Research on end mill vibration in machining of VT9 titanium alloy

The reason for the failure of carbide end mills is the chipping of the cutting edges at the transition from the radius edges to the helix edges on the cylindrical part of the cutter. One of the reasons for the chipping of the cutting edges are the vibrations of the end mills which arise due to the intermittent cutting process and the variability of forces acting on the end mill. The principle of operation of a vibration measuring device is considered which allows vibration measurements to be carried out when milling with an end mill. The main measuring elements of the device are two eddy current sensors that allow measuring the vibration displacement of the milling cutter in two directions – perpendicular and parallel to the movement of the longitudinal feed. The device has a compensation sensor that takes into account the influence of related factors, and a sensor for fixing the instantaneous rotation speed of the machine spindle. The milling cutter itself, fixed in a collet chuck, was used as an elastic element of the oscillating system. The data of measuring the amplitude of vibrations during milling of titanium alloy VT9 with a four-tooth and six-tooth end mill are presented. The study of vibrations of end mills included two stages. At the first stage, the influence of milling parameters and modes, as well as milling schemes (up and down milling) on the frequency and amplitude was investigated. At the second stage, measures were worked out to reduce the intensity of vibrations and increase the reliability and durability of the milling cutters. The research results showed lower amplitude values when working with a six-tooth cutter.