Cu-Be alloy, whose thermal conductivity is 3 to 10 times higher than the common mold steels, has been identified as an effective material for improving the cooling uniformity of resin when applied it to plastic injection molds as inserts. However, arranging an optimum shape and size of the Cu-Be alloy into a mold is still one of the major problems in using this technology. In this paper, an evaluation method of cooling uniformity to a resin product is proposed by observing the temperature distribution and its variation on the resin surface. This method can be used for judging the validity of a cooling system inside an injection mold, such as the layout of cooling channels, or the shape and the arranging location of a embedded Cu-Be alloy block. This can be realized by comparing the result values gained from a defined evaluation function. Simultaneously, by making the evaluation value to converge to the minimum, a procedure is provided for the automatic search of the Cu-Be black from an arbitrarily assigned initial arrangement to the optimum shape. Furthermore, case studies are presented to discuss the process of realizing the automatic shape generation of Cu-Be alloy inserts based on numerical analysis.
Treating geometrical similarities of 3-D objects is especially important in the fields of pattern recognition, robot vision and CAD/CAM. This paper describes a method for deciding similarities of polyhedra by using the two layer structures of polyhedral objects proposed in the 1st report. The basic idea of the method is as follows. (1) The two layer structure of an object is compared with that of another object. (2) When those two layer structures are similar to each other, the shape and position of each component of an object are compared with those of the corresponding component of the other object and the similarity of each component is decided. (3) Then, similar parts and dissimilar parts can be recognized for those two concave objects. Various examples of polyhedral objects have been tested. The method gives results closely matching with human perception.
This paper discusses about the maintenance routing problem of the elevators, which are the typical case of the infrastructure equipment. The purpose of this paper is to give the practical formulation and the proper solution to the maintenance routing problem to seek the optimal routing schedule, which minimizes the Cost Of Quality (the loss evaluated in terms of cost, to be incurred when an elevator breaks down), the time for the maintenance team to access the malfunctioning elevator, and the total visiting and working time of each maintenance team. To plan the routing schedule, two indexes are proposed; one is named the "customer satisfaction index" that expresses how well each maintenance team's visiting route can manage the unpredictable failures and the other the "route length index." The problem to be solved is divided into two steps of Generalized Assignment Problem and Traveling Salesman Problem by using these two indexes. Furthermore, Lagrangian Decomposition and Coordination Method and Local Search Method are applied as the solution. From numerical experiments, the characteristics of the proposal method are clarified, and it is shown that this approach can provide a more cost-effective and better routing schedule than the one given by the traditional method.
A stirling engine genetates its power through the change in temperature and pressure of the working fluid. Its characteristics are the independence of any kind of heat souce, the low noise and the high efficiency. However, its specific power is much smaller than that of the internal combustion engine, as a result, it is not utilize as the source power. Namely, the point of this stirling engine is the decrease in its weight. This report describes the way of the weight decrease is the stirling engine, the result of flight of a small sized model airplane installed this engine.
In this paper, an operation algorithm of a virtual object is proposed, using a 6-DOF haptic device in a virtual environment. Haptic sensation, such as a feeling of contact between objects, has an effect in raising efficiency of an operator's work. Motion of the operated object by the haptic device is composed of two motions. One is caused of two forces, gravity and operating force from the haptic device. The other is caused of colliding or contacting other objects. The former is obtained by numerical computation using Newton and Euler's equation. The latter is obtained by calculating change of motion by impulsive force between objects. By real-time computation of these motions, the operator could operate the object freely in the virtual environment. And the feeling of contact of the operated object could generate to the operator's hand through the haptic device, without penetration between objects. Since objects never interfere, it will be applicable in the field of mechanical design, such as verification of the assembly procedure of parts, examination of the validity of parts shape, etc..
Bilateral servo systems are useful on remote control manipulators because operators can defend objects against damages by reaction force feeling. In this study an adaptive control method is introduced on a slave manipulator with unknown dynamic parameters on the basis of the bilateral servo system including force error compensation method. This system is stable by means of Liapunov stability theorem. This method is confirmed to be effective on the basis of simulation and experimental results.
To use for single specimen determination of R-curve with three-point bending of JIS R 1607 type II specimen (span-to-width ratio, S/W=7.5), calculation formulas for analyses with the elastic compliance method are presented. Numerical analyses of stress intensity factor and specimen compliance are carried out and based on these results, crack length and stress intensity factor are expressed as functions of specimen compliance. These are defined in the entire range of crack length relative to specimen width, a1W. A formula of a/W as a function of specimen compliance, inverse compliance, is also derived. In this procedure, two different techniques, boundary collocation and finite element method, are performed independently. The results of the both calculation show good agreement in the most range of a/W and the uncertainty is estimated to be within 0.8%. The reliability of proposed formulas is also examined in experiments. Crack length and stress intensity factor of borosilicated glass samples are calculated with proposed formulas and verified with other experimental facts. As a result of these experiments the reliability of calculated values is estimated to be within 3%.
This paper proposes a method for high-speed image template matching by using partial selected block areas in a template image. The template image is separated into block areas and the normalized correlation matching is executed by each block area in the reference images. The block areas that perform the successful matching are recognized by the voted result based on the searched locations of all block areas. Next, partial block areas that are supposed to be useful for image matching are selected in the order of the SN-ratio of matching rates. The experimental results show that the processing time for image matching was reduced to 25% and the reliability of matching was kept in comparison with the conventional method.
This paper describes the measurement of the process reaction force that is generated in EDM using Hopkinson bar method. The reaction force is an integral of both the pressure inside the bubble and that in the dielectric liquid over the working surface area. Using the Hopkinson bar method, the correct waveform of the process reaction force was obtained without influenced by the natural frequency of the measuring system. The results show that the reaction force reaches almost 100N in a semi-finishing condition in a single pulse discharge when the discharge gap is filled with a working fluid. Besides, the measured results were compared with the calculated results which were obtained by neglecting the viscosity of the working fluid under various machining conditions, and the relationships between the reaction force and machining conditions were investigated.
The ultrasonic grinding has been developed for the purpose of machining brittle materials such as advanced ceramics. And its effectiveness is highly appreciated because of its efficiency in machining advanced ceramics with very little damage on the grinding surface. Since the super abrasive wheel with vitrified bond is regarded as a kind of brittle material, we can consider that the ultrasonic grinding is also effective for the vitrified super abrasive wheel in the aspect of its high efficiency in truing and dressing with very little damage on the working surface. In this study, we present the experimental rotary ultrasonic dressing equipment and its experiments of truing and dressing on the vitrified diamond wheel. And the effectiveness of the rotary ultrasonic dressing equipment is also examined.
The friction torque on a double nut preloaded ball screw dynamically varies after motion direction change. The transient friction torque after motion direction change is less than that in the steady state. Although this friction torque variation is often mistaken for the backlash, the theoretical analysis shows that it is caused by the change in ball contact points. Experimental results coincide well with simulation results. This paper discusses the effect of the axial play, the preload, and the lead on the friction torque. Furthermore, this paper clarifies the difference of friction torque characteristics between a double nut preloaded ball screw and an over-size ball preloaded ball screw.
The purpose of this study is to clarify the adhesion mechanism in cutting process on the difficult-to-machine material such as Ni-base alloys like Inconel 718, Inconel 600 and so on. For the elucidation of the adhesion mechanism, it seems to be important to know the reaction which is generated at the interface between cutting tool and material. However, it is difficult that the reactive phenomenon is observed in detail because the region where cutting tool contacts the material in cutting process is very small. Then, the friction welding test between cutting tool material, K10 (8mm diameter) and material was carried out. The reactive phenomenon between cutting tool and material in cutting process was analogized by the observation of the interface of friction welded joint. In addition, 4 point bending test at high temperature was carried out for diffusion bonding joint between K10 and material at 1373K. From analyzing fracture strength and rupture position, the strength of the bonded interface between K10 and material was examined. As a result of the friction welding test, Ni-base alloys and K10 were bonded together only for the friction time of 0.4s. Friction welding of Inconel 718 was easy to be done in comparison with Inconel 600 and pure Ni. In either material, the reaction layer was not observed in the interface of friction welding. On the other hand, the width of the reaction layer increased with the increase in the bonding time in the interface of the diffusion bonding joint. The growth of the reaction layer was the biggest in Inconel 718. This reaction phase was the η phase. High-temperature bending strength of the diffusion bonding joint in Inconel 718 and Inconel 600 was bigger than that in pure Ni. From the above experimental result, the reason why Inconel 718 and Inconel 600 are easy to adhere to cutting tool comparing with pure Ni was seemed to be that these materials were easy to react with cutting tool and bonding strength between these materials and cutting tool were high.