This paper proposes a newly developed monitoring system for grinding ultra-precision small size casting die having asphericl surface. Small size aspheric glass lenses are widely used for IT industry. The lenses are cast in cemented carbide die because of its high melting temperature and the die is usually ground by small size diamond grinding wheels. The wheel can not be changed or dressed in finish grinding, because changing or dressing the wheel brings deterioration of die accuracy, therefore, very light grinding conditions must be adopted, such as less than one micrometer of depth of cut. In such conditions, monitoring of grinding state, such as that of grinding force, is indispensable to achieve high quality and high efficient grinding. However sensing of very low grinding force is quite difficult, because of the system stability and Signal/Noise ratio in the sensing. In the system developed, an induced current was applied to a closed circuit, which was consisted from die, diamond wheel, spindle, air bearing and machine tool, by a ring coil coupling with the circuit and the current was detected by an another ring coil. The current was depended on an impedance of the circuit, and the impedance was influenced by the conditions between die and grinding wheel, Stable or unstable grinding conditions was detected, so that high efficiency ultra-precision grinding was achieved by using the system.

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This paper describes the elucidation about influence of dilute NaCl electrolyzed water on character of Al-Mg alloy cutting surface. First, the immersing experiment was conducted for cutting sample of Al-Mg alloy A5056B on the electrolyzed reduced water and electrolyzed oxidized water of 0.10wt% NaCl. Next, checked whether discoloration had occurred on sample surface, and analyzed the element distribution and chemical bond state on cutting surface by ASE (Auger Electron Spectroscopy) and ESCA (Electron Spectroscopy for Chemical Analysis). As results of the study, following could be identified. (1) Dilute NaCl electrolyzed water can be applied to processes, such as machining and surface treatment of Al-Mg alloy. (2) The element distribution of the Al-Mg alloy on cutting surface is controllable by dilute NaCl electrolyzed water. (3) The chemical bond state of aluminum element on Al-Mg alloy cutting surface is controllable by dilute NaCl electrolyzed water.

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This paper deals with a control structure and a method for reducing relative displacement in a three-dimensional coordinate measuring machine. In general, this system consists of a numerical controller, a servo motor, an elastic feed mechanism and a scanning mechanism. In a scanning mechanism, a tip position attached to the tool or the probe and the controlled position are usually arranged at the other positions each other, so that the relative displacement between both positions causes measuring errors. We clarify the control structure that can provide a relative displacement based on a three-inertia system and then propose a control method for reducing relative displacement. In the proposed method, current, velocity and position control loops with a damping compensator are applied to the control object modeled by the three-inertia system. The result of the control structure analysis is validated by simulation and experiments.

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The study deals with the automation of polishing process for free-form surfaces by means of an industrial robot. In general, the polishing process has been performed by handwork of skilled workers. Since the polishing environment is extremely inferior and the polishing process is time-consuming and tedious work, the automation of polishing process is strongly desired and the robot systems have been introduced recently. However, the polishing by robots has not necessarily been performed in success. In the study, the polishing path generation is devised to improve the surface quality of workpieces. Thus, the relationship between the surface curvature of workpiece and the contact length of polishing tool is investigated by polishing experiments, which results in the new polishing path generation method. The method is successfully applied to polish an impeller of food and osmetics agitators, which consists of free-form surfaces. As a result, it is found that the new polishing path generation method is effective for polishing automation by robots.

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A new three-color infrared radiation pyrometer using an optical fiber is developed for measuring cutting temperature in high speed machining by small ball end mill. The high speed air spindle unit is adopted to the ordinary milling machine so that the maximum spindle revolution of 40000rpm is attainable. The ball radius of the carbide cutter is 3mm and the side cutting of carbon steel with ballnose is executed without cutting fluid. Cutting temperature distribution along the ball-nosed cutting-edge is measured. The influences of spindle rotational speed, radial depth of cut and feed per tooth on the temperature distribution at the flank face are examined. The maximum temperature of peripheral cutting edge about 700°C is obtained even at the rotation angle of 180° after cutting, and it drops along the ballnose toward the ball tip. Relatively large temperature gradient arises along the ball cutting-edge at higher spindle revolution because cutting speed depends on the local tool radius. Depth of cut and feed per tooth, at the same time, affect the overall temperature at the ball cutting edges. The cooling characteristics in air cutting reveals that the temperature difference during one cycle of intermittent cutting increases as spindle speed decreases. The relationship between the peripheral cutting speed and the tool temperature varies from tool shank to ball tip because the interactions between cutting edge and workpiece change along the ballnose.

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This paper describes a new method of making molds for injection molding of plastics. In this method, since molds are made by laminating metal sheets cut by laser, both delivery time and cost can be reduced compared with conventional die making methods. Furthermore, since channels for cooling water can be circulated arbitrarily inside the mold, higher production rate and quality of products can be achieved. In this study, diffusion bonding was used to bond the sheets, and a mold with excellent forming efficiency and accuracy was manufactured.

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Electrorheological fluids (ERF) are functional fluids whose viscoelastic properties vary with the intensity of the applied electric field. The property of ERF has been expected to control the performances of machine elements, and the ERF has been applied to machine elements such as variable dampers and clutches. However, the disadvantages of ERF are the sedimentation of ER particles and the requirement of seal mechanism. The sedimentation of ER particles reduces the ER effects, results in low stability of ER devices. To solve these problems, gel structured elecrorheological fluids (ERG) were developed in this study. The separation and sedimentation of ER particles from the base oil are successfully suppressed because the frames of gel prevent the particles from sedimentation. The basic characteristics of ERG were experimentally analyzed in this study. The ERG sheet was sandwiched between a pair of plate electrodes and the variation of shear stress between the sheet and the upper electrode was measured when an electric field is applied to the ERG. Comparing with a conventional ERF, the developed ERG provides extremely higher shear stress and the long durability of ER performance. The dynamic response of shear stress of ERG film was also evaluated.

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This study aims to fabricate 3 dimensional microstructures on single crystal silicon by nano-scale machining using mechanism of friction force microscope (FFM) and subsequent alkaline etching. Machined area by diamond tip acts as a mask against KOH solution because of formation of amorphous layer, and consequently microstructure can be fabricated. The influence of machining conditions on masking effect is studied. As a result, it is found that masking effect can be controlled by adjusting normal load and pitch of machining line. In this way, mechanism of height change is investigated, and also 3 dimensional microstructure can be fabricated with precise control of machining parameters.

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Glass-like carbons (GCs) for press molding die of micro optical glass lens and electroless Ni-P alloy films for injection molding die of micro optical plastic lens were machined by focused ion beam (FIB) and their dimensional accuracy, surface roughness and transcriptional performance were investigated. The GCs completed a fine surface roughness of Ra=1nm after FIB machining, although their FIB etching rate was decreased to a half rate of Si(100) single crystal. On the other hand, amorphous Ni-P alloy films containing phosphorus more than 7wt% possessed higher etching rate than Si(100) crystal, as well as fine surface roughness less than 8nm. Precision GCs and Ni-P alloy films molding dies with 3-D microlens array of 7μm square were fabricated by FIB. Subsequently, transcriptional performance to micro optical lens was evaluated on precision GC dies.

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Thin semiconductor wafer is more required for portable devices due to its mechanical flexibility or space gain. In dicing process for this thin wafer, suppression of micro-cracks is indispensable, which result in starting point of substrate breakage. In this research, laser cutting was performed for thin silicon wafer as a new dicing technique to conventional diamond blade dicing. Nano-, pico- and femtosecond laser were used to cut substrates in order to investigate the dependence of the flexural strength on the pulse width and the irradiated laser energy. As a result of that, the average strength of the diced wafer with the femtosecond laser was about three times larger than that with the nanosecond laser. In the case using the femtosecond laser, moreover, the minimum strength was about three times as large as that of the conventional blade dicer.

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This paper deals with the data-transmission system adopting the opto-electronic parts for the remote-controller of electric appliances. The signal with appropriate bit-pattern and specified wave-form is used, and the system has much longer distance nearly 1,000mm between the light-emitting-diode and the light-receiving-module than the maximum length of 3-20mm in the reported system of faster-transmission rate. Then the data-transmission from not only rotating spindle but also revolving body is realized. Three techniques, which are adoption of one-way data-transmission, one-chip micro-controller and digital-filtering process, are adopted as same as in the faster-transmission system. The data-transmissions from the end-surface of rotating spindle and from the cylindrical-surface are confirmed.

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In tapping, chips jamming in the tap's flute or twining around the tap cause tool breakage very frequently. It has been an obstacle to automation of tapping. In order to resolve this problem, a chip-breaking tool has been developed, which forms grooves axially on the inner wall of hole before tapping. In this paper described are design of the tool and its effectiveness. The tool was composed of a cylindrical body and three V-groove cutting edges. The diameter of body was equal to that of tap drills. The major diameter of V-groove cutting edges was slightly larger than that of taps. Each V-groove cutting edge had a chip pocket designed after observing the chip formation in similar V-groove cutting. To investigate the effectiveness of the tool, tapping experiments for M3 and M6 threads were performed with and without using the tool. The work material was structural steel SS400 and the taps used were the conventional spiral fluted taps made of high speed steel. By using a machining center the tapping operations were automatically repeated till when the tap was broken without any human assistance for removing the chips jamming in the tap's flute or twining around the tap. To shorten the experimental time, the cutting velocity for tapping was set at 30m/min which was much higher than conventional, and besides, the thread was long as two and a half times of diameter. It has been ascertained by experiments that by using the newly developed tool, the tool life of tap lasts much longer and the tapping torque becomes smaller and stable, and moreover, the surface roughness becomes smoother.

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Many highly precise computer simulation tools have been developed for assembly line design, such as for simulation of assembly processes, but these tools require much input information and are generally utilized only in detailed design stages. This paper proposes a rapid analysis method for manual assembly line design, which can be utilized in the conceptual design stage. This method is constructed based on a layout tool where design engineers can construct assembly line models using 2- and 3-D views, and provide evaluation techniques for multiple important criteria such as volume flexibility, and visibility, based on the data structures. Spatial evaluation and quantitative efficiency analyses can be simultaneously performed, which enhances collaborative decision-making in the conceptual design stage.

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In this paper, we propose new application methods of t-FFD¹⁾, a free-form deformation by using triangular mesh, or base-mesh. The first application is “skeleton based modeling”. This method is a shape deformation by line segments, or “control skeleton”, which is used by a designer to control the base-mesh with a rigid transformation. The second application is “tensegrity modeling”. In this method, a TGM³⁾, or a tensegrity model, is generated automatically to control the shape of base-mesh. A designer can manipulate the TGM to get the deformed shape based on the physical characteristics of the TGM. These methods enable an intuitive modeling by a designer with simple and visual operations.

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Although rational polynomial curves and surfaces have become standard forms in computer-aided design, they have many problems. For example, a Newton-Raphson algorithm for dealing with rational polynomial curves tends to be non-robust. This is a fatal problem. In the past, we proposed a new Newton-Raphson method for dealing with the rational polynomial curves. In the method, we homogenize the coordinates of a rational curve when it is applied to the Newton-Raphson algorithm. Then it becomes very robust.
This paper proposes a method of adapting the algorithm to the Newton-Raphson method for dealing with the surface-surface intersection problem. Like the case of a curve, the Newton-Raphson algorithm was found to be very robust when the coordinates of a curved surface are homogenized. In this paper, we discuss the reason why the conventional method tends to be non-robust while the new method is robust. The conventional method deals with a rational function that always has a horizontal asymptote as well as vertical ones while the new method deals with a non-rational function and thus has no asymptote. The result of our analysis points out that the cause of the non-robustness lies in the horizontal asymptote of the rational function inherent in the conventional Newton-Raphson method. Our numerical experiments show that our method is very robust.

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