Abstract
The vibrations produced in a boring tool in internal turning deteriorate the machined surface quality and reduce the tool life, which results in a massive noise during the machining. Therefore, unwanted vibrations are necessary to be eliminated by improving the boring bar's dynamic stiffness and damping capacity. This paper investigates a passive constrained layer damping (CLD) boring bar with a hybrid damping layer to study the internal turning system's stability. Initially, the dynamic models of the conventional and CLD tools are thoroughly studied using Euler-Bernoulli beam theory (EBT) and validated them with finite element modelling (FEM). The frequency response functions (FRFs) obtained from the impact hammer tests are used to estimate the modal parameters. With modal parameters, the semi-analytical stability lobe diagrams (SLDs) are plotted for the boring system with the conventional and CLD boring bar. Tool-tip responses for various cutting conditions are simulated numerically to validate and to study stability. The cutting experiments with traditional and CLD boring bar are conducted for stability analysis and compared tool-tip responses with numerical results. It is observed that both the numerical and experimental results agree with the selected cutting conditions from SLDs. It is also observed that the CLD boring bar with a hybrid damping layer reduced the vibration displacements by five times compared to the conventional one.
Highlights
Manufacturing industries, nowadays, produce various components despite the obstacles in obtaining more accurate products
It is obvious that the tool-tip response of the conventional and constrained layer damping (CLD) boring bar is satisfying the cutting condition taken from the stability diagram, which shows the authenticity
It is observed that the CLD performs better compared to the conventional boring bar at the same cutting condition due to the dissipation of higher energy and improved stiffness of CLD boring bar
Summary
Manufacturing industries, nowadays, produce various components despite the obstacles in obtaining more accurate products. Internal turning or boring is one of the oldest machining processes for enlarging the cast holes or pre-drilled in a component. In this process, a highly accurate surface finish of the machined product is essential. The deformation in the workpiece during internal turning, introduces vibration or dynamic motion in the boring tool. These vibrations worsen the quality of machined surface the surface finish, which results in the reduced tool life. The recent attention among researchers is to suppress the regenerative vibrations induced by the tool during machining.
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