Power and stability limits in milling

The metal removal rate (MRR) in milling is typically limited by the dynamics of the tool-spindle combination or by the power. If the tool is stiff, the power is limiting, and the spindle stalls before chattering. If the tool is flexible, there is a spindle speed range where chatter is limiting. Many tools have some spindle speeds where chatter is limiting and others where power is limiting. This paper presents a new `power lobe' diagram which is independent of the workpiece material. Combined with the power curve for the spindle, this `stable power' diagram defines the achievable MRR for the entire machine dynamics.