Fluid Mechanics Approach to Machining at High Speeds: Part Ii: A Potential Flow Model

Abstract

& Finite element models of machining at high speeds usually assume that there is a stagnation point at the tool tip as is the norm in the machining community. However, at ultra-high speeds the yield strength of the workpiece is easily exceeded in the material around the tool tip, allowing that material to ''flow'' and possibly allowing the stagnation point to migrate away from the tool tip. A potential flow solution is used to model the behavior of the material around a sharp tool tip during machining at high speeds. Interestingly, the flow solution predicts that there is a stagnation point on the rake face, not at the tool tip as is usually assumed. Because the stagnation point is not at the tool tip, the flow solution predicts a significant amount of deformation in the workpiece resulting in large residual strains and a possible related temperature rise on the finished surface.

Analysis of the minimum chip thickness during turning of duplex stainless steel

“…Consequently, h 1 min can be used to describe the deformation of the machined surface and its influence on the workpiece surface integrity. 10–16…”

“…Several analytical efforts have been published on the size and importance of h 1 min . 10,12–17 However, only a few methods to experimentally determine h 1 min have been published. 17–19 De Oliveira et al 20 proposed an experimental method; however, the indirect nature of optically examining the machined surface texture decreases the practical usability.…”