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Project Overview

Impeller Assembly - An approach in methodology

The impeller assembly is a conceptual design for a mechanism to translate water flow into axial rotation. For this course, consider the design to be in progress and know that it will not be totally completed in this class.

The design you will model may or may not be the correct approach. This in itself mimics real life situations. As a design is reviewed by different disciplines, it matures from the recommendations made by those disciplines. In this class, what is more important is gaining an understanding of the methodology of using a combination of NX functions to capture an aspect of the total design intent.

Below is an illustration of the impeller assembly you will model.

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Section

1 The Inner Moldline of the

Bottom Housing

Overview

The design intent for the bottom housing is that its size and shape be controlled parametrically. This will be achieved by creating a sketch that defines the inner moldline of the bottom housing. This same sketch will also be used later to define the outside shape of the impeller.

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Creating the Inner Moldline of the Bottom Housing

Step 1: Create a new (inch) part file called userID_housing_bottom.

Step 2: Create generator geometry for the inside moldline. Since one of the design requirements is that

the size and shape be controlled parametrically, the inside moldline will be sketched in Task

Environment.

Be sure to turn off Auto Constraints Dimensioning function of the NX system. The moldline sketch

should be dimensioned and constrained exactly as the figure on the next page shows.

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0 Create a sketch named, moldline, on the X-Z absolute

coordinate plane.

0 Sketch the curves as illustrated below and apply the required constraints.

• Rename the dimensional constraint (1) inside radius as shown below.

This is being done so that this constraint may be identified easier, later in

the course.

• The inside moldline is made up of two lines and two arcs.

• Curves that have a common end point should be constrained

tangent to each other.

• The left endpoint of the lower left horizontal line is aligned

with the vertical datum axis.

• The two lines should have horizontal constraints.

Step 3: Save the part and close

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Section

2 Creating the Bottom Housing

Overview

In the previous section, an aspect of the design intent for the bottom housing was captured by creating a sketch that controlled the size and shape of the inner moldline. In this section of the activity you will continue to capture additional design intent for the bottom housing. The additional aspects are: • The flange width is based on the bolt hole size

• The number of bolt holes is controlled parametrically

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Creating the Flange

Step 1:

Step 2:

Open userID_housing_bottom.

Revolve the sketch geometry to create the housing body. The wall

thickness is 0.5". Remember, the sketch is defining the inside moldline (i.e. thickness 0.5” goes outside moldline, use in revolve operation a two-

sided offset, start at +0.5 or -0.5, depending on offset vector direction in your case) Define the a x i s o f revolution by using the sketch datum XC axis. Delta angle is 180°. Using a start angle of -90° and an end angle of 90° will give the

desired orientation as shown below.

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Step 3: Create a variable expression.

In creating the end flanges for this part, a couple of design issues

need to be taken into consideration.

1. When adding the flange, the length of the part should not increase.

2. The allowance for hole size and edge distance determine

flange width.

For our design the hole diameter is 0.75” and the edge distance is 2D (2 x the diameter). These circumstances provide a good opportunity to create an expression for the hole size. This variable can then be referenced in other features that rely on its value.

Create the following length expression variable:

hole_dia = .75 in

Step 4: Create the first end flange.

0 Extrude (with two-sided offset) and unite the part edge indicated

below. The extrusion should not change the length (along

the XC axis) of the solid body of the Bottom Housing. Use

the following values:

Start Distance = 0

End Distance = .5

Two sided offset:

Start = 0

End = 1.25+3.5*hole_dia

The sign (±) of the second offset value will vary depending on the direction of the offset

vector.

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Your part should now look as below:

Step 5: Create the second flange.

The parameter for the second offset was 1.25+3.5*hole_dia. The

1.25 value is an allowance for the wall thickness of the

revolved section, a 0.25 offset, and for a 0.5 fillet that will be

applied later. The "3.5*hole_dia" is an allowance for the edge

distance, hole radius, and clearance for the bolt head up to the fillet.

Extrude the inside edge shown below and unite to the solid body. Use the

same values as before. Again, the extrusion should not change the length of the

solid body. The sign (±) of the second offset value will vary depending on the direction of

the offset vector.

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Your part should now look as below.

Remember to save your part periodically.

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Step 6: Create the first top flange, as shown below and described on the next page.

The illustration below points out the requirements for the top flanges. Notice that the inside edge (1) and outside edge (2) run parallel to each other. Also notice how the top flange is indented 0.25” from the end flanges.

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0 Extrude the four solid edges that define the inside edge as illustrated

below and unite.

Remember that Selection Intent allows you to select these edges

as tangent curves with one pick.

Remember, this Bottom Housing is only 1/2 of the total housing. When both halves are put together, a cross section normal to the cylindrical axis should produce a round cross section.

So, with the WCS oriented alongside the Absolute Coordinate

System, make sure the extrude vector points in the -ZC direction

(thus, the top face of the side flange is aligned with the XC-YC

plane).

0 Use the following values:

Start Distance = 0

End Distance = .5

Offset Start = 0

Offset End = 1+3.5*hole_dia

The sign (±) of the end offset value will vary depending on the

direction of the offset vector.

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Your part should now resemble the illustration below.

Step 7: Mirror the top flange.

0 Mirror the top flange feature through a datum plane aligned with X-Z

plane.

Your part should now resemble the illustration below.

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Step 8: Create the bolt holes on the top flange. The design requirements for this hole pattern are as follows:

0.75” diameter (hole_dia variable)

Edge distance equals 2 times the hole diameter.

3 holes equally spaced b y 15 degrees

In the next few actions you will create some reference features. The first reference feature, a datum plane, will be used to locate the initial hole feature on the flange. The next reference feature, a datum axis, will be used to define the rotation axis of a circular pattern.

0 Choose Datum Plane.

0 Place the cursor over the edge shown below until the Quick Pick cursor appears,

and then select the edge (i.e. not the Arc Center!).

0 Choose the selection that defines the inner edge.

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0 Choose Alternate Solution (in Plane Orientation) until the datum plane is

oriented in the plane of the arc as shown below.

0 Choose OK.

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0 Create a relative datum axis defined by the flange face (1) illustrated below.

This datum axis will pass through the center of the original arc sketched in

moldline.

0 Create a sketch for a simple hole by defining the diameter with the hole_dia variable.

Select the placement face as shown below.

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Position the hole by using a perpendicular dimension from the edge illustrated below. This

distance should be defined by 2.0*hole_dia, while in the other direction place the hole

right on the datum plane (as shown in previous picture).

Create a circular pattern of the holes as illustrated below. The pattern centerline is to be defined

by the datum axis shown below. Use the following values: Count = 3, Pitch angle = 15 (±

apply the right hand rule.)

0 Add a duplicate set of holes to the opposite flange (mirror feature – you may decide to

mirror flange with hole pattern in one mirror feature operation).

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Step 10: Create the blends.

Create a single blend with four edges and two radius sets, as shown below.

Set 1 = 0.5” radius

Set 2 = 1.0” radius

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0 Ensure that the Selection Intent is set to Tangent Curves.

0 Select one of the edges illustrated below. All of the tangent edges are also

selected.

0 Now select the other edge illustrated below. Once again, the tangent edges

are selected.

0 Apply a 0.5” blend to this set of edges.

0 Select the four small edges as illustrated below and apply a 0.1875” blend.

.

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Finished Bottom Housing should look as below

Save the part and close the part file.

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Section

3 Creating the Assembly Part File

Overview

In this section of the activity you will create an assembly part file that will be used to integrate the different parts of the impeller assembly. You will then add the bottom housing to the assembly part file, using the Bottom-Up modeling technique, making it

the first component part file of the assembly.

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Creating the Assembly

Step 1: Create a new empty inch part file called userID_impeller_assm.

Step 2: Add userID_housing_bottom to the assembly part file at Absolute Origin

Step 3: Save all parts and close them.

•

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Section

4 Creating the Upper Housing The upper half of the housing is almost identical to the lower half except for the inspection port located on top. The design intent dictates that if the bottom half of the housing changes the top half will reflect those edits. The WAVE Geometry Linker Mirror Body function will be used to capture this aspect of the design intent. Also, the size of the inspection port is based on the overall size of the housing. Because it is the sketch in the lower housing that controls size and shape; interpart expressions will be used to make the size of the inspection port associative

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.

Creating the Upper Housing

Step 1: Open userID_impeller_assm.

Step 2: Create a new empty component part file named userID_housing_top.

Step 3: Use the Wave Geometry Linker to mirror the bottom housing into

the userID_housing_top component part file.

0 Create a relative datum plane in the userID_housing_bottom part file to mirror

the housing through.

Make sure you save the userID_housing_bottom after creating the datum

plane.

Return to the assembly, if your new datum plane in the bottom housing is not visible change its Reference Set from “MODEL” to “Entire part”.

The - still not yet done - housing top should be your work part when doing the Mirror Body link.

0 Mirror the bottom housing body. Your assembly should look as shown below:

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Step 4: Create datum planes that will be used to create the inspection port.

Because the design intent for the housing is to be able to change in size and shape, the inspection port must also be modeled to address these possible changes. With that in mind the following design intent will be imposed on the inspection port feature.

Length = 2/3 of the housing's “ inside radius” perpendicular to the

revolution axis.

Width = 3/5 of the port's length.

Height = 4 inches above the outside cylindrical face. Port is centered

on the housing cylindrical axis.

Port is located 2 inches from cylindrical face edge (see illustration

below).

0 Make the userID_housing_top part the Displayed Part.

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O Create the relative datum plane (1) shown below, that is tangent to the cylindrical face (2) and

parallel to the flange (3).

O Create the next datum plane show below. This datum plane is associative to the previous

datum plane and is offset by 4 inches.

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0 Create the next datum plane (1) show below. This associative datum plane is to be

created through the cylindrical axis of the cylindrical face (2) at 90° to the

previously created datum plane (3).

Step 5: Create a sketch to define the shape of the inspection port.

0 Create a sketch named port

0 Define the sketch plane by the datum plane labeled 1and the vertical reference by the datum plane labeled 2. The vertical reference direction should point in the XC direction of the WCS.

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Step 6: Create the sketch geometry and apply dimensional constraints as illustrated below.

Arrow 1is pointing to the edge endpoint that p5 is dimensioned to. Arrow 2 is pointing

to a datum plane.

(Your expression names may vary from those illustrated below.)

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Step 7: Create interpart expressions to control the length of the port.

The design intent is that the length of the port is 2/3 of the housing's variable inside radius as shown below. This step will capture that design requirement.

First you must identify which expression controls the interior radius.

0 Review the MOLDLINE sketch in the userID_housing_bottom part file. Identify the expression that controls the interior radius (inside_radius=15.000 in) as illustrated below.

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0 Review the PORT sketch in the userID_housing_top part file.

Identify the expression that controls the length (1) of the port as illustrated below.

0 Create an interpart expression that links the port length to the lower housings interior radius and then factor the 2/3 constant into the expression. The expression should look

similar to the following:

p2 = “userID_housing_bottom”::inside_radius*2/3

The sketch will define the inside shape and size of the port. Next, you will create

associative offset curves to define the exterior shape and size of the port.

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Step 8: Create a set of curves that are an associative offset (1) to the sketch curves (2) as

shown below.

Step 9: Extrude the associative offset curves to the exterior housing face, with a 5° draft, and

unite.

The part could be cast with the inside draft of the inspection port facing either way, up or down. The differences are which half of the mold will form the interior, and more importantly, whether or not the walls are constant thickness.

The design intent calls for a constant wall thickness on the port.

Step 10: Extrude the sketch to the interior face of the housing with 5° of draft and subtract it.

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Step 11: Create a three-set blend feature on the inspection port in the order listed below.

Set 1 0.5 interior corners and around the interior

opening

Set 2 1.0 exterior corners

Set 3 0.5 around the base

Step 12: In the userID_impeller_assm part file, verify that the reference set for all the component

parts is MODEL.

Step 13: Save all: the assembly and all of the component part files.

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Section

5 Creating the Impeller, Part 1

Overview

The design intent in this section of the impeller creation is: • To allow the number of blades to change.

• To parametrically control the shape of the blade.

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Defining Body & Blade

Step 1: In the impeller assembly, create a new empty component named

userID_impeller.

Step 2: Change the work part to userID_impeller

Step 3: Create the main body of the impeller.

Create the cone to the specifications and orientation as shown below. The WCS

is shown in the absolute coordinate orientation and location of (0,0,0).

Make the cone (impeller part) the displayed part

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Step 4: Create reference features.

These reference features will be used to create the sketch that the imported

geometry will be added to.

1. Create a datum plane through the conical face axis.

2. Create a datum axis through the conical face axis.

3. Create a datum axis through the .intersection of the smaller planar face and the

datum plane.

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Step 5: Create a sketch for the blade cross section.

0 Define the sketch with the following parameters:

Sketch name is blade

Sketch plane is defined by the datum plane

• The sketch plane normal points in the +Z direction.

0 After the sketch is created choose Finish.

0 Delete the datum axis as indicated below (if it was created by the sketch

function).

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0 Create the dimensional constraints as illustrated below.

Note that the p 754 dimension is a constraint between the R 1.5 arc center and

the horizontal datum axis (cone centerline).

Step 6: Extrude the blade geometry.

0 Extrude the sketch 15 inches in the +ZC direction and unite it to the cone

feature.

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Step 7: Create interpart expressions to control the length of the extrusion.

In order to create a minimum clearance between the outside edge of the blade and the inside of the

housing in a later step, the extrusion distance must always equal the largest interior radius of the

housing. This will be accomplished by using an interpart expression.

0 Review the MOLDLINE sketch in the userID_housing_bottom part file. Identify the expression that controls the interior radius as illustrated below.

0 Identify the expression that controls the length of the blade extrusion.

0 Create an interpart expression, which links the blade extrusion length expression,

to the bottom housing's inside radius as shown above.

Step 8: Save all: the assembly and all component parts; close all parts.

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Section

6 Creating the Impeller, Part 2

Overview

The design intent in this section of the impeller creation is: • The end of the blade conforms to the interior shape of the housing with a

0.125” clearance between the end of the blade and the housing.

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Trimming the Blades

Step 1: Open userID_impeller_assm.

Step 2: Review the assembly.

Notice how the blade pierces the housing walls.

Step 3: Create an associative sheet (surface of revolution).

This step will guide you through creating an associative sheet that will be used to

trim the blades to the inside profile of the housing.

The first step in creating the sheet is to use the WAVE Geometry Linker to create

a link between the housing profile and the impeller.

In the assembly part file we need to see the housing sketch geometry. One way to do this is to display the bottom housing as the “Entire part” reference set so that the sketch geometry becomes visible.

0 Use the Wave Geometry Linker to link the sketch from the bottom housing to the

userID_impeller component part file.

0 In the userID_impeller part file, revolve about the X axis by 360°.the

linked sketch geometry, changing the Body Type (in revolve command

Settings) from solid to sheet.

Step 4: Use Offset Faces to edit the sheet to provide the 0.125” clearance (you may have to use + or –

sign of the offset) needed between the impeller and housing.

The sheet that was created follows the exact shape of the inner moldline.

If the blades were trimmed to this sheet solid in the present configuration, there would

be no clearance.

In this step you will use the Offset Face function to offset the entire feature a distance of 0.125. The offset face function is parametric so, if the size or shape of the parent geometry changes, the sheet solid will update to maintain the 0.125 clearance.

Step 5: Trim the impeller blade to the offset sheet. After the trim operation you may make the sheet and the

linked sketch invisible by moving them to a different layer and making this layer invisible (in both the

impeller part and the assembly file).

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Adding Blends

Step 1: If necessary open userID_impeller_assm

Step 2: Display the userID_impeller.

Step 3: Create a variable radius blend on the end of the blade.

0 Assign the variable radii as instructed below.

At the end of the edge labeled 2, assign a radius of 0.5.

At the end of the edge labeled 3, assign a radius of 0.0625.

At the end of the edge labeled 1, assign a radius of 1.25

0 Create also a .5 blend at the base of the single blade

Step 4: Using Pattern Face, create a circular pattern of 6 blades (for this

command, be sure to pick all faces of your single blade, including all blends)

Pick all the faces of the blade for

Pattern Face command

The resulting impeller should look

like this

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Step 5: Create .25 x 45° chamfers on the edges as indicated below.

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Step 6: Create the central hole features as illustrated below (one way of doing this would be to

create a sketch following the shape of the hole and revolving it around the cone centerline with

subtraction).

6-3

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Step 7: Create the keyway.

0 Create the datum plane as illustrated below through the cylindrical axis at 90° to the first

datum plane.

0 Create a Rectangular Pocket feature on the XC-YC datum plane; the normal vector should point

up. Identify the horizontal axis with the datum axis that is the centerline of the cone.

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0 Enter the following parameters for the rectangular pocket:

Length =

7.5

Width = 1.250

Depth = 2.372

Corner Radius = .0625

(The value of 2” in the Depth parameter accounts for the radius of the central hole.)

0 Position the pocket by:

• using Line onto Line between the datum plane (1) and the pocket's XZ

centerline.

• using Horizontal 0 (zero) value between the arc's (2) center point and the front bottom

edge of the pocket (3).

Step 8: Save all: the assembly and all component parts; close all parts.

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Section

8 Creating the Impeller, Part 3

Overview

The design intent in this section of the impeller creation is:

• Build associativity in the assembly so that the impeller maintains the

correct location and orientation.

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Constraining the Impeller to the Assembly

Step 1: Open userID_impeller_assm.

Step 2: In the top level assembly verify that the current reference sets of the

userID_impeller and userID_housing_bottom component part files

are displayed with the MODEL reference set.

Step 3: Constrain the impeller to the housing.

0 Use infer center/axis constraint to center the impeller in the bottom housing using

the conical face of the impeller (1) and the cylindrical face of the lower housing (2).

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0 Assign a distance constraint with a 4 inch offset between the impeller and

housing using the faces shown below.

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Step 4: Edit the color of the assembly components.

To better distinguish parts color attributes of components may be edited at the assembly level. This will

not affect the colors of the bodies in the part file where they reside.

The bottom housing will remain as created. You will edit the top housing component color and

change the translucency to allow the impeller to be seen. You will also edit the impeller component.

.

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Step 5: Review the assembly using View Section – Edit Work Section.

0 See if you can adjust the sectioning plane to visually verify the blade clearance.

Step 6: Save the assembly and all component parts; close all parts.

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Section

9 Creating the Shaft Subassembly .

Overview

The design intent of the shaft subassembly is that the shaft_impeller component will control the diameter of the other shaft subassembly components. This will be achieved by linking an edge of the shaft_impeller component to the shaft_extension component.

Another aspect of the design intent is that the wall thickness of the shaft_extension is

always 0.375 in. I

•

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Creating the Impeller Interface of the Shaft subassembly

In this approach you will model the first component of the shaft assembly in the

shaft_subassembly part file. You will then create a component part file in the shaft assembly and

add the existing solid body to it.

Step 1: Create an (inch!) part called userID_shaft_subassm.

Step 2: Create a 4.0" diameter x 11.0" long primitive cylinder in the orientation

shown below. The WCS shown remains oriented alongside the Absolute CSYS.

Step 3: Create a 6.0" diameter x 2.0" long boss positioned Point onto Point to the

cylinder as shown below.

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Step 4: Create a boss that will have a diameter 0.75 in less than that of the boss created in the

previous step and has a height of 1.0 in. Position the boss Point onto Point to the solid body as shown below.

Step 5: Create the chamfers and fillet as instructed below.

0 Create a 0.125 x 45° chamfer at location 1.

0 Create a 0.25 x 45° chamfer at location 2.

0 Create a 0.5 radius at location 3.

Step 6: Create the keyway.

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0 Create the two datum planes as shown below.

•Datum plane 1 passes through the cylindrical axis of the cylinder feature.

•Datum plane 2 is tangent to the cylindrical face of the first feature (cylinder) and 90° to datum plane 1.

0 Create two additional datum planes on the two planar faces indicated below:

""··

1

2

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0 Create a sketch named keyway on the datum plane through the cylinder axis,

shown below (1):

The sketch represents a path milled by a 4 inch diameter slot mill 0.524 inches deep in the shaft. The mill tool selected by the designer has a 1/16 inch (0.0625) corner radius.

Since only the portion of the path of the tool intersecting the part will be cut, the height of the sketch need not be constrained.

Since the tool must cut from the small end of the shaft as far as possible along the cylinder without gouging the large boss on the end of the shaft, the necessary length can be determined by geometric constraints.

0 Create a rectangle approximately in the proportions illustrated, and

fillet one corner as shown.

0 Constrain the two vertical sketch lines collinear with the two datums as

illustrated.

0 Add the 2 inch radius dimension and the dimension from the lower line to the

tangent datum. If necessary, drag curves to the approximate location before

dimensioning or use alternate solutions to obtain the proportions illustrated.

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Step 7: Extrude the sketch 1.25/2 inches with the Symmetric Distance and Subtract

options.

Step 8: Create a .0625” blend on the edges of the keyway as shown.

Step 9: Create a hole that is 1.0" diameter x 3.0" deep with a 118° tip.

Locate the hole concentric to the shaft.

The part is now complete in the subassembly file. The next step is to create a

component part file and add the part to it.

Step 10: Create a component part file called userID_shaft_impeller and add the solid

body to it.

There should no w be a component part file in the

userID_shaft_subassm part file. The new component part file,

userID_shaft_impeller, consists of the solid body and all of the

features used to create it, only the component object remains in the subassembly

file.

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Step 11: In the userID_shaft_subassm part file, verify that the

userID_shaft_impeller's current reference is the MODEL

reference set.

Step 12: Save the userID_shaft_impeller and userID_shaft_subassm part files.

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Creating the Center Section of the Shaft subassembly

The userID_shaft_impeller part must control the diameter and orientation

of the center section.

You will create the center section of the shaft subassembly. You will start by creating an

empty component part file in the subassembly and then link an edge of the

userID_shaft_impeller part to it.

Step 1: In the userID_shaft_subassm, create an empty component part file called

userID_shaft_extension.

Step 2: Link the edge of the component shown below to the

userID_shaft_extension part file. Make sure that you are not

selecting the edge of the chamfer.

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Step 3: In the userID_shaft_extension part file extrude the linked geometry using the values below.

Start =

0

End = 36

Start Offset = 0

End Offset = .375

The sign (±) of the Second Offset value should create an edge that has a larger

diameter than the generator curve.

The illustration below shows how the shaft_extension (1) will fit with the shaft_impeller.

If the shaft-impeller's feature that interfaces with the extension changes size, then the

extension diameter will also change and maintain the .375” wall thickness.

Step 4: Create the two .25 x 45° chamfers as illustrated.

Step 5: In the userID_shaft_subassm part file, check if the

userID_shaft_extension’s current reference set is the MODEL

reference set.

Step 6: Save the userID_shaft_extension and userID_shaft_subassm part files.

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Creating the Final Section of the Shaft subassembly

The modeling approach for the final component of the shaft subassembly is similar to that of the center section, in that you will link geometry from the center section to this component. When the first component of the subassembly, the userID_shaft_impeller, changes in diameter, the center section also changes, followed by an update in the final component.

Step 1: In the userID_shaft_subassm, create an empty component part file called

userID_shaft_load.

Step 2: Link the edge of the component shown below to the userID_shaft_load part

file.

When creating the extruded features in the next two steps, pay close attention to

the vector directions. You may need to alter the direction of the values given.

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Step 3: In the userID_shaft_load part file extrude the linked geometry in the -Y direction (WCS oriented to the Absolute CSYS) using the values below.

The extrusion starts with a negative value. This negative val ue will provide the 1.0"

interface into the userID_shaft_extension with an

8.0” length outside the extension.

Start = -1

End = 8

Step 4: Extrude and unite the edge shown below using the following values.

Start Distance = 0

End Distance = 8

Two sided offset:

Start

0

End -.375

The sign (±) of the End Offset value should create an edge that has a larger diameter

than the generator curve.

Step 5: Create the four flat faces, as described in the next page.

Before extrude After extrude and unite

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0 First create the 3 reference features as shown below.

1 - Datum axis through cylindrical face axis

2 - Datum plane through cylindrical face axis

3 - Datum plane tangent to cylindrical face and parallel to first datum

plane.

Do not be concerned if your datum axis does not point in the same

direction as illustrated above.

0 Create a Rectangular Pocket by selecting the placement face

(1) and horizontal reference (2) as shown below.

0 Use the following parameters:

Length =

10

Width = 6

Depth = .75

Corner Radius = 0

Floor Radius = .5

0 Create the first positioning constraint by using Line onto Line and selecting the

datum axis and the pocket's XC centerline.

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Notice that the pocket is presently hanging over the back edge of the extrusion. You will enter a negative value to position the pocket on the opposite side of the arc's edge.

0 Create the second positioning constraint by using Horizontal and selecting the arc center

(1) and the pocket edge (2). Use a value of -2.

0 Model the other flats as illustrated below by creating a Circular Pattern Face about the

datum axis.

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0 Create the chamfers on the edges as directed below.

1 - 0.25 X 45°

2- 0.125 X 45°

Step 6: Save the part.

Your finished shaft subassembly should look (in a sectional view) as below:

Step 7: Save the shaft subassembly.

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Step 10: Add the userID_shaft_subassm to the userID_impeller_assm, using the MODEL reference set and absolute positioning. Don't worry with orientation or position, which will be dealt with in the next step.

Step 11: Constrain the shaft subassembly to the main assembly.

The shaft subassembly is probably not in the correct orientation. This step will orient the subassembly to the impeller. Keep in mind that the shaft and the impeller have a keyway in common.

O Apply Touch constraint to the faces shown below.

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0 Apply Infer Center/Axis to the faces shown below.

0 Apply Align to the faces of the keyways as shown below.

The shaft subassembly should now be constrained to the impeller.

Step 12: Edit the color of the three shaft subassembly components to any choices

that satisfy you.

Step 13: Save and close the assembly and all component parts.

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Section

10 Adding Standard Hardware to the

Assembly

Overview

In this section of the activity you will add and constrain required hardware using

different part families.

The fasteners that hold the lower and upper housing together must be constrained to an instanced hole, so that if the hole number and positions change the number and placement of fasteners will update accordingly.

key4.prt

bolt075.prt

HexSocketHead1.prt

washer075.prt

nut075.prt

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Adding Fasteners

In previous page drawing: 1 - Impeller Key; 2- Housing Fasteners; 3 - Impeller Socket Head Cap Screw

Step 1: Open userID_impeller_assm.

Step 2: Add a 1.25" wide x 4" long key to the impeller assembly by bringing in the key4 part

file.

Step 3: Constrain the key to the keyway.

0 Touch the faces as shown below.

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O Touch the faces as shown below.

0 Touch the faces as shown below.

Step 4: Fasten the Impeller to the shaft subassembly using a 1.0 inch diameter x 6 in long socket

head cap screw. Constrain the fastener to the counter-bored hole in the impeller.

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Step 5: Add the first bolt that will hold the upper and lower housing together.

0 Add a 0.75" diameter x 2.5" long Hex head bolt.

0 Constrain the bolt to the assembly by:

• Apply an infer center/axis constraint from the face labeled 1 to the cylindrical

face of the hole in the bottom housing. The constraint must be made to the hole in the bottom housing.

• Apply a touch constraint from the bottom of the bolt head to the face labeled

2, or – alternatively – use a distance constraint (of 0.5 in) between bolt head

bottom face and top face of the bottom housing

The first bolts used to hold the two halves of the housing together on

each side of the assembly need to have at least one constraint to the hole

feature in the circular pattern of holes in the bottom housing (You may, as

well, make ALL constraints to the hole in the bottom housing). The holes

that appear in the top housing do not belong to a circular pattern because

the top housing was created by a mirroring function. By constraining the

bolt as instructed above, the Component Pattern function may be used

later to populate the remaining holes with bolts. This practice will also

be applied to the first washers and nuts.

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Step 6: Add the first lock washer.

0 Add a 0.75" diameter lock washer to the assembly file.

0 Constrain the washer by:

• Apply a touch constraint from the planar face of the washer (1) to the bottom face

of the bottom housing's flange.

• Apply an infer center/axis constraint between the cylindrical face of the washer and the cylindrical face of the hole in the bottom housing. The constraint must be made to the hole in the bottom housing.

Step 7: Add the first nut that will hold the upper and lower housing together.

0 Add a 0.75" diameter nut to the assembly part file.

Notice that one side of the nut is beveled and the other side is flat.

0 Touch the flat side of the nut to the bottom face of the washer (or distance –

by washer thickness 0.187” - the flat side of the nut to the bottom face of the side

flange of the bottom housing)

0 Infer center/axis the nut by selecting the nut's cylindrical face and the

cylindrical face of the hole in the bottom housing and choose OK.

Step 8: Apply the assembly constraints for the bolt, washer, and nut.

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Step 9: Add the rest of the fasteners to this side of the housing making the Component

Pattern (use Reference Pattern type)

To be successful in the use of the Component Pattern function, a couple of

points must be kept in mind.

First, at least one assembly constraint must be related to the circular array of

holes. In this activity, the circular pattern of holes is only present in the

userID_housing_bottom part file. The hole pattern in the upper housing is

part of the feature was created by mirroring with Wave Geometry Linker and

is not recognized as a pattern instance.

Second, the fastener constraints must be applied to the first instance of the

hole pattern (the “master” hole).

Step 10: Continue by adding the fasteners to the opposite side of the housing, by applying

the same methods as used on the previous side. In case you encounter difficulties

with the hole pattern on the other side of the housing (which was mirrored) being

recognized, delete the mirrored pattern of holes and replace them with a new

pattern, done the same way as the first pattern.

When selecting the components for the Component Pattern function; select components in the graphics window. If selection is made in the dialog box window, duplication of fasteners will occur on the side that is already done.

Step 11: Save and close the assembly and its component parts.

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Section

11 Modifying the Assembly

Overview

The design has been modified; thus, placement and numbers of some assembly components must change. Your capture of design intent will help to maintain the desired form, fit, and function as you make the edit of the inside_radius variable at the assembly level form 15 to 18 inches. This will also require modifying the moldline sketch, and changing the number of holes and bolts in housings.

• •

Modifying the Assembly

Step 1: Open the userID_impeller_assm part file and load all components fully.

Step 2: Provide the assembly controlling variable inside_radius = 15 in, at the impeller assembly

level (if you haven’t done that earlier).

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Step 3: Provide for the modifications of the inner moldline of the bottom housing to

accommodate the increase of the inside_radius to 18 inches by editing the MOLDLINE

sketch to the values shown below (with conditional if statements). Link the inside_radius

of the bottom housing to the controlling inside radius variable at the impeller assembly file.

Step 4: Edit the number of holes shown below to 4 for each of the top flanges, when the inside

radius changes to 18 inches by editing the appropriate hole pattern. Maintain the existing

angle of 15 degrees.

Step 5: Review the impeller assembly. Upon inside _radius variable change at the assembly level

from 15 to 18 inches, all changes should occur automatically as shown on the next page.

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Did the upper housing and impeller update? If not, it may be because these components are only partially loaded. If the upper housing and impeller components did not update; open them fully using the Assembly Navigator. If the components still have not updated, check all your links between files, Save and close all your files.

Impeller Assembly for

inside _radius = 15 in

Impeller Assembly for

inside_radius=18in