Optimization of hollow cantilevered boring bar stiffness

Precision line boring is a very demanding application in terms of both quality and production rate requirements. Machining of long bores as needed in cam and crankshafts of engine blocks requires use of dedicated equipment. In this research, cantilevered boring bar mechanics, in particular bar stiffness, is studied. First, the effects of shape optimization are studied, including the effect of hollowing the boring bar. Secondly, the effects of reinforcing a bar with axial reinforcement materials are studied, followed by a derivation of the equations for deflections, natural frequency of vibration, and stiffness. Finally, finite elements are used to verify these equations.