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Abstract: Adding slicing to push cutting processes can significantly reduce cutting forces. Creating an appropriate model for the calculation of forces is necessary to completely understand manufacturing processes. In this investigation, a model detailing the cutting forces of stacked thin material using an asymmetrical knife is developed. Equilibrium of forces and frictional effects at the cutting edge are analyzed to determine the components in vertical and horizontal direction of the total cutting force, and their dependency on the slice-push ratio. The friction effects of the new model are based on Coulomb friction. For comparison purposes, an existing shear friction model is extended to discuss the new presented Coulomb friction model. To support the findings, the newly developed model is experimentally verified. [Copyright &y& Elsevier]

In this paper, the revolutions of wafer and pad were considered the same and the force forms including the pressure exerted on the top of wafer surface and the carrier back pressure were axisymmetric distributed, a 2D axisymmetric quasi-static model for chemical mechanical polishing process (CMP) was first established. Based on the principle of minimum total potential energy, a 2D axisymmetric quasi-static finite element model with a carrier back pressure compensation for CMP was then established. In this model, the four-layer structures including wafer carrier, carrier film, wafer and pad are involved. The effect of a given carrier back pressure on the stress components and von Mises stress on wafer surface was analyzed and the effect of different carrier back pressures on the von Mises stress and nonuniformity on wafer surface was investigated. The findings indicated that the axial stress was the dominant factor to the von Mises stress distribution on wafer surface. Because that the back pressure had the maximum affect on the axial stress and it made the axial stress increased along the −z direction. Thus, while applying a back pressure, the von Mises stress distribution increased. In addition, the changes of back pressure had the trend to be proportional to the von Mises stress variation and to be inversely proportional to the nonuniformity variation. The result showed obviously that during the CMP process, it could achieve the purpose to improve the planarization of wafer surface by compensating the different carrier back pressures. [Copyright &y& Elsevier]

Asperity flattening study plays an important role in predicting the friction behavior at the interface and the surface roughness transfer during sheet metal-forming process. This paper presents a comparison of asperity flattening activities under 1-wavelength, 2-wavelength and 3-wavelength finite-element models developed based on a power spectral density (PSD) analysis of measured data on steel sheet surfaces. First, a proper asperity thickness for the modeling has been determined by the investigation of plastic strain distribution along the depth of asperity. The comparison then examines the evolution of real contact area, surface roughness, contact pressure distribution and variation of friction force at the interface between a tool and a workpiece drawn from different wavelength simplification models under various friction conditions. It is concluded that 3-wavelength model has closer results to experimental measurements and introduces less contact area and more local pressure concentrations than those from the other two models. [Copyright &y& Elsevier]

In this paper, we use a prevalent finite element analysis software, MARC, to simulate the process for a subject material undergoing equal channel angular extrusion (ECAE), as well as calculating the strain conditions. For a single ECAE pass, the transversal strain distribution in the deformed body will be analyzed to investigate the influences from channel angle, friction between die and pressed material, and curved joining channels. Simulations involving double passes of the subject material were also conducted, something that has not been previously pursued much elsewhere. [Copyright &y& Elsevier]

In this paper, the effects of cutting speed on the variation of surface texture and lattice rotation of diamond-turned surfaces were investigated. The {1 1 1} pole figures were determined at various locations by the X-ray diffraction method. The local lattice rotation at various locations on a machined groove by the electron back-scatter diffraction (EBSD) method was also obtained. A simulation of the orientation change was performed and the theoretical prediction was compared with the experimental results. [Copyright &y& Elsevier]

In this paper, a non-destructive nano-precision measurement method for diamond tool cutting edge radius is presented. The basis of the method is that the profile of a tool cutting edge can be copied by indenting the tool cutting edge into the surface of a selected material, and that the copy of the profile can be measured at nano-precision level using AFM. The selected material elastic error compensation coefficient has to be determined to cancel out the effect of elastic spring-back. Copper was selected as the indentation piece material due to its (1) high rigidity and high density, (2) large Young’s modulus and (3) low yield strength. The elastic error compensation coefficient for the copper material is determined through the indentation of a tungsten carbide tool edge on the copper surface. By comparing the actual tool edge radius measured using scanning electron microscope (SEM) on the sectional view of the tungsten carbide tool with the one measured from the copied profile of the tool edge on the copper surface, the coefficient is obtained. Three diamond tool edge radii were obtained using the proposed method. Analysis is given for the accuracy of the proposed method, showing that as far as the error elastic compensation coefficient is consistent with the copper material used, the only source of errors with the measurement will come from the device for measuring the indented profile on the surface. [Copyright &y& Elsevier]

Electrochemical mechanical polishing (ECMP) is a polishing process combining electrochemical and mechanical action. It has higher efficiency and better quality.Mechanism, processing regulation and application are introduced in the paper. [Copyright &y& Elsevier]