This paper presents a study where acoustic imaging technology was employed for problem identification and high damping interfaces (HDI) were implemented in the machine tool structure to improve performance of process machine interaction, in bevel gear cutting, in terms of resistance to instability. Chatter marks at the gear root and tool fracturing represent a serious and widespread problem in the studied process. The acoustic image approach showed good agreement with modal analysis and also allowed to identify the chatter frequency. Once identified the problem, the paper also presents a novel approach for improving resistance to cutting instability by implementing HDI in the structure. The HDI consists of a viscoelastic composite material and is used to damp out the stick blade motion relative to the clamp block by transformation of vibratory energy, into heat. The primary contributions of this paper are the introduction of acoustic imaging for identification of chatter in gear cutting and employment of HDI for performance improvement for rotating tools.

This paper presents a novel test concept for the evaluation of the accuracy of NC machine tools. The evaluation of machine tools deformations is performed by help of a device similar to the double ball bar (DBB) with the difference that an adjustable load generated by the device can be applied between spindle nose and machine tool table. This load eliminates the play existing in machine tool joints, thus reproducing the testing conditions that exist during machining. Collected data are used to plot diagrams displaying characteristic aspects of achine tool performance and a number of key figures such as static stiffness may be etermined. The data can also be used for trend analysis; to predict any accuracy deviations, and further to conduct preventive maintenance instead of emergency calls. The determined static behaviour could also be used to improve digital models for process simulations and compensation of errors that are caused by deflection.