Stability analysis for milling system with variable pitch cutters under variable speed

Abstract

Regenerative chatter can reduce machining quality, tool life, and productivity during milling process. In order to control the milling chatter, the stability analysis of milling system is very important. It has been found that variable spindle speed milling and the use of variable-angle tools are effective to control milling chatter. This paper mainly studies the control effect when these two methods are used simultaneously. Firstly, the improved full-discretization method is used to predict the stability of variable spindle speed milling process with variable pitch cutters. And on the basis of stability prediction, the influence of spindle speed modulation parameters on stability is analyzed. Meanwhile, the stability prediction results of down-milling and up-milling operations, different radial immersion ratio and different tooth pitch variation form are compared. The results show that the stability of variable spindle speed milling process with variable pitch cutters is better than that of variable pitch cutters in constant spindle speed milling process. And the improvement of the stability is related to the spindle speed modulation parameters. When the modulation parameters are bigger, the stable cutting area of the stability lobes diagram will be larger. Secondly, in the up-milling operation and the low immersion operation, the variable spindle milling with variable pitch cutters has better stability than the down milling operation and the high immersion operation. Under the condition that the pitch angles vary linearly, the stability is better. Finally, the time domain simulation is performed and the simulation results verify the accuracy of the stability prediction results.

Uncharted Stable Peninsula for Multivariable Milling Tools by High-Order Homotopy Perturbation Method

“…the solution of order m for Equation (31) was obtained by adding each of the approximations k of Equation (35). Similar to Equation (15), to obtain the stability graphs the solution of Equation ( 35) is rewritten by grouping the discrete states, which results in:…”

“…Using an extended second-order SDM, Zhan et al [15] predicted the stability lobe diagrams for tools with variable pitch angles. Meanwhile, Huang et al [31] conducted a stability analysis for milling operations with variable pitch mills at variable speed, while Cai et al [32] proposed an integrated process machine model based on the computer graphics method to simulate the milling process of a variable pitch cutter.…”