The economics of machining aerospace structural components is fundamentally limited by regenerative chatter and process-damping. Harnessing these two phenomena will lead to enormous productivity gains and superior competitive advantage. For example, a recent project at Sheffield was able to avoid chatter and reduce machining times by a factor of 5, resulting in a multi-million pound contract being awarded to the sponsor. However, current scientific understanding of process-damping is inadequate, so that recent research has resorted to intuition, trial and error, or exhaustive experimental testing. This project aims to overcome these barriers by providing new scientific understanding and engineering tools, and to transfer this technology to the manufacturing community.