Regenerative instabilities in guided metal circular sawing.

This paper reports on new research that: characterizes the influence of regenerative lateral forces on the stability of metal circular sawing; describes the role of process damping in potentially stabilizing the sawing process; and investigates the role that distributed and lubricated guides play in a sawing process prone to regenerative instabilities. We model the saw as a rotating disc using the Von Kármán plate theory. Equations of motion are derived using the Hamilton’s principle. Guides are modelled as being distributed and properties of the fluid are modelled to be a function of the guide size and its placement relative to the saw. The regenerative and process damping effects are incorporated based on other similar models for milling processes. Our model-based analysis suggests that: regenerative instabilities are characterized by a growth in the real part of the eigenvalue of the system; clearance between the guide and the rotating saw and the guide’s circumferential placement with respect to the cutting zone both influence the severity and speed regions of instabilities; material being cut and changing cutting engagements do not significantly influence the region of instabilities; and that process damping can help stabilize an otherwise unstable process. Though models need to be validated, our observations can still instruct the design of stable guided metal sawing processes in industries. [ABSTRACT FROM AUTHOR]