Time domain simulation of chatter vibrations in indexable drills

Abstract

Regenerative chatter vibrations are common in drilling processes. These unwanted vibrations lead to considerable noise levels, damage the quality of the workpiece, and reduce tool life. The aim of this study is to simulate torsional and axial chatter vibrations as they play important roles in dynamic behavior of indexable insert drills with helical chip flutes. While asymmetric indexable drills are not the focal points in most of previous researches, this paper proposes a simulation routine which is adapted for indexable drills. Based on the theory of regenerative chatter vibration, a model is developed to include the asymmetric geometries and loadings that are inherent in the design of many indexable insert drills. Most indexable insert drills have two inserts located at different radial distances, namely central and peripheral inserts. Since the positions of the central and peripheral inserts are different, the displacement and thereby the change in chip thickness differs between the inserts. Additionally, the inserts have different geometries and cutting conditions, e.g., rake angle, coating, and cutting speed, which result in different cutting forces. This paper presents a time-domain simulation of torsional and axial vibrations by considering the differences in dynamics, cutting conditions, and cutting resistance for the central and peripheral inserts on the drill. The time-domain approach is chosen to be able to include nonlinearities in the model arising from the inserts jumping out of cut, multiple delays, backward motions of edges, and variable time delays in the system. The model is used to simulate cutting forces produced by each insert and responses of the system, in the form of displacements, to these forces. It is shown that displacements induced by dynamic torques are larger than those induced by dynamic axial forces. Finally, the vibration of a measurement point is simulated which is favorably comparable to the measurement results.

Takma Uçlu Matkap Ve Kesme Parametrelerinin Seçimi için Bir Uzman Sistem

“…avantajlarından dolayı öne çıkan kesici takımlardır. Helisel yekpare matkaplara kıyasla, takma uçlu matkaplar ile yapılan bir delik delme işlemi, son (finish) işleme operasyonu olarak yapılmaktadır [22]. Bununla birlikte, normal helisel matkapların kesici ağızları matkap gövdesi ile bir bütün olurken, takma uçlu matkaplarda ise kesici ağızlar ise çıkarılabilir, değişebilir olacak şekilde gövdeye bağlanmaktır (Şekil 1'de bir takma uçlu matkap ve uçları verilmiştir).…”

Effect of wavy tool path on the stability properties of milling by the implicit subspace iteration method

“…In what follows, numerical simulations are presented to validate the stability properties [47,48], in which the forced vibration is also considered. Simulations are performed at three points (stable, unstable, stable) around each stability boundary denoted by A, B and C in Fig.…”

Coupled Eulerian–Lagrangian simulation and experimental investigation of indexable drilling

“…The analysis performed in [5] shows that the radial forces lead to both static and dynamic deflections that is affecting the shape of the drilled hole. The forces can also cause regenerative chatter that leads to unpleasant noise levels, damage on workpiece and tool, poor surface quality and reduced tool life [6]. Furthermore the workpiece temperature, clamping loads and drill run-out can also significantly impact the hole quality [7,8].…”