Brakes absorb energy and convert it to heat. Thus, prime concerns in a brake are: 1. Generating a force capable of retarding a rotating shaft. 2. Dissipating or absorbing the heat generated in the process.

Mechanical brakes all act by generating frictional forces as two surfaces rub against each other. The stopping power or capacity of a brake depends largely on the surface area of frictional surfaces as well as on the actuation force applied. The friction and wear encountered by the working surfaces are severe. Thus, the durability of a brake or service life between maintenance depends heavily on the type of material used to line the shoe or pad.