Variable Pitch Helical Extension Spring Pro/ENGINEER Wildfire 2.0

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ME-430 INTRODUCTION TO COMPUTER AIDED DESIGN
Variable Pitch Helical Extension Spring

Pro/ENGINEER Wildfire 2.0
Dr. Herli Surjanhata


Create a part named extension_spring and begin with three default datum planes. You don’t
need to change the Units since inches is the Pro/ENGINEER default units.




Create a Protrusion using the Helical Sweep options.


From Insert pull-down
menu, select Helical
Sweep -> Protrusion

Accept all other default
Attributes. (Constant -
> Thru Axis -> Right
Handed -> Done)


Select Done

Click the

Create new
object icon.

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Pick FRONT datum plane as the sketching plane for the sweep profile – click Okay, and TOP
datum plane as the Top reference.

Begin with sketching a vertical centerline along RIGHT datum plane. Then sketch an inclined
line as shown below



Note:

To activate the drawing tools, right-click the
graphics are, then select the appropriate tool, e.g.
select Centerline or Line etc.

Or use the tool


3


Note that start point of the line is on TOP datum plane, and inclined to the right. Re-
dimension and Modify the dimension of the profile as shown above.

To obtain diametrical dimension 2.0”, do the following:

Left-click end point of line at the bottom -> left-click center line -> Left-click

end point of line at the bottom again -> middle-click to accept the position of
the dimension.



Click this icon to continue.


Enter [1.0] for the pitch.



Centerline for
symmetry
Draw this
Centerline first as
an axis of
revolution

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Sketch a circle with diameter 0.25 centered
on the centerlines.

Click this icon
to continue.

Preview the defined elements and choose
OK from the dialog box to complete the
helical sweep feature.





The finished part in pictorial view should appear as shown below.

Sketch a circle here

5





Modify the Profile of the sweep and change the value of the pitch to [0.5]. Then
Regenerate to see the effect.



Right-click the Protrusion from the Model
Tree, and choose Edit.


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Pick the trajectory.

Right click the mouse button, and select
Edit.








Double click PITCH1.00, and change the value
0.5.

Pick the Regenerate icon
.







Pick the
trajectory.

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Save the model by selecting

Change the spring to variable pitch and add pitch points to the profile.



Redefine the feature.

Right-click the helical protrusion from the Model Tree
and select Edit Definition.



Left-click Attributes, press and hold Shift key and pick
Swp Profile, Picth.

Attributes, Swp Profile and Pitch are highlighted.

Click Define button.

Select Variable -> Done.

Modify -> Done.
Select Sketch from SECTION menu. Use Point icon
to add two sketcher points as
shown in Figure below.


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Dimension the points as shown above. When you are done with the section,


Click this icon to continue.


Double-click Pitch from the dialog box.

Specify the pitch at the trajectory start and end. Type [0.5] for both locations.





A PITCH GRAPH will appear in a sub-window.

Pick the two sketcher points from the profile in the main window, select the lower point first,
and the system will prompt for the pitch at each added point and move up to the next point
until all points are added. Type [0.5] and [1.0] as a pitch at each of these points as shown
below. The graph will automatically update as shown below.