Catia 装配设计基础详细步骤
A s s e m b l y D e s i g n F u n d a m e n t a l s
D e t a i l e d S t e p s
Table of Contents
Connector Assembly (3)
Step (1): Assembling Components (3)
Step (2): Positioning Components (6)
Step (3): Analysing the assembly (13)
Step (4): Editing Part (16)
Step (5): Working with Components (20)
Vice Assembly (24)
Step 1: Creating the Structure (24)
Step 2: Positioning the components (33)
Step 3: Designing Parts (50)
Step 4: Inserting Fitting Components (62)
Flexible sub-assemblies (86)
Step (1): Assembling Components (86)
Step (2): Constrain Full Assembly (90)
Step (3): Change configuration (92)
Connector Assembly
In this exercise, you will assemble the different components making up the connector assembly and learn how to analyze an assembly.
Step (1): Assembling Components
1. Start a new CATProduct assembly with Start menu +Mechanical Design+ Assembly Design or
File + New + Product.
2. Watch out : with the CATIA Companion, click on the exercise icon (load model) : this will open a
default empty Product. Then, select File + Open menu and click on the Cancel button in the File Selection box (This is a necessary step that will set the selection path for the rest of this exercise).
3.
4. Right-click on the default product in the specification tree and select Properties option in the
contextual menu to get the Properties dialog box.
5. Type“Assembly Connector” in the Part Number field located in the “Product” tab:
6.
7. The name is displayed in the specification tree:
8.
9. Let’s add the components that are ready (=already designed) in this assembly.
10. Right-click on the blue Connector Assembly and select “Existing components…” under
"Components" branch in the contextual menu (or use the icon or the menu Insert + Existing component…”) and in the folder ConnectorAssembly_MasterExercise, select
CATASMConnector_Shell.CATPart
11. Repeat the same procedure and select: CATASMConnector_Card_Assembly.CATProduct
12. Using the [ctrl] key you could have selected and inserted both components at once.
13. The part and the assembly, are added in the geometry and in the tree:
14.
15. Now let’s duplicate the shell for the bottom part of the connector assembly:
16. Copy the Connector Shell
17.
18. Paste it into Connector Assembly.
19.
20. The second instance of the connector shell is added in the tree and in the geometry. Hint: you do not
see it in the geometry as it is at the exact same position as the first instance.
21.
22. Let’s give some more explicit names to the instances :
23. In Properties of the first instance (i.e.: Connector Shell (Connector shell.1)) Key in "Top Shell" in the
top “Instance name” field;
24. Repeat the procedure on the second instance and type“Bottom shell” in the“Instance name”
field:
25.
26. Both instances are renamed in the tree.
27. With File + Save All as .., save the assembly in your work folder under the name
“ConnectorAssembly2”and make a Propagate Directory before validating.
Step (2): Positioning Components
In this step, we will define all the necessary constraints to define the relation between the card subassembly and the 2 shells.
1. Starting from the ConnectorAssembly2 that you saved, let’s first fix the card assembly in space: it
will be the reference element.
2. In the tree or in the geometry, select the Connector Card Assembly component and click on the
fix icon , the component is now fixed in space
3. Let’s now position the components in the geometry roughly as they will be assembled and in such a
way as to be able to select all the necessary elements later to put the constraints. We will start by separating the 2 shells:
4. - Make sure that the Connector Assembly is the active component (blue node in the tree)
5. - Drag and drop the compass onto the top face of one of the connector shell instances until it turns
green
6. - Select the Top Shell instance in the tree so this one will be moved with the compass
7.
8.
9. Position your cursor anywhere along the z axis on the compass and drag upwards
10. To move the Bottom Shell now, select it in the tree or in the geometry to have it highlighted in orange
(note that the compass stays green) and in the same way, move your cursor on the z axis of the compass and drag downwards this time:
5. Now let’s flip the Bottom Shell to have it match the top one: Select the zy arc on the compass (see
picture above) and drag along it until the shell is flipped 180 degrees
6. Now let’s reposition the 2 shells with respect to the Card: they both need to be rotated 180 degrees
on the xy plane of the compass.
7. Multi select with [ctrl] key both components.Select the xy arc on the compass and drag clockwise
until both components are flipped 180 degrees
8. Now that all components are roughly in place, let’s start constraining them: We will first set the axial
constraints between the holes of the top shell and the card.
9. Select the axial icon , zoom on the left holes, and select the inside of the left hole on the top
shell and the inside of the corresponding hole on the card:
10.
Note: do not hesitate to zoom: with the inside of the hole selected, the hole axis only appears when the zoom is big.
When the constraint is set, the top shell moves above the card so as to have both hole axes perfectly aligned (see right picture above). The 2 red circles are the symbols showing the coaxial constraint.
11. Repeat the same procedure on the right hole of the top shell with its corresponding hole in the
card:
12.
13. Note: that both coaxial constraints appear as 2 Coincidence nodes under the new Constraints node
added in the tree.
Now the top shell cann ot slide anymore on the horizontal plane, but it can still move up or down, so let’s finish constraining it in that direction:
Select the contact icon , and the top face of the card. Then rotate the assembly so as to be able to select the bottom face of one of the standoffs on the top shell:
Note: again do not hesitate to zoom enough to be able to select the bottom face of the standoff.
The Surface contact is added in the tree and 2 square symbols appear on the geometry.
Now the Top Shell is fully constrained with respect to the Card assembly.
14. Now let’s repeat the same procedure to constrain the Bottom Shell to the card:
15. Doucle-click the axial icon so as to keep it on for both holes.
- Select the inside of the Bottom Shell left hole and the inside of the corresponding hole
on the card. Note that you need to zoom to have the axes showing and to rotate the whole
assembly to be able to select the hole on the card.
-Repeat for the right hole.
The circle symbols are added on the geometry and both constraints appear in the tree.
16. Finally constrain the Bottom Shell to Card in the vertical direction:
Select the Contact icon and the bottom face of the Card, then rotate again and zoom well to be able to select the top face of one of the standoffs:
The bottom shell automatically moves up so as to match the top shell around the card assembly,
The last constraint is added in the tree (Surface contact.6) and the 2 square symbols are added on the geometry
Save the constrained assembly with the same name (with File + Save).
Note that you can check that the assembly is properly and fully constrained by moving all components apart with the compass and then updating it with the Update icon: all components must be back in place:
Step (3): Analysing the assembly
In this step, we will analyze our Connector Assembly for clashes.
1. Starting from the ConnectorAssembly2 that you saved in step 2, check that the top node is active (=
Connector Assembly node is blue in the tree) and pull down the Analyze menu to get the Compute Clash option:
The “Clash Detection” dialog box is displayed empty.
2. Check that the top pull down list is set to “Clash” and as you can analyze clashes between 2
compone nts only: let’s start with the Top Shell and the Connector Card Assembly. Use the Control key to multi-select them in the tree. When their names are in the Clash Detection box list, then click on the Apply button:
3. Note that the icon under the list shows a red light to indicate the Clash.
4. Here you need to click in the geometry space to better see where the clash is:
5. Repeat the same analysis with the Bottom Shell: you will find the same result.
6. Save the Assembly.
Step (4): Editing Part
In this step, we will eliminate the clashes between the Connector Card Assembly and Connector Shells by editing the Connector Shell in-context of the assembly The idea is to make an opening in the Connector Shell so that the Card Socket Receptacle can stick out of the shell, and to leave a small clearance space around it so that it mounts easily.
Let’s modify the design of the Shell.
a) Note that as the Top Shell and the Bottom Shell are 2 instances of the same Shell, we only need to modify the source Connector Shell, it will modify both instances.
b) Note also that we do not need to know the exact size of the Socket Receptacle. By designing in context, we will use the outer edges of the Socket Receptacle to set a 1mm clearance around it when we define the pocket to remove the material to make the opening.
1. Starting from the Connector Assembly that you saved in step 2 or 3
(ConnectorAssembly_withClashes for us), hide the bottom shell component
2.
3. Open the Top Shell node in the tree and double click on the Connector Shell CATPart icon
to enter the Part Design workbench.
4. Then select the front face of the Connector Socket Receptacle
and enter the Sketcher
5. Select the Rectangle tool to draw the profile of the pocket around the Socket Receptacle.
6. Note that you draw 2 rectangles at the same time as you are drawing on both instances of the Shell
at the same time.
7. Note also that you can draw the pocket profile roughly here – do not try to have any exact values.
8.
9. To make things easier and see better, we can hide the second instance, the Bottom Shell:
10. select the Connector Shell (Bottom Shell) node in the tree and the hide/show tool
11.
12. Now let’s position the rectangle at exactly 1mm d istance around the Socket Receptacle:
13. Double-click on the Dimension tool to keep it active for a while
14.
15. Select the left most edge of Socket Receptacle and the left side of the rectangle
16. (Hint: you may have to zoom or rotate the connector a little to select the edge)
17. When the dimension is displayed, double-click on it to set it exactly to 1mm
18.
19. While the Dimension tool is still on, select the top edge of the Socket Receptacle and the top
side of the rectangle and double-click on the value to set the distance to 1mm
20.
21. While the Dimension tool is still on, select the right most edge of the Socket Receptacle and the
right side of the rectangle and double-click on the value to set the distance to 1mm
22.
You can check here that the length of the rectangle top edge by selecting it: the 66mm dimension will be displayed in purple to show that it is over constrained. Use undo or delete it as the 1mm clearance on each size is enough to define the pocket size in relation with the Socket Receptacle.
Note that the height of the rectangle is not important as the pocket will remove the material.
23. Exit the Sketcher and while the rectangular profile is selected, click on the Pocket tool
24. In the Pocket Definition dialog box, select “Dimension” in the Type drop down list, key 8mm in
depth field and click on OK.
25.
The opening is performed exactly around the Socket Receptacle with a clearance of 1mm and Pocket2 node is added in the tree.
26. Retrieve the Bottom Shell by clicking on it in the tree and on the Hide/show icon:
27.
28. Things looking good,let’s save our work:
29. as we are now in the Part Design workbench with the Connector Shell active and highlighted in blue
in the tree, we are asked to save the the shell first. Use Save As…. to save it as ConnectorShell5 or ConnectorShell_withOpening for example.
30. Activate the Connector Assembly now by double-clicking on the top node in the tree and use again
the Save As option to save the whole assembly as ConnectorAssembly5 or
ConnectorAssembly_withOpening for example.
Step (5): Working with Components
In this step, we will add and constrain a Screw and then duplicate the Screw and its constraints using a pattern
Go on with the assembly you saved in step 4 or open the CATASMConnector_Assembly_5.CATProduct. In order
Let’s add the screw in the assembly. With your cursor over the Connector Assembly node at the top of the tree, open the contextual menu and select the Existing Component option.
In the current folder select the CATASMConnector_Screw.CATPart.
The Connector Screw node is added in the tree and the screw geometry is displayed. Here we used the compass to locate it roughly above the left of the hole of the Shell.
Let’s now constrain the screw position. Let’s start with the coincidence between the 2 axes.
Select the coincidence icon and the screw axis and the corresponding hole axis. Hint: zoom enough on the screw cylinder or use the Other selection… option in the contextual menu on the screw.