Open a new “part” file in SolidWorks. The default screen which appears is shown in Figure 1.
Figure 1. Default Soldworks screen
By default, SolidWorks opens “Sketch” tab. Go to “Features” Tab and click the “Extrude
Boss/base” option available at topmost left corner in features tab as shown in Figure 2.
Figure 2. Extruded Boss/Base option in Features Tab
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Select the “Front Plane” as shown in Figure 3.
Figure 3. Selection of Front Plane.
By default the “Sketch” Tab opens. Now select “Centerline” option to draw centerlines, as
shown in Figure 4.
Figure 4. Select Centerline Option to Draw Centerlines.
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Draw a centerline of approximately 3 inches from the origin. Repeat the same procedure 12
times. The angle between the centerlines is also approximate at this time. Your screen should
look like Figure 5.
Figure 5. Drawing Centerlines
Use “Smart Dimension” option to change the arbitrary angle between the centerlines to exactly
30 degrees as shown in Figure 6.
Figure 6. Changing angle between arbitrarily drawn centerline to 30 degrees.
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Repeat this process for all the 12 centerlines. The screen will now show centerlines at 0, 30, 60,
90, 120, 150, 180, 210, 240, 270, 300, 330, 360 degrees (see Figure 7).
Figure 7. Centerlines with proper angles between them.
The 30 degree labels can be deleted to clear space. This will not change the angle between the
centerlines.
Next step is to add points to the centerlines according to your follower profiles. Use the option of
adding points as shown in Figure 8. Simply add one point on every centerline (so 12 points in
total) anywhere on centerline.
Figure 8. Adding points to sketch.
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Change the dimension of the points according to follower travel. In this tutorial points will be
dimensioned on specific centerlines according to the following table.
Angle (degrees)
0
30
60
90
120
150
180
210
240
270
300
330
360
Displacement (inches)
0
0.5
1
2
2.5
2.5
2.5
2.5
2
1.5
1
0.5
0.
A base circle radius of 0.5 inches will be added to displacement before dimensioning points.
After adding points, connect them using “Spline” option (a smooth curve). To connect using
splines, select each point sequentially either clockwise or counterclockwise. Begin and end with
the same point to draw a spline as shown in Figure 9.
Figure 9. Spline used for drawing a smooth curve.
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Go back to “Features” tab and select “Extruded Base/Boss” option. Change thickness of the cam
to 0.25 inches as shown in Figure 10.
Figure 10. Changing thickness of the cam.
Press “Enter” or click the green checkmark on the left to see the final profile of the cam (Figure
11)
Figure 11. Final cam profile
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Check for any interference or undercutting before you submit the final cam profile for
fabrication. To check for interference or undercutting in case of a roller follower, add circles on
the centerlines representing the roller by editing the sketch. A simple way to draw circles is to
first add points on centerlines and edit their dimensions to a distance of 0.25 “ (roller radius)
between the profile point and the roller center. After you have drawn the 12 circles, one on each
centerline, fit a spline such that the spline is tangent to the circles as shown in Figure 12.
Figure 12. Drawing roller circles and fitting spline tangent to the circles.
Notice that the old fit might interfere with the circles (see Figure 13), so delete the fit and use the
new spline fit as the final cam profile.
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Figure 13. Spline fit without interference or undercutting.
Finally extrude the profile to given thickness and submit your drawing for fabrication.
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