2)

But if designer wants a sharp edge for the parting, an other methodology has to be used (see it next slide)

Parting plane: No sharp edge

Parting plane: Sharp edge

Open parting_radius.CATPart

This option is a workaround to solve some issues that arise when the lateral fillets get distorted if the ‘Draft both sides’ option is used:

Open parting_radius.CATPartYou can see that the fillets are not correctly limited on the parting elementEdit the Draft PropertiesPut 1mm as Parting RadiusYou can see the lateral fillets are now re-limited by the parting fillet

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The exact expected solution (when the parting is not planar) is provided by the Cast Forged Optimizer (CFO) product (PDG toolbar advance dress up feature).

Parting Radius in the Draft Properties Definition (2/2)

Open: Parting_Radius_Not_Allowed.CATPart

If the designer wants a sharp edge for the parting, the recommendation is :

Alternative2 : Use a feature with local modifier limited by the parting plane.

Alternative1 : create one body for each side of the parting element and then import the result in the Partbody

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Possible Ribs Creation

Ribs in Auxiliary Functional body(Added features)

Main Shell

Shape created in the Rib Body must be “Added” or any function that adds to the cavity in order to be used in the main body. Otherwise the shape has no representation (unless there is a shell) and the functional solid is empty.

‘Rib Body’ used as Internal Feature in Main Shape Definition

Ribs can also be created using any one of the following way:

The advantages are:You can precisely control Rib definition (Variable thinness as example)Ribs are created in a separated Body

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Defining Mold ModelsIn this lesson, you will see specific aspects when your are defining Mold Models.


2. Improving the Performance3. Data Structure4. Shell Management5. Design in Context6. Design for Manufacturing7. Tips for Reference8. Defining Mold Models9. Creating and Using

Powercopies


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Mold Model Example

Core for milling Cavity for milling EDM Base for Core Cavity Inserts

Movable insert Cavity model resultCore model result

Let us study an example of a mobile phone part shown below to study the extraction of core, cavity and other mold inserts.

The Part

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How to Extract the Core as it is in the Part Model

This resulting core is the core as per the shape of Part. The Core for milling is extracted in a different way and is explained later.

The Resulting Core

Using the ‘Added Feature’, create its base upto the ‘Parting Surface’

Use Core Extraction command for extracting the “Core”, as per the shape of Part.

The Part

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How to Extract the Cavity as it is in the Part Model

The Resulting Cavity

The Part

Use Cavity Extraction command for extracting the “Cavity”, as per the shape of Part model.The result is a Protected Volume.

This protected volume when substracted from the ‘Added’ block (creating using ‘External Feature’ gives the cavity exactly as per the shape of Part. To get the Cavity, create an added Cavity Block using Added Feature upto the parting surface. The result of this operation is shown above.

This resulting cavity is the cavity exactly as per the shape of Part. The cavity for milling is extracted in a different way and is explained later.

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How to Define the Core and Cavity for Milling (1/2)

New Cavity

Part Body default

ExtractionProperties

(in the Part)

The Part

The Extraction Properties command allows you to exchange the default assignment of features selectively to Core or Cavity. Using this tool you can switch the protected volumes to affect either the core or the cavity. The difference in result caused by such operation is shown below.

Now the new Cavity is closer to the expectations, but not yet ready for milling.

Old Cavity

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How to Define the Core and Cavity for Milling (2/2)

Core Cavity

In the “Added Extracted Core” of the Core body exclude the features not to be milled

In the “Protected Extracted Cavity”of the Cavity body exclude the features not to be milled

Core for milling. Cavity for milling.

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How to Define the Model for EDM Tools (1/2)

This can be the model for drilling and a fixed insert too

Extract Volumes from all Features of Part defined for reserving spaces (except the holes).Change the ‘Protected’ behavior of the extracted volumes to ‘Added’.Extract the features to be machined separately from the Part body, using the BehaviorExtraction, changing their behavior to Added, (normally the Ribs and Internal Shapes)Extract any Push/Pull features if present (the extraction just generates a protected volume equivalent to the push tool body)Push, Pull and other functional features are not yet fully supported by the Behavior Extractions, therefore they need to be recreated in each body required for tooling.The effect of a Push feature can be propagated into the Core using a Pull feature with the same tool body with clearance = 0 and Wall thickness = Push (Wall Thickness + Clearance) [ without the Protected Volume option]. This is necessary to generate a solid equal to the push tool body + the wall thickness and the defined clearance.

Following are some recommendations / facts necessary to define the EDM tools

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How to Define the Model for EDM Tools (2/2)

The following explanation and example can be applied for building EDM tools.

Show its ProfileCopy/Paste the feature into the same Functional BodyRename the copied feature according to its parent name plus a suffix.Edit the copied feature by changing the profile using the “Go to profile definition” option or use the Output/Profile Feature in the sketch and select the elements of the sketch to be isolated.Once the isolation of features is completed, you can deleted them without deactivating the aggregated elements.An isolated element can be obtained in a new body, using the extraction behavior on any one of the isolated features. Later the behavior of all the protected features should be changed to Added.Extract Volume of all the Protected and Hole Features.Change the Protected behavior of the extracted features to Added.Perform a Behavior Extraction of the isolated feature, changing its behavior to AddedFrom the Parting Line, (or a similar construction element), limit the extracted features using a ‘Cutout’with no wall thickness and the ‘Complement’ option.

In such a way the design model represents the manufacturing model too, and any change will automatically update the tool model. A document per each isolated tool can be obtained using the Instant or the Design Collaboration.

For each element (isolated from a feature):

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How to Define the Model for Fixed Inserts

The Part

For geometry defined with any Protected Feature:Perform a Behavior Extraction of the Protected Feature, and change its behavior to Added.

For Geometry defined using a Push:Create an Added Body using the Push tool as the External Shape.

For other geometry:Extract the desired feature(s), change the behavior to Added. Make sure that you relimit the extracted features, wherever required.

Extract the protected volumes and all other volumes in the Part defined for reserving space (except holes). Change the behavior of thesevolumes to Added.

The following explanation and example can be applied for building Fixed Inserts.

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How to Insert the Shrinkage

Normally the shrinkage is inserted when a model for tooling is complete. However, the shrinkage can even be inserted at the begining of the tooling model. Following is the process to do it.

Use the Transform type = Scale, specify the shrinkage center (reference) and factor (scale) (Transform type Affinity allows you to define non homotetic shrinkage factors)Apply the Transform to the Extracted Core & Cavity and also to any other feature extraction done from the original Part Body.

Note: This method significantly reduces the number of times shrinkage has to be introduced, but it might occasionally generate impossible geometry.Individual shrinkage can also be applied on any extracted feature.

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Simulating Results of the Models Defined for Molding

Goal here is to obtain the volume of the part before shrinkage (real volume of the mold cavity)This is just a boolean process using all the bodies of the mold:

1. In two new bodies, define the result of “machining” the Core & Cavity respectively:

Add the body defined for milling

Remove the bodies defined for EDM or other machining type

Add any insert

2. In a new “Result” body

Create an ‘Added Prism’, using the profile used for defining the Core & Cavity bases, For this Added Prism, the limits should be from the ‘Core base bottom limit’ to the ‘Cavity base upper limit’

Remove the two bodies “Core & Cavitry machined” defined above to get the result.

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Creating and Using PowercopiesIn this lesson you will learn to create and store interactive features. You will also learn to reuse and adapt them to a new context.



Powercopies


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PowerCopy is a set of design features grouped together in order to be reproduced: it is a kind of advanced copying tool.

You can edit it (set contained features, entries, previews …).You can instantiate and customize it in the design of any part.

PowerCopy tools are available in the Insert menu (Advanced Replication Tools) of those workbenches:

Part designWireframe and SurfaceSheet Metal DesignFunctional Molded Part

Advantages of Functional PWC:Easy to createRobustness

What is a PowerCopy?

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Recommended Structure For a PowerCopy

Since R16, the following structure is recommended :

Functional Set (Feature to select for creating a PowerCopy)|- Functional Spec1|- Functional Spec2|- Sketches|- GSD

Advantages :After instantiation if there is only one node that is collapsible, delete operation is easily possible.

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The Power Copy created this way can be instantiated in the usual way:The template instantiation protocol does not change from its part design one.Once a behavior is defined, there is not need for a “Union Tim” or any other Boolean operation after instantiation.

InstantiateTemplate.CATPartand select inputs as shown.

Create an Internal Feature by selecting template’s main body

Edit Existing Power Copy

Select the inputs again starting from the ‘Internal Feature’.

Pattern the instantiated feature. Note that its functional behavior is preserved.

Final

Reusing Existing Part Design Templates

You can assign a behavior to the existing Part Design templatesFor a complex template, it may be more productive to reuse certified design components that are already defined in Part design by adding a functional behavior to them.

1 3

12

2

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How to Use PowerCopy (1/2)

To use your PWC open the part where you want to instantiate the Power Copy.

Create a shell with function design features.

Using the sketch, create points to position the screw holders.

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How to Use PowerCopy (2/2)

Select Catalog Brower icon :Search your PWC

Select inputs in the order they are askedXY planePoint

Click on Parameters If required, change the parameters of the published values.

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Additional Information (1/3)

The recommendations for creating PowerCopies are given below:

Whole bodies or Functional Sets can be selected to make your PowerCopy and it is recommended to do so because after instantiation, it will be easier to identify the result of a PowerCopy instantiation. For example if it is in an external body it can be easily deleted.

Try to have less geometric inputs as possible :While creating geometry that will make up a PowerCopy, try to select references (supporting faces, directions) on existing geometry that will also make up the PowerCopy (except for cases where you want them to be controlled during the instantiation).

Try to make geometry in the sketch iso-constrained (green lines).

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When you instantiate a PowerCopy from a CATPart containing several ones you can choose it through the reference

If you want to use the PowerCopy several times, check the repeat option.

Use identical names allows the automatic selection of the geometric inputs that have the same name as those used for the creation of the PowerCopy

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In the first case position and orientation of the axis in the created sketch will be controlled

In the second case position and orientation of the axis in the created sketch will be uncertain

Here, the face selected to support the sketch is a face of a local axis system: origin of created sketch is the origin of the local axis and the H and V axis orientations are determined by the local system

Here, the face selected to support the sketch is a face of a the geometry: origin of the created sketch is a vertex of the selected face and orientation of H and V axis is not the expected one

When selecting a supporting face for a sketch, it is recommended to select the face of a positioned and oriented local system instead of a face of the geometry.

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To Sum Up

You have learned:

What is a PowerCopy PowerCopy is a set of design features grouped together to be reproduced. It is an advanced copy tool. PowerCopy tools are available in Insert menu in Part design, Wireframe and surface, sheet metal design workbenches.

How to create a PowerCopy During creation you have to set definition, identify and name inputs, publish parameters, choose icon and preview.

How to save a PowerCopy Saving of PowerCopy is necessary. If not saved, PowerCopy can never be instantiated. This can be done through Insert menu > Knowledge Templates > Save in catalog.

How to instantiate a PowerCopyFor instantiation you have to first select PowerCopy which has been previously created. This can be done through two ways. First way is through catalog and second way is from Insert menu > Instantiate from document.

Documents

Catia Functional Design