IMPELLER ASSEMBLY

We will assemble the impeller component objects. All the part files will be provided to you.

¾ Create a new file and save it as Impeller_assembly.prt

¾ Choose APPLICATION → MODELING

¾ Click on APPLICATION again and make sure there is a check mark next to ASSEMBLIES. If not, click on it

A new toolbar will appear on the screen as shown below.

¾ Click on ASSEMBLIES from the menu bar

We will be mostly using the COMPONENTS option, which includes:

• ADD COMPONENT – add new component objects whose part files are already present

• REPOSITION COMPONENT – reposition component objects

• MATE COMPONENT – mate or align the component objects

¾ Choose ASSEMBLIES → COMPONENTS → ADD COMPONENT The following dialogue box will pop up.

You can select the part files from those existing or else you can load the part files using the OPEN file options in the dialog box. This will load the selected part file into the LOADED PARTS dialog box.

¾ Click on the file Impeller_upper-casing.prt

You will see the object on the screen as follows:

Now we will add the second component, the lower casing.

¾ Click on ASSEMBLIES → COMPONENTS → ADD COMPONENT

¾ Select the file Impeller_lower-casing.prt

¾ In the POISTIONING dialog box change the option to MATE

¾ Choose APPLY

This will show you the added component in a COMPONENT PREVIEW window.

Now let us mate the upper and the lower casing.

The following dialog box will appear.

Here you can see the different Mating Types, which were explained above in section 8.4.

Now let us give the Mate constraint.

¾ Make sure the Mate icon is selected in the window

¾ First, select the face that the arrow is pointing to in the Component Preview window as shown below in the figure on the right figure below

¾ Click on the face of the Upper Casing in the main screen as shown in the figure on the right.

You may have to rotate the figure in order to select the face

Now let us give the second constraint.

¾ Click on the Center icon in the Mating Conditions window

¾ First select the face on the lower casing in the Component Preview window as shown in the left figure

¾ Select the face on the upper casing in the main screen as shown in the right figure

We will give one more constraint to fix the degrees of freedom for the lower casing.

¾ Click on the Align icon in the Mating Conditions window

¾ Select the two surfaces, first on the lower casing and then on the upper casing, as shown in the figure below

¾ Click APPLY and then OK

The two assembled components will be seen as shown in the figure below.

The lower casing is constrained with respect to the upper casing. Now let us add the impeller.

¾ Choose ASSEMBLIES → COMPONENTS → ADD COMPONENT

¾ Open the file Impeller_impeller.prt

¾ Click OK on the dialog box We will apply the Distance constraint.

¾ Click on the Distance icon in the Mating Conditions window

¾ Select the two faces, first on the impeller and then on the casing, as shown in the figure below

¾ In the Offset Expression box on the Mating Conditions window, enter a value of -3

¾ On the Mating Conditions window, click Preview

The preview will show the impeller oriented in the direction opposite to the one we want.

¾ On the Mating Conditions window, right-click on the Distance constraint we gave

¾ Choose ALTERNATE SOLUTION OR

¾ Click on this Icon near the Selection Steps in the Dialog Box Now the impeller will be oriented in the right direction.

Now we will apply the Center constraint to the model.

¾ Click on the Center icon

¾ Select the two surfaces, first on the impeller and then on the casing, as shown in the figure

¾ Click APPLY and then OK

Save the assembly file. We will now add the shaft.

¾ Click on ASSEMBLIES → COMPONENTS → ADD COMPONENT

¾ Open the file Impeller_shaft.prt

¾ Click OK on the dialog box

¾ Choose the Center icon

¾ Select the two surfaces, first on the shaft in the preview window and then on the impeller on the main screen as shown in the figures below

¾ Choose the Mate constraint

¾ First, select the face on the shaft and then select the bottom face of the hole in the impeller as shown.

¾ Choose APPLY and then click OK

The assembly will now look like the figure below.

¾ Click on ASSEMBLIES → COMPONENTS → ADD COMPONENT

¾ Open the file Impeller_hexa-bolt.prt

¾ Choose the Center constraint

¾ First, select the outer cylindrical threading on the bolt and then select the inner surface of the hole on the upper casing as show in the figures below.

¾ Now choose the Mate constraint

¾ Select the flat face on the bolt and the face on the rib of the upper casing as shown

¾ Click APPLY and then OK

The assembly is shown below.

¾ Repeat the same procedure as before to add the part file Impeller_washer.prt

¾ Choose the Center constraint

¾ Select the inner face of the washer and the cylindrical threading on the bolt as shown

¾ Choose the Mate constraint

¾ Select the flat face of the washer and then the face on the rib of the lower casing as shown

¾ Click APPLY and then OK

The Assembly is shown below.

¾ Add the part file Impeller_hexa-nut.prt

¾ Choose the Center constraint

¾ First select the inner cylindrical face of the nut and then the outer cylindrical face of the washer as shown

¾ Choose the Mate constraint

¾ First select the flat face on the nut and then on the face on the washer as shown.

¾ Click APPLY and then OK

The assembly now will look as shown in the figures below.

¾ Repeat the same procedure to add bolts, washers, and nuts to all the holes in the casing. This completes the assembly of the impeller

There is a simpler way to assemble the bolt, washer, and nut set. Instead of adding the three parts individually, you can assemble these components separately in another file. This will be a sub-assembly. You can insert this subassembly and mate it with the main assembly.

The Final Assembly will look as the shown below. Save the Model.