As reported before, the removal rate of the insulating ZrO_2 ceramics were improved using the Zn coated wire tool electrode that had the several rugged types cracks. However, it was the difficult problem to evaluate them qualitatively because of the their in homogeneity. In this report, to investigate the effects of rugged surface of the wire tool electrode on the electrical discharged properties, the new wet blast machine was manufactured. The abrasive grain shape and blast pressure were selected as the experimental factors. The sintered insulated Si3N4 ceramics was used for the workpiece. The following results were obtained: When the blast pressure increased, the rugged depth also expanded lineally and the removal rate increased. The detected discharge waveforms patterns changed with the variation of the blast pressure.

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The accuracy of wire EDM process is affected by the wire orientation. For high accuracy of wire EDM process, the wire orientation should be controlled accurately. However, the wire orientation does not always coincide with the ideal orientation, because of the process reaction force, deformation of the wire due to stiffness, and clearance between the wire guide and wire. For the purpose of improving the accuracy in taper cutting, the wire orientation should be compensated based on measurement of the wire orientation. Thus, an in-process measurement was conducted using two optical displacement sensors newly developed. From the results, it was found that the in-process measurement is possible and the machined surface shape can be estimated from orientation measured.

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Width of kerf depends on spot diameter of laser beam, power density and cutting speed. Especially the strongest relation exists between kerf width and spot diameter. Power density comes from spot diameter is considered as most important factor in laser materials processing. In fact, Cutting speed of processing is increasing when power density is high. In order to focus with conventional optical system in industrial high power laser, single lens is used and beam also has high order mode factor. Keeping the certain distance of focal length, convergent limit of laser spot is obtained by created new optical system that reduced the aberration and smallest diffraction limit. Using this optical system, fundamental material processing was done to confirm optimum beam spot for cutting application.

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When a permeable nanosecond pulse laser which is focused into the inside of a silicon wafer is scanned in the horizontal direction, a belt-shaped high dislocation density layer is formed at an arbitrary depth in the wafer. Applying tensile stress perpendicularly to this belt-shaped modified layer, silicon wafer can be separated easily into individual chip without creating any damage to the wafer surface comparing with the conventional blade dicing method, because the cracks that spread from the modified layer up and down progress to the surface. This technology is called "stealth dicing" (SD), and attracts attentions as a novel dicing technology in semiconductor industries. In order to clarify the formation mechanism of modified layer, we paid attention to an experimental result that the absorption coefficient varies with temperature. We analyzed a coupling problem composed of focused laser propagation in a silicon single crystal, laser absorption, temperature rise, and heat conduction. Simple thermal stress analysis was also conducted based on those results. As a result, formation mechanism of the modified layer could be explained clearly. Temperature dependence of absorption coefficient is the most important factor of the modified layer formation.

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In laser bending, heating along a curved scanning path is required for complex 3D forming process. The present experiments deal with the deformation behavior of the process and the effect of curves on the bending angle. The results show that curved irradiation laser bending redaus the bending angle compared with the linear laser bending.

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Newly laser imprint method was proposed in this paper. It is possible to imprint rapidly at a limited part of glass surface without heating whole of glass by the method. In this process, laser beam going through a mold is irradiated on glass. Then glass is melted and filled into a mold. A pulsed YAG laser (λ=1064nm) was used in the experiment. Phosphoric acid glass which had low melting point and high absorption of IR was used as a workpiece. As the result, it succeeded in transcribing a plane and unevenness of the sub-micron size onto phosphoric acid glass.

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Laser correcting of a sheet metal is the plastic process caused by the thermal stresses which is produced in the sheet by laser irradiation. In this paper, a circular distortion on a sheet metal is corrected by laser irradiation. A circular dsitortion is made by pressing steel ball against a sheet metal. Radial laser paths is used for laser correcting a distorted sheet metal. The center of radial laser paths is the highest point of distortion on a sheet metal. In each paths, CO_2 laser beam of 100W is irradiated on the surface of the distorted sheet at a speed of 2mm/s. After laser correcting, a distortion with a height of 200μm becomes flat without melting irradiated surface.

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Recently, Hard Gear Finishing for reduction of gear noise and stabilization of gear accuracy has been increasing. We developed a gear generating grinding worm, combined with an accurate production technology of steel body and a uniform cBN electro deposition technology. In this report we introduce the features of the cBN grinding worm and gear grinding examples.

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Ultra precision machining of steels with geometrically defined single crystal diamond cutting tools is handicapped by excessive tool wear. In general, it is said that the wear of diamond tool is caused by chemically reactive wear, such as diffusion into steel, oxidation, graphitization and carbide-formation of diamond under high temperature and high pressure conditions. This paper presents a new approach to suppress the tool wear of single crystal diamond in cutting of steels. In order to suppress such chemical reactions, the contact time in a cycle between the diamond tool and the steel workpiece was controlled by employing the intermittent cutting method. Series of intermittent cutting experiments were carried out to examine the effect of the chip thickness in a cycle and the shape of the diamond tool (rake angle and clearance angle) upon the wear of diamond tool. The experimental results show that the tool wear is reduced by reducing the chip thickness in a cycle and increasing the clearance angle of the diamond tool.

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In tapping, chips jammed in the tap's flute or twined around the tap cause tool breakage very frequently. In previous study, to resolve this problem, a chip-breaking tool has been developed. The chip-breaking tool forms V-grooves axially on the inner wall of hole before tapping. In tapping, the axial V-grooves make the cutting discontinuous and short chips are produced. It can obtain a good performance in tapping. However, the axial V-grooves remain in the internal thread and the thread ridge becomes discontinuous. Therefore it may reduce the strength of tapped thread. In this study, strength of threads tapped by above-mentioned method was investigated by tensile test and compared with strength of threads tapped by conventional method where the chip-breaking tool was not used. As a result, there found little difference between the tensile strengths of both type of tapped thread. That was demonstrated by considering about the various fracture mode observed in the experiments.

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The first characteristic of the Major Dream Holder is the dampening mechanism to absorb the micro vibration. Thus, the cutting condition can be increased and the cutter life will be expanded. The second characteristic is the front chucking mechanism of the taper collet chuck with the TiN bearing nut. When tightening the nut, between the nut and the upper surface of the TiN bearing is sliding and between the lower surface of the TiN bearing and the collet is not sliding, therefore the TiN bearing is pushing the collet straight down to the taper hole of the chuck. Thus, the run-out accuracy and the gripping torque are improved substantially.

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With the widespread use of high-speed milling, shrink-fit tool holders have became the mainstream among the tool holders. They have increasingly been recognized as providing an indispensable holding method in the entire range of cutting from mold cutting to micro or ultra-precise cutting. The materials used for those shrink-fit tool holders are diverse, but all of them are required to have durability against heating involved in shrink fit. This article examines and reports the diffierences in characteristics between the materials exclusively for shrink-fit tool holders and the general materials from the aspect of accuracy, which is an important element for tool holders.

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The MQL (Minimum Quantity Lubrication) machining method was a very famous method for machining processes several years ago, but many companies gave up to adapt this innovative way for two reasons. It required special machine tools. In addition, problems were caused in aluminum drilling due to a material build-up on the cutting edges. Our "MQL tooling system" has many advantages for MQL aluminum deep hole drilling, with 6 oil-jet spray nozzles and MQL inducers for existing machining centers. We would like to introduce MQL inducers and MQL collets based on semi-dry cutting examples.

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Sales of multi-task machine have increased rapidly in recent year. However, the interface between the machine spindle and the tool holder does not exist as a common standard. Therefore, the committee (Interface Committee for Turning Mills, ICTM) was organized to make a new opened standard. As a result of this activity, ICTM-HSK standard based on ISO-HSK was established in October 2002. This standard has been proposed to ISO as the HSK-T type in 2005. The condition of HSK-T in ISO will be reported here.

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High accuracy, high productivity, high efficiency and low cost are necessities for productive machining. Three types of Micron Chucks are fulfilling such performance requirements. High accuracy and high rigidity are provided by the ball screw and double-face-contact thrust ring mechanism.

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