[in Japanese]

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[in Japanese]

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The paper represents the shell geometric modelling for sheet metal products and shell structured products. A modelling method for the shell geometry objects adopts the Euler topology based model firstly developed by Baumgart for the solid geometric modelling. The Euler characteristic equation for the shell geometric modelling is derived in the general form as ν-e+f-a=s-h and the Euler operations are introduced by the. use of the derived equation. The newly developed Euler equation makes it possible to deal with holes and flaps within faces, which are not homeomorphic to the 2-dimensional simplex. Verification to the derived equation is discussed from the view point of the graph theory as well. Some examples show that the new equation is applicable to a variety of shell geometries with the holes and flaps. Furthermore, a surface orientability is discussed and a recognition algorithm is offered to get rid of unoriented surface geometries. This algorithm also makes a difference between inner edges and boundary edges in the shell.

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Recently automatic input of drawing informations into a computer has been a matter of great interest in the field of CAD/CAM. This paper deals with the system that realize input of drawing informations into computer automatically from a handwritten drawing and producing NC part program for an NC lathe successively. A drawing of a turning part without any boring operation and written according to JIS drafting rule is read optically. Picture data is processed in the computer and informations of patterns and dimensions are extracted to produce NC part program. This system has the possibility to be extended for the applications to parts which are manufactured by other kinds of operation besides turning.

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This paper comprehensively presents a method to recognize 3-dimensional objects within one second. Slit light data from a range finder and gray scale image from a TV-camera are used jointly. First, by subtracting the background image from the background with slit light image, an image containing only, the slit light is obtained. ±0.3 pixel accuracy in fixing the slit line position in the image is obtained by using a statistical method. The extracting time is 200 ms. Then syntax analysis for labeling objects and extraction of contour lines from the gray scale image line is reported. The threshold for processing the gray scale image is decided automatically by making use of the slit light. At last, the method to reconstruct 3-dimensional data from 2-dimensional data is presented. The coefficients between picture coordinates (I, J) and a spacial coordinates (x, y, z) are calculated using a least squares method. Totally, 400 ms for all execution time and ±0.2 mm in accuracy, are obtained.

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A new method for the numerical calculation of the contact stress of machine elements by finite element method is proposed. In the present method, for the size of the contact region given in advance, the contact stress distribution in the region is obtained. In the process, finite element method is used to calculate the compliance of elastic bodies at each node in the contact region. Thus, usual finite element programs can be used with no special change of the programs. Some contact problems of elastic and rigid bodies, and elastic bodies are analysed. Numerical results are obtained with good accuracy, comparing with the results by Hertz theory.

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Noncontact wafer identification suitable for a highly clean LSI fabrication process is described. Noncontact identification is established using a video image processing technique to detect an orientation fiat edge of a wafer and read out a mark scribed parallel to the flat edge. This mark, composed of diffraction grating-like bar code modules, and circular strobo flash lamp illumination are both adopted to obtain a good contrast mark image independent of wafer position and orientation. The image processing presented in this paper demonstrates that the flat edge can effectively be detected by a circular mask search and that the mark brightness change problem due to the different wafer surface condition can be resolved by the floating threshold method. Identification experiments are successfully carried out for wafers of different surface conditions which are either bare or coated with SiO₂ film and/or a photoresist.

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This paper deals with a simple design method for optimizing the support compliance for square parts insertion. A theoretical analysis of the quasi-static inserting process during chamfer crossing is presented under the assumption that no tilting error occurs. The validity of the analysis is examined experimentally. Moreover, the effects of the lateral-to-torsional compliance ratio on the maximum insertion force are revealed by the numerical simulation of the inserting process. Consequently, it is found that an optimum compliance ratio exists where the maximum insertion force is minimized, and that considering the increase rate of the insertion force under each contact condition, a simple method is obtained for determining the desirable compliance ratio for lowering the maximum insertion force. These results are applicable to the optimum design of compliant supports used in automatic square parts assembly.

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Integrating CAD/CAM processes is essential for higher productivity and better quality of products. The basis of the integration is to construct a product modeling system where information about products and their production are represented and managed throughout design and manufacturing activities. In this paper, treatment of dimensions is discussed as one of the major problems of the product model construction, since dimensions are significant for product information description. A new dimension description framework is introduced for solid models, based on the idea that dimensions impose geometric constraints on elements of solid models. This dimension description is formalized in the form of first order logic and is utilized for parametric design of solid models. In this design process, the shapes of solid models are parametrically modified by changing dimension values. The basic algorithm of this parametric design consists of 2 major steps ; (1) modifying all surface equations of the solid according to the modified dimensions, (2) calculating new curve equations and points of the solid by intersecting those modified surfaces. Details of this algorithm and its illustrative examples are shown.

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The relationship is derived between the second moment of the power-spectrum for random surfaces of plane shape and patterns of laser light scattered from them, where the autocorrelation functions of their profiles are assumed to be expressed by the summation of the Gaussian-shape functions. This result is extended to the case of laser light scattered from rough surfaces of arbitrary shapes. The expansion of the scattered light from a curved and rough surface is concluded to be expressed by a simple function of the second moment of power-spectrum, a radius of the laser beam and a radius of curvature of the surface. The theoretical conclusion is supported by the experiments using test samples of ground cylinders.

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It is important in the strength design to estimate the fatigue strength under these situations because most of the bolted connections used popularly is clamped and loaded eccentrically. In this study, five types of the clamped parts which are the same in the configurations but have different eccentric clamping position are used and keeping the clamping force constant, the fatigue limits to these bolted connections have been tested. On the condition that the bolted connection is separated partially or wholly, the theoretical expression of the fatigue limit on the bolted connections from the fatigue limit diagram of the bolt is developed, considering the loss of initial clamping force because of the clamping in plastic region, and the theoretical values are compared with the experimental values. The obtained results are as follows : (1) The theoretical expression of the fatigue limit of bolted connections under the conditions of the eccentric clamping and eccentric loading can be derived from the fatigue limit diagram of bolt. (2) The theoretical values of the fatigue limit for five kinds of the bolted connections almost correspond with the experimental values. (3) In the case of the clamped part of the same configuration, the farther the clamping position is away from the loading position, the more the fatigue limit decreases.

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This paper describes a marked reasonable technique extracting a two-valued picture from a scanning moiré picture in case of computer-input of moiré patterns. Recently, a variety of thresholding techniques are used for computer-input of moiré patterns. However, there are some troubles on post-treatment, since they are nothing but unreasonable for moiré pictures. In this study, by using basic properties of moiré patterns, a philosophy of moiré picture processing is suggested. By means of this technique, a thresholding of scanning moiré picture can be reasonably and quickly performed. Therefore, a two-valued picture for computer-input can be easily extracted. Results show that this method is useful in the 3-dimension auto-measurement with moiré topography.

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When any tooth profile of gears is given by the value of coordinates and gradients about some points on the tooth profile, a method for calculating the profile of the cutting edge of hobs generating the given profile of gears is proposed. In this method, one point on the tooth profile of gears is transferred to a certain point on the rack tooth profile and moreover the point is transferred to a certain point on the hob tooth profile. Like this, one-to-one strict correspondence between points is considered. Approximate calculations or iterative ones are not used in this method. Therefore, the hob tooth profile with sufficient accuracy, can be obtained in short time by any micro-computer. The checking procedure of the interference between the work tooth profile and the hob tooth one is also given.

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Many methods have been proposed for in-process sensing of the flank wear and the breakage of cutting tools, however, there are a few methods which have been applied to the adaptive control of machine tools or the unmanned machine operations. The aim of the present paper is to find a method which detects the flank wear by the cutting force ratios under feed control. The achievements in this study are as follows : (1) An empirical formula which is expressed as a function of the depth of cut and the corner flank wear land is proposed. (2) The wear sensing criterion based on the empirical formula is applied to turning, in which the feed is controlled by the cutting load to maximize the productivity within constrained conditions. (3) It is verified that the proposed empirical formula is available to detect and control the corner flank wear under feed control in the same way as under constant cutting conditions.

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It was made clear through this study, effects of wheel peripheral speed, wheel diameter and work diameter on grinding performance of CBN grinding wheels. Following results were obtained : (1) Wheel life is longer at the rate of raising the increasing of the wheel peripheral speed to the 1.32th power. The optimum work peripheral speed must be faster at the rate of raising the increasing of the wheel peripheral speed to the 1.13th power. (2) At the optimum grinding condition, the grinding performance is constant not depending on the wheel diameter or the work diameter. It is obtained that it is important to select the grinding conditions shown in this paper for wheel peripheral speed, wheel diameter, and work diameter when CBN grinding wheel is used in FMS or Grinding Center.

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This paper describes a newly developed plane magnetic-abrasive finishing apparatus and its finishing performance using magnetic-abrasives made of both iron and alumina particles in magnetic field. The process principle and the construction of the finishing apparatus are explained in detail respectively for applicating magnetic-abrasive finishing process to plane workpiece, and the calculating method is also described on magnetic circuit needed to design the finishing apparatus. The finishing performance obtained by the experiments shows that the prefinished surface roughness value of 1.3 μmR_max (material ; SUS 304 stainless steel, thickness ; 1.2 mm, finished area ; 44 cm²) is improved to 0.15 μmR_max in two minutes finishing time.

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