This paper presents a design support method to establish an eco-design concept of a product and its life cycle by assigning appropriate life cycle options to the components of the product. The product life cycle planning (LCP) method consists of the following four steps. The first is the specification process, in which target values of product and its life cycle are set. The second is the concept evaluation at product level, which selects a basic eco-design concept. The third is the solution generation process, in which solution ideas at component level are generated by using various analysis charts such as upgradability, maintainability, reusability and recyclability analysis chart. In the last step, eco-design concepts at component level, which consist of eco-design solutions, are evaluated. In the LCP method, environmental aspect is integrated into quality and cost aspects systematically. The design support tool was made for efficiently planning a product life cycle by using QFD and LCA data. A case study verifies that the proposed method and the tool are useful for developing an environmentally conscious product.
This paper presents a model for a multiple agent (multi-agent) system and a learning agent. The purpose of this study is to make it clear what is a reword for the learning agent and how the learning agent is constructed. The multi-agent system is defined as a pair of agents and their environment. A multi-agent system problem is defined as a set of the multi-agent system and its criteria so as to design the environment and agents maximizing the given criteria. An individual agent system is also defined as a set of the specified agent and his environment. Then, an individual agent problem is defined by a set of the specified agent, its environment, and its criteria. The agent reward is derived from this definition as an incremental value of the multi-agent system criteria. The agent learning process is formulated as a process of improving the agent criteria in order to maximize the agent criteria. Based on this analysis, necessary functions for the learning agent are derived. Namely, those are (1) a set of agent states sampled from the agent environment, (2) a set of agent behaviors, (3) the relational model between the agent state and behavior, (4) the estimating function for the criteria derived from the relational model, and (5) the agent behavior decision function. Finally, two cases are shown to construct the learning agent model using a gradient method and stochastic dynamic programming.
Existed historical pictures contain more or less granular noise and shading on the background, and that they show blurred contours. The blurred picture would adversely affect to the image processing by computer. A method is proposed in this paper to improve adaptive visibility for blurred image of ancient characters written on the "Paper Squeezes". Images are calculated to extract the character edge, using both gradient operator and wavelet transform. Two images are superposed to emphasize the edge pattern. An image space is divided into small square blocks as sub-images. These are compared with template blocks using image correlation, and are classified into eight patterns. Desirable results in terms of the experiment were obtained for the adaptive visibility improvement.
This study deals with positioning accuracy of SCARA-type manipulator from viewpoints of precision positioning technology. A SCARA-type manipulator is considered as a Planar Multi joint Positioning System. Nowadays, they are used widely in production lines, so that it is expected to use the manipulator not only for assembly but also for coordinate measurement in the lines. The requirements for positioning accuracy with the manipulators become more demanding. However, existing manipulators have a positioning error of over 0.1 mm, its accuracy is much inferior to Cartesian-type positioning mechanism. The accuracy has not been easy to improve because a standard measuring method for the positioning accuracy of multi joint manipulators has not been established. This report discusses a method of accuracy measurement using CCD camera and reference board on a XY stage. A measurement system for PTP positioning accuracy with resolution of 1.2 pm over the area of 400×200 mm is constructed, and some measurement results of PTP positioning accuracy are shown in local to global range on a horizontal plane.
A machine which can detect flaws larger than 30μm produced by the barrel finishing process on edges of vanes is developed. The edge part is illuminated from the direction of ±60°, which is measured from the vector normal to the edge, in a plane composed of an edge and a normal vector. The flaw on the edge is detected with a lens and a CCD camera. A detectable angle of the flaw surface is analyzed theoretically and compared with experimental results. A method of classifying the detected images into two groups, the dust images and the flaw images, is also developed. When the angle between the flaw surface and one of the surfaces of the edge is small, the flaw cannot be detected. However, when the above-mentioned angle is in the region of 90± 10.6°, all flaws can be automatically detected.
This study has proposed a new coordinate measuring machine (CMM) based on a three degree-of-freedom parallel mechanism. This paper describes a kinematic calibration method using a double ball bar (DBB) system with fixed ball distance. The CMM with a touch trigger probe measures the moving ball of the DBB, and calculates position errors of the ball using kinematic parameters. The least square method using Jacobian matrix corrects gradually the kinematic parameters so that the position errors are minimized. The above calculations have been repeated in both numerical simulations and experiments. The position error approaches a zero level, but has never reached it. The calibration with 19 parameters decreased the position errors of the DBB from 168 μm to 9μm in the experiments. Furthermore, accuracies of both length measurement with block gauges and profile measurement with an optical flat have been improved after the calibration. The measurement accuracy most improves when the repetitive operation is discontinued after three or five calculations.
In order to realize an autonomous milling, the tool paths and the cutting conditions have to be decided in real time using the predicted and the measured information of machining process. In this paper, the algorithm of in-process tool path generation for rough cutting is proposed to enable the modification of the cutting conditions according to the machining status and the machining troubles such as chatter vibration. Machining area is divided into some small cells and the tool path is generated as a removal sequence of machining cells based on the pattern of the relation among eight neighboring cells in 3×3 cells termed mask. The modification of the tool path is also realized by a change of an axial depth of cut and a radial depth of cut during a machining operation. As a case study, suitable cutting conditions are maintained according to the cutting force predicted in real time. In other words, the in-process tool path generation is made by deciding the cutting conditions in parallel with predicting the cutting force using a PC based milling process simulator called VMSim, which was developed already, and the feasibility of autonomous milling is demonstrated.
The simulation analysis of non-linear chatter onset process developed in the previous reports is further extended to chatter vibration caused by the finite amplitude instability. The instability is induced with a step of undeformed chip thickness placed at the start point of turning. The chatter onset process and the lowered stability threshold predicted by the simulation analysis are in good agreement with the experimental results. The amplitude-depth of cut stability chart which involves the finite amplitude instability is obtained through the analysis, and the apparent difference between chatter arising and disappearing depth of cut is discussed. The respective role of non-linearity in machine structure and dynamic cutting force is also discussed for non-linear chatter generation, and for quantitative prediction it is stressed that both the non-linearities are indispensable.
This paper aims at developing of tipped-saw suited for cutting-off of various steels, and deals with an application of residual tensile stress which occurs in the outer aria of disk when brazing tips. Disk material is first investigated from the viewpoint of vibration characteristics. Next, tipped-saws utilized the thermal stress are produced with SK5 displayed the largest damping ratio and then the sawing performances such as tool failure, flank wear rate, surface roughness and so on are estimated. In addition, the results are compared with tipped-saws tensioned near the bottom of saws by rolling in order to ease the excessive tensile thermal stress. The examinations are carried out by two kinds of tip material i.e. cemented carbide and cermet. The obtained results are as follows. When the feed rate is at 0.07-0.10 mm/tooth, surface roughness and noise level are smaller. Tool fracture did not occur at 300 cutting numbers for cemented carbide, while 5 teeth of the cutting edge fractured up to 210 cutting numbers for cermet. Compared with tipped-saw of the only brazing, a deformed disk leads to higher elastic rigidity and smaller surface roughness.
For specular processing of Al-Si alloys material, it is necessary to remove the ruggedness of the film of the CVD diamond coated cutting tool, because the surface of poly-crystal diamond film is very rough with the roughness of 2-5 μmRz. To unbreakably process diamond film and secure a permissible value of the size accuracy and the shape accuracy are very difficult because the shape of the cutting tool is three-dimensional complex. OSG Corporation and Matsushita Electric Industrial Co. Ltd. have jointly researched and successfully developed a grinding technology for the film of the diamond coated cutting tools. This article describes the grinding technology and shows the results of cutting tests. Finally, it was confirmed that the surface roughness of the work-piece processed with the ground tool was greatly improved.
This paper aims at investigating the influence of (Al, Ti)N coated high-speed steel (HSS) hob materials on the behavior of crater wear when changing the kinds of work materials in dry bobbing. Experiments were carried out using a fly tool. As a consequence, the following points were clarified: (1) The three kinds of HSS hob substrates tested showed the small depth of crater wear when cutting the work material of SCM415. (2) It was suggested that the crater wear reduction, when cutting the SCM415, is caused by the deposited metal covering the contact surface. (3) Among the tool materials tested, the corresponding to SKH55+(Al, Ti)N coated tool is suitable irrespective of the change in the work materials, in terms of the crater wear, the flank wear and the surface finished in dry bobbing.
Frequency-conversion techniques such as SHG, THG and FOHG with nonlinear optical crystals are indispensable for the applications of all solid-state lasers to precision microfabrication. It is well known that the conversion efficiency is very sensitive to the temperature rise of the crystal, which is induced by laser absorption. In this study, temperature dependence of SHG efficiency has been investigated theoretically, supposing Nd:YAG laser of uniform intensity and KDP (KH 2PO 4) crystal. The coupling problem composed of complex wave amplitude equations and one-dimensional heat conduction equation was analyzed. The complex wave amplitude equations were derived considering the absorption of laser in the crystal. The main results obtained are summarized as follows: (1) Decreasing of SHG efficiency due to laser absorption for the single pulse irradiation to a crystal of 10 mm long, is less than five percent. (2) When SHG efficiency is higher, temperature-rise of the crystal is smaller. Because absorption coefficient for the fundamental wave is larger than that of the second harmonic. (3) When the temperature of crystal rises due to repeated irradiation of pulse laser, SHG efficiency fluctuates and decreases gradually. Remarkable inverse-conversion of SHG appears during laser irradiation with high power density. (4) As either pulse width or irradiation time becomes longer, analytical SHG efficiency agrees with the approximated results obtained under the simple phase-mismatching conditions.
In this study, a new technique of in-process evaluation of the wheel surface is proposed. Five specified wheel surfaces are prepared as the references via the appropriate dressing procedure, and grinding sounds generated by these wheels are discrimi-nated by analyzing the dynamic frequency spectrum with a neural network technique. In the case of conventional vitrified-bonded alumina wheel, grinding sound can be identified under the optimum network configuration in such that learning rate is 0.0029 and number of hidden layer is 420. This system can recognize instantaneously the difference of the wheel surface in a good degree of accuracy insofar as the dressing conditions are relatively widely changed. In addition, the network perceives the wheel wear because the grain tips are flattened as grinding proceeds and the grinding sound resembles to that of the wheel generated with lower dressing feed.
A novel polishing pad system and machine were designed and developed to perform a uniform removal rate for a whole wafer surface in CUP (Chemical Mechanical Polishing) planarization process. The pad materials which are composed of hard and soft two layers, and the dimensions were designed based on the calculation of polishing pressure distribution by FEM. The CMP machine developed has good and original features of the followings: Five wafers which are chucked on high precision and rigid stages are simultaneously polished rotating with planetary motion The wafers surface to be polished are set with up and the pad surface is determined by the five wafers envelope. The hard pad which practices the wafer surface polishing do not attached on platen, but are stretched from the periphery of the platen. Using this CMP system, the polishing pressure distribution was measured and calculated for whole wafer area in static state. Then the wafers on which have oxide film were actually polished and the removal rate distribution of the wafers were measured. The actual surface profile corresponds well to the measured and calculated pressure profile. It is found that the removal rate distribution of a wafer is controllable from the center-fast to center-slow by using the base-plate which has different radius under the pad system.
Various types of 5-axis controlled machining centers have been developed to produce molds, dies and mechanical parts with complicated shape as well as aero parts. The most fundamental cause of the machining errors is the deviation of the configuration of the machining center. However, any calibration method for the 5-axis machining centers including two rotary axes has not been investigated. In this paper, a calibration method using simultaneous 3-axis control technique is proposed for 5-axis machining centers with a tilting rotary table. The ball-bar system is used as a measurement instrument. In this method, one rotary axis and two linear axes are simultaneously controlled and the sensitive direction of the ball bar system is kept constant in radial, tangential or axial accordingly. The influence of the positional and angular deviations on 3-axis motion is evaluated through the characteristic diagrams. In the experiments, the positional and angular deviations existing in the 5-axis machining center are estimated by the proposed method. The results show that the deviations can be estimated with high accuracy.
High speed flow finishing method has recently developed, which has an excellent performance for polishing an inner wall of stainless steel capillary D Present paper focuses on the finishing characteristics of the inner wall of stainless steel pipe with high speed flow finishing method D It is found that bar-type mandrel inserted into the hole of pipe has great performance in finishing, in which a diameter of mandrel is slightly smaller than inside diameter of the pipe D Experiments indicate that surface roughness of the inner wall of pipe decreases with the number of slurry flow pass D It is shown that both of larger grain size and higher concentration of the abrasive in water solvent, have a greater finishing rate of the pipe D. It is described that larger flow pressure of slurry yields greater surface roughness decrease D