Regenerative vibration avoidance due to tool tangential dynamics in interrupted turning operations

• A numerical method is proposed for the stability analysis of interrupted turning.
• The approach uses experimentally identified dynamic displacement coefficients.
• The simulated boundary limits agree well with the validation tests.
• Practical stability criteria have been formulated.

Linear stability models are often used to predict regenerative vibrations in turning representing continuous operations, simple cutting geometries with constant coefficients and/or dominant modes acting in the feed direction. However, turning of components with interrupted features, such as turbine cases, may lead to large tool overhangs with vibration motions in the cutting speed direction and tool cut-off periods that result in the latter approaches being insufficient. This paper proposes a stability model for chatter in interrupted turning when the dominant vibration is orthogonal to the chip section plane. The method requires the calculation of a dynamic displacement factor that depends on the tool vibration frequency. The simulations of the model are supported by experimental tests for different contact fractions.