Cam Size
Terminology that relates to 'CamSize'.
•  Base Circle: the diameter of the smallest circle that is tangent to the cam surface. 
•  Prime Circle: the diameter of the smallest circle that is tangent to the . 
•  Cam Lift (also called Follower Stroke): the difference between the 'PrimeCircle' and the maximum radius of the PitchCurve. 
Advantages of a 'smaller' Cam.
A smaller cam:
•  reduces material costs (but a 'very' small and 'very' large cam increase manufacturing costs). 
•  reduces its inertia for rapid or emergency stopping. 
•  reduces outofbalance forces. 
•  reduces the numberofrotations that camfollower roller makes for each rotation of the cam 
•  reduces the angular velocity and angular acceleration of the camfollower roller 
•  reduces the sliding distance the flatfaced follower makes for each rotation of the cam, thus reducing wear 
•  reduces the sliding velocity with flatfaced follower, thus reducing wear 
Disadvantages of a 'smaller' Cam.
A smaller cam:
•  reduces the flywheel effect that helps to rotate the camshaft at constant angular velocity as the drive torque varies 
•  increases the required accuracy of a machine tool to manufacture 
Cam Size Measurement
To measure the Cam, use a Measurement FB.
Measurement of the Base Circle, Prime Circle, Cam Lift

Basic Circle [See image: BaseCircle = 80mm]
2.  Click the small Point at the contact between the CamFollower and the Cam 
3.  Click the Point at the centre of the rotating Cam 
4.  Click the graphicarea. 
The measurement in the graphicarea continually updates as you cycle the model.
Use the measurement dimension in the graphicarea to find the minimum measurement  the BaseCircle Radius  in the image it is 80mm  or use a Graph FB to plot the variation of radius.
Cam Lift
The difference between the minimum and maximum values of the Measurement is the CamLift.
You can also use a Stats FB to find the maximum and minimum values.
PrimeCircle (also called the Reference Circle) [See image: PrimeCircle = 100mm]
1.  Click Add Measurement FB 
2.  Click the Point at the centre of the Cam and then the centre of the CamFollower. 
The Prime Circle Radius is the minimum measurement in the machine cycle.

