This paper presents comparison studies between a multi-task machine tool and conventional machine tools with respect to the production lead time and cost. In particular, the machining of a part that has both box and cylindrical geometries is considered. For small lot production of a part that has 6∿8 surfaces to be machined (excluding the ones machined by turning), an estimation method of the machining lead time and the total machining cost (including the machine cost) is presented. Two case studies show that the machining by a multi-task machine tool is more effective than the conventional machining strategy using a lathe and a vertical-type machining center, from the viewpoint of not only the machining lead time, but also the machining cost.

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In the area of machining, laborsaving and automation of operations are comparatively realized mainly by the contribution of NC machine tools so far. However, conventional NC machine tools are not enough autonomous or intelligent to achieve "Raped Manufacturing" that is available to start real machining operations immediately following product design without manual process and operation planning. In this study, in order to realize an autonomous NC machine tool, feed back mechanism that can adapt cutting parameters depending on monitored machining information is realized by integrating the developed function of generating tool paths in real time and the proposed machining strategy. And they are connected to the commercial CAD software customized to actualize automatic process and operation planning. As a result, an NC machine tool can be driven directly, rapidly and autonomously by a designed product model to achieve "Rapid Manufacturing".

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A circular motion test is usually used for evaluating the performance of the feed drive systems. In the circular trajectories, quadrant glitches are often found, and it is known that the phenomenon is caused by friction force. Various friction models have been proposed in order to analyze the behavior of the systems. However, the friction models already proposed can not been applied to the design of controller because the friction models have several parameters to be determined by experiment. In this study, a new simple friction model is proposed by considering the relationship between the driving force and friction one. As a result of simulation using the proposed model, the quadrant glitches are well expressed. The relationship between the value of parameter of the friction model and the height of the quadrant glitch is also discussed. Moreover, the circular motion is simulated at various radii and feed rates, and the improved friction model is proposed for high feed rate.

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This paper deals with a stick motion compensation system. Stick motion damages extremely the accuracy and the quality of workpieces in circular motions or on free form surfaces. In the conventional compensation system, it needed to tune parameters for each combination of radius and feed rate. This research proposes a new stick motion compensation system. The new system has a dynamic model that simulates the friction. The simulated friction consists of two components. One is spring resistance in proportion to a reverse distance from a quadrant change. The other is viscous damping friction in proportion to velocity. The system can compensate stick motions suitably for wide range conditions of radii and feed rate.

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The growing need for higher precision and productivity in manufacturing industry has lead to an increased interest in computer numerical control (CNC) systems. It is well known fact that the cross-coupling control (CCC) is an effective method for contouring applications. In this paper a new CCC is introduced based on a contour error vector using parametric curve interpolator. The contour error vector is a vector from the actual tool position to the nearest point on the desired path. The contour error vector is the closest error model to the contour error. The simulation results show that the new CCC is more accurate than the conventional CCC for a biaxial motion system. In addition, the experimental results on 3 axis motion system shows that the new CCC is simply applied to 3 axis motions and contouring accuracy is significantly improved.

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In this paper, we propose a simple sliding guideway with a hydraulically operated brake unit, which can control sliding friction force on a feed drive system. The sliding friction force is controlled by the brake force command generated from velocity information of a table and/or a servomotor. Several damping control laws are implemented in the brake force control unit. Structural vibration of ballscrew drives can be successfully controlled by this actively controlled sliding guideway in experiments.

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The heterodyne He-Ne laser interferometer is the most widely used system to measure the position error. It measures the positioning error from the displacement of a moving reflector in terms of the wave length. But, the wave length is affected by the variation of atmospheric temperature. Temperature variation of 1℃ results in the measuring error of 1ppm. In this paper, for measuring the position error of the ultra precision stage more accurately, the refractive index compensation method is introduced. The wave length of the laser interferometer is compensated using the simultaneously measured the variation of room temperature in the method. In order to investigate the limit of compensation, the stationary test against two fixed reflectors mounted on the zerodur plate is performed firstly. From the experiment, it is confirmed that the measuring error of the laser interferometer can be improved from 0.34μm to 0.11μm by the application of the method. Secondly, for the verification of the compensating effect, it is applied to estimate the positioning accuracy of a ultra precision aerostatic stage. Two times of the refractive index compensation are performed to acquire the positioning error of the stage from the initially measured data, that is, to the initially measured positioning error and to the measured positioning error profile after the NC compensation. Although the positioning error of the aerostatic stage cannot be obtained clearly, it is known that by the compensation method, the measuring error in the laser interferometer can be improved to within 0.1μm in the practical measurement on ultra precision stage.

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In order to overcome the disadvantage of the inchworm mechanism that has stepwise motion, a piezo-driven linear motion stage with smooth motion, long travel range and high resolution is proposed. It consists of two clamp piezo-actuators, two feed piezo-actuators and a precise guide using cross roller. The two clamp piezo-actuators are linked with the outer two feed piezo-actuators in symmetry fashion. The moving carriage of the stage is set between the two feed piezo-actuators. To avoid stepwise motion of the carriage, a new sequence of motion procedure is applied for the clamp and the feed piezo-actuators. The procedure includes simultaneous extending and shrinking of the two feed piezo-actuators with opposite polarities in collaborate with clamp and unclamp actions. This mechanism can theoretically generate smooth stage motion and long travel range.

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In this paper we discuss a method of realizing high precision radial magnetic bearings that are capable of high-speed operation by the suppression and reduction of the harmonic disturbance forces generated by the induction motor that is used to drive the magnetic bearing. Experimental data shows that a rotational accuracy of 31.8nm (3σ) can be achieved at 5,400rpm for an experimental radial magnetic bearing in which the spindle has a diameter of 80mm and a mass of 3.29kg.

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For the intelligent manufacturing by a machining center, the authors have proposed an extension of fixed cycles to end milling processes in our previous works. For the enhancement of machining productivity, the extension of tool life, and the improvement of machining accuracies, we have proposed a scheme to optimize machining parameters within such a fixed cycle based on the regulation of cutting forces by using the initial machining database. In continuous machining, cutting forces gradually increase as the tool wear progresses. Therefore, it is crucial to perform a more reliable process control by continuously monitoring the cutting force. It is, however, unfavorable to install and additional sensor to monitor cutting forces from the viewpoint of the cost, reliability, and maintainability. To address this issue, this paper presents a scheme to estimate cutting forces by monitoring spindle and servo motor currents, along with a kinematic parameter defined by the geometrical interference between a tool and a workpiece.

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It is known that a very hard nitride layer may be formed by nitriding low-alloy tool steel containing forming elements such as chromium and aluminum. The hard layer on the steel surface is formed by depositing thin aluminum film on the steel, diffusing aluminum into the steel, and nitriding. However, significant thermal deformations are formed on the specimen surface by performing this process. Therefore a method which achieves quenching, tempering, and shape correction was attempted before the abovementioned process. We examined the wear characteristics for surface modified alloy tool steel made by use of the above processes with varying aluminum film thickness. Excellent resistances to the abrasive wear at an aluminum film thickness of 2.0μm and to the adhesive wear at aluminum film thickness of 1.5 to 1.6μm are obtained.

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This paper presents an assessment of a new driven rotary tool in the turning operation of a titanium alloy at high cutting speeds. Two types of cutting tools were used for comparison : a stationary tool (ST) and a driven rotary tool (DRT). Experiments were conducted at different feeds, depths of cut, cutting speeds, and rotary speeds. Tool wear and cutting forces were recorded and analyzed. Tool life equations were derived for both tools. The results show that a significant advantage of the DRT is its long tool life that eliminates the need for frequent indexing of worn insert during high speed machining of titanium alloys.

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Using a binderless cBN tool, improvement of processing efficiency was tried in machining of a vanadium-free titanium alloy, Ti-6Al-2Nb-1Ta which was recently applied for a surgical implant material. The tool which is prepared through the direct conversion sintering of h-BN under both high pressure and temperature, exhibits an improved high temperature durability. It was confirmed that a binderless cBN tool exhibited lower flank wear and kept sharper cutting edge compared to the tools made of sintered carbide, conventional cBN with binder and polycrystalline diamond with Co-based binder, after turning in cutting speed of 4.2m/s, feed rate of 0.15mm/rev, depth of cut of 0.5mm under an application of a high pressure coolant. Also, milling tests were conducted with a radius end mill tool which was made of the binderless cBN material. The possibility of high speed cutting in milling process was found.

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In the present investigation, the improvement of surface roughness in high-speed end milling of the super engineering plastics has made to be a purpose. The cutting performance of the diamond coated end mill in high-speed milling is investigated. The fine crystalline diamond coated end mill is effective for the wear resistant as compared with the cemented carbide end mill, and it became the tool life over 100 times under cutting speed of 13.3m/s. Also, end cutting edge polishing technique of the end mill tool was devised, and the polishing of the end cutting edge after the fine crystalline diamond coating was enabled in the short time (about 30 seconds). It is clarified that the finished surface roughness becomes 1μm or less by polishing the ruggedness of surface crystal of the end cutting edge after the fine crystalline diamond coating.

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This paper presents the dynamic cutting force and cutting temperature during cutting 29Ni-17Co alloy using φ1-3mm end mills rotating at a spindle speed of 10,000-40,000/min. A dynamic cutting a force in the frequency range of more than 10kHz, and a cutting temperature at a sampling rate of less than 30 μs, were detected. Tool wear is explained in view of the dynamic cutting force and the cutting temperature. As a result, and increase in cutting speed and feed per tooth in milling conditions is significantly effective in minimizing tool wear.

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The effect of the shank form error of tools on the chucking accuracy was examined for various milling Furthermore the requirement of the shank of tools was also considered for effective use of the chucks. By the experiments, following results were obtained. (1) The chucking accuracy of the shrink-fit and the hydraulic type chuck are better than the roll-lock and sleeve-lock type chuck regardless of the shank form error of tools. (2) The shank form error of tools affects greatly the chucking accuracy of the shrink-fit and hydraulic type chuck. (3) The shank form error of tools hardly affects the chucking accuracy of the roll-lock and sleeve-lock type chuck. (4) In order to make the best use of the shrink-fit and hydraulic type chuck, it is necessary to use the tool whose shank is good cylindricity and has proper interference for clamping.

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The effect of cutting speed, feed rate and tool wear on the surfaces generated when machining nickel base, Inconel 718,alloy with conventional and high pressure coolant supplies was investigated. Tool life, failure modes, surface roughness (Ra) values and component forces were recorded. Machined surfaces were examined with the SEM and optical microscopes. Microhardness analysis show evidence of hardening of the top machined surfaces. In most cases the microhardness reading tend to approach the hardness of the base material at 0.3mm below the machined surface. This is due to the austenitic structure of Inconel 718 which promote work hardening when machining as a result of the high temperature and stresses generated at the cutting interface. The hardening effect decreased with increasing coolant pressures up to 203 bar as the coolant gain access closer to the cutting interface, thus minimising the cutting interface temperature. Analysis of machined surfaces shows that severe plastic deformation occurred when machining with conventional coolant supply than with high pressure coolant supplies. Surface damage or phase transformation was not observed when machining Inconel 718 under high pressure coolant supplies. Increasing the feed rate from 0.15 mm/rev to 0.25mm/rev when machining with ceramic tools at a cutting speed of 250m/min decreased the hardness of the machined surface. An increase in feed rate from 0.25mm/rev to 0.3mm/rev increased hardness of the machined surface when machining with coated carbide tools at a speed of 30m/min due to increased shearing forces encountered and consequent strain hardening of the machined surface.

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A new multiple chemical-pretreatment for K10 drills was developed and by which the diamond films with high adhesive strength could be obtained in the electron aided hot filament chemical vapor deposition (EACVD) process. The pretreatment was especially suitable to the substrates with complex geometries. It was consisted of microwave oxidation, alkaline reaction, and cleaning in acid solution. Adhesive strength and quality of diamond films were evaluated by SEM, AFM, XRD, Raman spectrum, and drilling experiments. The friction coefficient increased with the surface roughness of the diamond films. A new multiple coating technology based on varying parameters was also developed and by this the diamond-coated drills were of both high adhesive strength and low surface roughness. The multiple diamond-coated drills yielded longer tool life and smoother holes than those of the conventional diamond-coated ones. The wear mechanism of diamond-coated drills is the abrasive mechanical attrition.

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In this study, the axis compositions of five-axis machining centers (MCs) are collected through websites and catalogues. The analysed 5-axis MCs are divided into three types. The deviations of the axes motion are discussed. Telescoping magnetic ball bar (TMBB) is applied in the measurement method of the effectiveness of deviations. The proposed procedure of ball-bar setting is evaluated for general structural codes of all types according to the simultaneous motion of four and five axes. They are simulated using software of dynamic analysis and design system (DADS). The influence of deviations in the measurement method is discussed. The results show that the geometric deviations can be estimated by the proposed method. The simultaneous motion of five axes using a simple jig is proposed as an alternative method of measurement. It is found that the proposed method is effective to evaluate the geometric deviations in simultaneous five-axis motion as well in simultaneous four-axis motion.

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A new compensation method that enables not only to improve the geometric accuracy of a machining center but also to improve the workpiece accuracy has been developed. The strategy of our evaluation and compensation method utilizes coordinates measuring machine (CMM) as a master gauge because of its accuracy so that machine operator devote himself to machining and estimator of accuracy dedicate in measurement. As each operator knows the characteristics of machining center and/or CMM, the results obtained are enough reliable to evaluate the accuracy of both machining center and workpiece under the established cutting condition. In our study, these errors except the geometric accuracy of a machining center are neglected by setting the cutting condition not to affect the desired machined workpiece previously. The total pitch error and geometric error are predicted by using the transform formula including error parameters measured by CMM. The predicted results are enough accurate to compensate the error of geometrical and position as the inverse problem. In this report, the effects of predicted results and compensated results are shown with the experimental procedure.

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This paper proposes a motion error compensation methodology for a Hexapod-type parallel mechanism machine tool. First, the contouring error attributable to the elastic deformation of struts caused by the gravity is predicted for an arbitrary position and orientation of spindle head. By compensating the predicted error on a reference trajectory, the machine's motion accuracy can be improved. It is experimentally verified that predicted and measured motion trajectories coincide well, even when the spindle is tilted by more than 23 degrees, where the gravity significantly deteriorates the machine's motion accuracy. By applying the proposed compensation method, the motion accuracy is significantly improved particularly near an edge of the machine's workspace.

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A measurement and evaluation method for thermal deviations caused by machine tool spindle rotation was standardized in ISO 230-3,then it began to be widely used. However, the method is not efficient since many cold start tests must be carried out. Therefore, a more efficient method is proposed in the study that the Z directional thermal deviation is modeled as first order lag, and this model parameters are identified using only one spindle pattern operation to evaluate the thermal characteristics. The effectiveness of the method is made clear form comparing the results from some cold start tests and two spindle pattern operation tests.

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In this paper, a quite simple and novel straightness measurement system was proposed. The laser beam from a single-mode fiber-coupled laser module is highly stable, and can be used as the reference line for straightness measurement. Base on the characteristics of a corner retro-reflector, the corner retro-reflector is used as the moving target in the straightness measurement system in order to reflect laser beam from measurement head back to it. In this way, there is no cable connection in the moving target, which is very convenient for straightness measurements in workshops. At the same time, relationship between voltage output from a quadrant photodiode detector and its displacement was analyzed theoretically, theoretical analysis shows a good consistence with practical measurement results. The accuracy of a micrometer at a distance of one meter was gotten by the system.

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One of the problems of current monitoring systems is lack of flexibility against changes in machining environment. The purpose of this research is to construct a monitoring system that can flexibly cope with changes in the machining environment without sacrificing the accuracy of detection. Developed monitoring system is conducted by plural decision-making systems, and is applied to monitoring of chipping of the end mill. The subsystems employ artificial neural networks based on the cutting force signals and the cutting conditions. It is concluded that the flexibility and the reliability of the monitoring system is much improved by operating the subsystems in parallel.

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Ultrasound waves are pulsed through the cutting tool insert towards the nose and are reflected back off the cutting edge. Fluctuating states of contact and non-contact between the tool insert and the workpiece, generated as a result of tool chatter, affects the amount of the transmitted ultrasound energy into the workpiece material and, in turn, the amount of the reflected energy. The change in the energy of the echo signals can be related directly to the severity and frequency of tool chatter. Wavelet packet analysis was used to filter the ultrasound signals. A three layer multi-layer perceptron (MLP) artificial neural network (ANN) was used to correlate the response of the ultrasound sensor to the accelerometer measurement of tool tool-workpiece first contact, tool chipping, and flank gradual tool wear.

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In this paper, a numerical model based on the finite difference method is presented to predict tool and chip temperature fields in continuous machining and time varying milling processes. Machining operations are studied by modeling the heat transfer between the tool and chip at the tool rake face contact zone. The shear energy created in the primary zone, the friction energy produced at the rake face-chip contact zone and the heat balance between the moving chip and stationary tool are considered. The temperature distribution is solved using finite difference method. The model is also extended to milling where the cutting is interrupted and the chip thickness varies with time. The proposed model models combines the steady-state temperature prediction in continuous machining and the transient temperature evaluation in interrupted cutting operations. The mathematical models and simulation results are in satisfactory agreement with experimental temperature measurements reported in the literature.

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A proposed mathematical model is presented for predicting the residual stresses caused by ball burnishing. Effects of change in three burnishing parameters which are burnishing speed, burnishing force, and burnishing feed on the residual stress of 6061-T6 aluminum alloy are investigated. The residual stress distribution in the surface region due to ball burnishing is determined using a deflection-etching technique. To reduce the number of experiments required and build the mathematical model for these variable, Response Surface Methodology (RSM) is used. In addition, variance analysis and an experimental check are conducted to determine the prominent parameters and the adequacy of the model. The residual stress of the burnished surface is influenced by the three parameters used. The burnishing force plays a major role and its effect can be considered as the most important input parameters. The proposed model, that offering good correlation between the experimental and predicted results, is useful in selecting suitable parameters for ball burnishing process.

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This paper reports about fundamental relationship between tip thickness of crushed cutter and thickness of wedged sheet. By varying the tip thickness of trapezoidal center bevel cutter, the resistance of cutter indentation and the shared profile of aluminum sheet were investigated experimentally. For discussing the deformation mechanism of aluminum sheet in the necking stage, Hill's solution with slip line theory and finite element analysis with elasto-plastic model were applied to this wedge indentation. The derived results were as follows : the necked height of sheet material is varied with the tip thickness of cutter; the occurrence limit of necking deformation exists in terms of the sheet thickness; the line force at the deflection point is varied with the tip thickness of the cutter, but not with the sheet thickness; the residual sheet thickness beneath the cutter tip depends on the tip thickness of cutter.

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The small and hard particles exist in particle dispersion hardened aluminum alloys. Those cause the complex cutting mechanism. Then the new materials were developed to improve that problem recently. It was necessary to clarify their cutting mechanism. In this study, the micro cutting in the SEM was carried out and the strain rate was calculated from the in-situ observation images using the PIV (Particle Image Velocimetry) in order to make clear the cutting behavior in cutting aluminum alloys including the new material. The main results obtained are as follows : Using the PIV, the displacement in the sub micro meter order was measured and the cutting behavior in the micro cutting could be clarified. In cutting of the AFT and the AST, the chip formation and the strain rates along the shear plane were made clear. In cutting of 19Si, when the particle impacted the cutting edge, the matrix began to deform before the particle was divided. It was clarified that the matrix around the particle was deformed widely and it played the role of the cushion.

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The monitoring of cutting states is indispensable for reliable and trouble-free machining. In this paper a monitoring system for classifying the levels of tool wear in high speed machining into some categories has been developed using an ART2,one of unsupervised and self-organizing artificial neural networks. The input pattern used for the ART2 was an array of normalized wavelet coefficients of feed force. The outputs of ART2 were four or five categorized tool wear levels : the incipient stage, intermediate stage, final stage and hazardous stage in the case of four categories. For two apparently different series of the force data obtained under the same cutting conditions, which are often seen in experiment, the ART2 neural network showed quite similar classification of tool wear levels from the beginning to the end of cutting. Further study proved that this monitoring system worked well for different cutting speeds V=5-7 m/s or different feed rates &fonf;=0.10-0.20 mm/rev.

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Chip forming process of ultrasonic vibration cutting is simulated by FEM as first. The change of the strain rate is larger, and cutting force acts on rake face and cutting temperature is slightly higher than the conventional cutting. Secondly, it is shown that the cutting force transfer from cutting point to the tool-work piece system, which has much lower natural frequency comparing with ultrasonic vibration, mainly depends on the ratio of net cutting time to vibration cycle in vibration cutting (tc/T). It is confirmed by the cutting experiment of resonated hone type work piece. The elastic deformation or recovery of several microns is also indicated both analytically and experimentally. The influence of this elastic behavior bocomes large relatively when tc/T is small.

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A 3D transient simulation model of the tool heating and cutting fluid cooling of a drilling operation has been developed. The possibility of capturing the physics involved in the heat transfer process in drilling in a simulation model is discussed. Validation of the simulation has been done using thermocouples measuring the temperature of the outgoing cutting fluid. A temperature profile of the cutting fluid was investigated with thermocouples mounted in different positions along the periphery of the drilled hole. Pressure distribution was investigated experimentally to give boundary conditions and furthermore provide information for validating the model.

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This paper proposes a methodology to identify the material coefficients of constitutive equation within the practical range of stress, strain, strain rate, and temperature encountered in metal cutting. Besides, it investigates the characterization of the material fracture necessary to the modeling and analysis of the chip segmentation. A methodology is therefore proposed to identify the shear stress at which the fracture occurs and the corresponding strain, strain rate and temperature necessary to define the shear localization onset. Both methodologies are based on analytical modeling of the orthogonal cutting process in conjunction with orthogonal cutting experiments. The basic mechanics governing the primary shear zone have been reevaluated for continuous and segmented chip formation processes. The stress, strain, strain rate and temperature fields have been theoretically derived leading to the expressions of the effective stress, strain, strain rate, and temperature on the main shear plane. Applying the least-square approximation techniques to the continuous chip formation results yields an estimation of the material coefficients of the constitutive equation described herein by a Johnson-Cook model. However, the segmented chip results provide data to characterize the shear localization onset. The identification results of the constitutive equation agree well with those obtained using the Compressive Split Hopkinson Bar technique (CSHB) in the case of 42CD4U steel. The identification of the shear localization onset yields encouraging results in the case of hardened AISI D2 tool steel (62 HRc).

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Low-cost and multifunctional automation technologies are still indispensable to industry today for the enhancement of cost competitiveness. This study focuses on the analysis of human dexterousness to develop new automation methods, because workers often find simpler work methods by task learning and the methods can be a clue to low-cost automation. This study presents a new "Station-less Assembly System" in which component parts are directly assembled by base parts moving on a belt conveyor without positioning. This paper first quantifies the remarkable characteristics of the human manual system, and next, based on the analysis, describes the new automation system that introduces a force-changeable gripper and human assembly algorithms.

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This paper deals with work monitoring for autonomous computer support. We have mentioned that a key technology for realizing autonomous support is computer recognition of a work sequence and work motion performed by human workers. In this paper, the effectiveness of using RFID (Radio Frequency Identification) for monitoring human work is discussed. Since RFID can identify the individual tag without physical contact, the work sequence is monitored by the detection of the RFID tag that is set on assembly parts. This function of RFID leads to the realization of a parallel monitoring structure that is a reliable recognition process of a work sequence, and a motion recognition algorithm without position sensing that had some problems in assembly environments. Experimental results show that RFID is effectively used for monitoring a work sequence and ensuring motion recognition in mechanical assembly work.

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This paper is directed toward the development of models, methods and tools suitable for effective, profitable, and autonomous cellular manufacturing as a new vision for 21st Century. The cellular manufacturing is mainly concerned with the efficient integration of three major concerns : (1) planning-oriented predictive cellular layout design; (2) an unexpected order-adapted cellular manufacturing through the integration between manufacturing decision processes and cellular layout, and (3) a contingency-driving shop floor adaptation for supporting continuous improvement. The system supports the user with five modules : real-time status monitoring, data acquisition and analysis, diagnosis through intelligent decision support system, simulation optimization, and results evaluation and performance measurement.

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The cellular machine, which we have been developing, is a mechanical system composed of distributed autonomous intelligent units, called cells, of as few kinds as possible, and with no central control as opposed to highly centralized present systems. Based on the technology of cellular machine, we have already developed an automatic warehouse, an assembling system, a manufacturing system, and a re-manufacturing system. In our most recent work, we have introduced the concept of movable cells to promote the expandability and the flexibility of the previously developed system. This paper reports the development of new cellular manufacturing system with movable cells and attachable/detachable machining equipment, and verification with actual hardware prototyping.

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A holonic fixturing system : HOLOFIX, to autonomously and cooperatively execute fixturing works of a workpiece is described and evaluated in this paper. HOLOFIX is developed by applying the concept of a holonic manufacturing system : HMS. All of elements in the system are holons, which comprise a black board and sub-holons and composed of a hierarchical structure : a holarchy. A holon can carry out tasks with other holons in autonomous and cooperative works. The effectiveness of a holonic system is clarified by experiments with a developed test bed of HOLOFIX; the black board communication system realizes autonomous and cooperative works between holons, and a workpiece is fixed on a pallet without giving sequential tasks like a program.

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The present research proposes a reactive scheduling method based on Genetic Algorithm (GA). This method modifies the initial production schedule reactively, when the unscheduled input of emergent jobs are added to the manufacturing systems. A prototype of reactive scheduling system was implemented, and computational experiments were carried out to verify the effectiveness of the proposed method for the cases of the unscheduled input of the emergent jobs.

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The purpose of this study is a development of component based Computer Numerical Controller (CNC) that can reconfigure software applications according to operator's requests in the network computation environment that consists of CNC, Personal Computer system and EWS. In this study, components for configuring software applications of CNC are managed in the network computation environment. CNC doesn't always have many software applications, however, necessary applications are configured dynamically by gathering necessary components from the network computation environment when it is needed. This paper describes a concept of the component based CNC and an outline of a basic system for achieving the component based CNC in the network computation environment.

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The paper deals with statistical analysis of geometric features within tolerance zone. The geometric features and their tolerance zone are firstly analyzed based on the JIS standards, and the parameters are established to represent the deviations of the geometric features from the nominal shapes. A systematic method is then proposed to analyze the probability that the geometric feature is included in the tolerance zone and to estimate the standard deviations of the deviation parameters that satisfy the constraints specified by the tolerance zones. The statistical properties of the deviation parameters of the geometric features are analyzed, and the statistical distributions of the deviation parameters of the geometric features are theoretically clarified.

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This paper deals with an automated computer-aided process planning and die design system with which designer can determine operation sequences even after only a little experience in process planning and die design of multi former-bolt products by multistsage former working. The approach is based on knowledge-based rules, and a process knowledge base consisting of design rules is built. Knowledge for the system is formulated from plasticity theories, empirical results and the empirical knowledge of field experts. Programs for the system have been written in AutoLISP for AutoCAD with a personal computer. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system is composed of four main modules, which are input and shape treatment, production feasibility check, process planning, and die design modules. The process planning and die design module considers several factors, such as the complexities of perform geometry, punch and die profiles, specifications of available multi former, and the availability of standard parts. It can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution and the level of the required forming loads at the last forming step by controlling the forming ratios. The system uses 2D geometry recognition and is integrated with the technology of process planning, die design, and CAE analysis. The stanardization of die parts for multi former-bolt products requiring a cold forging process is described. The strip layout and die layout drawings, which are automatically generated by formulization and quantification of experimental technology, will minimize trial and error and reduce the period for developing new products. The system developed makes it possible to design and manufacture multi former-bolt products more efficiently.

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In machining process planning, delta volume, which is derived by subtracting required shapes from raw material, is decomposed into some elements that are assigned to specific machining features and related to the specific machining processes. Therefore, the removed material of the raw stock, the removal volume, is the key element for deriving the previous shape of raw stock and determining the machining sequence in the machining process planning. It is thought that the removal volume contains information about the shape of the removed material and the machining process. This paper proposes a removal volume model which has the shape of the removed material and the machining process for a machining process plan based on a working tool model derived from the Form-Shaping Function mathematical model of machining operation.

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New architectures of manufacturing systems have been proposed aiming at realizing more flexible control structures of manufacturing systems, which can cope with dynamic changes in volume and variety of products. They are so called as autonomous manufacturing system like random manufacturing system, biological manufacturing system and holonic manufacturing system. The purpose of the present research is to develop an integrated process planning and scheduling system, which is applicable to the holonic manufacturing systems. A systematic method is proposed to select suitable machining sequences and sequences of machining equipment for optimal time and cost objectives, by applying a combined method of genetic algorithm (GA) and dynamic programming (DP).

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This paper deals with the analysis of the surface generating mechanism of a ball end mill based on deflection. The FEM model of a ball end mill is made out and the cutter deflection due to cutting force is calculated using the model. The shape of the machined surface is predicted by summation of cutting edge positions which are obtained by the cutter deflection and the cutter rotation during machining. The predicted surface is almost coincident to the experimental shape, so the method of calculation of the machined shape is verified.

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Recently, CAD embedded CAE has been realized, so structural analysis can be carried out smoothly after designing product shape. In this research, CAM embedded virtual manufacturing system has been proposed to realize the effective process and operation planning. In order to show the feasibility of it, estimation models of cutting force, machining error and environmental impact for end milling operation are introduced for the decision of machining strategy such as cutting conditions and tool path pattern. As a case study, different machining strategies are compared with requiring the thesholds of cutting force and machining error, and low environmental impact in this paper.

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This paper clarifies the analysis method for the undeformed chip thickness and the geometric influence of the tool orientation on the ball-nosed end milling. It has been firstly pointed out that the geometric situations on the determination of the thickness are categorized in three cases based on the relationship among the milling parameters. Secondly each corresponding case has been reduced into a comprehensive equation with introducing a coordinate system of tool axis orientation. Then the result of analysis has been displayed in graphics. Through the analysis of the equations, it was found that the tool axis orientation had direct influence to the undeformed chip thickness. Besides the description of analytical solving procedures, some experiments of undeformed chip thickness have been shown. For example, the distribution of undeformed chip thickness, the cutting length at any position of cutting edge, the area of cutting cross section and so on.

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This paper deals with an accurate cutting force prediction method of end milling. Cutting condition with small feed rate is often adopted in finish machining. In such conditions, the depth of cut in the radial direction of end mill cannot be estimated accurately by conventional cutting force prediction methods. When the depth of cut is quite small, the error on workpiece surface and the displacement of cutting edge are regarded as dominant factors to determine cutting force. Then, two estimation models about tool deflection and elastic recovery named "Actual depth of cut" are introduced in order to predict the depth of cut. In order to evaluate the effectiveness of introduced models, a prototype simulation system is developed and an experimental cutting is conducted. The measured cutting force in the experiment shows a good qualitative agreement with the predicted force.

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An approach is presented to simulate cutting process in the machining with curved-edge end mill, which has cutter radius and rake angle changing with cutter height. Those geometrical parameters are defined as functions of cutter height in the presented approach. Chip flow in the milling process is modeled as a pilling up of orthogonal cutting planes containing cutting velocity and chip flow velocity. Shear plane model can be made by orthogonal cutting data, which associates shear angle, shear stress and friction angle with rake angle. Chip flow direction can be given to minimize cutting energy calculated in the cutting model made. Cutting force can be predicted with cutting model having the minimum cutting energy. Some examples are shown to verify the presented approach in the machining with ball end mill and roughing end mill.

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