Question

why a roller follower is preferred to a knife edge follower

Answer 1

heyy ur answer dear...........

Simply because rolling friction is always less than sliding friction.

Yes, in the starting conditions, a knife edge follower may have just a point contact, but eventually it will rub continuously and increase area of contact, thus increasing sliding friction.

On the other hand, a roller is always having a line contact and will not wear due to the same line of contact not being in contact continuously with the cam. Thus, we can say that ideally the sliding friction here is zero.

Hope this clears it up…cheers!.................@kundan