Features of Peripheral End milling: Formation of Machined Surface Profile

Abstract

The profile of the machined surface at the peripheral end milling is made when various types of fluctuations occur. At milling under self-exited oscillations, the machined surface, in addition to traces from cutting in with each tooth, has a wavy profile. The purpose of the article is to consider the peculiarities of the mechanism for making the profile of the machined surface under up and down peripheral end milling in case of chatter appearance. The experiments have been carried out on a special bench, using a technique that allows estimating the law of the vibrational motion of a part in the milling process by recording oscillograms of part fluctuation. The profile of the machined surface was evaluated by strip chart recording. The basic fragments of the oscillograms were used to determine the values of the parameters, which made it possible to establish the relationship between the waviness on the machined surface and the oscillatory movements of the part during milling with different feed directions. On the basis of the conducted experimental research, the mechanisms of surface finish formation during the up and down peripheral end milling in the third velocity zone have been determined. The height of the waviness during the cut-up milling with self-exited oscillations is formed by cavities, the depth of which is determined by the deviation of the part from the elastic equilibrium line on the first wave of auto-oscillations. The number of cuts determines the waviness stroke. At the cut-down milling, shaping cavities are formed by the part deviation from the elastic equilibrium line when the tool leaves the cutting zone. The waviness stroke on the machined surface depends on the change in the length of the cutting surface. Keywords—profile; number of cuts; oscillogram; the vibrational motion, waviness; profilogram