| Abstract: | Chatter develops easily when turning slender parts on a lathe because of low stiffness and damping of the system. Also, due to a great variation of the stiffness along the workpiece, the machining accuracy is usually very poor. An analysis of the system characteristics is given and a two degrees of freedom model is developed considering parameters of the cutting process. The effective stiffness of the cutting process can be modeled as a spring during machining and its constants can be obtained by frequency analysis of the cutting system. After modeling the system it is found that by adding a damping element in series with the cutting tool and by a judicious choice of the stiffness of this element, the system stability can be increased even though the actual stiffness of the cutting tool is reduced. It can be seen also that significant benefits in terms of both dynamic behavior and machining accuracy (cylindricity) can be achieved in many cases if proper damping materials are used in judiciously designed embodiments. |
