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Nowadays, a free-form surface, such as molding die surface, is required to be finished by reducing the environmental burden. Therefore, a novel polishing technology is needed with a less abrasive slurry,for the reduction of which a magnetic abrasive finishing method is attracting attention. However, it is well known that a conventional magnetic polishing method is unstable and insufficient to obtain the required surface roughness. In the present paper, we discuss the reasons causing instability in conventional magnetic polishing. We systematically investigate the magnetic pressure distribution characteristics and measure the pressing force distribution of the magnetic brush during machining. Furthermore, to observethe impact of an iron particle shape on the pressing force, we used steel balls (steel-ball brush) and abrasive slurry. Moreover, we compared this brush with a brush that uses iron powder paste (employed in the conventional magnetic polishing method). Thus, we determined the possibility of the wide range control of the pressing force by changing the shape and size of the magnetic material. The setting of the approach conditions should be sufficient because it could deteriorate the shape accuracy through very high pressure.

Recently, with the fabrication of the magic-mirror having the micro C2-continuous surface, it is difficult to hand down magic-mirror fabrication technology, due to downsizing of veteran engineers or even their successors. Therefore, the purpose of this study is to digitalize the magic-mirror fabrication technology using a CNC technology. The novel method which integrate a ball end-milling and magnetic polishing on a conventional machining center is proposed, and a workpiece that was machined by this method is groove cut with straight end-mill from opposite side of its. The micro deformation is occurred by residual stress during the groove cutting. And, in order to evaluate a surface integrity of machined workpiece, a magic-mirror testing which use an artificial sunlight is carried out. In this report, as the results, we signified an optimum ball end-milling condition and a requisite polishing amount, to generate a mirror surface efficiency with the magnetic polishing.