Investigation of Ultra-precision Machining Using Molecular Dynamics Simulation and Experiments on Single Crystal Silicon

Ultra-precision machining is an advanced method for production of materials with nanoscale surface roughness. It is widely used in the manufacturing of precision components for defense, aerospace, optics, and electronics industries. For this feature, only a few industrial countries have access to this technology. Due to the high precision of this technology, many factors can affect the final surface quality. Machine components, machining conditions, tool geometry and material, environmental condition, workpiece material as well as vibration, are among the factors that are reviewed in this article. Afterwards, the effect of cutting depth on machining mechanism and surface quality is investigated using molecular dynamics investigation. The results revealed that when the ratio of cutting depth to tool edge radius becomes lower than 0.5, the effective rake angle would be bigger than the nominal rake angle. Furthermore, under this condition, the dominant machining mechanism is extrusion, which is different from the micro cutting mechanism. Finally, a series of experiments was conducted to study the impact of the undeformed chip thickness on the chip morphology and surface topography. For this purpose, Field Emission Scanning Electron Microscopy, 2D ultra-precision point autofocus probe as well as white light interferometer were exploited. The results indicated that at the lower relative tool sharpness, chip tearing occurs. Besides, by increasing this parameter to 100nm, silicon nano-ribbons is created.