The polishing process, which is the final process in the manufacturing of precision metal molds, takes a long time and often depends on the experience and specialized skills of skilled workers. Development of a skill-less polishing technology and automation of its process, therefore, has become a requirement. One of the most promising polishing technologies is Field-assisted Fine Finishing (FFF). In FFF, an electric field or a magnetic field is applied to control the behavior of the abrasive grains in the polishing process. Here, a new polishing technology using Electro-rheological Gel (ERG) is proposed. The developed ERG is a functional material the induced shear force of which changes according to the applied electric field intensity. A thin ERG sheet on which abrasive grains are scattered is used as the polishing pad of a rotary polisher. The results showed that the polishing efficiency and attained surface roughness of STAVAX stainless steel can be improved by the ERG pad.

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The cutting performance of a small ball endmill was investigated by measuring the temperature of the cutting edge. The hardness of the workpiece, which is made by sintering metal powder with laser beam irradiation, is slightly higher at the surface layer within about 1 mm of the surface than that internally. The tool temperature at the cutting of the surface layer is higher than that at the inside. The cutting temperature increases with increasing cutting speed, but the influence of depth of cut and feed rate on the tool temperature is not so great. The diameters of ball end mills used were 0.6, 1, 2, and 6 mm, so that there were large differences in cutting speed but the tool temperatures of these end mills were not markedly different with equal revolutions. The thermal conductivity of the sintered materials was so small that its influence on tool temperature was very high.

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The purpose of this study was to develop a method for rapid on-machine measurement of surface roughness, which can rapidly obtain the surface roughness of a workpiece rotating as fast as in the grinding process and allow total surface roughness inspection of ground workpieces on machine tools. A new method involving measurement of surface roughness using the thermoelectric effect is proposed and the feasibility of rapid on-machine measurement was verified by investigation of measuring characteristics of the developed system. The surface roughness could be obtained from the electromotive force, which is generated as soon as the developed sensor using thermocouple wires makes contact with the workpiece rotating on the machine. The measurement can be done even if the workpiece is rotated at a peripheral speed about 2000 times larger than the usual trace speed of conventional surface roughness testers.

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Titanium (Type 2 in JIS) and titanium alloys (Ti-6Al-4V of Type 60 in JIS and Ti-15V-3Cr-3Sn-3Al) of different phases were finished in dry centrifugal barrel finishing, and their finishing characteristics were examined experimentally. A square plate 15 mm on a side and 4 mm in thickness was used as a workpiece. Three types of media made from nylon 6 containing abrasive grains of aluminum oxide for dry barrel finishing were used. The media charging ratio and the turret rotation speed were fixed at 50 vol% and 200 min^-1, respectively. The stock removal, surface roughness, and edge radius of the workpiece were measured after every hour of finishing. The weight loss of media was also measured at the same time. The stock removal and edge radius increased with weight loss of the media. The surface roughness was achieved according to the media used although stock removal showed a different tendency from the surface roughness.

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