About Chatter

Definition of Chatter: "Chatter is a self-excited vibration that occurs in metal cutting if the chip width is too large with respect to the dynamic stiffness of the system."

Recognizing Chatter: Chatter is easily identified from both an audible and a visual perspective. There is a distinct sound associated with chatter and is a resultant from the vibrations occurring during the metal cutting process. The resulting surface finish is marred and unacceptable when chatter is present during the machining process.

The Occurrence of Chatter: Due to either normal wear conditions or by selecting a non-optimal combination of spindle speed and depth of cut all machine tools will experience chatter at some point during their useful life.

It should be noted that the feed rate is not a dependent variable of chatter. Therefore, adjusting the feed rate will neither help to eliminate chatter nor will it induce chatter.

Understanding and Analyzing Chatter: Given that chatter is a sound wave phenomenon, it lends itself to being modeled using a mathematical approach. This mathematical approach provides a means to which the chatter sound wave can be analyzed, interpreted and useful information returned to the operator. The information returned by the yap testing can be used to select cutting conditions for a given machine tool that will avoid the occurrence of chatter.