Fast chatter stability prediction for variable helix milling tools

Abstract

Regenerative chatter is a well-known form of self-excited vibration that limits the productivity of machining operations, in particular for milling. Variable helix tools have been previously proposed as a means of avoiding regenerative chatter, and although recent work has analysed the stability of such tools there has not always been a strong agreement with experimentally observed behaviour. Furthermore, the analysis of variable helix tool stability can be tedious and numerically slow, compared to standard tools. Consequently it has been difficult to gain insight into the potential advantages of variable helix tools. The present work attempts to address these issues, by first developing an efficient approach to variable helix tool stability based upon the Laplace transform. Then, this new analysis method is used to demonstrate the importance of multi-frequency effects and nonlinear cutting stiffness. The work suggests that whilst variable-helix tools can have more operating regions that are stable, un-modelled behaviour (such as nonlinearity and multi-frequency effects) can have a critical influence on the accuracy of model predictions.

Stability Analysis of Milling Process with Variable Spindle Speed and Pitch Angle considering Helix Angle and Process Phase Difference

“…Aiming at predicting the stability of milling process with VPC, frequency-domain model [12,13], the Cluster Treatment of Characteristic Roots [14], unified SDM [15], improved FDM [16,17], and improved SDM [18] have been proposed successively. Furthermore, Sims et al [19], Sims [20], Dombovari and Stepan [21], and Jin et al [22,23] proposed efficient methods to predict the stability for VPC and variable helix cutter, while Yusoff and Sims [24] optimized the geometry of variable helix tool to suppress regenerative chatter. Besides, the use of serrated cutters [25] also exhibited good capacity and potential for a higher stable depth of cuts.…”

Dynamic milling stability prediction of thin-walled components based on VPC and VSS combined method

“…And then, Stepan et al [14] improved the milling stability with VPC. Jin et al [15], Sims [16], and Guo et al [17] improved the efficiency and accuracy for predicting the stability with VPC.…”

A novel stability prediction method for milling operations using the holistic-interpolation scheme

“…Consequently, many research efforts have been focused on the modeling, prediction, detection, and suppression of such detrimental vibration. 9–14 Theoretically speaking, DDEs with time-periodic coefficients have an infinite dimensional state space. As a consequence, there is not closed-form solution for the determination of the milling stability limits.…”