The influence of feed rate on process damping in milling: modelling and experiments

Abstract

eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. DOI: 10.1243/09544054JEM2141Abstract: The performance of milling operations is limited by the onset of unstable self-excited vibrations known as regenerative chatter. Over the past few decades there has been a great deal of research to help predict and explain regenerative chatter. Consequently, high-speed milling operations are now frequently employed, with judicious choice of spindle speeds and depths of cut so as to avoid chatter whilst maintaining high productivity. However, many materials that are increasingly used in aerospace components are difficult to machine at high spindle speeds because of their thermal properties. Examples include titanium and nickel alloys. For these materials, low-speed machining must be employed, and in this regime the role of regenerative chatter is less clearly understood due to the phenomenon of process damping. In the present study, a time domain model of process damping is developed. This model is used to explore the relationship between cutting conditions and the amplitude of chatter vibrations. A qualitative agreement is found between experimental behaviour and the numerical model. In particular, the model predicts a strong relationship between the workpiece feed rate (expressed as a feed per tooth), and the acceptable chatter stability defined by the process damping wavelength. Further work is needed to properly calibrate some of the model parameters.

Machining chatter in continuous facing under a constant nominal cutting speed: Tool vibration with time-varying delay

“…The authors were fully cognizant of the effect of tool wear and process parameters altering process damping 14,15 . However, tool wear and gross loss of size on the part were not noticeable at the end of the cut.…”

Fast chatter stability prediction for variable helix milling tools

“…This raises the question of whether variable helix tools are more likely to benefit from damping, compared to regular helix tools. This damping could be in the form of structural damping (inherent, or intentionally added), or un-modelled damping mechanisms (such as process damping 25,26 ). Further work could explore this experimentally.…”

Chatter stability and surface location error predictions in milling with mode coupling and process damping

“…Apart from mode coupling, process damping originating from the interaction between tool and workpiece has also been one of the hot issues in machining dynamics. 30,31 Process damping is well known as a beneficial phenomenon that may suppress chatter and increase stability, especially in low-speed milling of difficult-to-machine materials such as titanium and nickel alloy. Given its complicated mechanism, most of the previous researches ignored this beneficial phenomenon when modeling the dynamic milling process.…”