A novel machining method combined with the irradiation of atmospheric pressure plasma was proposed for the finishing of difficult-to-machine materials. The irradiation of helium-based water vapor plasma efficiently oxidized the surface of single-crystal 4H-SiC (0001), and a ball-on-disc test using an alumina ceramic ball indicated that the wear rate of SiC, the surface of which was modified by irradiation with water vapor plasma, is 20-fold higher than that of the surface without plasma irradiation. Plasma-assisted polishing using CeO₂ abrasives improved the surface roughness of SiC without introducing crystallographic subsurface damage, and a scratch-free surface with a roughness of less than 0.3 nm rms was obtained.

View full abstract

This paper describes fabrication of a Makyoh magic-mirror with an extremely small concavo-convex surface, which is invisible to the naked eye. The magic-mirror was fabricated by end-milling with a machining center on the rear of the workpiece after polishing. Incident light was applied to the mirror surface and the reflected light was projected on a screen. Analysis of the image on the screen allowed completion of Makyoh magic-mirror surface generation. Moreover, the integrated Makyoh magic-mirror production process on the machining center could be achieved by application of on-machine magnetic polishing.

View full abstract

Viscoelastic polymers are used as coating materials for protecting various products from scratching. At present, repair of the coating surface for removing dust or extraneous material has been performed through several polishing processes. However, it becomes increasingly difficult to polish the surface applying only skill and experience of skilled workers because leading-edge viscoelastic polymers for coating are further scratch-resistant. Thus, based on quantitative evaluation of the relation between the polishing process and finished surface, it is necessary to develop an appropriate polishing process for leading-edge viscoelastic polymers. This study was performed to establish a method for evaluation of polished surfaces and to clarify the surface conditions with invisible scratches.

View full abstract

There is increasing demand for improved grinding accuracy and eco-friendly machining techniques. To address these social demands, we are engaged in the development and practical application of eco-friendly ELID grinding methods. Here, we propose a new ELID grinding technique using electrolyzed reduced water as the grinding solution, and discuss the results of investigations conducted on the fundamental characteristics of this technique. We carried out grinding experiments on Ti alloy on an ELID grinding system using electrolyzed reduced water with NaCl as the electrolyte saline solution, and conductive rubber bond grinding wheel. The results showed that stable mirror-surface grinding can be achieved by ELID grinding using electrolyzed reduced water. We also analyzed the workpiece surface and found that a rich layer of oxygen and reduced water components formed on the workpiece surface. The results of frictional wear tests indicated that there is little specific wear on the ground surface. These experimental results confirmed that this technique is effective for the ELID grinding system.

View full abstract