TABLE OF CONTENTS The author can remember instances of machinists (many years ago) saying something like "Make a cam? No problem, I just lay it out with bluing using circle arcs and straight lines, cut it out on the band saw, sand it smooth with the belt sander and stick it in the machine." This may have worked (and apparently did) when machine speeds were relatively low, but it definitely will not work with current cam speeds that are typically hundreds to thousands of rpm, nor in cases requiring great precision.
This chapter will first show how one should NOT design a cam for a multi-dwell application that involves moderate to high speed operation. What does that mean? What is high speed? Well, it is relative. If the mass of the follower train is very small and its stiffness high, then one can get away with poor dynamic design at higher speeds than one can if the follower train has large mass and/or low stiffness. Newton's second law determines all in this context. Finally, the key to properly designing a cam for good dynamic behavior will be discussed.
The first task faced by the cam designer, when presented with a timing diagram, is to select the mathematical functions to be used to define the motions of the followers. The easiest approach to this process is to "linearize" the cam, i.e., "unwrap it" from its circular shape [1] and consider it as a function...
