Introduction To Cam

Present day requirements usually dictate that machine components move in a prescribed, exact path. Connected members alone can rarely fulfill this requirement. It is therefore necessary to resort to the use of miscellaneous surfaces called cams. Since the cam may have any shape, it is simple and adaptable. To design by use of other mechanisms to produce a given motion, velocity and acceleration is complicated; to do so with a cam is by comparison easy, accurate and efficient.
A cam may be defined as a rotating or a reciprocating element of a mechanism which imparts a rotating, reciprocating or oscillating motion to another element termed as follower. In most of the cases the cam is connected to a frame, forming a turning pair and the follower is connected to the frame to form a sliding pair. The cam and the follower form a three-link mechanism of the higher pair type. The three links of the mechanism are:
i) The cam which is driving link and has a curved or a straight contact surface.
ii) The follower which is the driving link and it gets motion
by contact with the surface of the cam and
iii) The frame which is used to support the cam and guide the follower.
Complicated output motions which are otherwise difficult to achieve can be easily produced with the help of cams. The cams are widely used for operating the inlet and exhaust valves of internal combustion engines, automatic attachment of machineries, printing control mechanisms,
spinning and weaving textile machineries ,shoe-making machinery, feed mechanism of automatic lathes etc. In fact all modern automatic machines require the help of a cam. A cam is difficult to manufacture, especially when it is to be produced in small quantities. When produced on a mass scale, it is manufactured by a punch press, by die-casting or by milling from the master cam.