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金沢大学理工研究域 機械工学系, 本研究では，クロム-モリブデン鋼とパーライト可鍛鋳鉄を対象として，ミストホール付きMQL専用バイトを用いたMQL旋削加工を行っている．MQL専用バイトはシャンク内にインサート近傍まで２つのオイル穴を有しており，オイルミストをすくい面および逃げ面の両方にピンポイントで供給することができる．クロム-モリブデン鋼においては工具すくい面にオイルミストを供給することで，100.m/min以下の低切削速度域で切削抵抗が大きく減少する．一方，工具逃げ面側からのオイルミストの供給は，30~300.m/minの広範囲の切削速度域で仕上げ面粗さの改善に寄与する．工具逃げ面温度については，乾式に比べ逃げ面ノズルからのオイルミスト供給でおよそ70ºC，すくい面ノズルからの供給でおよそ30ºC低下し，同時に供給することで両者の冷却効果を加算した100ºC程度温度冷却される．

The oil mist or kitchen exhaust diffuses into various parts of a house as well as the kitchen itself, the mist is responsible for the formation of oil stains on the surface of respective rooms, i.e., the surface of the ceiling and walls. With an open type kitchen, a range of the oil mist diffusion tends to expand, and the authors believe that the condition of the living-cum-dining room might be deteriorated as a result. Twelve residences in Niigata City were chosen to clarify the extent of the oil stain accumulation. In the first place, four to five Teflon sample plates (20×40 mm) were installed at four corners of the ceiling of the kitchen and living-cum-dining room. Three months after the installation, a process of removing the plates that had been installed in the corners of the ceiling started: the plates were removed one at a time in an interval of one month in order to measure the color difference (△E^*ab reading) by chroma meter. Furthermore, in some of the houses chosen, the sample plates were installed in the other rooms as well. It was confirmed that △E^*ab reading in all residences had increased in accordance with the passage of time. It was noted that the oil stain had a high tendency to accumulate at points where the ventilation stayed, and that the sagarikabe wall was effective for preventing the diffusion of the oil mist. It is also to be noted that the kitchen layout as well as the cooking performance at respective homes had much to do with the accumulation as well as the condition of the oil stains.

In this paper, the MQL turning of two types of ferrous metals: chromium-molybdenum steel SCM440H and pearlite malleable cast iron FCMP: is dealt with. The appropriate generating system of oil mist is constructed and the specified turning tool with oil hole is used. In order to verify the cooling effect of MQL, the tool temperature at the flank face is measured using a newly assembled fiber-coupled two-color pyrometer. In this new technique, a sensing fiber is inserted into a small hole that extends to the outer surface of the tubelike workpiece and it rotates with the workpiece. The thermal radiation accepted by a sensing fiber is noncontactly transmitted to the other fixed fiber and led to the two-color detectors. As for cutting force in turning of SCM440H, MQL is more effective in low cutting speed below 100 m/min. The tool temperature in MQL turning is approximately 100°C lower than that in dry turning over the wide range of 30∼300 m/min. In the case of FCMP, the tool temperature in dry turning at a cutting speed of 600 m/min reaches as much as about 1040°C, but it drops 920°C in MQL turning.

The diffusion of the oil mist while cooking affects the entire room, leaving stains on the ceiling and walls. The validity of measuring the color difference of stains was examined by installing teflon plates in the kitchen and the adjacent space with a view to assessing the oil diffusion. Four houses were designated for the examination. In each house, four teflon plates (20×40mm) were installed on the ceiling and walls of the kitchen and the space adjacent to it. Then, one plate was removed at an interval of one month to measure the color difference (ΔE^* ab reading) with chroma meter. ΔE^* ab reading began to increase from the third month and the color difference was evident at different spots. For example, the reading on the ceiling at the corner of the space adjacent to the kitchen was higher than that on the ceiling of the kitchen itself.