In conventional studies, cutting force optimization methods from NC simulation result have been proposed, and have been widely used. These methods are based on an assumption that machine tool is driven exactly as NC data command. However, the actual motion of recent highly-efficient machine does not often match with trajectory command by NC data. In such a case, it is difficult to predict the exact cutting force, and will lead to the sudden tool breakage or to excessively low feed rate to prevent the foregoing events. This paper deals with the development of off-line system of predicting the cutting force by using the actual cutting motion information for each machine axis from the CNC controller. The effectiveness of the proposed method has been confirmed by examining the experimental result of the prediction of surge cutting force especially in the corner area of workpieces.

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In the machine tools, low frequency vibration, which is called rocking vibration has a great influence on the tool-workpiece vibration. In this paper, to reduce the rocking vibration, a new damping systems is proposed to increase the damping of support system without decreasing the stiffness of support. This support system is based on stiffness tuning technique proposed in the previous study. An experiment is conducted to verify the effect of the proposed damper system. As a result, the proposed damper increases the damping of support system without decreasing the stiffness in an appropriate range of damper preload.

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The purpose of this study is to develop the new machine bed support mechanism which can reduce the vibration generated in high speed tracking motion. In order to achieve the purpose, frequency response and motion trajectory are measured on the machine supported by the proposed machine bed support which has sliding surface, and compared with the results measured on the machine supported by the conventional one. A mathematical model that can represent the influence of the machine support characteristic is also developed. The simulated frequency responses are compared with the measured ones. As the results from the experiments and simulations, it is confirmed that the vibration generated in high speed tracking motion can be reduced by the proposed machine bed support which has sliding surface.

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Unexpected problems may occur on the finished surface machined by the 5-axis machining centers, because of geometric and dynamic synchronous errors of the machine. In this study, actual ball-end milling tests of hemispheres and its finished surface simulations considering the different geometric errors and different position loop gain of feed drive systems were carried out, in order to clarify the influence of the errors onto machined surface. As the results, it is clarified that the influence of geometric errors onto the machined surface is depending on the relationships between the movement of the axes and the surface geometry. In addition, the dynamic synchronous error also influences the machined surface when the velocity of translational and rotational axes changed rapidly.

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The water driven stage was developed as a feed table for ultra-precision machine tool. The motion accuracy of the feed table is quite important in the ultra-precision machining. The paper thus deals with the attitude control of the table of the water driven stage. In particular, the paper focuses on the pitching control of the table. Trial pitching control tests of the water driven stage are carried out based on the pressure control of the water hydrostatic bearings of the stage. The feedback pitching control system for the water driven stage is then designed based on the approximated transfer function of the stage and flow control valve. The static and dynamic characteristics of the designed feedback control system are investigated via experiments.

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This paper presents a novel approach to the micromachining of quartz glass using a self-regulating feed-rate grinding-milling technique. To overcome the difficulties in machining hard-brittle materials, a tabletop linear 3-axis CNC machine tool providing grinding-milling at depths of several nanometers is first constructed. A feedback control loop (FCL) design which corrects in real time the feed-rate of the tool is proposed. Load-cells are devised on 3 axes to sense grinding-milling force and provide real-time feed-rate feedback control for protecting the quartz glass against brittle fracturing. Experimental results demonstrated that the self-regulating feed-rate approach creates a proper feedback control over the grinding-milling force; quartz glass is machined layer-by-layer, which realizes a quasi-ductile regime material removal. A twin-slot microstructure with 3 mm in length and a miniature 3-step-shaped pyramid of Ra0.139 μm surface roughness are accomplished. Experimental confirmation of the proposed approach is presented. Satisfactory cutting of two elaborate miniature microstructures reveal that the developed self-regulating feed-rate machine tool is effective, and should be very useful in the manufacture of intricate micro-parts.

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Trapezoidal acceleration based feed profiling has been widely used in high-speed motion generation for machine tools. Although it delivers continuous acceleration with limited jerk, the profile cannot be tuned to avoid exciting particular modal frequencies and eliminate residual vibrations. This paper proposes a novel FIR based trajectory generation algorithm that generates continuous trajectories with confined contouring errors suitable to deliver rapid motion with attenuated residual vibration. Specifically, fundamental formulation is presented to interpolate circular paths with confined contouring error while accounting for the FIR filter dynamics and path kinematics. Proposed method has been validated though simulations, and it shows significant improvement towards minimizing cycle time and accuracy of contouring multi-segmented Cartesian tool paths.

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A new CNC lathe with a tandem table unit driven by two linear motors has been developed to machine the non-axisymmetric curved surfaces by turning. This lathe, which is equipped with four axes (X_1 X_2, Z and C), enables to realize the NACS-turning (Non-Axisymmetric Curved Surfaces Turning) , machine the 3D surfaces by turning synchronizing with the spindle rotational position. The key factors for this turning method is to realize precise tool trajectory for the commanded position even in high acceleration motion. In this method, the large inertia force caused by the rapid motion with high acceleration and deceleration is another problem. Therefore, canceling the innertia force, tandem tables for X axis are equiped on the CNC lathe. These two tables are controlled opposite direction to cancel the vibration transmission to the base and the sipindle. In this study, a new CNC lathe with 4 axes including a tandem table unit is introduced and the fundamental dynamic performances of the table motion of the CNC lathe are measured and evaluated. The effects of tandem tables during the motion control for the curved surfaces is also evaluated.

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This study deals with non-axisymmetric curved surface turning (NACS-Turning) by a CNC lathe composed of a turning axis and two translation axes. We confirmed that NACS-Turning can be achieved with high efficiency compared with general methods. However, this novel turning method has inadequate machining accuracy. Therefore, this study developed an on-machine measurement method for improved machining accuracy in NACS-Turning. In this method, a line laser sensor measures the 3D profile of a machined workpiece, the profile is fed back to the CAM system, and the workpiece is reprocessed. In this paper, the system of on-machine measurement is explained, and its effectiveness is confirmed.

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In order to achieve accuracy assurance of machining parts, on-machine shape measurement is an important technology. Former research of on-machine measurement has not satisfied both of accuracy and efficiency. The objective of this research is to utilize line laser displacement sensor by improving the measurement accuracy. Error tendency of the sensor is evaluated by measuring accurate workpiece such as gauge blocks and pin gauges. From the experimental results, accuracy of the sensor can be compensated by considering a working distance and a target surface inclination.

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For the ultra-precision machine tools, vibration isolators are used in the machine support to reduce influence of the floor vibration. Particularly, rocking vibrations have influences not only on the tool-work piece displacement but also on the servo drive system. In this research, the location of the vibration isolators for the ultra-precision machine tools is analyzed in conjunction with the vibration induced by machine motion. The measurement of the transfer functions with the hammering was carried out for this purpose. It was found that the four-points-support has better vibration reduction performance to the machine motion than three-points-support in the rocking mode.

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Existing numerically controlled (NC) machine tools contribute to improving machining accuracy and productivity by tool motion control that is specified in part programs or NC programs. However, it is not possible to realize intelligent machine tools using existing methods in which machining operations are instructed by an NC program. Rather, a new concept, CAM-CNC integration, is needed to realize innovative intelligent machine tools. In our research, a new methodology to generate instruction commands for real-time machine control instead of preparing NC programs is developed using the CAM-CNC integration concept. The new methodology, which digitalizes the principle of copy milling, viz. Digital Copy Milling (DCM), can control the NC machine tool directly using 3D CAD models of the product and the raw material shapes and enable the NC machine tool to perform cutting process control. This innovative intelligent NC machine tool enables a reduction in NC program preparation time for rapid manufacturing and also avoids machining troubles.

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Recently, global warming and power supply shortages have increased awareness of the need for saving power. We propose a system for reducing power consumption of machine tools called Idling Reduction System (IRS). We specifically focus on the power consumption of servo motors of machine tools. We also focus on servo motor temperature. We investigated the effect of servo activation frequency on servo motor temperature of machine tools with our IRS. We examined methods to reduce the energy loss due to the temperature increase by measuring temperature change.

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Frequency Response Function measurements are carried out on two different industrial HSM Spindles rotating up to 24000rpm and powered from 40 to 70kW. An electromagnetic excitation device capable of applying a dynamic force to ±80N at 5kHz is used to perform the experiment. Measurements are made on four points by two displacement sensors and two accelerometers. A specific signal processing method that uses the cepstrum of the signal is applied to remove harmonics of the rotation in the signal. Variations of the dynamic behavior of the spindles with speed are observed and analyzed.

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A triangulation-based laser displacement sensor, using the diffuse reflection light, has a strong advantage in its robustness against the tilting of the object surface to the sensor's sensitive direction. On the other hand, it is often subject to higher-frequency noise-like measurement error in high-speed scanning operations. This paper first reviews that it is caused by the speckle in the reflected laser beam spot. Then, a scheme to reduce this speckle-induced scanning error is proposed by using two CCD image sensors aligned symmetrically about the laser beam axis. Its effectiveness is verified by preliminary experimentation.

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We apply magnetomechanical effect of ferromagnetic Co binder to investigate distributions of plastic strain in cemented carbide tools under turning. By turning without magnetic field, pre-magnetized WC-Co inserts showed demagnetization at plastic deformed area. In opposition, by turning under magnetic field, pre-demagnetized inserts showed magnetization at almost the same area with certain differences. The change of residual magnetization increased with the cutting force and cutting length, and showed saturation afterwards. These magnetic changes are explained from a magnetomechanical effect of the "law of approach" from hysteresis to anhysteresis curve under the plastic deformation, which makes magnetic domain walls unpinned from dislocations. Under no influence from the external magnetic field, demagnetization distribution will well predict area of plastic strain in machining tools.

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The minimum quantity lubrication (MQL) machining is capable to reduce the machining cost and cutting fluid consumption, while enhancing machining performance. However, the performance of machining with MQL cooling technique to reduce machining temperature is still ineffective. In recent study, machining with supercritical carbon dioxide (SCCO_2) cooling technique has been investigated to effectively reduce the machining temperature and subsequently prolong the tool life. In this paper, the characterization of SCCO_2 has been studied on two different input chamber pressures. Experiments were carried out using an orthogonal cutting process in which the efficiency of different SCCO_2 input chamber pressure was compared to MQL technique with respect to cutting temperature, cutting force and tool-chip contact length. The experimental results showed that the cooling effect of SCCO_2 was more efficient at high input chamber pressure. It reduces the cutting temperature, cutting force, and tool-chip contact length compared to SCCO_2 at low input chamber pressure and MQL machining technique.

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It is reported that a preheating process on hard-to-machine materials is an effective solution to enhance the machining performance. A number of studies have shown that the application of laser as a pre-heating medium significantly improved the tool life and surface quality. In addition, numerous studies in laser assisted micro milling have been reported using a micro end milling tools. However, the material removal mechanism of the micro ball mill tool is far complicated compared to flat end mill or turning process. In this study, the chips formation and machined surface condition of conventional and laser assisted micro ball milling on titanium alloy Ti6Al4V has been observed and compared. Linear grooves machining were conducted at various feeds, depth of cuts and spindle rotational speeds. The air bearing spindle was tilted at 80°. The condition of tools and chips were observed using scanning electron microscope and measuring microscope. It is understood that the tool wear and failure modes are highly influenced by the chips pattern. The application of pre-heating as a softening process of the work piece in micro ball milling process has consequently initiated a drawback such as formation of connected chips and built up edges. Machining with moderate chips length and width is found to be preferable in micro ball milling due to less possibility of chips interference and built up edges formation. Connected chips formation is not recommended in laser assisted machining due to the extreme plastic deformation behavior and excessive cutting temperature generation. Higher depth of cut has produced groves with built up layers at the up milling region. This is due to the poor chips evacuation and large size conical shape of chips.

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Multi-tasking machine tools are rapidly expanding because they can do both turning and milling processes. There is no accuracy test standard because multi-tasking machine tool is not defined exactly. However, it can be tested by referring to the accuracy test standard for turning centers and the newly revised one for 5-axis machining centers. In this research, three axes simultaneous interpolation motion measurement with R-test was performed and the motion errors for the multi-tasking machine were evaluated. Moreover, measurement with two-dimensional scale was also performed. The result was revealed to obtain much more information at once by performing data process similar to the R-test.

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Reliable production processes require an identical behaviour of identical machine tools. In the course of this paper a measuring method to estimate the variation of behaviour of feed axes by friction is conducted at machine tools in serial production. Thereby severe variances of friction are detected, which are caused by assembly variances. The reasons of these variances are examined by variation of assembly conditions of a test stand and verified by simulation. A modelling approach for simulating assembly variances reliably has been developed.

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This study reports an extended investigation on the wear, cutting forces and temperature on TiAlN, TiN coated and K15 carbide tool coated and uncoated tungsten carbide tools during the turning of four grades of ductile cast iron. During the machining of low strength grades, the flank wear rate was considerably lower and the steady-state longer, furthermore adhesion was observed on the rake and clearance faces. In the machining of high strength grades, the high wear resistance of the coated TiAlN coated tool caused a steady-state behavior then the flank wear rate change drastically. The K15 carbide tool had the worst performance respecting cutting force and flank wear. Although the cutting forces were similar for both coated tools, the TiAlN coated tool has better performance concerning to flank wear.

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This study presents a simple methodology for capturing power consumption by acceleration and deceleration of feed drive on a vertical three-axis milling machine only using a High Speed Power Meter (HSPM). Because of configurations of axes and inertia, not only feed rate but also acceleration power consumption varies in each axis. Acceleration of feed drive brings about peak power and additional energy consumption. Peak power and additional energy consumption by feed rate can be estimated by 2^<nd> order polynomial according to change of feed rate. For evaluation of developed model, some zigzag tool paths with different workpiece orientations were tested.

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In this study, influence of coating material on the curl diameter of chip in tapping of AISI 304 were investigated. In turning where chip is not ejected thorough flute, friction characteristic of AlCrN coating was better than TiN. However in tapping, both of the average torque and thrust using AlCrN was the largest. The curl of chip of tapping using AlCrN was larger than that of TiN and CrN. The chip curl diameter was larger than the diameter of an inscribed circle at cross section of the flute. Therefore ejection resistance of chip might cause an increase of torque in tapping. Tendency of curl of chip in turning was similar with that of tapping. In tapping, chip clogging lead to breakage. Hence, it is important to investigate the chip curl tendency in advance.

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The use of machine tools for on-machine coordinate measurement on the workpiece is becoming commonplace. However, numerous errors can adversely affect the measurement accuracy. For instance, the inter-axis parameters are major contributors to the overall machine tool's inaccuracy hence estimation and compensation of such errors are prerequisite to fully exploit the machine measurement potential. This paper presents a scheme to assess the accuracy of coordinate measurement by probing a precision sphere mounted on the machine table and probed for different rotary axes indexations. The individual probing data, and not the computed sphere centre, are used for the assessment thus providing a richer data set. Machine readings are processed either directly, using the machine nominal model or using a compensated model. This provides a fast method to validate on-machine measurement before and after compensation.

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Several methods to evaluate the motion accuracy of the rotary axis of 5-axis machining centers have been proposed and attracts attention. However, the influence by the translational axes is included in an evaluation result because the translational axes turn over at the motion direction changing point of the rotary axis in a general simultaneous motion of the rotary and translational axes. In this study, a measurement system to evaluate the dynamic characteristics of rotary axis around the motion direction changing point which can eliminate the influence of translational axes is developed. In addition, it is confirmed by the actual machining tests that the influence of tracking error on the machined surface is related with the size/shape of the tools and geometrical relationships between the tracking error and the machined surface.

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NAS 979 is a standard to evaluate accuracy of five-axis machining centers. Five-axis machining centers evaluate motion accuracy by to cut cone frustum in NAS 979. Geometric movement of five-axis machining center is determined by using form-shaping-function. This paper focuses to relationship between half apex angle and tilt angle of cone frustum. Movement of rotary axes can be divided into three types by relationship between magnitudes of half apex angle and tilt angle. Change velocity of rotary axis can choose by relationship between magnitudes of half apex angle and tilt angle. It became possible to determine command value, velocity, and acceleration of each axis mathematically, not experimentally.

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Several industrial fields show a growing interest in producing components with tiny features realized through micro-cutting processes. Micro-cutting processes cannot be considered as simple downscaling of the conventional process since some phenomena, neglected in macro scale, become predominant in micro scale. Nowadays, in micro-cutting field, guidelines suitable for performing standardized machining tests able to evaluate the performance of a micro-cutting process considering the influence of machine-tool, tool holder, tool, workpiece material microstructure, workpiece fixtures and process parameters are not available. The aim of this paper is to propose a testing procedure for micro-milling process defining the set up to be used and the output to be considered. The suggested procedure was applied using an ultra-precision micro milling machine-tool. This machine was characterized through experimental modal analysis for identify its natural frequencies. The test results show the suitability of the proposed guidelines in evaluating the performance of machine-tool and process when micro-milling features are realized.

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Multi-tasking machine tools are widely applied to reduce production lead-time and improve productivity. However, unexpected collisions can often occur among the machine structures, including the workpiece and jig on multi-tasking machine tools. Thus a machine simulator is essential for avoiding collisions during machine operation. In a commercial machine simulator, however, unexpected collisions can still occur when the setup of a workpiece or a jig differs from the simulation models created in advance. Therefore, this study deals with a development of a machine simulator that imports 3D models created by measuring the shapes of the workpiece and jig by using a touch-trigger probe after they have been setup for a machining operation.

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In the manufacturing industry, there is an urgent need to shorten the manufacturing lead-time of products. Therefore, optimizing process planning is essential for realizing high efficiency machining. In this study, in order to develop a computer aided process planning (CAPP) system using previously proposed machining features, a prediction method for some process evaluation indexes is proposed. Furthermore, case studies of process planning are conducted to confirm that the operator's strategy affects the selection of the machining process candidates. From the case study results, it is found that the proposed evaluation indexes have the potential to be useful for determining the machining process, and are suitable for a flexible CAPP system for multi-tasking machining tools.

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The square and radius end mills have been mainly used for rough cutting due to its large amount of removal volume. The cutting load was only considered by changing the tool feed speed. However, the cutting time becomes long by that change. In this report, the tool path that cuts the interference surface next to the machining surface by five-axis controlled side cutting was generated, and the generated tool path was revised on the basis of the removal volume per unit of time to prevent the sudden change of cutting load by changing tool posture. As the result, the effectiveness of the proposed method was confirmed by machining simulation.

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This study proposes a new, efficient method to control the direction of the instantaneous cutting force xerted on a workpiece surface in continuous multi-axis controlled machining. During the finishing process for aerospace parts with a thin wall shape, workpieces with low rigidity are often deformed by the exerted cutting force. To reduce such machining errors, in the proposed method, the tool posture in each cutter location is modified gradually according to estimated results from model-based computer simulation of the instantaneous cutting force. To shorten calculation time, the developed prototype system introduced a new application of the ultra-parallel processing technology known as GPGPU. This technology showed good performance in a complicated NC programs generated by a commercial CAM system.

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Generally, ball end-mills are used for machining free-form surfaces. When machining free-form curved surfaces using ball end-mills, removing the cutting remnants known as cusps formed on machined surfaces is necessary. Since cusp removal is performed manually by hand, much time and labor is required. This paper proposes several methods to decide optimal tool postures and tool paths for 5-axis control machining using flat end-mills and radius end-mills in order to efficiently and precisely machine free-form surfaces. A basic system based on the proposed methods was constructed, and the effectiveness of the proposed methods was verified through simulations and experiments.

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At the spindle unit, thermal deformation is rapid, because the spindle unit has a small thermal capacity. There is highly relationship between temperature and deformation. However, it is difficult to measure temperature directly when the spindle is turning. And also it is difficult to measure temperature directly that is closer to a heat source. Rapid thermal deformation is caused by variation of rotation speed of spindle. Estimating method is developed used the temperature distribution. And other methods are studied. The study proposes the method to estimate thermal deformation from a number of rotations histories.

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Dual-arm industrial robots have been gaining attention as novel tools in automation. We therefore focus on using them to flexibly control both the linear motion and the rotational motion of a working plate. However, it is difficult to measure the synchronous accuracy of two rotary axes of a working plate. The working plate uses dual-arm cooperative control to keep the ball rolling in a circular path on it. In this report, we estimate the effect of the synchronous accuracy of two rotary axes under upper and lower poses to support the working plate and avoid ball-rolling error. We discuss a method to improve the robot motion accuracy based on the double ball bar (DBB) method to generate a robot on-line program by teaching the playback method in industrial fields.

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The purpose of this research is to optimize the arrangement of industrial robots when two robots cooperate in movement. In this study, We evaluated the joint torque of two robots and estimated the size their output margin, on the basis of which We proposed a method for arranging the two robots. Based on the relationship of work area of two robots and margin of torque,We optimized the arrangement of the two robots. We estimate the output torque by measuring the current flowing through motors. And it confirmed the usefulness of the technique.

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The friction compensation of guideways is critical to realize feed drive systems that have both high load capacity and high precision. It is difficult to predict the friction force with conventional friction models because they do not consider the friction characteristics in the transient state. In this report, we propose an analysis method for friction characteristics in the transient state. With our proposed method, we investigated the maximum state friction, the kinetic friction, and the friction characteristics while the feed drive system is standstill..

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In vertical positioning systems, the friction force and the gravity load may cause serious positioning error. This paper presents the noncontact gravity compensator applying magnetic fluid seals. The magnetic fluid seals were designed for the reciprocating system and the sealing performance of the seals were estimated by the magnetic field analysis using FEM and the results were verified by the experiment. Then the gravity compensating system using the magnetic fluid seals was constructed, and the effectiveness of the system was confirmed.

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Based on the example of the open industrial Ethernet Technology standard 'EtherCAT', the paper discusses the influence of superior communication performance on precision, throughput, mechanical lifetime, costs and raw material saving of manufacturing equipment. Several practical examples are shown. It also shows how bandwidth usage, switch delays and stack processing times limit the usage of classical Ethernet for control applications and briefly introduces the EtherCAT communication technology itself.

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The problems associated with machining CFRTP (carbon fiber reinforced thermoplastics) are short tool life and burrs. In this study, side milling tests are carried out dry and with two types of coolants liquefied carbon dioxide (LCO_2 ) and liquefied nitrogen (LN_2 ). The workpiece material is a composite material made of carbon fibers and polyetheretherketon (CF/PEEK) Cutting force, surface integrity and tool wear are evaluated, and the elastic modulus of the CF/PEEK is examined. The use of liquefied nitrogen as a coolant suppresses burrs effectively. There is no significant difference in tool wear between the dry and cryogenic conditions. The finished surface roughness increases with the cutting length, and milling with liquefied nitrogen shows the highest surface roughness. The elastic modulus of CF/PEEK under cryogenic condition is higher than that at room temperature.

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Optical scanning parts that reduce optical aberration, scatter, and diffraction are required in laser printers. It is necessary to improve the geometric surface roughness achieved in mirror cutting of Al alloys, and to remove tear-out marks and scratch marks that occur during the cutting process. Therefore, we investigated the cutting edge shape using a straight diamond tool to decrease surface defects during ultra-precision cutting of Al alloys. We obtained the result that when the feed rate is 100μm/rev using the improved triple-facet tool, we can achieve a good machined surface without scratch marks and tear-out marks.

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Recently, high-combustion-efficiency jet engines have become essential in the aircraft industry. High burning temperatures are necessary to maximize the combustion efficiency of jet engines. Inconel 718, which has excellent mechanical and chemical properties, has been selected for use in many jet engine parts. However, it is difficult to cut this alloy because of its low-thermal-conductivity. Consequently, wet cutting is typically used to reduce the heat generated in cutting Inconel 718. In this study, the authors conducted experiments to examine the relationships between high-efficiency cutting and tool wear in high-pressure coolant system. These results indicate that, high-efficiency cutting is possible.

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Micro-channel chips, which are used in micro total analysis systems, are attracting attention in the medical field. The photolithography technology used in semiconductor manufacturing is generally used to manufacture micro-channel chip dies. However, this technology requires many processes, such as mask fabrication and the application of photoresist to a substrate, as well as expensive clean room facilities. Therefore, this study examines how to form a fine groove by cutting with micro-endmills. This investigation experimentally examined a method for reducing the influence of tool run-out on machining accuracy with multi-tooth endmills. As a result, the effects of tool run-out on micro-groove milling, such as decrease in groove increment, were clarified.

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This research deals with the hard turning of cemented carbide with CBN and diamond tools and focused ontool performance, mainly tool wear, taking into account cutting temperature and cutting force. Five types of tool materials: SC, two PCDs, BL-PCD and CBN: are selected for cutting three grades of cemented carbide (WC), differentiated by the Co binder content (12%, 20% and 25%). Attrition has been found to be the main tool wear mechanism for all tools with slight adhesion of the workpiece binder on the tool face. Cutting temperature is influenced by thermal conductivity of the tool as well as cutting force and tool wear.

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Machining for thin-walled hollow cylindrical becomes one of the most difficult tasks. It is because those workpieces have low rigidity. Owing to low rigidity, chatter in the cutting process is easy to result. The main purposes of this research to analyze the dynamic characteristics and observe the chatter stability limit. The study compared the experiment and the simulation method. The results show that the dynamic characteristics and chatter phenomenon are determined by the variations of wall thickness. The agreement between the simulation and experimental results is satisfactory although there are little different case of them.

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Low-frequency vibration drilling can suppress drilling temperature, and extend tool life. During low-frequency vibration drilling, there are drilling times and non-drilling times in one vibration cycle. The temperature increases during drilling and decreases during non-drilling. In this study, temperature transition of the cutting edge was simulated from the heat input caused by the cutting energy, calculated from principal cutting force and speed. To simulate the temperature change of the drill edge, the principal force acting on the cutting edge was calculated from two-dimensional cutting data. Temperature near the cutting edge was measured experimentally by embedded K-type thermocouple for verification of the simulation results. It was shown that the simulated temperature transition agreed well qualitatively with the measured results during low-frequency vibration drilling.

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This study presents the in-process tool wear detection of the square end mill in down cut application. The developed high-speed tool wear detection system based on DC two terminal method uses the contact resistance between the tool and workpiece as a gauge to observe the progression of the tool wear. Depending on the width of tool flank wear, the electrical resistance signal decreases according to the increase of the contact area on the tool flank. The influence of the thermo-electromotive force (E.M.F) should be considered in detecting the contact resistance. In the previous experiment, the target was the face milling process. In this experiment, all attentions were focused on square end mill applying to up cut, down cut and center cut. The results were presented through the observation of the relationship between tool flank wear width and tool-work contact resistance which has not been evaluated until now. As a conclusion; the results of the experiment show that the present high-speed tool wear detection system based on DC two terminal method is effective as an in-process detection tool wear system also for the square end mill.

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Finite element (FE) method has been widely used for investigating the machining process of SiC_P/Al composites. However, SiC particle is always considered as a rigid body, which is inconsistent with the practical machining of SiC_P/Al composites and reduces the value of the computational analysis. This paper aims to propose an FE model by considering the fracture of SiC particle to investigate the material removal process in cutting SiC_P/Al composites. The tensile strength of SiC was utilized as the critical cracking stress of the particle. It was found that the tool-particle relative location has significant effects on the fracture of the particles and machined surface quality.

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Understanding the cutting process of particle reinforced aluminum matrix composites is important for a more appropriate application of the composites. However, in the previous finite element modeling, the reinforcement particles, such as SiC, are generally treated as spheres. Such a simplification is inconsistent with the actual geometries of the particles whose shapes are mostly irregular. This paper established a microstructure-based finite element model with the aid of Abaqus/Explicit, imitating the real particle morphologies obtained from the micrographs of SiCp/Al composites. The defect formation mechanisms of the SiC fracture, the cavitation, the pit and the protuberance in machined surfaces of the composites were then investigated and verified by experiment. It was found that the microstructure-based model can more appropriately mimic the cutting of SiCp/Al composites.

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Many difficult-to-cut materials such as Ni-base super alloy, titanium alloy, and austenite stainless steel which are used extensively in aerospace generally have high strength-to-weight ratios, high corrosion resistance, high strength retention ability at elevated temperatures, and low thermal conductivity. These characteristics can result in uneven tool wear and chatter vibration. Therefore, determining the appropriate end-milling conditions is more difficult for difficult-to-cut materials than for other materials. There has been much research on the high-speed milling of difficult-to-cut materials, and effective end-milling conditions, end-mill tool shapes, and processing methods have been reported. In addition, irregular pitch and lead end-mills with different helix angles have been developed by tool maker's to reduce chatter vibration, making it easier to perform high-speed milling. However, there have been few reports of slotting information useful for determining appropriate end-milling conditions and processing methods for Ni-base super alloy. The aim of this study is to derive end-milling condition with high efficiency grooving process for Ni-base super alloy (Inconel 718) sheet. Effects of cutting parameters were examined from the view point of cutting resistance, tool tip maximum temperature and tool flank wear width. As a result from experiments, if the grooving process condition of axial depth of cut is smaller than other conditions on the same material removable rate value, it has been found that it is possible to reduce the tool tip maximum temperature and prolong the tool life.

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An FEM-based model to predict the deformation of thin-wall parts to minimize the static deformation have been previously studied. In order to apply the simulation to design of cutting strategies, a simplified and practical force model covering variable radial depth of cut and axial depth of cut was proposed. The instantaneous cutting force was normalized as a rectangular function. The duty factor of the rectangular function was calculated from cutting conditions. Cutting tests on an aluminum alloy workpiece with slant paths were conducted to identify the parameters, where the radial depth of cut and/or axial depth of cut varied from zero to the nominal values. The cutting force calculated by the model was compared with experimental data for validation.

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