Spatial Frequency Analysis of Chatter Marks

Chatter vibration induces a characteristic pattern on the milled surface, known as chatter marks, causing a poor surface quality. This paper investigates the chatter marks generation mechanisms focusing on their distribution, i.e., the surface spectral proprieties. The generation of the surface profile is regarded as a problem of sampling at the tooth pass frequency (in the time domain) and reconstruction (in the spatial domain) of the cutting tool displacements. Using this analogy, the paper highlights two main effects (aliasing and pseudo moiré), proposing specific formulations. The method is validated by a numerical investigation, based on a surface generation model coupled with a time domain simulator of the milling process, and an experimental validation on peripheral milling. The formulations presented in this work could support the selection of cutting parameters that enables the generation of an acceptable surface even in highly unstable cutting conditions.