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Optical spectroscopic analyses have been performed to study luminescence from plasmas produced by ablation of YBa2Cu3O7 single-phase high Tc bulk superconductors exposed to XeCl excimer laser (308 nm) pulses. Only excited atomic neutral and single ionized species (Cu/Cu+, Ba/Ba+, Y/Y+) were observed within the experimental resolution of an optical multichannel analyzer detection system, when irradiating the targets in vacuum (∼10−5–10−4 Torr). Conspicuously absent in the spectra (300–800 nm range) are molecular emission bands that would appear if large excited molecules or fragments were present. Implications of the present results are discussed which relate to an early hypothesis about the laser ablation mechanism and their influence on high Tc film characteristics.

A mechanistic modeling approach to predicting machining forces for grooved tools is developed. The models are based solely on the grooved tool geometry and the specific normal cutting energy and friction energy for flat tools. Special grooved tools (M2 grade HSS) were designed and fabricated and orthogonal cutting tests were performed to validate the model. The workpiece material used was Al 6061-T6. The force predictions from the model are found in good agreement with the measured forces. The effects of groove design parameters on the cutting forces are also determined.

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A partially constrained Eulerian finite element model for orthogonal machining with chip control tools is described. A new constrained free surface algorithm was developed in which the chip thickness was constrained to be uniform along the length of the chip. Using the model, the deformed chip shape and thickness, chip-tool contact, and the velocity, strain, stress, and temperature distributions can be determined. Simulations for machining of stainless steel 304 (SS 304) with obstruction and groove tools are presented. Good agreement was found, between measured and predicted tool forces and chip thicknesses.