Top-Down Design Tools Managing Complex Assemblies

Victor Remmers Holland Engineering Consultants BVTips & Techniques

2006 PTC*

Top-Down Design Philosophy

2006 PTC*

Traditional Design ApproachBottom-Up Design Design of individual components independent of the assemblyManual approach to ensure that components fit properly and meet the design criteriaComponents and those placed in sub-assemblies are brought together to develop the top-level assembly Errors are manually identified and modifications to each component are made to make the adjustment. As assembly grows, detecting these inconsistencies and correcting them can consume a considerable amount of time Top Level AssemblyComponentDesignComponentDesignComponentDesign

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Possible example Bottom Up?Mate

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Top-Down Design PhilosophyTop-Down Design Method of placing critical information in a high-level locationCommunicating that information to the lower levels of the product structure Capturing the overall design information in one centralized locationDesign InformationComponentComponentComponent

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A more integrated approach.

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Top Down Design Stages It is a concept.6-Stage Process

Conceptual Engineering PhaseLayouts and Engineering NotebookPreliminary Product Structure Phase Pro/INTRALINK, Model TreeCapturing Design Intent Phase Skeleton ModelsManage Interdependencies PhaseReference Viewer & Reference GraphCommunication of Design Intent Phase Copy Geoms, Publish Geoms & ShrinkwrapPopulation of the Assembly PhaseAutomatic Component Constraints & Component Interfaces

2006 PTC*

The Bobcat example

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Conceptual Engineering PhaseLayouts and Engineering NotebookUnderstand Existing SituationHigh-level RequirementsSpace AllocationDefine New Space and Motion2D Sketches3D ModelsRapid Iteration & ConvergenceAnimationsCapture Key Design IntentParametersNotesSpreadsheetsProprietary DataStage 1

2006 PTC*

Preliminary Product Structure Phase Pro/INTRALINK, Model TreeQuickly define product hierarchyBefore any of the components geometry is definedIntuitive, automatic mapping to start modelsTemplates ensure all designs share the necessary common elements such as layers, views & parametersFoundation for efficient task distributionAssembly Population EnvironmentsPro/E menus and Model Tree pop-up menus Pro/INTRALINK and PDMLinkComponent Creation MethodsEmpty Components; Copy from start modelsAutomatic assembly of default datumsUnplaced, Partially- & Over-Constrained ComponentsStage 2

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Capturing Design Intent Phase Skeleton ModelsWhat needs to happen?Capture conceptual design parameters within the context of the assemblyCapture & control critical object interfaces in a single, convenient locationHow? Skeleton ModelsCentralized pathway for communicationFacilitate task distributionPromote well-organized design environmentsEnable faster, more efficient propagation of changeSpecial Treatment in BOMs, Simplified Reps, Drawings, Model Tree & Mass Property CalculationsUniquely supported Scope Control Setting

Stage 3

2006 PTC*

Manage Interdependencies PhaseReference Viewer & Reference GraphStage 4Tools to Manage ReferencesExternal Reference ControlEnsures Top-Down Design methodology is followedIncorporate design management rules directly into the designEnsures proper design reusePro/INTRALINKModel TreeGlobal Reference ViewerReference Graph

2006 PTC*

Communication of Design Intent Phase Publish Geoms, Copy Geoms & InheritancePublish Geometry FeaturesProvides ability to pre-determine the geometry to be referenced by a Copy Geometry featureAllows designers to define their interfaces to the rest of the designCopy Geometry FeaturesAllows copying of all types of geometrySurfaces, edges, curves, datums, quilts, copy/publish geometryRetains copied geometry name and layer settingsDependency on parent geometry can be toggledCan be ExternalizedExternal Copy GeometryBuild relationships on external models independent of an assemblyUseful for coordinate system assembly practicesInheritance Inherit model geometry for one-way associativityShrinkwrap (included in Foundation Advantage Package)Stage 5

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Population of the Assembly PhaseAutomatic Component Constraints & Component InterfacesStage 6What tools are available for populating the assembly?Assembly ToolsDrag & Drop PlacementComponent InterfacesComponent CreationWithin the context of the assemblyMirror Parts or Subassemblies

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How does Top Down Design relate to company goals?Four Goals from Upper Management1) Cycle Time Reduction.2) Increase User Satisfaction with Software.3) Margin Increase.4) Cost Reduction.

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Why should you use it?Benefits:Reduced design timeReduced errors (right the first time)Increased qualityBetter project management visibilityConcurrent engineeringConfidence in top-level regenerationKnowledge of how modules interfaceTop-level change control

2006 PTC*

Example: to design an alternator...What information should a designer need to work with most times? Complete Top-Level Assembly540 MBAll Skeleton Models in Top-Level Assembly70 MBNeighboring Subassemblies320MBSubassembly, with Skeleton Model containing all required information ~ 20 MB

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What does an example look like?Three PhasesPro/INTRALINKPro/CONCEPTISDX Pro/ENGINEERPro/NOTEBOOKCONCEPTUAL DESIGNCAPTURE DESIGN CRITERIADETAILED DESIGN

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Product Definition

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Product Definition: Engineering LayoutWhat it is: First thing done in design cycleWhat it is Not: Used to evaluate key interface points Used to evaluate key components of project Three dimensional solids Fully detailed

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Advantages of Using a LayoutDocument design information in one centralized locationDocument design information before creating solid modelsInvestigate design options without involving the entire assemblyEasily make design changes because all of the design information is contained in one location

2006 PTC*

#2 Product Definition: Assembly Structure What it is: Virtual Assembly / BOM What it is Not: Used to organize assembly & assigning of design tasks Used to input non-geometrical data up-front Three dimensional solids Fully detailed Fully constrained

2006 PTC*

Advantages of Defining Preliminary Product StructureDefining the product structure prior to defining geometry can assist you in organizing the assembly into manageable tasks that can be assigned to design teams or individual designers.Associate specific library parts (that are to be used on the project) with the assembly at the start of the design, preventing confusion later.

2006 PTC*

Advantages of Defining Preliminary Product StructureContSubmit the assembly to Pro/INTRALINK or PDMLink and assign models to the appropriate vaults or folders. Individual designers can focus on specific design tasks instead of on how their design is going to fit into the overall structure.Input non-geometrical information such as the part number, designers name, etc., at a very early stage.

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#3 Product Definition: Skeletons What it is: Zero-mass geometry What it is Not: Exact location detail Three dimensional solids Fully detailed Minimized geometric detail

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And Definitely Not This!!

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Advantages of Using SkeletonsProvides a centralized location for design dataSimplifies assembly creation / visualizationAids in assembling mechanismsMinimizes unwanted parent-child relationshipsAllows you to assemble components in any orderControls propagation of external references

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Central source for informationBenefits of Communicating Information From a Central SourceTask distributionConcurrent ModelingManaging External References

ToolsDeclaration

Publish Geometry

Copy Geometry

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HierarchyTop_level.asmTop_level_skeleton.prtSub_assy_1.asmSub_assy_1_skeleton.prtSub_assy_2.asmSub_assy_2_skeleton.prt Sub_assy_x.asmSub_assy_x_skeleton.prt

2006 PTC*

3D Design Finally!The foundation is set but topologically modifiable its time for 3D.

With Reference Control Manager, you are safe to create your parts directly in the assembly.

2006 PTC*

More Than Meets The Eye!Interchangeability:

Family of Tables

Interchange Assembly

Layout Declarations

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Power of Top-Down DesignTo Achieve Advanced Automation, consider using:

Relations

Pro/Program

2006 PTC*

Miscellaneous TipsSeparate Part Versus Assembly for Skeleton FeaturesAvoid constructing assembly-level skeleton features since the system requires that you perform all edits of these features in Assembly mode. The components can become an obstruction and degrade performance. Furthermore, you cannot easily reuse skeleton features at the assembly level in other subassemblies. By using a separate part file, you can edit the feature in Part Mode and reassemble it into many different assemblies.Geometry FeaturesPlace all static information in a skeleton as early as possible and place all dynamic information later in the design process cycle.

2006 PTC*

Miscellaneous TipsDatums for Skeleton ModelsConsider renaming skeleton datums to sk_VisualizationUse simplified reps and transparency prolifically to make viewing easierUse display states to highlight different items at different timesUse surfaces to clarify meaning of centerlines & axesConceptualizationDont be afraid to use simple hand sketches before delving into complex situations its NOT illegal

2006 PTC*

Pro/E Wildfire EnhancementsHigh-performance Assembly ModelingLightweight ComponentsRepresent common components with lightweight graphics for optimum display speedAccurate mass properties and BOMsCustomizable symbolic representationsFlexible Components Represent multiple states of a single component in an assembly Addresses critical need for consistency between BOM and assembly model Intelligent RegenerationAssembly regeneration is up to 80% Faster!

2006 PTC*

Highlights of Top-Down DesignCapture knowledge, or design intent, allowing you to concentrate on significant issues by making the software perform tedious, repetitive calculations.

Enable the framework for interchangeability of components allowing for high-velocity product development by supporting rapid iterations of product variations.

Create a concurrent design environment by spreading project design responsibility across many organizational levels.

2006 PTC*

New in Advanced Assembly in Wildfire 3.0Data Sharing DashboardThe Data Sharing dashboard consolidates the Merge, Cutout, and Inheritance features in a modern user interface. Enhancements to Data Sharing features in a new dashboard offer many benefits:Allows changing of multiple feature types at any point Offers a user-friendly user interface with easy access to commands Supports object-action workflow for increased productivityConsolidates Data Sharing features, such as Merge, Cutout, and Inheritance

2006 PTC*

New in Advanced Assembly in Wildfire 3.0 (#2)Top-Down Design with Mechanism AssembliesYou can now design a skeleton model that includes motion.Motion skeletons are available in Assembly, allowing motion to be incorporated into the model at the beginning of the design process. There is no longer a need to recreate an assembly to include a mechanism analysis.You can create mechanism bodies and connections as a motion skeleton, then run a simple kinematic analysis to ensure that the skeleton provides the appropriate degrees of freedom. You can then create and assemble components to the motion skeleton. Motion skeletons are defined in the same way as normal assembly skeletons and include reference control settings. They do not appear in the assembly bill of materials.

2006 PTC*

POWER OF TOP DOWN DESIGN!!!

2006 PTC*

Visit www.ptc.com* Copyright 2000 Parametric Technology CorporationPage *Visit www.ptc.com* Copyright 2000 Parametric Technology CorporationPage *Pro/ENGINEER Wildfire offers a new lightweight component representation. This lets you replace a component with a 2D symbol while maintaining an accurate BOM and mass properties. This allows for improved visualization of large models and faster regeneration times.

Additionally, Flexible Models allow you to define variable dimensions, features, parameters and geometric tolerances for the same part within the same assembly. This allows for multiple geometric variations along with a completely accurate Bill of Material.

Visit www.ptc.com* Copyright 2000 Parametric Technology CorporationPage *