Mass loading effect of accelerometers on tool point FRF and stability diagrams

Chatter is one of the major problems in machining resulting in poor surface quality and reduced productivity. Stability diagrams can be used to determine chatter-free process conditions with high productivity. For generation of stability diagrams, frequency re-sponse functions (FRF) at the tool tip is needed to be used in stability model. Impact tests involving accelerometers are commonly used in FRF measurements. Although mass of a typical accelerometer used in these measurements is extremely small com-pared to the cutting tool, it can have a significant effect on the FRF measurement. In this paper, the effect of accelerometer’s on tool point FRFs and stability diagrams will be demonstrated on several cases with different tool-to-accelerometer mass ratios using laser velocity sensor measurement. In addition, a structural modification method which can be used to compensate this effect will also be presented on several cases. The structural modification method can be used to correct the FRFs measured with acceler-ometers, and thus the resulting stability diagram.