Diamond grinding is often used for silicon wafer thinning. This process brings about not only efficient material removal of wafer, but also the subsurface damage which is accompanied by residual stress on the wafer surface. The residual stress greatly contributes to the distortion of thin wafer. Reported in this paper are deflection behavior of wafer when it is subjected to the residual stress and a practical method of the residual stress estimation based on the wafer deflection. Based on the numerical FEM analysis results, the thin wafer is found to undergo three stages of deformation, dependent on the quantity of residual stress. When the residual stress is sufficiently small, the wafer is deflected into a sphere shape which is able to be described by the Stoney's Equation with its corrective coefficient. With an increase in the residual stress, the wafer deflection starts to depart from the sphere shape, but still maintains in axisymmetric form until the deflection reach to 1 ~ 2 times larger than the wafer thickness. Beyond this critical point, the shape of deflected wafer is transformed into a cylindrical warping. The amount of wafer deflection is then associated to the residual stress to provide an easy way of estimation for residual stress on wafer with different thickness.

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In the present research, a simulation model of wafer behavior during double-sided lapping was developed. Understanding wafer behavior during lapping process is essential to clarify and improve the process. In the model, contact between the wafer and an upper platen, a lower platen and a carrier is considered, and the wafer behavior is calculated based on equilibria of the forces and the moments applied to the wafer. The behavior simulated with the developed model shows that the rotational speed of the wafer is not constant. In addition, contact status, i.e. sticking, sliding or non-contact, between the wafer and the carrier changes during the lapping process. The behavior does not agree with conventional models, where the contact status between the wafer and the carrier is assumed to be sticking or to be frictionless sliding. In addition, the amount of material removed was estimated by the developed model and the conventional models, and the results showed a considerable difference. Since contact between the wafer and the carrier is not modeled accurately in the conventional models, the developed model was confirmed as a useful tool for simulating the double-sided lapping process.

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Titanium alloys are applied in various industrial applications due to their high specific strength and corrosion resistance. However, these alloys are well known as poor machinability materials, and tool life in end milling of these alloys was shorter than that of carbon steel. Severe tool wear may result in unacceptable precision and surface roughness of a workpiece. In order to reduce machining cost and improve quality of workpiece, monitoring or prediction of tool wear is one of the important techniques. The purpose of this study is to find out parameters to evaluate tool wear, and we focused on cutting force at perpendicular to tool flank. End milling of Ti-6Al-4V alloy was carried out on various cutting conditions to examine influence of cutting force on tool wear. As a result, flank wear tend to be decreased with decreasing cutting force at perpendicular to tool flank. It was proposed that cutting force had a potential to become available parameters for evaluating tool wear in end milling of Ti-6Al-4V alloy.

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The main objective of this paper is to clarify the formation mechanism of built-up layer (BUL) in cutting of hardened steel, as BUL formed on the tool surface under certain cutting conditions can act as a protective layer, increase the tool wear resistance, extend the tool life and so on. Detailed analyses of tool surface, the microstructure feature of BUL and chip inside surface after cutting hardened steel S45C (H-S45C) were done by Scanning Electron Microscope (SEM). Experimental evidences show that the formation of BUL is a process of the nucleus formation on the tool rake face. Furthermore, a nucleus formation mechanism of BUL formation mechanism is proposed. The model is based on a qualitative and quantitative analytical approach including an atomic-scale contact model at the tool/ chip interface and a nucleus formation of BUL from irreversible thermodynamics point of view. A quantitative comparison between model and experimental results is also provided. It is verified that simulation results are in good agreement with the experimental results and the model is able to predict the position of the nucleus formation of BUL. This study may help researchers deepen the understanding of the formation mechanism of BUL and clarify some previous concepts on it.

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The miniaturization of many machine parts for machine tools is desired for the purpose of effectively utilizing space, energy saving, and realizing desktop factories. However, it is predicted that the reduction of the calorific capacity of machine leads increase in thermal deformation caused by downsizing of the machine. Thus, there are few effective report to reduce this thermal deformation.
Therefore, in spite of the many requirements of the market related to the miniaturization of machine tools, a miniaturized NC machine tool has not been widely regarded. The conventional structure of machine tools such as a cast body or welded steel plate body is recognized as being the best. This preconception is one of the obstacles to solving this problem.
We have developed a new CNC lathe with a pipe frame structure. This structure is expected to enable the miniaturization of machine tools while ensuring sufficient space for the discharge of cutting chips. In this structure, the heat transfer between the pipe elements and connecting blocks strongly affects the axial displacement of the pipes. Therefore, the heat transfer between the pipes can be reduced by controlling the temperature at the appropriate connecting blocks. The thermal deformation is controlled by using Peltier devices set on the connecting blocks. Results for the thermal deformation control of this lathe and the effects on workpiece dimensions by cutting are reported in this paper.

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In this study, the function of the Robot Motion Performance Platform was enhanced. The low of the reusability which is the conventional problems was solved. Thus, the ability which can perform many motions from few basic motions was improved. Two functions were added. The first is the fast-forward function of motions. By this, it isn't necessary to make new motion data for different in only the motion speed. The second is the synchronous function during the motion using the existing motion mixture function. By this, it isn't necessary to make new motion data for combination motion of the motions. For example, step motion of the biped robot. Conventional the Robot Motion Performance Platform was able to perform bending-and-stretching the right leg, bending-and-stretching the left leg and squat motion by motion data of bending-and-stretching the right leg and bending-and-stretching the left leg. The step motion using the same motion data was possible by the synchronous function between motions.

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This research deals with the high precision flat surface finishing method by automatic scraping machine. By Whitworth method, high-precision surface plates were finished without using a reference surface automatically, and it was certainly the work process from the pattern scraping (rough scraping) up to fine scraping. Scraper direction was changed every time to make scraping pattern on the surface. The method of dividing some image matrix that is one of image processing technique was able to take high precious image. Finally, surface flatness and scraped marks per square inch was measured to estimate the scraping performance of automatic scraping machine.

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Recently, it has become necessary to develop a more advanced reverse engineering (RE) technique that can generate CAD models of complex shapes from scanned mesh more efficiently. In this study, we propose a new efficient reverse engineering method of castings. In the method, machining and casting surfaces of the scanned mesh are separated, and precise surface fitting is applied only to the machining surfaces. The method can realizes an efficient RE process since different geometric processing and modeling techniques can be applicable to machining and casting surfaces individually. In addition, suitable geometric processes in the applications of the CAD models, such as machining margin addition and machining planning for machining surfaces in the duplication, can be automatically applied to each machining and casting surfaces, because they are recognized in our method. In this paper, we develop two methods. First, the surfaces are classified into the casting and machining surfaces based on triangle roughness. Second, boundaries of the casting surfaces are smoothed and modified so as to intersect machining surfaces for generation of the CAD models. We show some experimental results using some scanned meshes of castings.

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