Papers by Keyword: Micro Cutting

Abstract: A finite element model based on Abaqus/Explicit is built. Micro cutting mechanism of Al7075 with different cutting depth is simulated and analyzed. The simulation results show that if the cutting depth is more than 10μm, the chip is a kind of continuous curl. If the cutting depth is less than 10μm, the chip is a kind of feathery squeeze debris. When the cutting depth is very small (3μm), the shape of chips is just like discontinuous wrinkle. By contrasting the simulation results of cutting force with its theoretical values, they have the same result. The model of the chip prediction could achieve ideal simulation results.

Abstract: Micro cutting is a promising manufacturing method to obtain good surface integrity. Surface roughness shows size effect when the uncut chip thickness is smaller than the cutting edge radius. A special micro slot on the flank face of cutting tools was manufactured with discharge. Two groups of micro orthogonal cutting were conducted. The surface roughness of machined surface was measured and compared to each other. The results show that surface roughness decreases first and then increases with the ratio of uncut chip thickness to cutting edge radius. The surface machined with micro slot is better than that of without micro slot due to the micro slot restrain the back side flow of work piece based on the finite element model.

Abstract: Micro cutting is a promising way for manufacturing micro parts, especially micro three dimension parts. Micro hardness is an important character to evaluate surface integrity of machined surface. Micro cutting is different from macro cutting due to size effect of specific cutting energy because of the influence of the ratio of uncut chip thickness to cutting edge radius. A group of micro cutting experiments were conducted to investigate the cutting parameters on the micro hardness of machined surface. The micro hardness of machines surface decreases with the ratio of uncut chip thickness to cutting edge radius first, and then increase when the uncut chip thickness is smaller than the cutting edge radius. The micro hardness shows size effect due to the machined surface compressed twice with the round cutting edge. The micro hardness decreases with the distance increasing far away from the machined surface.

Abstract: Micro turn-milling has superiority on the productivity and the quality of work pieces, and is more suitable to machine micro-shaft parts and desirable miniature parts based on the turn-milling technology. On the basis of ADAMS and UG software, kinematics simulation of complete machine has been performed, meanwhile, the natural frequency and vibration mode of micro turn-milling machine tool has been analyzed by adoption of modal analysis in this paper. The results forecasts dynamic characteristics of micro turn-milling machine tool. It also provides important reference frame of dynamic optimization design of micro turn-milling machine tool.

Abstract: Now there is not engough basic theory to explain the friction mechanism on the shear deformation zone and tool-workpiece deformation zone in the process of metal cutting.But the constant coefficient of friction model is not in accord with the actual cutting tool friction. So Friction law of micro friction process were studied by friction test and simulation, the friction model of micro - cutting are very important which can improve the micro-cutting mechanism, finite element modeling and Simulation of metal cutting process and etc.

Abstract: A micro dimple machining is studied to control the surface functions with the micro-scale structures on the solid surfaces. The micro dimples are machined in milling with the inclined ball end mill. When the feed rate of the tool is high enough that the removal area of an edge does not overlap with that of the previous edge, periodical concave dimples are machined. A mechanistic model is presented to control the shape and the size of the dimples to be machined. Then, a machining error model is presented to control the deviation of the dimple shapes. Some machining examples are shown to verify the dimple model and the error model.

Abstract: The present paper highlights the importance of size effect consideration during the modelling of material removal by cutting tool, especially when passing from maco-to-micro scales. For that, the presented study concerns an orthogonal case of down-cut milling where the chip thickness is evolving. Consequently, to capture the scale effect when passing from macro to micro dimensions, the theory of gradient plasticity were adopted.

Abstract: Abstract: Though the observation in micro cutting of 45 steel, the deformation zone of fracture characteristics was studied, and the corresponding cutting model was established; on dynamic tensile and situ observation of 45 steel by transmission electron microscopy , micro cutting ductile fracture process is simulated by the experiment on the steel tensile of 45 film sample, and the mechanism on initiation and propagation of crack in micro cutting fracture was studied with dislocation theory.

Abstract: Subminiature fuel cell is a representative eco-friendly power source which possesses the merits of having the potential of being implemented in portable electronic devices and other subminiature devices, as well as having high energy density as compared to existing secondary cells. The size of the bipolar plate which is implemented in a subminiature fuel cell should be of a small size according to the size of the fuel cell, and the flow channel inside the bipolar plate also has be reduced to match the overall size of the bipolar plate. Therefore, a higher level of difficulty in the manufacturing process is involved in producing bipolar plate for subminiature fuel cells and mass production is extremely difficult. In this study, powder injection molding was applied to the production of subminiature metal bipolar plate to verify the possibility of mass production. For that, a bipolar plate and mold were designed and then a test injection forming was carried out. This was attempted to validate the feasibility of a subminiature metallic bipolar plate prepared through a debinding and sintering process by evaluating its electric conductivity and density.

Abstract: Sapphire has high mechanical strength at high temperatures and high pressure. Thus, micro devices made of sapphire are expected to be used in extreme environments such as aerospace, defense and marine. Then, the machining technology is required for manufacturing of 3 dimensional shapes. The paper discusses the micro cutting process of sapphire to determine the applicable cutting parameters in planing and milling. First, the critical stress at which crack initiation occurs is measured in the indentation test with detecting AE signal. The critical stress of sapphire is beyond 22.6 GPa, which is much higher than those of glasses. Then, the critical depths of cut, maximum depths of cut in which crack-free surfaces were finished, were measured in cutting of r crystal plane. The critical depth of cut is maximized when the cutting is performed in a crystal axis direction. In milling of sapphire, adhesion of chip onto the surface finish should be considered as well as brittle fracture. In milling of r crystal plane, the surface finish is improved better than those of the other crystal planes. Adhesion of material can also be controlled by supplying lubrication.