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When milling with tools of a high length to diameter ratio, there is often a non negligible runout. Since those tools tend towards chatter because of their low stiffness, the effect of runout on the dynamic behavior of the tool must be considered. Runout adds an additional dynamic component to the tool vibration and thus to the dynamicly changing cutting forces. Furthermore runout affects the surface quality even in stable machining. This paper analyzes the effect of runout by simulation of the dynamic milling process and compares the results to experimental data. One aspect is the difference of the vibration patterns with and without runout. Furthermore, a method for the analysis of timeseries is presented in order to distinguish between chatter and runout. Another topic is the expected surface quality resulting from stable processes with runout. This surface is modeled, examined and compared to the one produced by a process without runout.

One serious problem in deep-hole drilling is the formation of a dynamic disturbance called spiralling which causes a multi-lobe shaped distortion of the bore hole cross section. An important factor governing the occurrence of spiralling is the coincidence of a bending eigenfrequency of the boring tool with a multiple of the spindle rotation frequency. This article presents a discrete dynamic model of the tool/boring-bar assembly including a Lanchesterdamper and containing free parameters for the unknown stiffness of the tools lateral supports. Furthermore, a method for estimating these parameters by determining the changing eigenfrequencies over the drilling depth from spectrogram data using the maximum likelihood method is proposed.

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