This paper discusses the resistance force, including the friction force, of guideways used in ultra-precision machine tools. Among linear rolling guideways, V-V roller guideways enable particularly high motion accuracy. In this study, the resistance force of the V-V roller guideways is measured to investigate its fluctuation behavior. The feed drive system consists of V-V roller guideways and linear motors. The resistance force is calculated from the motor current feedback of the linear motor. The experimental results confirmed that the resistance force remaining after table motion, the so-called stick friction force, is small with the V-V roller guideways. Similar to the resistance force of general linear rolling guideways, the resistance force is dependent on the Herzian contact area at the start of motion. Compared with general linear rolling guideways, the variation of the resistance force is small with V-V roller guideways.

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Soft magnetic powder cores are made by pressurizing and molding pure iron powder covered with insulation film. These materials are used as components of electromagnetic converter parts. The recent stringent requirements for performance and dimensional accuracy necessitate new processing technology to achieve the required levels of both magnetic performance and surface quality of the material. However, processing of soft magnetic powder cores can result in degradation of magnetic performance and/or chipping or plucking of the ground surface due to mechanical damage of the insulation film and/or loss of structural particles from the material due to the increase in grinding resistance. Basic studies were performed to examine various grinding conditions and wheels that could affect the quality of the material with a view toward eliminating these problems. Factors affecting the surface quality were identified, and a method to achieve greater surface quality is proposed.

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As a promising processing technique for machining hard and brittle materials, ultrasonic-assisted grinding (UAG) has been extensively employed in manufacturing industries. To determine the material removal mechanism in the UAG of SiC ceramics, the deformation features of SiC ceramics in ultrasonic-assisted scratching (UAS) tests were compared with those in conventional scratching (CS) tests using a combination of simulations and experimental observations. The results indicated that the scratching groove formed in the CS process appears straight, while it is sinusoidal in the UAS process. There are two scratching modes in the UAS process: an intermittent mode and a continuous mode. The critical depth of cut in UAS is deeper than that in CS. This study confirmed that UAG is a highly effective processing method for machining hard and brittle materials.

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Pure titanium has excellent biocompatibility. However, due to its low thermal conductivity and high chemical reactivity, the machining of pure titanium is very difficult. Therefore, pure titanium is not widely used in dental materials. Recently, we developed Ti-Ag alloys and investigated their properties. The machining properties of Ti-Ag alloys were superior to those of pure titanium. In this study, pure titanium and Ti-Ag alloys were polished using a polyurea resin-bonded mounted silicon carbide wheel. Under the same polishing conditions, the surface roughness Ra of Ti-Ag alloys was lower than that of pure titanium.

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