Soft composite materials are used for a functional film for a thermal interface material. The surface of this functional film must be flatter and thinner, and contacting fillers to have a better thermal conductivity. Cutting would meet these requirements to slice such soft materials. Soft composite materials consisting of acrylic rubber bulk and graphite fillers were prepared and sliced into films (1mm thickness) as thermal interface materials by developed cutting method. Measurements of curl radius and cutting forces were conducted on the orthogonal cutting experiments. It was found that the following three strategies were effective for reducing curl of chip and cutting force : (1) higher operating temperature, (2) slower cutting speed, and (3) larger tool rake angle. This result suggested a useful method for the effective slicing by controlling the cutting conditions.
This paper describes the etching effects of Na2SO4 electrolyzed oxidizing water on the surface of pure iron. First, we threw light on the etching characteristic of electrolyzed oxidizing water on the surface of pure iron by comparative immersion experiments with H2SO4 solution. The results show that etching effects of electrolyzed oxidizing water are huge. In addition, the higher the ORP/pH value of the electrolyzed oxidizing water becomes, the quicker the etching effects works. Next, we threw light on the influence of electrolyzed oxidizing water on the surface shape of pure iron, by the observation using the SEM image. The results indicated that electrolyzed oxidizing water did not have a big influence on the surface shape of pure iron. Lastly, by analyzing the surface, we made it clear that electrolyzed oxidizing water had no bad influence on the chemical composition of the pure iron surface. The study indicates that Na2SO4 electrolyzed oxidizing water can be applied to the surface treatment and washing of pure iron. Na2SO4 electrolyzed oxidizing water does not have chloride ion, unlike NaCl electrolyzed oxidizing water. Therefore, Na2SO4 electrolyzed oxidizing water is wide in the application scope, compared with NaCl electrolyzed oxidizing water.
High-aspect-ratio microdrilling of borosilicate glass has been demonstrated by the forth harmonic of nanosecond Nd : YVO4 laser. In this paper, we investigated about the influence of the beam profile on the hole profile. Beam profile was changed by using focal lens with the focal length of 10 mm, 20 mm, 30 mm, 50 mm and 100 mm. As a result the glass was drilled deeper than 2200 μm using the focusing lenses with the focal length of 20 mm, 30 mm and 50 mm. On the other hand, the depths of the holes were less than 800 μm using the focusing lenses with the focal length of 10 mm and 100 mm. The profiles of the holes drilled with the focusing lens with the focal length of 20 mm, 30 mm and 50 mm were almost same. The diameters of the holes were smaller than 15 μm in the range deeper than 500 μm, therefore the aspect ratio was higher than 110. Drilled depths and profiles were measured with changing focus positions. No clear were difference were observed when the defocus distances were less than ∼70 % of Rayleigh range. Transmitted laser energy passing through the holes were measured by using the glass plates with different thickness and compared with calculated energy supposing the laser beam propagates as Gaussian beam and no reflection on the inner surface of the drilled hole. As a result the energy of the transmitted light was almost same as that of the calculated energy when the plate was thinner than 1 mm. On contrast, when the plate thickness was 2 mm, the transmitted light was larger than that of the calculated energy. This result conducts the laser beam was reflected and the reflected laser was dominant when the hole was deeper than 1mm.
A machine tool spindle is a key component affecting the performance of machine tools. Spindle vibration of machine tools causes short tool life and low machining accuracy. The vibration changes depending on the used tooling and the rotation speed during various machining operations. In particular, even small unbalance mass of the spindle makes large centrifugal force in high speed machining. However, real-time balancing for a machine tool spindle has not yet been realized successfully including the influence of the used tooling. In the previous paper, in order to compensate unbalance mass of a machine tool spindle and to achieve high accuracy machining, a real-time balancing mechanism using magnetic fluid was proposed. The magnetic fluid is enclosed inside the spindle, and the distribution of circumferential mass is controlled to compensate for unbalance mass in real-time. A machine tool spindle equipped with the proposed real-time balancing mechanism is developed in this paper. It is experimentally confirmed that unbalance mass of the spindle is significantly improved in real-time, and tool vibration is suppressed effectively.
Polishing is generally used in fabricating high-quality silicon wafers. Polishing efficiency and accuracy depend not only on the pad surface texture but also the actual conditions of contact between the wafer and the pad. Furthermore, the pad surface texture is affected by the dressing conditions. Currently, no effective quantitative methods or parameters for pad surface evaluation have been established. In this study, we propose a technique based on contact image analysis using an image rotation prism. We also discuss the effect of dressing conditions on the following parameters : (1) contact ratio, (2) number of contact points, (3) spacing of contact points and (4) spatial FFT results of a contact image. These parameters were found to be effective for evaluating pad surface texture.
Micro machining of single-crystalline silicon is performed with the second-harmonic of Nd:YAG laser in this study. In experiments, various shapes of plastic microlens are fabricated on a transparent substrate by the developed die-less method. These microlenses are shaped by thermal deformation induced by the Er:YAG laser beam absorbable for the acrylate resin. And then, these lenses are used as optical devices to generate the local high energy density desired for machining of silicon in air and water. Machining characteristics are investigated in the single groove machining process, and the grid groove pattern and the herringbone pattern are formed to demonstrate the feasibility of proposed methods.
Ecodesign plays one of the most important roles in manufacturing sectors towards a sustainable society. As a practical tool of ecodesign, manufactures often use checklists to support product design as well as to obtain eco-label certification. However, current checklists are insufficient due to undetermined effects of individual requirements in the checklists on environmental impact. This paper proposes a method for supporting ecodesign assessment by developing a weighted checklist, where potential environmental improvements in each requirement are derived based on the life cycle simulation. In the case study involving a digital duplicator, the proposed method successfully identified requirements that needed to be improved. When suggested improvements were applied, 8% of total CO2 emissions were estimated to be reduced.
In this paper, a novel approach for designing grain patterns based on digital technology is proposed. In the previous paper, the basic tree growth model was developed by investigating the basic growth-features of trees and the responding growth features on growing environment conditions : daylight hours, precipitation, temperature, and the ground inclination angle. The basic tree growth model was constructed by using the electric charge method which can easily represent the trunk and branches and could generate a variety of woodgrain patterns by changing the growing environment conditions. The tree model developed in the previous paper enables to reproduct the trunk and branches. However, it is required to make a more realistic digital tee model. In this paper, in order to generate more natural woodgrain patterns which can be used for industry design, the method to construct a more precise digital trees model is proposed. A design system of grain patterns is developed based on the proposed method. The digital woodgrain patterns generated by the system are evaluated.
Overload prevention is important for a force sensor in order to avoid fatal damage due to unexpected external force. Until now, most of the proposed mechanisms for this purpose prevent the damage to the sensor by using a screw and a straight pin. Few reports on the utility of these mechanisms have been published. In our previous work, we proposed a unidirectional force sensor based on an H-slit type parallel beam structure. The H-slit beam structure is a part of a force sensor and it can perform as an overload prevention mechanism without any additional mechanical parts. In this paper, we verify the utility of the H-slit type beam based overload prevention mechanism. Besides, based on the verification result, this paper proposes a new slit type beam overload prevention mechanism.
This paper proposes a method to measure thickness and warp of silicon wafer simultaneously. Warp was measured using the three-point-support inverting method. Then, thickness was obtained from the measured shapes of both top and back surfaces and the wafer deflection due to gravity which was calculated by numerical analysis. Since the calculated wafer deflection is affected by the thickness distribution, the self-consistent solution of the thickness was obtained by iteration. As a result, the error of the thickness measurement was ±0.72μm, indicating that the warp and thickness of the silicon wafer can be measured simultaneously.