Carbon and boron nitride super lattice films were deposited by RF sputtering using two semicircular targets. Super lattice (C/BN)_n films were deposited by control of the opposing time of substrate to each graphite and boron nitride semicircular targets respectively. Micro Vickers hardness, nanoindentation hardness and nanoscratch properties of these films were evaluated. Both micro Vickers and nanoindentation hardness of 4nm period (C/BN)_n multi layered film are the highest of all period (C/BN)_n films. The multi layered film with a proper period exhibits superior hardness and nanoscratch resistance. From the evaluation of nanoscratch test, oscillatory scratch test, and ball on disk tribo test, the friction coefficient of the 4-nm-period (C/BN)_n multi layered film is lower than those of other period (C/BN)_n, carbon, boron nitride and carbon nitride films. The 4-nm-period (C/BN)_n multi layered films show the least damage and superior sliding endurance.

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This paper describes the measurement of temperature distribution in EDM arc plasma using spectroscopic analysis. The temperature distribution measurement was achieved by using a lens system to magnify the image of the plasma and a mask to limit the plasma region to be observed. The fluxes of two different wavelength spectra radiated from the arc plasma were measured simultaneously with optical fibers and photomultipliers, after which the temperature distribution was computed from the radiant fluxes using the line pair method and Ablel's inversion. Also, the influences of machining conditions, such as electrode shape, gap distance and discharge current, on the temperature distribution were investigated.

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In a bevel gear, unlike a cylindrical gear, two gears shafts cross, and one of the shafts is basically a cantilever. Therefore, bevel gears are easily influenced by deflections of the gear shafts and bearings. These have a significant influence on transmission error, which produces vibration and noise. Therefore, in considering the deflection of the gear shafts and bearings, obtaining the transmission error of a bevel gear is very important for the design. In this report, transmission error was calculated when gear shafts were supported by two bearings. These calculated values were compared with the transmission error which was calculated without the deflection of the gear shafts and bearings.

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A newly developed ultra-fine micro piercing has been demonstrated successfully with only a few technical points that need improvement. The die material is mild steel and the strength of the die is equal or sometimes smaller than that of the pierced material. Therefore, pierced scrap accumulated in the die hole may stop the punch advancement. If the pierced material rises up unevenly from the die, a lateral force acts on the punch and the punch defect advances and thus results in shaving the surface of the hole. In this study, the advancing defects were suppressed by using a decompression chamber under the die. In doing so, the scrap is sucked away from the die hole at each stroke and the foil, material to be pierced, is pulled down through two holes that are 1mm apart from the die hole. The results of our experiment show a high precision continuous ultra-fine piercing process can be carried out with relative ease for various engineering materials.

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Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effects of the cutting conditions and the complicated factors on the machined surface integrity are the serious problems. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force acting point, the coefficient of the thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model.

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Corner motion is a common and important case in contouring applications. If the corner error is well-controlled, a machine can own maximal throughput while maintaining the machining accuracy. In this paper, we investigated corner error yielded by different Acc/Dec processing in the command generation phase. At first, we derive some analytical forms of corner error induced by Acc/Dec processing; both linear and FIR Acc/Dec types are studied. Then a simple method of controlling the corner error without changing the Acc/Dec structure is presented. The method is simply to add some delay time to retard the execution of the second linear command. Although some results here do not explicitly present their final exact analytic expressions, their numerical solutions can be easily solved.

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This article provides a design for the real-time interpolator of the B-Spline free surface. The goal is to increase both the accuracy and the speed of manufacturing production by eliminating the bottleneck caused by the off-line interpolator of the CNC tool machines, by reducing manufacturing errors, and by resolving the issue of long numeric control code (NC code). The design of the surface interpolator includes location planning using the real-time cutter contact data, the interpolation of the cutter contact data, and the cutting compensation of the cutter location data. This paper provides a surface interpolation method for reading the surface NC code of a three-dimensional surface and for implementing the surface interpolation. To simplify the complexity of the calculation, one can first use knot interpolation to decompose the B-Spline surface into sections of Bezier surface, which are then used as the surface for real-time surface interpolation. Subsequently, the approximation of the second order Taylor expansion is used to obtain the location interpolation points. Fixed machining parameters are adopted to avoid the low efficiency and low quality of manufacturing caused by variation of the feeding speed. The derived cutting locations are further combined to obtain the cutting locations of the original B-Spline surface. The verification of the experiments is shown with comparing the manufacturing profile errors and any variation of the feeding speed derived from computer simulation and the corresponding data obtained from the off-line interpolators.

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The roughness effects are not negligible in mixed lubrication regime. An average Reynolds equation using flow factors is useful to determine the effects of surface roughness on mixed lubrication. In this study, the effect of kurtosis on flow factors is investigated using random rough surfaces generated numerically. The results show that flow factors are very sensitive to h/σ according to the value of kurtosis in the partial lubrication regime.

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