Investigation of Parametric Instability in Milling Simulated by Screw Chasing Operation
The parametric instability in milling, resulting from the equivalent periodic stiffness variation of the machine structure is investigated, using a special machining set-up which eliminates regeneration. A theoretical model has been developed to predict this type of instability for a specially designed workpiece of a single degree of freedom. The principal axis of vibration of this system rotates in relation to the cutting force orientation. The analysis led to a Mathieu’s equation incorporating a damping term. Good correlation has been achieved between the predicted results and those experimentally obtained from cutting tests.
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