In the present report, attempts were made to improve the surface roughness of ground workpiece due to oscillating a wheel by numerical control (NC) function with a machining center. An adequate NC programming for oscillation grinding with a machining center is examined. As a result, it is an effective method to improve the surface roughness in creep feed grinding by a small diameter wheel. In this case, small amplitude of oscillation also makes it feasible to improve the surface roughness after grinding.
This paper deals with the experimental investigation for the ultra-precision cutting of titanium alloys. Titanium alloys, which are well-known as difficult-to-cut materials, have excellent mechanical and chemical properties. In order to produce the value-added high quality components of titanium alloys, the productive cutting technique of high dimension accuracy with high smoothness surface has been strongly required. The cutting technique, however, has not progressed well because the surface roughness and product accuracy become over the necessary finished values in the extremely short cutting length due to rapid cutting tool wear. The research aims to develop the practical ultra-precision cutting technique of titanium alloys. In the experiments, the β titanium alloy and α-β titanium alloy are face-turned by various kinds of commercial cutting bites such as a single crystal diamond bite, carbide bite, cermet bite and coated carbide bite. From the experimental results, a coated carbide bite is found available for ultra-precision cutting of titanium alloys. Over the cutting length of 2, 000m which is enough length to produce some high quality components of β titanium alloy, the cutting tool wear is little and the finished surface roughness, which includes the step over 100 nm between the crystal grain boundarys, is keep smoother than 200nm(P-V). The best finished surface roughness obtained by using TiCN coated carbide bite is about 60nm(P-V) for a-β titanium alloy.
Chips break excessively in cutting by using the tool with a narrow chip breaker. Consequently, tool edge is destroyed because cutting forces increase. For the purpose of avoiding this trouble, the optimum chip breaker dimensions are important. The chip curls even in cutting with a tool without a chip breaker, which is called natural curl. In this paper, the natural upward curl radius is measured in cutting with a special geometry tool. It is clear that the natural upward curl radius is influenced chiefly by the chip width and the chip flow angle. If the calculated curl radius is remarkably smaller than the natural curl radius, it follows that chips break excessively. That is confirmed from the curl radius and the cutting forces in cutting by using a throwaway tip with a groove type chip breaker.
In the oil-air lubrication applied to the high-speed spindle supported with a set of ball bearings, very severe sound noise is emitted so that the high-pressure air supplied through a couple of thin nozzles may collide with balls which are rolling at high speed. In this paper, the sound noise radiated from the spindle unit has been measured, changing the supplied air pressure and the number of nozzles as well as the flange shape of HSK tool holder. A special spindle supported by magnetic bearings is also used for comparison. From those experimental results, it is confirmed that the collision air causes to emit such sound noise.
Recently agile manufacturing is strongly required to meet diversified customer orders and shorten product life cycle in the globally competitive market. This study aims for realizing new assembly process planning methodology. First, a concept of simplified assembly process planning composed of three characterized planning items is newly proposed by analyzing 20 actual assembly process. Next, a new assembly process planning model based on the unique new description method of the model is newly proposed to realize fast accurate assembly planning. Finally, the model is demonstrated the effectiveness by applying for the process planning of a blower in an auto air-conditioner.
The present paper introduces an optimum design of the hip prosthesis and a method for shape optimization which minimizes the stress concentration within the cement mantle. A gradient projection method of numerical optimization and a p-version three-dimensional FEM of stress analysis were employed. A generic three-dimensional FEM model of the proximal femur containing a cemented fomoral stem of a total hip arthroplasty was developed. The three types of analysis was then performed in this study. First, stastic stress analysis measuring the stress in the bone cement was performed. The generic model was then valified parametrically by changing the each parameters individually that compose the stem geometry measureing the stress occuring within the cement mantle concurrently. As it is called design sensitivity analysis was performed. Finally, optimal stem shape was desigend using shape optimization. The design objective was to minimize the largest maximum principal stress in the cement. The results of shape optimization showed considerable reduction in stress concentration within the cement mantle compared to the starting design that were used. Moreover, the optimal stem shape obtained in this study showed unique geometry differ from the standard trend that has been believed to be better. The results of this study has shown to be attractive for evaluating stem design and develop the optimal new stem shape.
This paper describes two indispensable techniques to develop a flexible sanding robot. One is the impedance model following force control for industrial robots which can delicately control the contact force acting between the sanding tool and the workpiece. The other is the surface following controller using the cutter location data to suitably keep the position and orientation of the sanding tool without complicated teaching process. The techniques are applied to an open architectural industrial robot FS-20 with an air-driven double action sander, so that a useful robot sander can be easily realized. Some sanding experiments have demonstrated that the proposed robot sander can successfully accomplish the sanding tasks of wooden workpieces with curved surface.
This paper deals with a new measuring method of specular reflectance of a plane surface using a single slit. Illuminating light and its light reflected at the surface are incident on the slit simultaneously. A ratio of second to first peak intensity of the diffraction pattern formed by the slit is proportional to the reflectance of the plane surface. An angle of incidence is variable from 80°up to 89°with the slit of width 100μm. It is possible to measure a small surface of 18 mm 2 at 89°. The measurements of reflectance are carried out with some specimens using a linearly polarized light. The measured reflectance R s and R p of Optical flat(Quartz, flatness λ/10, nd=1.4538) agree well with those of calculated by Fresnel's formulae. This method is applicable to the measurement of the surface roughness and the glossiness of low reflectivity.
This paper presents a new in-process measurement method for evaluating small defects on a silicon wafer surface by detecting the intensity distribution, "Laser Scattered Defect Pattern (LSDP), " corresponding to the superposition of scattered light from a defect and reflected light from a surface. In order to apply this optical measurement method to in-process measurement, two-stage measurement is proposed. That is, the first stage means "detection of defect positions" and the second stage does "evaluation of defect type". The several basic scanning experiments show that the proposed two-stage measurement method is effective automatic in-process measurement technology for measuring the silicon wafer surface defects with the sub-micro meter scale size at high speed.
Equipment for measuring the shape of a groove with a depth of 3.6-4.5μm and a width of 0.15-0.30 mm inside a kinetic pressure bearing (K.P.B), which is used for magnetic discs, with a length of 8.75 mm and an inner diameter of 3 mm, is developed. The light projected to a specimen through a lens makes a small spot near the inside wall of the specimen. The position of the wall in the specimen is determined by detecting an image of the spot reflected on the wall. A two-dimensional theoretical analysis shows that the depth of the groove can be measured with an error of less than ±0.05μm. An experimental result shows that the depth of the groove can be measured with an amount of scatter less than -0.2 -+0.2 μm. As this scattering is sufficiently small to measure the depth of the groove, this equipment can be used in a production line.
A high-density mounting technology for a liquid crystal drive IC and for liquid crystal substrate has been developed to achieve high-definition liquid crystal displays. The material to join the liquid crystal drive IC and liquid crystal substrate is an anisotropic conductive film (ACF). Conventional ACFs use thermoplastic resins. The new ACF uses a thermosetting resin and has greatly improved junction reliability. The melt viscosity of the thermosetting resin is low when it is heated or pressure-joined. This facilitates intrusion of an adhesive onto the joining surface and achieves a high junction strength. The thermal expansion coefficient of the thermosetting resin is low and the thermosetting resin can be processed at the same temperature as that for conductive particles and has become a junction material with a high degree of freedom against temperature variations. The technology development reduces junction defects between the liquid crystal drive IC and liquid crystal substrate below 100ppm. At the same time, the technology allows mounting of a liquid crystal drive IC of junction pitch below 100μm.
In mechatronics systems driven by linear motors, performance of high speed and high accuracy motion compared to that driven by rotation motors is required. This paper describes a control method to achieve high speed positioning of linear motor driving table. The proposed method is based on the model reference feedforward control with the vibration model of the linear motor. In this proposed method, the reference model of FF control is derived from the rotational vibration caused by the inertia of the table and the stiffness of the bearing. The novelty of the proposed method is that the torque, velocity and position command in order to achieve the high speed and high accuracy motion of the reference model are regarded as the additional input in the feedback control. The effectiveness of the proposed method was assured by experimental results of XY linear motor driving table. The result showed that the settling time can be reduced 60% by the proposed method compared with that by P-PI and Velocity FF control generally used in industry. The proposed method can be easily adjusted for control parameters of actual machines, because the parameters in the reference model can be identified by the measurement of the transfer function in the XY linear motor driving table.