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A wire tool having electrodeposited diamond grains is frequently used for machining hard and brittle materials such as silicon ingots, magnetic materials, ceramics, and sapphires. This study aims to examine the wear characteristics of the tool during the microgrooving of ceramics. We conducted microgrooving experiments for alumina ceramics. The results indicate that the grooving time and the machining distance influence the groove depth. However, as the damage in a wire tool progresses, the groove depth does not depend on the machining distance. A fast relative velocity leads to serious damage in the wire tool even when the machining time is short. In the case of wet grooving, the damage to the wire tool was smaller than that in the case of dry grooving.

It is well-known that a series of cracks sometimes gets initiated perpendicular to the cutting edges on the rake faces of brittle cutting tools made of materials such as cemented carbide, ceramics, and cermet under high-speed intermittent cutting. The tools used in intermittent cutting processes are exposed to elevated temperatures during cutting and then cool quickly during the noncutting time. Previous studies have suggested that such repeated thermal shocks generate thermal stress in the tool and that the thermal cracks are then propagated by thermal fatigue. Recently, high-speed machining techniques have attracted the attention of researchers. To apply new cutting tool materials to this machining process, it is important to evaluate their thermal shock fatigue resistances. During high-speed intermittent cutting, the frequency of thermal shocks becomes high and the action area of the thermal shocks is limited to the rake face of the tool. Therefore, conventional thermal shock resistance evaluation methods are unsuitable for this case. Consequently, the authors have developed a new experimental evaluation method using a CO2 laser beam. In this study, we irradiated cemented carbide and TiN cermet cutting tools with the CO2 pulse laser beam and gauged the effectiveness of the proposed thermal shock fatigue resistance evaluation method. The results show a correlation between the thermal shock due to the CO2 pulse laser beam and those due to the intermittent cutting experiments.

Thinning of the silicon wafers and decrease in kerf loss can minimize the production costs of semiconductor products. Currently, the quantity of kerf loss is about the same as the volume of the wafer itself. If we drastically reduce kerf loss, we can easily lower production costs. Therefore, we studied techniques for slicing silicon wafers with reduced kerf loss using a wire tool. As a first step, we performed micro-grooving with a fine wire tool. In this paper, we discuss the micro-grooving performance of a fine wire tool made of tungsten. A borosilicate glass is used as the work material. The main conclusions are as follows: When a fine wire tool and small-diameter abrasives are used, the kerf loss decreases. However, the strength of fine wire tools is very low. The relative velocity and abrasive diameters have a significant influence on the micro-grooving characteristics. Fine wire tools are easily fractured at fast relative velocities and with large-diameter abrasives. However, the grooving rate increases. Groove depth and grooving efficiency do not depend on the relative velocity and are dependent on the abrasive diameter.

Magnetic immunostaining is a technique used to accelerate the antigen-antibody immunoreaction by increasing the local density of antibody on the surface of a tissue specimen using a magnetic field. The high density of antibody is achieved by applying a magnetic force to antibody-labeled ferrite beads toward the specimen. A technical challenge of using conventional magnets for this technique has been the inhomogeneous accumulation of magnetic beads on the specimen in accordance with the distribution of the magnetic field. Thus, in this study, a dome-shaped magnet that generated a strong and uniform magnetic force distribution was proposed and demonstrated. Numerical analysis was used to optimize the shape of the magnet. Analysis of the motion of magnetic beads showed that the accumulation of beads on the sample was complete within one minute and that the resulting homogeneity was sufficient for rapid and accurate immunostaining. Finally, experiments showed that the homogeneity of the bead distribution was improved by the use of a prototype dome-shaped magnet compared to conventional cylindrical magnets.Magnetic immunostaining is a technique used to accelerate the antigen-antibody immunoreaction by increasing the local density of antibody on the surface of a tissue specimen using a magnetic field. The high density of antibody is achieved by applying a magnetic force to antibody-labeled ferrite beads toward the specimen. A technical challenge of using conventional magnets for this technique has been the inhomogeneous accumulation of magnetic beads on the specimen in accordance with the distribution of the magnetic field. Thus, in this study, a dome-shaped magnet that generated a strong and uniform magnetic force distribution was proposed and demonstrated. Numerical analysis was used to optimize the shape of the magnet. Analysis of the motion of magnetic beads showed that the accumulation of beads on the sample was complete within one minute and that the resulting homogeneity was sufficient for rapid and accurate immunostaining. Finally, experiments showed that the homogeneity of the bead distribution was ...

The manufacturing costs of semiconductor products such as silicon wafers can be reduced by decreasing the kerf loss. In addition, a decrease in the kerf loss leads to an effective utilization of rare materials, which is environmentally beneficial from the viewpoint of saving resources. This study aims to reduce the kerf loss during slicing hard and brittle materials. Therefore, the possibility of using an extremely thin metal foil blade instead of a wire tool in slicing was examined. Initially, grooving characteristics using a metal foil blade (thickness: 50 μm or less) was investigated. The main conclusions are that grooving with a metal foil blade is possible and kerf loss can be reduced. The groove depth tends to increase as the machining time and particle size of abrasives increase. The groove width is smaller when a thin metal foil blade is used and vice versa. However, if the abrasive particle size is too large, grooving becomes impossible. Since the wear of metal foil blade increases with an increase in the particle size of the abrasive, it is necessary to use an abrasive with a particle size that is suitable for the thickness of the metal foil blade.

A fret-saw blade is commonly used in micromachining or curve machining of various woods. However, there is a curvature limit for machining of free-form surfaces because a fret-saw blade has a thickness of several hundred microns and a width of several millimeters. Additionally, cutting with a fret-saw blade produces much wood meal as chips. If a fine wire cutting tool is used, more flexible machining, such as machining of high curvature free-form surfaces, is possible and the quantity of chip production drastically decreases. The main purpose of this study is to clarify the fundamental machinability of anisotropic materials cut with a fine wire tool. In this report, we describe the machinability of various woods that are naturally anisotropic materials using a fine wire cutting tool that has electrodeposited diamond grains on its surface. In addition, this report discusses the performance of a trial manufactured hand tool employing the same wire cutting tool. The main conclusions obtained in this study are as follows. Acceptable machining of anisotropic woods is possible using a fine wire cutting tool, and the kerf width produced with this wire tool is narrower than that produced with a fret-saw blade. Additionally, the wood species and the cutting direction with respect to the wood grain have a significant influence on the machinability of various woods. Moreover, a relatively smooth cross section is provided when wood is cut by the hand tool using the fine wire tool.

We examined the relation between the cutting force and the cutting characteristics of CFRP in diamond saw cutting. When a larger cutting force was applied, the cutting had been propagated with a mixed mechanism of the cutting by cutting edges and the cleaving of carbon fiber by shear force. While a good cutting surface was formed in the case of cutting with less than 23 N of cutting force. In this condition, the cutting had been propagated only by the cutting with cutting edges.

It is well known that a series of cracks running perpendicular to the cutting edge are sometimes formed on the rake face of brittle cutting tools during intermittent cutting. The cutting tool is exposed to elevated temperatures during the periods of cutting and is cooled quickly during noncutting times. It has been suggested that repeated thermal shocks to the tool during intermittent cutting generate thermal fatigue and result in the observed thermal cracks. Recently, a high speed machining technique has attracted attention. The tool temperature during the period of cutting corresponds to the cutting speed. In addition, the cooling and lubricating conditions affect the tool temperature during noncutting times. The thermal shock applied to the tool increases with increasing cutting speed and cooling conditions. Therefore, to achieve high-speed cutting, the evaluation of the thermal shock and thermal crack resistance of the cutting tool is important. In this study, as a basis for improving the thermal shock resistance of brittle cutting tools during high-speed intermittent cutting from the viewpoint of cutting conditions, we focused on the cooling conditions of the cutting operation. An experimental study was conducted to examine the effects of noncutting time on thermal crack initiation. Thermal crack initiation was found to be restrained by reducing the noncutting time. In the turning experiments, when the noncutting time was less than 10 ms, thermal crack initiation was remarkably decreased even for a cutting speed of 500 m/min. In the milling operation, the number of cutting cycles before thermal crack initiation decreased with increasing cutting speed under conditions where the cutting speed was less than 500 m/min. However, when the cutting speed was greater than 600 m/min, thermal crack initiation was restrained. We applied the minimal quantity lubrication (MQL) coolant supply to the intermittent cutting operation. The experimental results showed that the MQL diminished tool wear compared with that under the dry cutting condition and inhibited thermal crack initiation compared with that under the wet cutting condition.

Anisotropic materials are used in various fields because of their superior mechanical properties such as high specific strength. However, the surface generation mechanism in loose abrasive machining such as multi-wire sawing of anisotropic materials has many unknown characteristics. This study mainly aims to clarify the sliced surface generation mechanism in multi-wire sawing of glass fiber reinforced plastics (GFRP). Therefore, the slicing experiments and the wet lapping experiments are carried out in this study. In this paper, we describe the fundamental slicing characteristics of GFRP and the influence that the orientation angle of reinforcement fibers has on the newly generated surface of GFRP. We find that high-precision machining of GFRP is possible using a multi-wire saw. The slicing rate and thickness variation are not dependent on the orientation angle. However, sliced surface roughness depends on the orientation angle, and it tends to decrease when the orientation angle increases. In addition, sliced surface generation and polished surface generation involve similar mechanisms and produce very similar surface characteristics.

We examined the slicing technique of silicon wafers with little kerf loss using an ultrafine wire tool. As the first step, we performed microgrooving with an ultrafine wire tool. The thinning of the wafer and the decrease in kerf loss can minimize production costs. We discuss the strength characteristics and the microgrooving performance of the ultrafine wire tool. The main results are as follows. The relative velocity greatly affects the grooving properties. The ultrafine wire tool easily breaks when the relative speed is high. When the ultrafine wire tool and abrasives with large diameter grains are used, the ultrafine wire easily breaks and chipping in the work material easily occurs; furthermore, the ultrafine wire strays.

Diffusion bonding requires loading relatively high pressures at elevated temperatures in order to advance an adhesion between surfaces. In the case of oxygen free copper, remarkable deformation occurs during the bonding process due to its poor mechanical strength at high temperatures. In the present study, the diffusion bonding of oxygen free copper under low pressures which enable the specimens to minimize deformation was attempted at 1073 K for 3.6 ks and 7.2 ks with other experimental factors. The process for increasing bonding areas consists of deformation and diffusion mechanisms. It was important to promote the latter because the former gets poorer under the low bonding pressures. Tensile strength of the specimens was increased with decreasing roughness on the bonding surfaces and comparable to that of the base metal in the specimens whose surfaces were polished with an emery paper #4000 and buffing. Furthermore, a fracture occurred at not the bonded interface but the base metal when contact between the bonding surfaces was delayed until a temperature was raised up to bonding condition. In the conventional procedure for diffusion bonding, the temperature has been generally raised with contact between the bonding surfaces so that copper oxides at the bonded interface are difficult to be decomposed due to depressed evacuation. The bonding surfaces were maintained as a free surface by the delayed contact procedure, which led to decomposing the copper oxides. Consequently, the tensile strength would be improved by reducing fracture origins. Grain boundary migration across the bonded interface was sufficiently generated only in the specimen prepared with buffing and prolonged for 7.2 ks in bonding time. In contrast, the fracture at the base metal was achieved in the specimens maintaining an original bonded interface. It was suggested that the grain boundary migration was not necessary to acquire superior joints.

A magnetic micro machine was fabricated by using photopolymerized resin structure as the base, and its motion in viscous liquid was evaluated. The production method of two kinds using a positive-type mold and a negative-type mold was proposed. With ultrasonic vibration after the surface treatment using the ultra-fine particles of silica, electroless copper plating was realized to negative-type resin mold even inside the concave structure of 20 μm in width and 100 μm in depth. The magnetic micro capsule was produced by carrying out ferrite plating to positive-type resin mold, and the magnetic field guidance experiments were conducted in silicone oil. The sample of full length 800 μm swam by the guidance, always turning the head in the advance direction, and it rotated on the same spot.

Tools coated with TiBON films of varying boron concentrations were made, and the influence of boron concentration on tool wear was investigated. The TiBON coating film acts as a lubricant at high temperature. Tools coated with such films were applied to the machining of difficult-to-cut materials (Ti-6Al-4V and Inconel 718), where the cutting temperature increases rapidly and heavy adhesion occurs. In the experiment, turning and interrupted cutting were performed. In cutting of Ti-6Al-4V, the tool coated with a film of high boron concentration showed long tool life. In turning of Inconel 718, the tool coated with a film of a boron concentration of 15% showed the longest tool life-about four times longer than that of a tool coated with TiAlN.

Thinning of silicon wafers and reduction of kerf loss can minimize the manufacturing costs of semiconductor products. Currently, the volume of kerf loss is about the same as the volume of the wafer itself. Therefore, we study slicing techniques for silicon wafers that result in reduced kerf loss by using an ultrafine wire tool and fine abrasive grains. As a first step, grooving characteristics using an ultrafine tungsten wire tool and fine abrasive grains are investigated in this paper. A borosilicate glass is used as the work material. The main conclusions are as follows: Precision machining using ultrafine wire tool is possible and the kerf loss decreases because the groove width decreases. However, a larger diameter of the wire tool results in a deeper groove. A faster relative speed produces a shorter wire tool lifetime, but a deeper groove. To supply enough abrasive grains to the machined portion, it is necessary to use abrasive grains having a suitable particle size for the specific diameter of the ultrafine wire tool.

Slicing with work rotating type multi-wire saw will be considered in the near future as one of the effective methods for slicing hard and brittle materials such as silicon ingots. In order to decrease the supplied value of slurry in slicing hard and brittle materials, the work rotating type multi-wire sawing characteristics using high viscosity slurry are investigated experimentally. This type of slurry is inferior to the conventional slurry in removing chips from the slicing regions due to its poor permeability. The work rotating type multi-wire saw is applied to improve the supply on slicing regions. Unlike the slicing process by a conventional multi-wire saw, the wire maintains intermittent contact with the workpiece during the process, thereby making it easy for slicing debris to escape from the slicing regions. Borosilicate glass, which is cylindrical (φ 10), is used as work material. The main results obtained are as follows. The work rotating type multi-wire saw makes it possible to use the slurry of high viscosity in slicing of hard and brittle materials. Using high viscosity slurry in work rotating type multiwire saw makes it possible to decrease the supplied volume of slurry. The use of high viscosity slurry in work rotating type multi-wire saw improves the surface roughness of the sliced surface.

The machining damage done to the surface of ceramics by superfinishing is investigated experimentally. The bending strength of the ceramics finished is measured. The influence of the grain size and the finishing conditions on the bending strength is investigated. The work materials used are alumina Al2O3 sintered under atmospheric pressure and Mn-Zn ferrite sintered under HIP. The results are as follows. Superfinishing is very effective in removing the machining damage and improving the bending strength of the ground ceramic. Using a finer grain under lower stone pressure makes it possible to remove the work material as chips by plastic deformation and decrease the machining damage on the surface. It is estimated that the bending strength is influenced by the median cracks which are formed under the bottom of the groove by active grains. It is possible to increase the bending strength, using the stone under the condition of glazing.

In order to simplify the treatment of coolant in production systems, the superfinishing characteristics under the condition of water-solution type coolant are investigated experimentally. This type of coolant is inferior to an oil type coolant in removing chips from the stone because of its poor permeability. Electrolytic in-process dressing is applied to promote the self-dressing of diamond stone. As work materials, alumina which is sintered under atmospheric pressure and soft steel (equivalent to 0.15% carbon steel) are used. The results obtained are as follows. Electrolytic in-process dressing makes it possible to use the coolant of water-solution in superfinishing. The suitable conditions in electrolytic in-process dressing depend on the machinability of work materials. The soft steel whose chips are easy to make a loading on the working surface of stone needs the stronger dressing. A concentration of some percent is sufficient for a coolant to maintain its essential properties. The electrolytic in-process dressing is more effective for harder or finer stone, because it can control the cutting ability of the stone.

A new method of the superfinishing is investigated, in which the cutting ability of diamond stone is controlled by changing the strength of electrolytic in-process dressing. Water-solution type coolant and metal bonded stone are used to employ the electrolytic dressing. As work materials, a carbon steel S 45 C, a bearing steel SUJ 2 and alumina are used. The results obtained are as follows. It is effective for control of electrolytic dressing to change the operating time of electrolysis or the ratio of on-time to off-time in electric pulse. As the dressing becomes stronger, the cutting ability of stone improves and the metal removal rate becomes larger. As the dressing becomes weaker, the cutting ability of stone is lost and then the surface roughness of workpiece becomes smaller. The cutting ability of stone which has been lost in finishing operation can be regenerated again applying the strong electrolysis. This in-process dressing method makes it possible to obtain the intended finishing performances of metal removal rate and surface roughness, and to finish several work materials of different machinability using a same kind of stone.