Analytical prediction of stability limit in turning operations

Unstable cutting due to chatter vibrations is one of the most important problems during metal cutting operations. Chatter can be a limitation for productivity and surface quality in turning operations, especially when long and slender tools and parts are involved. In this study, an analytical stability method for turning process is presented. The model takes the cutting geometry into consideration, and proposes a new solution procedure for the dynamic chip thickness at the insert nose. The analytically calculated absolute stable depth of cuts are compared with the chatter test results, and a good agreement is observed

Experimental analysis and modeling of orthogonal cutting using material and friction models

In this study, a process model for orthogonal cutting processes is proposed. The model involves the primary and secondary deformation zones. The primary shear zone is modeled by a Johnson-Cook constitutive relationship and a shear plane having constant thickness. The secondary deformation zone is modeled semi-analytically, where the coefficient of friction is calibrated experimentally. The cutting forces predicted using the calibrated sliding friction coefficients are in good agreement with the measurements. The experimental investigation of sliding friction coefficients also show promising results for the proposed model, which is still under development

Increasing productivity in high speed milling of airframe components using chatter stability diagrams

In this study, the application of chatter stability diagrams in industrial operations is presented with representative cases. Challenges arising due to the practical aspects of production systems are discussed in detail. Effects of tool, tool holder, spindle and CNC machine on chatter stability diagrams are presented. The implementation of the stability diagrams under such challenges is presented through real application examples showing significant reduction in machining times

Analytical stability models for turning and boring operations

In this paper an analytical model for stability limit predictions in turning and boring operations is proposed. The multi-dimensional model includes the 3D geometry of the processes. In addition a model for the chip thickness at the insert nose radius is also proposed to observe the effect of the insert nose radius on the chatter stability limit. Chatter experiments are conducted for both turning and boring in order to compare with analytical results and good agreement is observed

Analytical modeling of chatter stability in turning and boring operations: a multi-dimensional approach

In this study, an analytical model for the stability of turning and boring processes is proposed. The proposed model is a step ahead from the previous studies as it includes the dynamics of the system in a multidimensional form, uses the true process geometry and models the insert nose radius in a precise manner. Simulations are conducted in order to compare the results with the traditional oriented transfer function stability model, and to show the effects of the insert nose radius on the stability limit. It is shown that very high errors in stability limit predictions can be caused when the true process geometry is not considered in the calculations. The proposed stability model predictions are compared with experimental results and an acceptable agreement is observed