Development of Mathematical Equation for Chip Serration Frequency in End Milling of Titanium Alloy (Ti6Al4V) under the Influence of Magnetic Field from Permanent Magnets

Abstract

Machining of metals is generally accompanied by a violent relative vibration between work and tool, known as chatter. Chatter arises due to resonance when the vibrations of the instability of chip formation and the natural vibration modes of the machine-system components coincide. This paper focuses on a novel approach of minimizing chatter in end milling of Titanium alloy (Ti6Al4V) under magnetic field from permanent magnets. The method consists of two ferrite permanent magnet bars (dimensions: 1′′ x 6′′ x 3′′), mounted 5mm from the cutting tool using a specially designed fixture, to provide a uniform magnetic field of 2500-2700 Gausses (approximately). A titanium alloy Ti6Al4V block was then end milled using uncoated WC-Co inserts.The experiments were designed using the Design Expert software with three independent variables; cutting speed, feed, and depth of cut. Machining tests were conducted for two different conditions – with and without the application of magnets. Scanning Electron Microscope (SEM) was used to measure the chip segmentations.The SEM analysis of chip serrations demonstrated that the chip formations were more stable while cutting under the presence of permanent magnets due to lower intensity of chatter. Keywords: Chatter, Chip Serration Frequency, Permanent Magnet, Titanium Alloy.