Here, a new truing method for small-diameter CBN wheels is proposed. Truing of CBN wheels by polycrystalline diamond (PCD), which has excellent wear resistance, was performed and correlations between truing force, grinding force, and surface roughness were examined. In internal grinding of holes 4-mm in diameter with quills 3-mm in diameter, the main results obtained were as follows: (1) Truing force was less than 0.1 N and grinding force was less than 1.13N, and it did not affect the flexure of the quills. (2) Regardless of the use of abrasive grain #80/100, the average surface roughness Ra was less than 0.1 μm. (3) The accuracy of sharpness control of grain cutting edges was improved compared to conventional truing tools. In addition, it was verified experimentally that the new truing method is applicable for quills 3 – 0.6 mm in diameter.

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Chemical mechanical polishing/planarization (CMP) is an indispensable technology for fabricating high-efficiency semiconductor devices, and the CMP characteristics (removal rate, accuracy, etc.) are dependent on the various consumables represented by slurry, polishing pad, and dresser used in the CMP process. Previously, we developed a novel flexible fiber dresser that would ensure high performance and longer life of tools, and we have reported the fundamental characteristics obtained with the flexible fiber dresser compared with the diamond dresser. This paper presents the results of tool life evaluation of the flexible fiber dresser using a contact image analysis method and the results of the in situ observation of fiber behavior with a high-speed digital camera. The results indicated that the flexible fiber dresser can be used continuously over 35 hours. Furthermore, the results regarding the stability of the removal rate of silicon wafer are reported. The amount of the polishing pad cut by the dressing was markedly suppressed. Therefore, we found that the flexible fiber dresser is one of the most effective dressing methods with regard to polishing pad life and dresser life.

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The conductive rubber bonded grinding wheel is a type of finishing wheel used in the ELID grinding process. Compared to cast-iron bonded wheels and metal-resin bonded wheels, which are generally used, ELID grinding techniques applying the conductive rubber bonded grinding wheel produce good ground surfaces, but have a number of shortcomings, including poor electrolytic dressing characteristics and grinding performance. To resolve these problems, the authors attempted to develop a hybrid grinding wheel made by incorporating conductive rubber bond in the metal-resin bonded wheel. The results of grinding experiments using the developed wheel on cemented carbide confirmed that the surface roughness was the same as that obtained by the conductive rubber bonded grinding wheel. The hybrid grinding wheel showed better removal amount than the rubber bonded grinding wheel.

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In machining using abrasive grains, the heat generated at the cutting point affects deterioration of the work material, grain wear, etc. The influence of heat on the magnetic domain structure is investigated when an amorphous metal that has excellent magnetic properties is machined with abrasive grains. At a cutting speed of 51 m/min, the tool temperature is 220°C and it does not affect the properties of the amorphous metal because the temperature is below the Curie temperature of 643 K (370°C). At a cutting speed of 512 m/min, the tool temperature is 580°C and it markedly affects the magnetic domain structure of the amorphous metal because the temperature above that of crystallization (753 K, 480°C).

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