Papers by Author: Kazutoshi Katahira

Abstract: A compensation method was proposed for correcting wheel setting error and residual form error in nanogrinding of axisymmetric surfaces. In this method, profile data from on-machine measurement were used to obtain the setting error of grinding wheel, as well as the normal residual form error. Compensation model of single-point inclined-axis grinding was built up for generating new compensation path. Grinding test of aspheric tungsten carbide mould was conducted to evaluate performances of the compensation method. A profile error of 182 nm (peak to valley) and average surface roughness of 1.71 nm were achieved. These results indicated that the form error compensation method may significantly improve form accuracy of ground surface.

Abstract: Silicon is widely used as the most important substrate material in integrated circuit and micro electronic devices field. Electrolytic in-process dressing (ELID) grinding technique is an effective grinding process especially for machining hard and brittle material. In this paper, using super fine abrasive wheel, sets of ELID cross grinding experiment were conducted for investigating the influences of various grinding conditions including grain sizes, rotation speeds of grinding wheel, rotation speeds of workpiece and ELID conditions on surface roughness during grinding silicon wafers. Surface roughness characteristics of fine ELID cross grinding for silicon wafers were discussed. In an optimized condition, surface roughness of 2.2 nm in Ra can be achieved by using #20000 wheel.

Abstract: Ceramics has many advantages that cannot be substituted by metals, but its machining induced defects, such as crack and crater, are the obstacle of using ceramics in engineering. Thus, the further studies on the materials removal mechanism of ceramics should be done. As known, the cutting theory of metals is very successful and it is helpful to understand the material removal mechanism of ceramics. Through doing comparative experiments, the material removal mechanism of ceramics may be more deeply ascertained. Four types of material, such as ZrO2, SiC, STAVAX and SKD11, were ground by ELID (ELectrolytic In-process Dressing) method in this study. The grinding forces, roughness and topography of the ground surface were investigated. On the basis of this experiment, the difference of material removal mechanism between ceramics and steels was explained.

Abstract: The present paper describes the highly efficient and precise ELID grinding method and presents a discussion on the ELID grinding process and the grinding characteristics of several kinds of ceramic materials. The following conclusions are obtained; (1) Good ground surface roughness and accuracy are achieved using the #4000 metal-bonded grinding wheel in through-feed centerless grinding for ZrO2 optical fiber ferrules. (2) Efficient and precise grinding of spherical lens molds with cup wheels using the ELID CG-grinding process was proposed and tested in the present study. (3) The ELID grinding method can be used to fabricate machined surfaces exhibiting desirable characteristics for hard AlN ceramics. The ELID ground AlN demonstrated a surface hardness and sliding characteristics that were superior to those of the polished series. These advantages may be attributable to the diffusion phenomenon of the oxygen element produced by the ELID grinding.

Abstract: Ultraprecision optical components require ultra-fine smooth surface quality of sub-nanometer or sub-angstrom in Ra. To satisfy these requirements, ultraprecision on-machine measurement system is very important, by which the profile measurement and evaluation is conducted on the machine. The form accuracy is improved by compensating machining when the form accuracy is not enough. Ultraprecision on-machine measurement systems were developed for measurement with high-accuracy and high-efficiency. It was confirmed that the on-machine measurement with AFM was possible for surface roughness or complex form for local areas. In addition, a laser probe unit with a maximum resolution of 1nm, a measuring range of 10mm, a repeatability of 5.6nm and a maximum measurable angle of 60 degrees was developed. The possibility of the non-contact on-machine form measurement was confirmed for global form accuracy control.