This study focuses on experimental modeling of dry high-speed machining at 30 m/s cutting velocity using 6061-T6 aluminum alloy. A modified Hopkinson bar apparatus is employed to simulate orthogonal machining, a focused array of mercurycadmium-tellurium infrared detectors is used to measure the temperature distribution around the tool tip, and a three-component quartz force transducer is utilized in measuring the cutting and feed forces. The resulting measurements confirm the assumption of steady-state cutting and allow for estimation of the partition of cutting work into heating, shear, and momentum changes in the chip. In an earlier study, measurements of temperature distributions showed little heating of the finished surface. Therefore, a study of the temperature fields generated during machining with a cutting tool that has a wear-land was performed. The wear-land contributes significantly to the heating of the workpiece and, at this speed, is the most likely mechanism for the generation of residual stresses and a temperature rise on the finished surface.

& The need throughout the machining industry for cost reduction and increases in productivity has contributed to new interest in high-speed machining. Even though many models for machining exist, most of them are for low-speed machining, where momentum is negligible and material behavior is well approximated by quasi-static constitutive laws. In machining at high speeds, momentum can be important, and the strain rate can be exceedingly high. For these reasons, a fluid mechanics approach to understanding high-speed, very high-speed, and ultra-high-speed machining is attempted here. It is carefully argued that the potential flow solution is relevant and can be used as a first approximation to model the behavior of a metal during high-speed, very highspeed, or ultra-high-speed machining events. At a minimum, the potential flow solution is qualitatively useful in understanding mechanics of machining at high speeds.

& 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.

Even though many models for machining exist, most of them are for low-speed machining, where momentum is negligible and material behavior is well approximated by quasi-static plastic constitutive laws. In machining at high speeds, momentum can be important and the strain rate can be exceedingly high. For these reasons, a fluid mechanics approach to understanding high-speed, very high-speed, and ultra-high-speed machining is attempted here. Namely, a potential flow solution is used to model the behavior of the material around a sharp tool tip during machining at high speeds. It is carefully argued that the potential flow solution is relevant and can be used as a first approximation to model the behavior of a metal during high-speed, very high-speed, or ultra-high-speed machining events; and at a minimum, the potential flow solution is qualitatively useful in understanding mechanics of machining at high speeds and above. 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 that may lead to a temperature rise on the finished surface.