[in Japanese]

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This paper is intended as a development of a new quality design method of improving quality of products. Conventional quality design methods are for single characteristic and aim at minimizing quality costs. Optimal levels of design factors cannot be determined if there are 110 signal factors. They can be outside feasible regions even if there are signal factors. The proposed method minimizing manufacturing costs is applicable to products with multi objective characteristics and with or without signal factors. A generalized loss function and its statistical expectation for multi objective characteristics are introduced. Classified objective functions are presented considering properties of quality design problems. A minimization problem of the objective function is formulated as a nonlinear programming with a response surface methodology and a central composite design. The effectiveness of the proposed quality design method is shown by numerical examples.

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An asymmetrical groove on a sculptured surface is difficult to produce without sophisticated CAD/CAM systems. Thus, it is intended to develop a software system to create asymmetrical groove on sculptured surfaces by means of 5-axis control machining center. The software system consists of two subsystems : one defines a groove path and a groove shape with an arbitrary cross section, the other pastes the groove path together on the workpiece surface and to generate CL data corresponding to the groove shape. The generated CL data are converted to NC data of 5-axis control machining center by the postprocessor. From the experimental result, it is found that the system developed has potential of producing workpieces with an asymmetrical groove on it.

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In the CAD system, shape design or shape modeling is one of the bottle-necks because the shape design is a trial and error process, and it depends on designer's intuition and experience. Therefore, it is expected to develop an automatic shape design system or automatic shape design methodology. This paper presents methodology to generate the suitable shape automatically by using Genetic Algorithm (GA) and Free-Form Deformation (FFD). GA is one of the optimization techniques based on concepts from population genetics. To apply GA for shape design problem, arbitrary shapes must be coded as chromosomes and genetic operators (reproduction, crossover, mutation, etc.) should be defined for those chromosomes. In this paper, the lattice of the FFD is introduced as the chromosome of the shape. As the FFD technique, the shape is deformed by moving the positions of the control points of the FFD lattice. By this technique, the chromosome is expressed as a set of a few numbers of control points (floating point representations). Using GA and FFD, the genetic shape design system which permits user to define shape evaluation functions (fitness functions) is constructed. As the fitness functions, any technique can be used, such as FEM analysis, by the form of subroutine programs.

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This paper discusses about critical exposure value for the three dimensional photofabrication. Critical exposure is one of the important parameters for photopolymers to explain solidified depth in a conventional model. In this paper, critical exposures of several photopolymers are measured and the results show that the critical exposure is not constant value contrary to the conventional model but the laser power and scan speed have non-linear relationship. The fact that critical exposure is not constant value affected by exposure condition makes it difficult to compare between experiments under conventional model. This paper also discusses the reason of this non-linear experimental results with the consideration of the extent of reaction of photopolymers.

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In this paper, superfinishing mechanism of sintered silicon nitride (SSN) is experimentally investigated, analyzing superfinishing force, surface roughness, stock removal, finished surface and so on. Work surface is ground before superfinishing. Cutting ability influenced by superfinishing conditions is quantitatively evaluated by means of obtaining the equivalent depth of removal considering an oscillation locus of stone on work surface. Main conclusions obtained in this study are as follows : (1) In superfinishing process of SSN with metal bond diamond stone, equivalent depth of removal is decided by pressure of a grain and ratio of surface contact. (2) Finished surface roughness decreases with an increase of work speed but is hardly influenced by stone pressure. (3) Equivalent depth of removal is hardly influenced by superfinishing conditions which take part in an oscillation locus of stone on work surface, and increases with an increase of stone pressure in addition to a decrease of ratio of surface contact.

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Most polishing processes still rely on skilled laborers, who polish the finished surface by hands. Contour gages are manually placed on the curved surface and used to guide workers to the final shape. The purpose of this study is to simplify a teaching method for a five axis controlled polishing robot. A device which detects the normal vectors to complicated surfaces of a workpiece is to built by differential transformers and applied to an axial asymmetric workpiece such as turbine blade. The detected normal vectors are converted into polishing data, which include geometrical data and tool path. The polished workpiece is estimated by surface roughness and shape accuracy. It is confirmed that the developed method is available to simplify the teaching method of the robot.

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This report deals with the truing characteristics of metal bond CBN wheel by feeding a multipoint diamond truer and the influence of the truing on the wheel performance. The ratio of actual to setting truing depth of cut for metal bond CBN wheel is larger than resin bond one because of the higher elastic modulus of metal bond. The truing process of metal bond CBN wheel as well as resin bond one is classified into four stages. Until the middle of the second stage, truing force is low because of little truing of bond, and the wheel performance is kept well from the view point of the ratio of the actual to setting depth of cut, grinding force and temperature, and surface roughness. From about the middle of the second stage, the trued bond increases and begins to attach the cutting edges and the bond. As a result, as truing process proceeds, the truing characteristics and the wheel performance become worse. Then, dressing is necessary for large total truing depth of cut before the truing process enters into the middle of second stage.

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High speed face milling for plain carbon steel S 45 C was carried out with ceramic tools. TiC added alumina, and zirconia toughened alumina ceramic tools were mainly used. Among the tested ceramic tools, the zirconia toughened alumina ceramic tool showed the largest crater wear resistance in high speed face milling. However, in turning the same steel, the crater wear resistance of the ceramic tool was almost the same degree as compared to the other ceramic tools. The superior wear resistance of the zirconia toughened alumina ceramic tool is based on its stability for the reaction with Fe0 at high temperature.

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Lapping films are widely applied to the finishing processes. There are, however, a few research works on the machining characteristics of lapping films. In this study, finishing of cylindrical workpiece surfaces were carried out with measuring the grinding force, stock removal and finished surface roughness in order to examine the machining mechanism. Furthermore, the elastic contact conditions of contact roll, lapping film and workpiece were estimated by using the Finite Element Method (FEM). As a result, the effects of grinding conditions on the stock removal and finished surface roughness became clear and the behavior of grains in the contact area between lapping film and workpiece were also examined.

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This paper describes the development of a new laser soldering technique for surface mount assemblies. The new technique, using a focused YAG laser beam, has a superior performance. It can be applied to TCP (Tape Carrier Package) assemblies for fine pitch leads and offers a no-bridge soldering process. In this paper, the performance of the new technique is evaluated experimentally. First, the new technique is compared with the conventional laser-soldering technique in TCP assembly. As a result, the no-bridge soldering concept is proved by the new technique. Second, to obtain more flexibility in assembly, the solder flow is investigated by a beam scanning method. The beam scanning direction is determined by the analysis of the solder flow mechanism. From these experiments, the new technique of laser soldering offers the capacity to assemble high lead counts and fine pitch ICs such as TCP.

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Various kinds of sintered carbons such as amorphous carbon, graphite, graphite and amorphous carbon etc. are utilized for various purposes. In addition, the production conditions such as graphitized temperature, mass fraction of binder, grain size etc are varied in compliance with numerous requests. However, the influences of production conditions on tool failure have not been made clear. In this paper, when turning two-phase carbons consisted of filler and binder and commercial products by cemented carbide tool K10, the influence of graphitized temperature, binder fraction, and grain size on the tool wear pattern and the tool life are examined. In the case of amorphous and graphite carbons treated at the temperature below 2000°C, no crater wear generates but the relief face severely wears. On the other hand, in the case of graphite treated at the temperature above 2500°C a typical crater wear is observed in spite of the chips of crack type but flank wear rate is slower. The tool life is mutually related to thermal conductivity of sintered carbons. The generation of crater wear depends on the fact that the chips flow up along the rake face at a high speed.

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This study deals with the mechanism of single grain grinding for brittle materials. In this paper, it is experimentally discussed how the wave form of grinding force correlates the aspect of grinding trace and the grinding mechanism. The main results are as follows; (1) The grinding traces are classified in their aspects into different three types, that is, brittle type, semi-brittle type, and ductile type. (2) The wave forms are also classified into three types which correspond to those of the traces. (3) The wave form for ductile type trace shows that the grinding mechanism is complicated, involving the large amount of elastic deformation especially in its earlier stage. (4) The nose radius of an abrasive grain and the depth of cut make a great difference in the grinding mechanism for brittle materials.

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Focused ion beam (FIB) milling is widely used for circuit repair, mask repair, and SEM sample prepair for cross-section observation. In the circuit repair application, it is important to achive a higher material selectivity of Al/SiO₂, and a higher milling rate. In order to realize both of these, focused ion beam assisted etching (FIBAE), where a chlorine containing gas is injected towards the milling site, was performed. Using Cl₂ gas only caused a significant side etch, though the etching rate of aluminum was quite high. When etching Al-Cu-Si alloy with a chlorine containing gas, a residue of Cu-Cl compound was formed. This can be decreased by heating the sample as high as 200°C. An etching selectivity (Al/SiO₂) of 100 was achived, without side-etching, by a gas mixture of SiCl₄ (95%) and Cl₂ (5%).

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The surface roughness generated by ball endmill cutting is analysed by simulating the envelope of the cutting edge of the endmill by computer. It is found that the cut remainder is formed in the vicinity of the rotational center of the endmill and is generally higher than the cusp height. The further analytical results show that the decrease of the inclination angle of the endmill, the reduction of the feed rate, flattening at the tip of the endmill, and forth and back cutting by the endmill are very effective to improve the roughness of the machined surface. These are also confirmed by the cutting experiments.

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A measuring method using a newly developed laser diode probe for dynamic and static nanodisplacement characteristics of a ceramic piezo-element was studied. A beam from the probe is exposed in focus at the surface of the sample and the reflected beam is detected. The probe, being applicable to a rather rough surface of a material, can read nano-displacements by detecting the diffraction signal of the reflected beam. A soft ceramic material, PCM-33A (Pb Mg Nb Ti Zr0), 2mm thich 31×15 mm was suspended at the center by needles and the LE and TE were measured. The piezo-electric constants obtained by this method applying DC pulses are d₃₁=410×10^-12m/V /and d₃₃=1300×10^-12m/V, which are about twice those by the conventional electric method. Large resonance peaks at 47kHz for 31mm LE and 107kHz for 15mm LE are measured showing a complete coinsidence to those obtained by the conventional electrical measurement method. This direct displacement measurement method may become usefull to measure and describe the mechanical displacement characteristics of a piezo-element as mechanical moving means.

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A real-time phase detection method is proposed for restoring three-dimensional profile from fringe patterns generated by interferometry. The method uses the digital signal processing technique, linear digital phase-locked loop (L-DPLL), for extracting the phase distribution directly from the video signal of fringe image. This method is easy to apply to practical measurement and vision systems which need a fast information processing capability, because the phase distribution can be extracted in video-rate with high accuracy and it is suited to a computer base system. The principles and the experimental results are presented.

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This paper describes that the Fraunhofer diffraction patterns, which are generated by the slit aperture formed between a reference knife edge and a polished metal cylinder, are influenced by light reflected from the cylinder surface. An incident and diffracted light is partly reflected at the cylinder surface. To analyze the influence of reflected light, the diffraction patterns are simulated by using a personal computer. The intensity distribution of diffraction pattern used the turned cylinder is measured with a phto-detector. The experimental results agree well with the simulated patterns. When the slit aperture width is reduced, the position of the zeroth diffraction light maximum intensity moves from the center of slit aperture to the direction of the knife edge on the observation plane. The Fraunhofer patterns are mainly influenced by the reflection of the diffracted light.

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A cantilever resonant microbeam (MB), laser diodes (LD), and a photodiode are fabricated on the surface of a gallium arsenide (GaAs) substrate. The microbeam length, width and thickness are 110 (50), 3.0, and 5μm and the distances from the facet of LD 1 to the side wall of the MB and LD 2 to MB are 3.0 and 30μm. The microbeam is excited photothermally by light from one laser diode (LD 2). With a photodiode, the vibration is detected as the light output variation due to the optical length difference between the microbeam and another laser diode (LD 1). Carrier-to-noise ratio is very high (45 dB) due to an extremely short (3μm) external cavity length. Such small distance allows a lensless system, which makes it easier to fabricate.

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