What is a stability lobe diagram?
A stability lobe diagram is a plot that separates unstable combinations of chip width, or axial depth of cut in peripheral end milling, and spindle speed (i.e., those that produce chatter) from stable combinations. Stable cuts occur in the region below the stability boundary (or combination of all the stability ‘lobes’), while unstable cuts occur above the stability boundary. These stable and unstable regions are seen in Figure 1. As shown, it is often possible to increase the allowable axial depth of cut without chatter by increasing the spindle speed, rather than slowing down. This counterintuitive behavior is one reason that is important to characterize the dynamic response of the cutting tool and produce the corresponding stability lobe diagram.
