Dae-Eun Lee

Analysis of Tool and Workpiece Interaction in Diamond Turning using Graphical Analysis of Acoustic Emission

Abstract The surface quality obtained in diamond turning operations is highly influenced by the interaction between the tool and workpiece. These influences include changes in cutting forces, chip formation phenomena, microstructure of workpiece and others. Local changes in the depth of cut and material properties lead to variable cutting forces that may result in unacceptable form errors. This research proposes an innovative approach for mapping the AE RMS generated during diamond turning able to graphically represent several features of the interaction between tool and workpiece related to instant depth of cut distribution, grain boundaries and grain orientation.

Variation in Machinability of Single Crystal Materials in Micromachining

For practical application of micromechanical machining, four levels of process realization are required; fundamental understanding of process physics, development of microplanning (processing parameter optimization), macroplanning (tool path planning), and design optimization. This study surveyed the influence of localized variation in the microstructure on final process outcome and machinability of brittle optical material in a ductile regime. A clear correlation between burr height, critical depth of cut and crystallographic orientation was found on single crystal materials (copper and magnesium fluoride), giving insight into optimal orientations and process parameters for acceptable micromachining process outcome.

Surface and Edge Quality Variation in Precision Machining of Single Crystal and Polycrystalline Materials

Abstract The surface and edge quality of single-crystal and polycrystalline copper workpieces has been observed to vary significantly as a function of crystallographic orientation. On the precision scale, the chip formation process is influenced by the microstructure of the material, such as grain boundaries and grain orientation in polycrystalline materials, and crystallographic orientation in single-crystal materials. Such variation in the microstructure has a significant effect on the resulting surface, edge, and burr topography.