Coarse-Grained Molecular Dynamics Simulation Of Ultra-precision Cutting Of Single Crystal Copper

Ultra-precision cutting recently has attracted a large amount of attention for itsunique potential application in manufacturing at nanoscale. A full grasping about details ofultra-precision cutting is the prerequisite to produce highly sophisticated devices with highquality at large scale. Hence it is of significant essence to investigate process of cutting ofmental at nanoscale.Varieties of approaches have been manipulated to simulate the process ofultra-precision cutting. Earlier methods including Finite Element Methods (FEM) andMolecular Dynamics (MD) have gained abundant achievements. Nevertheless, FEMignores possible influences from minute elements internal to material. Albeit MD cananalyze micro processing features of solid model, yet it can merely be adapted to simulatesystem in small amount as computing speed is confined by configurations of computer.Thus, Coarse Grained Molecular Dynamics (CGMD) is commonly adapted at present.CGMD on the base of weighting function referred in FEM can run calculations atmultiscale, where dynamic as well as mechanical features comply with principles of MD.This method accelerate computing speed while ensures accuracy meanwhile.Our work here adapts MD and CGMD respectively to study features of the samemodel in the process of cutting. By compare calculating results from two methods, weobtain conclusions as follows. The calculating speed of CGMD is as8times as that of MDwhen parameter of CGMD is2, however calculating results are nearly the same. Suchresults prove the feasibility of CGMD on the ultra-precision cutting system of copper.Then, the cutting process of copper simulated by CGMD is discussed. Resultsindicate that the essence of cutting of copper is shearing and compressing of atoms. Withcutting continuing, lattice of copper atoms below cutting tool deforms forming amorphouslayer because of compression and shear force from blade of tool. Atom lattice of processed surface combined with amorphous layer, forming metamorphic layer shown on theprocessed surface. Atoms ahead of tool cannot combine with other atoms, which generatedust to get away from the workpiece. Amount of lattice which is deformed keeps accruing.Furthermore, influence of cutting parameters is investigated. It is found that thecutting thickness works the most obviously, the phenomenon that lattice deforms andatoms compress with each other aggravates with thickness increased, so does cutting forcein tangential and normal as well as the coarseness of working interface. In addition,acceleration of cutting velocity increases cutting force while has almost no impacts ondeformation of lattice and quality of cutting interface. Cutting tool with larger anteriorangle is beneficial to quality of working interface for less friction while strength of cuttingtool is impaired meanwhile. Increase of relief angle can relieve friction at the interface,which does benefit to improve quality of working interface with weaker cutting force andenergy. Rounded cutting edge radius can affect the workpiece largely. With larger roundercutting edge radius, quality of working surface gets impaired with reduction in energy andcutting force.Finally, possible affection of point defect is included in our work. It is found thatbound connection is dampen with more point defect, thus lattice is more apt to deforming,coarsening the surface of workpiece.To the limit of our knowledge, it is the first time to apply CGMD in the area ofultra-precision cutting of mental. Thus, our work provides a novel view in terms ofinvestigation of this area with providing insightful also full explanation about the cuttingprocess of copper.