Kenichi Iwatsuka

Tool Wear Characteristics for Near-Dry Cutting of Inconel 718

In recent years, high-combustion-efficiency jet engines are required in the aircraft industry. Inconel 718, which has excellent mechanical and chemical characteristics. However, Inconel 718 is difficult to cut material because of its low-thermal conductivity. Consequently, Wet cutting is ordinarily adopted to reduce the heat on cutting heat edge in Inconel 718 cutting. Wet cutting which uses large amount of cutting fluid requires much cost and energy on maintenance or disposal of cutting fluid, and this method is environmentally-unfriendly. From the view point of reducing cost and environmental load, we examined the method of Near-Dry cutting which uses very small amount of cutting fluid for the cylindrical cutting of Inconel 718. However, this method has some problems, such as tool wear and cutting stock removal rate. In this report, we experimentally examined the relationship between cutting speed, tool materials, and tool fracture of near-dry cutting of Inconel 718. We compared these results with those of wet cutting, a method which is more expensive, requires significantly greater amounts of energy, and is less environment-friendly. The results indicate that when cutting speed is 100 m/min, tool fracture occurs at a cutting distance of 200 m. When cutting speed is 50 m/min, tool fracture does not occur and near-dry cutting distances can continue beyond 600 m. Moreover, tool wear could be reduced when S05 tool material, which has high bending strength, was used.

Study on Ultrasonic Cavitation-Assisted Micro-Endmill Milling

Micro-channel chips used in micro total analysis systems are attracting attention in medicine. In generally the photolithography technology used in semiconductor manufacturing is used to manufacture micro-channel chip Si-dies. However, this technology requires many processes, such as mask fabrication and the application of photoresist to a substrate as well as expensive clean room facilities. A micro-channel chip has a micro-groove 30–100 μm wide. This study examined how to form a fine groove by cutting with a micro-endmill, with the aim of shortening the window time and reducing the cost. This steel die requires high accuracy, for example, a burr area ratio of not more than 5% of the groove bottom area, a surface roughness of the side and bottom faces of less than 1μmRz, and a change in the sectional area of less than 1%. So, this study examines micro-endmill’s cutting conditions, for example cutting speed, feed per tooth, and axial depth of cut. In MQL (minimum quantity of lubricant) cutting, the early fracture occurs when cutting was began. The cause has bad removing of the chips in MQL cutting, it is considered that the chips of hardened work have been re-cut as the result. Therefore, this study applied ultrasonic cavitation to milling, in order to solve this subject. This report experimentally examined the cutting performance of ultrasonic cavitation-assisted milling. We obtained the following results. In cutting distance of 20 m, the burr of MQL cutting is generated more than 5%, on the other hand, the burr of ultrasonic cavitation-assisted milling is less than that. In ultrasonic cavitation-assisted milling, a tool wear and fracture can be decreased by improvement of removing chips and lubrication.

Influence of Machining Characteristics on Ultra-Precision Cutting of Aluminum Alloys

In this study, we investigated ultra-precision cutting technology used in the production of Al alloy polygon mirrors. We compared characteristics of three Al alloys (Al–Mg, Al–Cu, and Al–Si) when cut with a straight diamond tool. When cutting Al alloys, it is desirable to reduce geometric surface roughness and remove tear-out marks and scratch marks. We investigated the relationship between end cutting edge length, surface roughness, and cutting force of straight diamond tools. In addition, we compared surface roughness and cutting force produced by double facet tools with microfacets at the end cutting edge and on the rake-face side. It was found that both tools have similar cutting characteristics and that Al–Mg has the best optical quality, followed by Al–Cu and Al–Si.

Fine groove milling of microchannel dies Relationship between tool run-out and groove accuracy

Recently, the use of microchannel chips in micro total analysis systems, which can provide savings of natural resources and energy, has attracted attention in the medical field. Generally, the photolithography technology employed in semiconductor manufacturing is used to manufacture microchannel chip dies. However, it involves several processes such as mask fabrication and the application of a photoresist to a substrate, as well as expensive clean room facilities. In light of this, methods to form a fine groove using a micro-endmill are examined. The effects of the tool run-out of a few micrometers on micro-endmilling, as well as on the groove accuracy of a microgroove, are examined.

Grinding of microgrooves in cemented carbide dies Influence of grinding conditions on groove shape accuracy

Recently, owing to the savings of resource and energy, the use of microchannel chips in micro total analysis systems has attracted attention in the medical field. Generally, microchannel chips are composed of plastic or glass. Glass is stronger than plastic in terms of heat and chemical erosion resistance. However, currently, dies for manufacturing glass microchannel chips are not viable because they are composed of cemented carbide. Therefore, in this study, for manufacturing cemented carbide microchannel chip dies, methods for forming a fine groove by grinding using an electrodeposited diamond wheel are examined. The relationships among grinding condition, surface roughness of the groove bottom face, and deviations in groove shape and depth are clarified by the results.

Study on Fine Groove Milling of Microchannel Dies – Tool Bending in Milling of Micro-Grooves

Microchannel chips for use in micro total analysis systems have recently been attracting attention in the medical field. The photolithography technology employed in semiconductor manufacturing is generally used to manufacture microchannel chip dies. However, this technology involves several processes such as mask fabrication and application of a photoresist to a substrate as well as expensive clean room facilities. In light of this, this study examines ways to form a fine groove by using a micro-end mill. The relationship between the cutting conditions and the bending of a micro-end mill were experimentally examined. In addition, we calculated the tilt angle of the tool used in micro-groove milling on the basis of specific cutting force and tool stiffness.

Advanced Diamond Charging Process Using Vibrating Charging Ring in Fixed Abrasive Lapping

In the lapping of magnetic heads and other electronic components composed of multiple materials, differences in the processing characteristics of the composite materials produce residual steps on the surface at composite interfaces. Residual step heights have been reduced to as small as a few nanometers. We investigated using fine abrasives in fixed abrasive lapping to further reduce the residual step height. This requires highly secure, high-density embedding of abrasives on the lapping plate. To this end, we evaluated the surface morphology of the lapping plate after diamond abrasive charging and investigated the embedding mechanism of diamond abrasive charging. The results obtained will assist in determining the direction of future research and development. A prototype charging ring that uses a vibrating system was developed to increase the density of abrasives embedded on the lapping plate. This diamond charging using a vibrating system was able to increase the embedded abrasive density and improve the flatness of the charging plate.

Mechanical Characterization of Lapping Plate Materials in Diamond Charging Process

In the lapping of magnetic heads and other electronic components composed of multiple materials, differences in the processing characteristics of the composite materials result in “residual steps” forming on the surface at composite interfaces. Residual step heights have been reduced to as little as a few nanometers. We investigated using fine abrasives in fixed abrasive lapping for this purpose, which requires highly secure, high-density embedding of the abrasives on the lapping plate. To this end, we modeled the abrasive embedding process and investigated the relationship between the mechanical properties of the lapping plate and the retention of the abrasive, to determine the direction of further research and development. The results of this investigation revealed a correlation between the work hardening in the plate and the resulting abrasive density and cutting edge height. The investigation also showed that it is possible to suppress the reduction in lapping rate that occurs during use by increasing the work hardening coefficient of the plate.