Week 11- Assembly Workbench

ASSEMBLY WORKBENCH

AIM 

To create assembly for quick return mechanism and cv joint

OBJECTIVES

1. To create individual part files according to the given drawings
2. To create assembly using the part files created 
3. To create drafting for tha part and assembly 

INTRODUCTION

Assembly Design

The Assembly Design used to create an assembly starting from scratch. Here is illustration of the several stages of creation you may encounter for an assembly.

1.1 Creating an Assembly Document

This task will show you how to enter the Assembly Design workbench to create a new assembly from scratch. Select the Start -> Mechanical Design -> Assembly Design command to launch the required workbench. The Assembly Design workbench is opened. You can see that “Product1” is displayed in the specification tree, indicating the building block of the assembly to be created. To create an assembly, you need products. The application uses the term “product” or “component” to indicate assemblies or parts. You can use parts to create products. Those products can in turn be used to create other products. The product document contains: a specification tree to the left of the application window, specific toolbars to the right of the application window, a number of contextual commands available in the specification tree and in the geometry. Note that these commands can also be accessed from the menu bar.

1.2 Inserting a Components

1.2.1 Inserting a New Component

This task will show you how to insert a component into an existing assembly. In the specification tree, select Product1 and click the New Component icon . The structure of your assembly now includes Product1 (Product1.1).

1.2.2 Inserting a New Product

This task will show you how to insert a product in an existing assembly. In the specification tree, select Product1 and click the New Product icon. The Product2 (Product2.1) is created in the specification tree.

1.2.3 Inserting a New Part

This task will show you how to insert a new part in an existing assembly. In the specification tree, select Product1 and click the New Part icon . If geometry exists in the assembly, the New Part: Origin Point dialog box is displayed, proposing two options to locate the part: Click Yes to locate the part origin point on a selected point, on another component for example. Click No to define the origin point of a component based on the origin point of the parent component.

1.3 Defining a Multi-Instantiation

This task shows you how to repeat components as many times as you wish in the direction of your choice. Select the component you wish to instantiate. Click the Define Multi-Instantiation icon . The Multi-Instantiation dialog box is displayed, indicating the name of the component to be instantiated. The Parameters option lets you choose between the following categories of parameters to define: Instances & Spacing, Instances & Length and Spacing & Length. To define the direction of creation, check x-axis. The application previews the location of the new components. Click OK to create the components.

1.4 Fast Multi-Instantiation

This task shows you how to repeat components using the parameters previously set in the Multi Instantiation command. You will use the Fast Multi-Instantiation command to quickly repeat the component of your choice. The operation is very simple. Select the component you wish to instantiate. Click the Fast Multi-Instantiation icon . The result is immediate. Three components are created according to the parameters defined in the Multi-Instantiation dialog box.

1.5 Using Assembly Constraints

This section describes the notions and operating modes you will need to set and use constraints in your assembly structure. Constraints allow you to position mechanical components correctly in relation to the other components of the assembly. You just need to specify the type of constraints you wish to set up between two components, and the system will place the components exactly the way you want. Setting constraints is rather an easy task. However, you should keep in mind the following: You can apply constraints only between the child components of the active component. You cannot define constraints between two geometric elements belonging to the same component. You cannot apply a constraint between two components belonging to the same subassembly if this subassembly is not the active component. The active component is blue framed (default color) and underlined. Double-clicking activates it. The selected component is orange framed (default color).

1.5.1 Creating a Coincidence Constraint 

Coincidence-type constraints are used to align elements. Depending on the selected elements, you may obtain concentricity, coaxiality or coplanarity. Click the Coincidence Constraint icon Select the face to be constrained. Select the second face to be constrained. Green arrows appear on the selected faces, indicating orientations. The Constraint Properties dialog box that appears displays the properties of the constraint. The components involved and their status are indicated. You can define the orientation of the faces to be constrained by choosing one of these options: Undefined (the application finds the best solution), Same, opposite. Click OK to create the coincidence constraint. This constraint is added to the specification tree too.

1.5.2 Creating a Contact Constraint 

Contact-type constraints can be created between two planar faces (directed planes). Click the

Contact Constraint icon . Select the faces to be constrained. As the contact constraint is created, one component is moved so as to adopt its new position. Green graphic symbols are displayed in the geometry area to indicate that this constraint has been defined. This constraint is added to the specification tree.

1.5.3 Creating an Offset Constraint

When defining an offset constraint between two components, you need to specify how faces should be oriented. Click the Offset Constraint icon . Select the faces to be constrained. The Constraint Properties dialog box that appears displays the properties of the constraint. The components involved and their status are indicated. You can define the orientation of the faces to be constrained by choosing one of these options. Click OK to create the offset constraint.

1.5.4 Creating an Angle Constraint 

Angle-type constraints fall into three categories: Angle, Parallelism (angle value equals zero), Perpendicularity (angle value equals 90 degrees). When setting an angle constraint, you will have to define an angle value. Click the Angle Constraint icon . Select the faces to be constrained. The Constraint Properties dialog box is displayed with the properties of the selected constraint and the list of available constraints. Keep the Angle option. Enter angle in the Angle field and keep

Sector 1. Note that four sectors are available: . Click OK to create the angle constraint.

1.5.5 Fixing a Component 

Fixing a component means preventing this component from moving from its parents during the update operation. There are two ways of fixing a component: by fixing its position according to the geometrical origin of the assembly, which means setting an absolute position. This operation is referred to as “Fix in space”. By fixing its position according to other components, which means setting a relative position. This operation is referred to as “Fix”.

Fix in Space: Click the Fix icon . Select the component to be fixed, that is the light blue component. The constraint is created. A green anchor is displayed in the geometry area to indicate that this constraint has been defined. Fix:Double-click the fix constraint you have just created to edit it. In the dialog box that appears,click More to expand the dialog box. Uncheck the Fix in space option to the left of the dialog box.The lock symbol is no longer displayed in the specification tree, meaning that the component is positioned according to the other components only. Move the fixed component. Click OK to confirm . Update the assembly: now the component remains at its location.

1.5.6 Fixing Components Together 

This task consists in fixing two components together. The Fix Together command attaches selected elements together. You can select as many components as you wish, but they must belong to the active component. Click the Fix Together icon . You can select the components in the specification tree or in the geometry area. The Fix Together dialog box appears, displaying the list of selected components. In the Name field, enter a new name for the group of components you want to create. Click OK. The components are attached to each other. Moving one of them moves the other one too.

1.5.7 Using the Quick Constraint Command 

The Quick Constraint command creates the first possible constraint as specified in the priority list. Double-click the Quick Constraint icon . Select the two entities to be constrained. The possible constrain between these will be according to list specifying the order of constraint creation: Surface contact, Coincidence, Offset, Angle and Parallelism. The first constraint in the list can now be set. A surface contact constraint is created & constraint is added to the specification tree.

1.5.8 Changing Constraints 

Changing a constraint means replacing the type of this constraint by another type. This operation is possible depending on the supporting elements. You can select any constraints, not necessarily in the active component. Select the constraint to be changed. Click the Change Constraint icon The Change Type dialog box that appears, displays all possible constraints. Select the new type of constraint. Click Apply to preview the constraint in the specification tree and the geometry. Click OK to validate the operation.

1.5.9 Deactivating or Activating Constraints

Deactivating or activating constraints means specifying if these constraints must be taken into account during updates or not. Select any activated constraint. Right-click and select the Deactivate contextual command. The constraint is deactivated. The graphic symbol representing the deactivated constraint is now displayed in white. Repeat step and right-click to select the Activate contextual command to activate the selected constraint.

1.6 Updating an Assembly

Updating an assembly means updating its components as well as its constraints. The application lets you choose between updating the whole assembly or the components of your choice. The constraints are in black, indicating they need an update. The default color is black, but the application allows you to redefine the colors you want. To do so, refer to Customizing Constraint Appearance. Select the Tools -> Options command, then expand the Mechanical Design section to the left to access Assembly Design options. You can choose between two update modes within the Assembly Design workbench: Automatic or Manual. Check the Manual option in the Update frame. Click OK to confirm and close the dialog box. Click the Update icon to update the whole assembly. The assembly is updated. 

1.7 Using a Part Design Pattern 

This task shows you how to repeat a component using a pattern created in Part Design. Select the rectangular pattern in the tree or in the geometry. Control-click to select the component to be. The Instantiation on a pattern dialog box is displayed, indicating the name of the pattern, the number of instances to be created (for information only) and the name of the component to be repeated. There are two work modes: Using associativity with the geometry: the option “Keep link with the pattern” is on, Using no associativity: the option is off. To define the first instance of the component to be duplicated, three options are available: Reuse the original component, create a new instance, cut & paste the original component. Click OK to repeat the second component. The new component “xxx on RectPattern.xx” is displayed in the tree. An entity “Assembly features” has been created in the tree. “Reused Rectangular Pattern.1” is displayed below this entity. If you use the option “generated constraints”, the Reuse Constraints section displays the constraints detected for the component and makes all original constraints available for selection: You can define whether you wish to reproduce one or more original constraints when instantiating the component.

1.8 Moving Components

1.8.1 Manipulating Components

1.8.2 Snapping Components

The Snap command projects the geometric element of a component onto another geometric element belonging to the same or to a different component. Using this command is a convenient

way to translate or rotate components. Depending on the selected elements, you will obtain

1.8.3 Smart Move

The Smart Move command combines the Manipulate and Snap capabilities. Optionally, it creates constraints. The Quick Constraint frame contains the list of the constraints that can be set. This list displays these constraints in a hierarchical order and can be edited by using both arrows to right of the dialog box. The application creates the first possible constraint as specified in the list of constraints having priority.

1.9 Sectioning

This task you will create section planes, orient the plane with respect to the absolute axis system,

invert the normal vector of the plane. Click the Sectioning icon. The section plane is automatically created. The plane is created parallel to absolute coordinates Y, Z. The center of the plane is located at the center of the bounding sphere around the products in the selection you defined. Line segments visualized represent the intersection of the plane with all products in the selection. The Sectioning Definition dialog box contains a wide variety of tools letting you position, move and rotate the section plane. A Preview window, showing the generated section, also appears. 3D section cuts cut away the material from the plane. Click the Volume Cut icon in the Sectioning Definition dialog box to obtain a section cut. You can position section planes with respect to a geometrical target (a face, edge, reference plane or cylinder axis). You can view the generated section in a separate viewer.

1.10 Assembly Features

Prior to creating assembly features, keep in mind the following. You can create assembly features only between the child components of the active product. The active product at least must include two components, which in turn must contain one part at least. You cannot create assembly features between two geometric elements belonging to the same component. The different assembly features you can create are: Split, Hole, Pocket, Remove, Add, Perform a Symmetry.

1.10.1 Assembly Split

The dialog box that appears when you click Assembly Split, displays the names as well as the paths of the parts that may be affected by the split action. Move the parts to the list ‘Affected parts”. Arrows in the geometry indicate the portion of parts that will be kept after splitting. If the arrows point in the wrong direction, click them to reverse the direction. Click OK to confirm. To edit an assembly split, double-click ‘Assembly Split.X’ in assembly features available in history tree.

1.11 Creating Scenes

Scenes enable you to: work on the evolution of an assembly in a separate window from the actual assembly and to impart updates to the assembly as you see fit. Save a copy of an assembly in a separate window, work on the evolution of that assembly directly on the assembly. You can modify the following attributes either in the scene or in the assembly without the modifications being replicated in the other: the viewpoint, the graphical attributes of the components, the “show” or “hide” state of the components, the “active” or “not-active” state of the components. Scenes are identified by name in the specification tree and by a graphical representation in the geometry area. . The Edit Scene dialog box and a scene representation in the document window are displayed. Click Ok to end the scene creation. You are now in a scene window: The background color turns to green. Scene 1 is identified in the specification tree. Perform the required modifications. For instance modify: viewpoint, graphical attributes, show-no show. Within a scene, click the Reset selected products icon to reposition the components as they were in the initial product. Note that color attributes and the show-hide specification are not taken into account when using the Reset selected products icon. Click the Exit From Scene icon to swap to the initial window. Double-click Scene 1 either in the specification tree or in the geometry area to swap to the scene window.

1.12 Exploding a Constrained Assembly

This task shows how to explode an assembly taking into account the assembly constraints. This Explode type is applicable only to specific cases. When the assembly is assigned coincidence constraints: axis/axis & plane/plane. Click the Explode icon . The Explode dialog box is displayed. Wheel Assembly is selected by default, keep the selection as it is. The Depth parameter lets you choose between a total (All levels) or partial (First level) exploded view. Keep All levels set by default. Set the explode type. 3D is the default type. Keep it. Click Apply to perform the operation.

1.13 Detecting Interferences

Checking for interferences is done in two steps: Initial computation: detects and identifies the different types of interference. Detailed computation: computes the graphics representation of interferences as well as the minimum distance. Two interference types are available: Contact + Clash, Clearance + Contact + Clash. Results differ depending on the interference type selected for the analysis. Four computation types are available: Between all components, Inside one selection, Selection against all, Between two selections. Click Apply to check for interferences. A progress bar is displayed letting you monitor and, if necessary, interrupt (Cancel option) the calculation. The Check Clash dialog box expands to show the results. Clash: red intersection curves identify clashing products. Contact: yellow triangles identify products in contact. Clearance: green triangles identify products separated by less than the specified clearance distance.

1.14 Customizing Assembly Design

1.14.1 Customizing Assembly Design Settings This task will show you how to customize Assembly Design settings. Select Tools -> Options. Click the Mechanical Design category, then the Assembly Design subcategory. The General tab appears, displaying the following options: Update, Access to geometry, Move components.

1.14.2 Customizing General Settings

Select the Tools -> Options… command. Click the Infrastructure category, then the Part Infrastructure subcategory. The General tab appears, containing three categories of options: External References, Update and Delete Operation

1.14.3 Customizing Assembly Constraints

Select Tools -> Options. Click the Mechanical Design category, then the Assembly Design subcategory. In the Constraints tab the following options are available: Paste Components, Constraint Creation, Quick Constraint.

QUICK RETURN ASSEMBLY

BODY 1

BODY 2

BODY 3

BODY 4

BODY 5

ASSEMBLY

CV JOINT

BODY 1

BODY 2

BODY 3

ASSEMBLY

CONCLUSION

Thus the QUICK RETURN MECHANISM AND CV JOINT PARTS, ASSEMBLY AND DRAFTING WERE DONE