Case Study – Advanced Part – Light Bulb
Goals:
1. Create this part from scratch.
2. Use surface features as a reference to generate
the path for the swept tube of the bulb.
3. Add threads to the base.
Instructions:
1. Begin a new part file. Set the units to IPS, with three decimal places.
2. Create a Revolved boss for the base using the sketch shown.
(Hint: Notice that the center point of the concentric arcs has a vertical relation to the origin).
Case Study – Advanced Part – Light Bulb
3. With the first Revolved Boss created, create two additional bosses to define the tube connection
points using the dimensions shown below.
4. Add Fillets to the base using the dimensions shown.
Case Study – Advanced Part – Light Bulb
5.
Create a revolved surface to define the outer shape of the bulb. The bulb height should be
between 5.5 and 6 inches from the bottom of the base to the top of the bulb.
Case Study – Advanced Part – Light Bulb
6.
Create a swept surface to define the pitch of the bulb that twists 1.5 turns and fits the
dimensions shown.
7.
Copy the surface and rotate it 180 degrees. The end result here should be 3 surface bodies (2
Swept and 1 Revolved) and 1 solid body.
Case Study – Advanced Part – Light Bulb
8. To create the sweep path for the bulb tube, create an intersection curve between the three
surfaces. Use 3D splines to connect the curves together and to the base, making sure the
minimum radius of curvature is always greater than 0.3 in. Ensure the path is smooth by adding
necessary relations.
Case Study – Advanced Part – Light Bulb
9. Create a circular sketch for the sweep profile that uses the dimensions shown.
10. Sweep the tube. Set the feature options appropriately to minimize kinks in the swept body.
Case Study – Advanced Part – Light Bulb
11. Create the base geometry where the threads will be located. Use the dimensions shown.
(Hint: The base is extruded in two directions using a draft angle)
12. Chamfer the bottom edge of the base using the dimensions shown.
Case Study – Advanced Part – Light Bulb
13. Next create a swept cut for the thread.
A. To create the path for the swept cut, create a helix starting at 90 degrees, with a pitch of
0.125 in and 4 revolutions.
B. Sketch a 3D spline at the end of the helix to terminate the thread path.
C. Create a new plane perpendicular to the endpoint of the helix, and sketch the profile shown
below.
Case Study – Advanced Part – Light Bulb
14. Create the Swept Cut. Orient the cut to twist along the path defined by 52 degrees.
15. To finish the part, add a fillet to the thread and the top of the base part with a radius of .02
inches.
Self-Check:
1. Assess the part by clicking on the Evaluate Tab of the CommandManager, and selecting Zebra
Stripes.
Do the surfaces of the part transition into each other with minimal kinks and discontinuities?
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If so, Good Job!
If not, double check the sketch relations and radius of curvature of your splines. In
addition, check that the path alignment type of the swept tube is set to minimize
twisting of the profile.