Dynamic Analysis of Tool–Workpiece Vibration Response with Focus on Chatter Behavior in Milling

Chatter vibration remains one of the primary barriers to high productivity milling because it limits the allowable axial depth of cut, deteriorates surface integrity, accelerates tool wear, and increases noise and spindle loading. The phenomenon is fundamentally dynamic: regenerative feedback couples the structural dynamics of the tool–holder–spindle–workpiece loop with the time-periodic cutting process. This paper presents a comprehensive framework for dynamic analysis of milling chatter with explicit emphasis on identifying and characterizing coupled tool and workpiece vibration response. Experimental modal analysis is used to obtain frequency response functions (FRFs) at the tool point and at critical workpiece locations under realistic fixturing. A finite element model (FEM) of the workpiece and fixture is developed to study stiffness distribution, mode shapes, and configuration sensitivity, and the model is calibrated using the measured modal parameters. The resulting reduced-order dynamic representation is integrated into a regenerative milling chatter formulation to generate stability lobe diagrams and position-dependent stability maps for flexible parts. In addition to model-based stability prediction, the paper proposes an in-cut chatter onset detection workflow based on Short-Time Fourier Transform (STFT) time–frequency analysis. STFT indicators are defined to separate forced tooth-passing components from self-excited chatter peaks near structural resonances, enabling robust onset detection during non-stationary toolpath segments. A structured experimental protocol is provided for stable and unstable cutting tests in representative steel and titanium milling cases. The combined EMA–FEM–STFT workflow yields interpretable stability guidance, clarifies whether chatter is tool-dominated or workpiece-dominated, and supports practical mitigation through spindle speed selection, tool overhang reduction, holder selection, and fixture reinforcement. The paper concludes with industrial recommendations and a reproducible reporting template for chatter-focused dynamic studies.

کلیدواژه ها:

Milling dynamics ، regenerative chatter ، frequency response function ، experimental modal analysis ، finite element modeling ، stability lobe diagram