A new cutting tool was developed from ultra-fine-grain (<100 nm), binderless cubic boron nitride (cBN) material fabricated by transforming hexagonal boron nitride to cBN by means of sintering under an ultra-high pressure of 10 GPa at 1800 ºC. The cutting edges of the newly developed cBN tool can be made as sharp as those of single-crystal diamond tools. In this experiment, cBN and single crystal diamond tools of the same shape were compared by precision cutting tests using stainless steel specimens and steel specimens coated with an electroless Ni-P layer. The surface roughness (R z ) of specimen surfaces cut with the cBN tool by means of planing was approximately 100 nm for both the Ni-P-coated steel and stainless steel specimens. Though similar R z values were obtained for Ni-P layers cut by the cBN and diamond tools, an R z value exceeding 2000 nm was obtained for stainless steel cut by the diamond tool. High-precision surfaces with R z values of 50 -100 nm were obtained for stainless steel specimens cut with the cBN tool under high-speed milling (942 m/min) conditions. These results indicate that the newly developed cBN tool is useful for the ultra-precision or precision cutting of ferrous materials.
Abstract:The elemental composition and microscopic-level shape of inclusions inside industrial materials are considered important factors in fracture analytical studies. In this work, a three-dimensional~3D! microscopic elemental analysis system based on a serial sectioning technique was developed to observe the internal structure of such materials. This 3D elemental mapping system included an X-ray fluorescence analyzer and a highprecision milling machine. Control signals for the X-ray observation process were automatically sent from a data I/O system synchronized with the precision positioning on the milling machine. Composite specimens were used to confirm the resolution and the accuracy of 3D models generated from this system. Each of the two specimens was composed of three metal wires of 0.5 mm diameter braided into a single twisted wire that was placed inside a metal pipe; the pipe was then filled with either epoxy resin or Sn. The milling machine was used to create a mirror-finish cross-sectional surface on these specimens, and elemental analyses were performed. The twisted wire structure was clearly observed in the resulting 3D models. This system enables automated investigation of the 3D internal structure of materials as well as the identification of their elemental components.
Abstract. Surgical navigation for abdominal organs has difficulties, such as dynamic deformation, compared with other organs (i.e. brain, bone). Organ deformations prevent surgical navigators from performing accurate navigation based on preoperative information. We are studying on a method for deforming preoperative organ models so that the models are matched to intraoperative shapes. The method is based on the ICP (iterative closest point) algorithm and modal representation of shape deformation. In this paper, we describe preliminary experiments for rigid parameter estimation in the entire registration process, by using range data and surface model reconstructed from X-ray CT of a liver phantom.
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