Thiết kế flash - Assembly modeling

Assembly ModelingParametric Assembly ModelingAssembly modeling is used to combine components to create a 3D parametric assembly modelA component is either a part or a subassembly of partsEssential tool for a work group developing a product composed of multiple partsRelatively new (1990’s)Used extensively in automotive and aerospace industriesAssembly Modeling ToolsAssembly modeling tools are used to:Combine components to create assembliesSpecify location and orientation of components within an assembly  constraintsPart/Assembly Modeling Similarities - 1Part ModelingAssembly ModelingTree StructureFeatures  PartComponents  AssemblyBaseFeatureComponentConstraintsGeometric and DimensionalAssemblyParent/Child Relationshipsbetween featuresbetween componentsPart/Assembly Modeling Similarities - 2Part ModelingAssembly ModelingEditingSketch, featurePartParametric equationsLocalGlobalDocumentationPart drawingsAssembly drawingsInstancingAre copies of a part definitionContain a reference to the part definition, plus positional information used to locate the partDo not significantly increase assembly file size (one definition, many positions)Are useful for standard partsAre referred to as occurrences in InventorPart instances:Assembly ConstraintsMate – positions selected faces so that their surface normals oppose one another, with faces coincident (or offset). Can also be used for lines and points Flush – positions selected faces flush with one another (surface normals in same direction), with faces aligned (or offset)Angle – positions planar faces at a specific angle Tangent – positions a curved surface tangent to another surfaceInsert – positions two cylindrical parts so that their axes are aligned; mate constraint also applied to two circular edgesMate - 1Mate face/faceMate edge/edgeMate - 2Mate point/pointFlush face/faceTangentTangent cylinder/faceAngleAngle face/faceInsertDegrees of FreedomA rigid body has six degrees of freedom (DOF):3 in translation3 in rotationAs assembly constraints are applied, DOF’s are reducedSimulation of part motion within an assembly is possible by properly constraining partsZero DOF  part is fixedSome DOF’s  moving partBottom-Up Assembly DesignDefine geometry of all partsParts placed in assembly filePosition parts using assembly constraints (e.g., mate, insert)Whenever possible, constrain parts in the order in which they would be assembled in manufacturingNOTE: Inventor’s adaptive design allows unconstrained part geometry to be defined based upon assembly constraintsTop-Down Assembly DesignBegin with design criteria for assembled productParts created within assembly fileOften start with 2D design layout that captures criteriaMiddle-Out Assembly DesignMost assembly modeling employs a combination of bottom-up and top-down designSome existing parts brought into assembly fileOther parts designed directly within the assemblyUses of Assembly ModelsMeasurements between partsExploded viewsInterference checksKinematics analysisBill of Materials (BOM) generationWalk throughsAssembly Modeling