Proceedings of the Korean Society of Machine Tool Engineers Conference (한국공작기계학회:학술대회논문집)
The Korean Society of Manufacturing Technology Engineers
- 기타
1999.10a
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One of the important considerations in designing a machine tool is the durability. In this study, a durability estimation systems for horizontal machining centers is developed to evaluate the effects of structural specification and driving conditions on the durability. All loads such as weights, inertia forces, cutting force and so on, are automatically transferred from the upper elements to the lower elements by the force flows which can be derived from the structural code of horizontal machining centers. And the external loads applied to the motion elements such as bearings, LM guides, ball screws and so on, are determined by the equilibrium conditions of force and moment. Especially, the durability of horizontal machining center is estimated based on the lifes of motion elements operating under the desired driving conditions.
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Monitoring of the cutting force signals in cutting process has been well emphasized in machine tool communities. Although the cutting force can be directly measured by a tool dynamometer, this method is not always feasible because of high cost and limitations in setup. In this paper an indirect cutting force monitoring system is developed so that the cutting force in turning process is estimated based on a AC spindle drive model. This monitoring system considers the cutting force as a disturbance input to the spindle drive and estimates the cutting force based on the inverse dynamic model. The inverse dynamic model represents the dynamic relation between the cutting force, the motor torque and the motor power. The proposed monitoring system is realized on a CNC lathe and its estimation performance is evaluated experimentally.
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본 연구에서는 컴퓨터 상에 제어기와 구동부 등으로 구성된 가상제조시스템(Virtual Manufacturing System)을 구축하고 시뮬레이션하는 방법론을 다룬다. 특히 설비들간의 이동시 발생할 수 있는 3차원 공간상의 충돌을 검출하는 이산사건 및 연속상태 혼합 시뮬레이션 방법론을 소개한다. 시뮬레이션 모델은 DEVS(discrete event system specification) 형식론(formalsim)에 기초한 형상기구학 정보를 갖는 이른바 GKDEVS(Geometrical Kinematic DEVS)을 이용하였고, 시뮬레이션 방법론은 DEVS의 추상화 시뮬레이션(abstract simulation)방법을 확장하였다.
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In general, three are many degrees of freedom (DOF) in industrial robots. That can generate several special end-effector's positions and orientations. For that reason, industrial robots are used in a wide scope of industrial applications such as welding, spray painting, deburring, and so on. In this research, new method is presented which safely maintain the desired constant end-effector's orientation and minimize the numbers of segments in path. These algorithms may apply to welding, painting, and assembling. The simulation study of straight line and circular motions in arc-welding operations is carried out to show the sure proof of these algorithms.
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In order to regulate cutting force at a desired level during NC lathe process, a feedrate override Adaptive Control Constraint system was developed. Nonlinear model of the cutting process was linearized as an adaptive model with a time varing process parameter. Performance of the ACC system was confirmed on the NC lathe equipped with the developed NC system through a large amount of experiment.
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If the on-line cutting conditions (e.g. speed, feedrate, radial and axal depth of cuts) can be identified in an end milling process, much information about cutting forces will be estimated from the cutting force model. Therefore, those estimated conditions can be applied to monitoring and control areas. In this paper, a real-time estimation algorithm for radial and axial depth of cuts is studied in end milling using the averaging cutting forces per tooth. The analytical estimation models of depth of cuts are derived from the geometric cutting force model. The validity of the estimation models is verified on a horizontal machining center through the experiments in various cutting conditions.
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The demands for robotic and automatic system are continually increasing in manufacturing fields. There have been many studies to monitor and predict the system, but they have mainly focused upon measuring cutting force, and current of motor spindle, and upon using acoustic sensor, etc.In this study, time series sequence of cutting force was acquired by taking advantage of piezoelectric type tool dynamometer. Radial cutting force was obtained from it and was available for useful observation data. The parameter was estimated using PAA (parameter adaptation algorithm) from observation data. ARMA(auto regressive moving average) model was selected for system model and second order was decided according to parameter estimation. Uncorrelation test was also carried out to verify convergence of parameter.
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This paper present a study on the application of sound pressure and vibration signals to detect the presence of defects in a rolling element bearing using a statistical analysis method. The well established statistical parameters such as the crest factor and the distribution of moments including kurtosis and skewless are utilized in this study. In addition, other statistical parameters derived from the beta distribution function are also used. A comparison study on the performance of the different types of parameter used is also performed. The statistical analysis is used because of its simplicity and quick computation. Under ideal conditions, the statistical method can be used to identify the different types of defect present in the bearing. In addition, the results also reveal that there is no significant advantages in using the beta function parameters when compared to using kurtosis and the crest factor for detecting and identifying defects in rolling element bearings from both sound and vibration signals.
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A disassembility assessment has mostly depend on the subjective decision making from the qualitative element. It is not useful in the practical assessement because it is not specified. The purpose of this paper is an assessmet based on Fuzzy-study-rule. This rule is definitely modified fromnon-fuzzy language of qualitative element. The new assessment method of design for disassembility assessment(DFDA) is practical to introduce the fuzzy number as the conversion of quantitative element from qualitative. It is appled to air-cleaner of passenger-vehicle for the usefulness.
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Because misaligned shafts have caused noise, vibration, bearing failures, and stress concentration of coupling part, which decrease the efficiency and life of a shaft system, the proper alignment of shaft system should be monitored continuously in dynamic condition. To solve these problems under dynamic condition, a telemetry system is this study is used to find the condition of the least bending moment, which is known by analyzing the structure and stress induced by misalignment is investigated. The moment derived from two shaft strain at the nearby coupling is measured. The bending strain is measured 5 times for average in static state as well as dynamic state with 100~700 rpm.
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This study discusses a non-contact optical technique, electronic speckle pattern interferometry(ESPI), that is well suited for in-plane and out-of-plane deformation measurement. AS4/PEEK[30/-30/90]s, composite laminate plate was analyzed by ESPI to determine the vibration characteristics with tensile loading and without it. vibration mode shapes are quantitatively compared with the result of numerical analysis. The experimental results agree well with those of numerical analysis. we found that when the composite laminate plate is under the tensile loading, vibration modes can be measured with high accuracy by ESPI.
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Work roll wear in the cold rolling of mild steel strip is strongly affected by rolling materials, rolling conditions such as roll arrangement in the cold rolling mill and lubrication. The tests were performed to find the effects of roll arrangement n the cold rolling mill on the work roll wear under the same lubricating conditions. The obtained results are as follows:If the distance of cold rolling is about 60km, the surface roughness of its was reduced by half(Ra 0.49
${\mu}{\textrm}{m}$ ) and Pc(peak count) also was decreased to 60 ea/cm.It is easier for CC(Continuous casting) to make a slip on rolling than IC(Ingot casting). It is due to surface mirror in which first residual product appears and iron powder included Al2O3 is sticked. Because bending degree of 4Hi-rolling mill is higher than 6Hi-rolling mill, the first surface mirror was occurred to its center-point which is loaded strongly. 6Hi-rolling mill shape-controlled by intermediate roll doesn't need the initial crown to work roll. Therefore, fatigue and wear would appear a little bit. -
Nowadays, as the development period of new products becomes shorter and consumer's requirement is more various, the importance of Rapid Protytyping Technology has been rapidly increased. Rapid Protytyping makes protytypes or functional parts directly using the 3D CAD data. But RP machines can make protytype in limit size. But RP machines can make protytype in limit size. For making large size protytype, we slice solid, which is made of STL file, and then glue sliced solid. This paper is concerned with slicing solid on STL file.
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The biggest challenge facing today manufacturing industry is better quality and high productivity. From an economic point of view, productivity is the most important parameter, as high productivity will reduce the cost. However, the customers of today are not only cost concerned, but also quality conscious. So high accuracy levels should also be achieved in the manufacturing process. This paper reports the development of a automatic design system based on AutoCAD program. This work is composed of three section that are design of top down menu, guide frame and gate lifter for water-gate programed by AutoLISP language and runned Windows system. The developed system ultimately generates the design for a water gate through AutoCAD program. In the design of the water gate, it needs about 23 hours with an expert, but this system can be only 80 seconds without an expert.
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Non-contacting capacitive sensors, based on principle of the cross capacitor, for measuring small displacement less than 1.95
$\pm$ 0.5 mm have been fabricated and characterized. To overcome disadvantages of the existed capacitive sensors, the new sensor is consisted of 4-electrodes which are formed 2 active electrodes and 2 guard electrodes on a sapphire plate with diameter 17mm and thickness 0.7 mm, and are symmetrically situated with constant gap of 0.2 mm among the electrodes. The sensor is evaluated to be correlation coefficient of 0.9987 for the range of 1.95$\pm$ 0.5 mm and that of 0.9995 for 1.95$\pm$ 0.25 mm range. This sensor can be used for in situ measurements in the mechanical mirror polishing with precision less than$\pm$ 1${\mu}{\textrm}{m}$ . -
This paper proposes an efficient method constructing a local map using the data of a scanning laser range finder. A laser range finder yields distance data of polar form, that is, distance data corresponding to every scanning directions. So, the data consists of directional angle and distance. We propose a new method to find a line fitting with a set of such data. The method uses Log-Hough Transformation. Usually, map building from these data requires some transformations between different coordinate systems. The new method alleviates such complication. Also, the method simplifies computation for line recognition and eliminates the slope quantization problems inherent in the classical Cartesian Hough transform method. To show the efficiency of the proposed method, it is applied to find a local map using the data from a laser range finder PLS(Proximity Laser Scanner, made by SICK).
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This paper presents a local obstacle avoidance method for indoor mobile robots using Lane method and velocity Space Command approach. The method locates local obstacles using the information form multi-sensors, such that ultrasonic sensor array and laser scanning sensor. The method uses lane method to determine optimum collision-free heading direction of a robot. Also, it deals with the robot motion dynamics problem to reduce some vibration and guarantee fast movement as well. It yields translational and rotational velocities required to avoid the detected obstacles and to keep the robot heading direction toward goal location as close as possible. For experimental verification of the method, a mobile robot driven by two AC servo motors, equipped with 24 ultrasonic sensor array and laser scanning sensor navigates using the method through a corridor cluttered with obstacle.
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This paper presents a new approach to the design of neural control system using digital signal processors in order to improve the precision and robustness. Robotic manipulators have become increasingly important n the field of flexible automation. High speed and high-precision trajectory tracking are indispensable capabilities for their versatile application. The need to meet demanding control requirement in increasingly complex dynamical control systems under significant uncertainties, leads toward design of intelligent manipulation robots. The TMS320C31 is used in implementing real time neural control to provide an enhanced motion control for robotic manipulators. In this control scheme, the networks introduced are neural nets with dynamic neurons, whose dynamics are distributed over all the network nodes. The nets are trained by the distributed dynamic back propagation algorithm. The proposed neural network control scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Performance of the neural controller is illustrated by simulation and experimental results for a SCARA robot.
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This paper presents new approach to technology pattern recognition of camera back cover and test of soldering. In real-time implementing of pattern recognition camera back cover and test of soldering, the MVB-03 vision board has been used. Image can be captured from standard CCD monochrome camera in resolutions up to 640
$\times$ 480 pixels. Various options re available for color cameras, a synchronous camera reset, and linescan cameras. Image processing os performed using Texas Instruments TMS320C31 digital signal processors. Image display is via a standard composite video monitor and supports non-destructive color overlay. System processing is possible using c30 machine code. Application software can be written in Borland C++ or Visual C++ -
In this paper, it is presented a new technique to the design and real-time implementation of fuzzy control system based-on digital signal processors in order to improve the precision and robustness for system of industrial robot. Fuzzy control has emerged as one of the most active and fruitful areas for research in the applications of fuzzy set theory, especially in the real of industrial processes. In this thesis, a self-organizing fuzzy controller for the industrial robot manipulator with a actuator located at the base is studied. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variable of the controller, In the synthesis of a FLC, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult, SOFC is proposed for a hierarchical control structure consisting of basic level and high level that modify control rules.
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This paper proposes the robot inverse calibration method using a neural networks. A highorder networks called Pi-Sigma networks has been used. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position, orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness, the SCARA type direct drive robot(4-DOF) and anthropomorphic robot(6-DOF) are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from
$\pm$ 2$^{\circ}$ to$\pm$ 0.1$^{\circ}$ . -
In this paper, we developed a Windows 95 version off-line programming system which can simulate a track vehicle model in 3D graphics space. The track vehicle was adopted as an objective model. The interface between users and the off-line program system in the Windows 95's graphic user interface environment was also studied. The developing language is Microsoft visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.
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This paper presents a new approach to the dynamic control technique for track vehicle system using neural network-fuzzy control method. The proposed control scheme uses a Gaussian function as a unit function in the neural network-fuzzy, and back propagation algorithm to train the fuzzy-neural network controller in the framework of the specialized learning architecture. It is proposed a learning controller consisting of two neural network-fuzzy based on independent reasoning and a connection net with fixed weights to simply the neural networks-fuzzy. The performance of the proposed controller is shown by simulation for trajectory tracking of the speed and azimuth of a track vehicle.
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In this paper, it is proposed the adaptive-sliding mode control technique which is new approach to implement the robust control of industrial robot manipulator with external disturbances and parameter uncertainties. Over the past decade, the design of advanced control systems for industrial robotic manipulators has been a very active area of research and two major design categories have emerged. Sliding mode control is a well-known technique for robust control of uncertain nonlinear systems. The robustness of sliding model controllers can be shown in continuous time, but digital implementation may not preserve robustness properties because the sampling process limits the existence of a true sliding mode. Adaptive control algorithm is designed by using the principle of the model reference adaptive control method based upon the hyperstability theory. The proposed control scheme has a simple structure is computationally fast and does not require knowledge of the complex dynamic model or the parameter values of the manipulator or the payload. Simulation results how that the proposed method not only improves the performance of the system but also reduces the chattering problem of sliding mode control. Consequently, it is expected that the new adaptive sliding mode control algorithm will be suited for various practical applications of industrial robot control system.
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This paper presents a new approach to the design of adaptive control system using DSPs(TMS320C30) for robotic manipulators to achieve trajectory tracking by the joint angles. Digital signal processors are used in implementing real time adaptive control algorithms to provide an enhanced motion control for robotic manipulators. In the proposed control scheme, adaptation laws are derived from the improved Lyapunov second stability analysis method based on the adaptive model reference control theory. The adaptive controller consists of an adaptive feedforward controller, feedback controller, and PID type time-varying auxillary control elements. The proposed adaptive control scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Moreover, this scheme does not require an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by simulation and experimental results for a SCARA robot.
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In this paper, it is presented a new scheme of adaptive-neuro control system to implement real-time control of robot manipulator using digital Signal Processors. Digital signal processors DSPs. are micro-processors that are particularly developed for variables. Digital version of most advanced control algorithms can be defined as sums and products of measured variables, thus it can be programmed and executed through DSPs. In addition, DSPs are as fast in computation as most 32-bit micro-processors and yet at a fraction of their prices. These features make DSPs a biable computatinal tool in digital implementation of sophisticated controllers. Unlike the well-established theory for the adaptive control of linear systems, there exists relatively little general theory for the adaptive control of nonlinear systems. Adaptive control technique is essential for providing a stable and robust performance for application of robot control. The proposed neuro control algorithm is one of learning a model based error back-propagation scheme using Lyapunov stability analysis method. The proposed adaptive-neuro control scheme is illustrated to be a efficient control scheme for implementation of real-time control of robot system by the simulation and experiment.
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Noncontact measuring methodology of 3-dimensional profile using CCD camera are very attractive because of it's high measuring speed and its's high sensitivity. Especially, when projecting a grid pattern over the object the captured image have 3 dimensional information of the object. Projection moire extract 3-D information with another grid pattern in front of CCD camera. However phase measuring profilometry(PMP) obtain similar results without additional grid pattern. In this paper, new method for grid pattern generation system by polygonal mirror and Laser Diode. This system is applied the projection moire and the PMP.
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When the steel containing Si is oxidated in hi temperature, Re2O3, Red scale is made on the metal side as the spike phase, and this scale invasion into matrix. Therefore, it affects the feature, after rolling. It is reported that the role of Si is FeO/Fe2SiO4 eutectic compound, but Si can not affect pure iron independently. There must be Ni, then the spike phase can exist. Prominence and depression made by Ni that is necessity at the process to work iron. Therefore, in this study after the change of the amount of Ni in pure iron and steel and oxidation, the structure of the oxide and the surface, and the distribution of the elements were considered. In conclusion, at 100
$0^{\circ}C$ , 110$0^{\circ}C$ , 120$0^{\circ}C$ the curves of oxidation weight are all S curves. Especially, in the beginning of oxidation as the amount of Ni increase, the amount of oxidation also increase. Practical steel has less oxidation than pure steel added Ni. There is much FeO in Fe-Ni alloy, compare to practical steel which has much Fe3O4. Especially, we could know considerable Ni was concentrated on the metal side in Fe-Ni alloy, practical steel. and the surface of the scale. -
There has been a considerable attention in Invar alloys because of its low thermal expansion property. A low thermal expansion property of Invar alloys, lower than 10-6 near the room temperature, is attractive for precision machine tools. However, the expansion property of Invar alloys is limited below about 520。K, and mechanical properties are relatively low to apply to machine tools. In order to improve mechanical properties in this alloy, Ti alloy element was added to an invar alloy. Microstructure changes and optimum heat-treatment conditions according to Ti addition were discussed in the Ni38-Mo2-Crl-Fe Invar alloy.
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Hot forgeability of STD 61 steel was boronzed in boronizing paste mainly consisted of B4C and Na2B4O7 at various temperatures and times. Microhardness and thickness of boride layers were measured and distributions of B, Si, Cr and V on the cross section of specimen were observed by EPMA line analysis. Microscopic examination and results of EPMA showed that the boride layer consisted of two layers outer layer of FeB and inner layer of Fe2B. Microhardness of these boride layers was in the range of Hv 1800~2300. Thickness of boride layer increased with times and temperatures. Si-rich
$\alpha$ layer was formed between boride layer and matrix. Element such as Cr concentration as Cr23(B, C)6 beneath the boride layer. -
Stainless steels in general has passive film having strong corrosion resistance on surface. Therefore it must be necessarily removed by etching in mixing solution of sulfuric and chloric acid before Nitriding treatment. But in the ion nitriding, nitride layer was easily formed because passive film was removed without difficult by sputtering effect. The removal extent of these passive films was greatly effected by gas mixing ratios and pressure and holding times of pre sputtering factors in pre sputtering stage. As a results of experiment it has been known that pre sputtering pressure and holding time was not nearly effective on the formation behavior of nitride layer. But when A/H2 gas mixing ratios was 1/2 (vol%) was the most effective of the all pre sputtering conditions. It was resulted from the combination of mechanical reaction byArgon bombardment and chemical reaction by reduction of hydrogen on the passive film.
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The dressing time monitoring in cylindrical grinding is very important with respect to machining efficiency. Therefore, the purpose of this paper is to determine the wheel life by monitoring behavior of grinding power for Wa, 19A and GC. For this purpose, we investigated indirectly the attritious wear of grain edge, the loading of grinding wheel and the breakage of grain through the grinding power and the surface roughness under various grinding conditions. From obtained the results, the relationship between the wheel life and the average sectional chip area is examined to guide for the determination of dressing time.
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The standing waves of the fourth bending ode of vibration and the first longitudinal mode of vibration were utilized to construct a ultrasonic linear motor. The geometrical dimensions of the vibrator were determined by Euler-Bernoulli theory. FEM(finite element method) employed to calculate the vibration mode of the metal-piezoceramic composite thin plate vibrator. ANSYS was used to design positions of the projections and calculate displacement of vibrator.
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In this paper, the feedback linearization technique is used with the sliding mode control for nonlinear system. The combination of these two control techniques can be achieved by proposing a novel sliding surface which has the nonminal dynamics of the original system controlled by feedback linearization technique. The noble design of the sliding surface is based on the augmented system whose dynamics have a higher order than that of the original system. The reaching phase is removed by using an initial virtual state which makes the initial sliding function equal to zero
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It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 50m/min using the high speed ball screw. Also, a lot of problems have happened the feed and servo drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed/accuracy control for feed/servo drive system of high speed/accuracy. In this study, we make use of high performance vertical machine center with a ball screw of large-scale-lead. Also, we'll apply the high-speed/accuracy control technology in this part of feedforward control, multi-buffering block size, etc. Using the design of the mechanical element and high-speed precision control, the basic design concept can be established.
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In this paper, the machining characteristics of high speed ball end milling affected by the rotational error of high speed spindle using air bearing are investigated. The error motions of a spindle have generally influenced on the surface roughness, the form accuracy, the tool life, etc. in end milling. Experiments are carried out over a wide range of rotational speeds(10,000-50,000rpm). The rotational errors of the spindle are measured by the gap sensor mounted on the spindle shaft at various cutting speeds. The relations between the surface roughness and the spindle error motion are presented. Results show that the rotational accuracy of the spindle directly affects the surface roughness of the machined surface.
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Cooling characteristics of cooling jacket for spindle system with built-in motor are studied. for the analysis, three dimensional model for the cooling jacket is built by using finite volume method. The three dimensional model includes the estimation on the amount of heat generation of bearing and built-in motor and the thermal characteristic values such as heat transfer coefficients on the boundary. The temperature distributions and the cooling characteristics are analyzed by using the commercial software FLUENT. Numerical results show that stream-wise cross section area and flow rate are important factors for cooling characteristics of cooling jacket. Cooling performance of cooling jacket is good in condition that stream-wise cross section's horizontal length is close to its vertical one and flow rate is high. This results show that heat transfer is dominated by velocity profile and heat transfer area.
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Radial immersion ratio is an important factor to determine the threshold in face milling and should be estimated in process for automatic force regulation. In this paper, presented is a method of on-line estimation of radial immersion ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. These force drops are equal to the cutting forces that act on a single tooth at the swept angle of cut and can be acquired from cutting force signals in feed and cross-feed directions. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting forces and predetermined ratio, the redial immersion ratio is estimated. various experiments show that the radial immersion ratio can be estimated by the proposed method very well.
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In order to design micro-fan appropriately, flow chacracteristics and mechanics should be carefully considered. The present work concerns with design procedure for a micro-fan using NACA(National Advisory Committee for Aeronautics) airfoil series. The generation of fan profiles is carried out automatically by defining related parameters, which is also converted to CAD/CAM data automatically. The optimal parting surface for the mold of micro-fan is also calculated by analyzing the geometric data numerically. As a consequence, the high capacity micro-fan can be developed successfully with a high-quality and an improved efficiency.
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"Ploughing" on the flank face of the tool in the metal cutting process is due to the tool in the metal cutting process is due to the finite edge radius of the tool and due to the development of flank wear. Because of the high stresses near the cutting edge, elastic-plastic deformation would be caused between the tool and the machined surface over a small area of the tool flank. The deformation would affect the roughness of the machined surface. Recently, some attempts have been made to predict the surface roughness, but elastic-plastic effect due to ploughing in the cutting process has not been considered. The research has analyzed mechanism of the ploughing of the cutting process using contact mechanics. Tool and workpiece material properties have been taken into account in the prediction of the surface roughness. The surface roughness has been simulated by the surface-shaping system. The results between experiment and simulation have been compared and analyzed. analyzed.
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On End Milling Process predict the cutting force is important. Dynamics the shear stress is the main parameter influencing the energy requirement in machining. It is well known that a nonzero force is obtained when cutting forces measured at different feed rates but otherwise constant cutting conditions are extrapolated to zero feed rate. In this paper, the cutting force measured in end-milling is compared with the simulated force models. The result show that stress measured in cutting is consistent with that stresses predicted.
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The most important things to the tube the of the heat exchanger are the precision of t hole position and the quality of the drill face. Nowadays, 6 and 12 spindle multi-drilling machine controlled by CNC or used to drill holes of the tube sheet. The drilling of 12 axes can offer high speover three times as fast as the drilling of axis. However, the drilling of 12 axes h difficulty in controlling many motors to d spindles and assigning a corresponded numbe accurately to each axis. In the past, conventional method to inspect the code the drilling was machining holes on a thin plate previously which resulted in the productivity because it required a h production cost by machining and weldin time. In this thesis, there are two drilling codes different from CNC code. M code is used to control many motors and S code is used to assign a correspondent number for each axis. For increasing the productivity by removing process, this paper is intended to take simulation of the drill machining c including 6 and 12 axis on the persona computer.
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This paper aims to DNC application of car fuel tank die working. DNC system is consist of CAD, CAM software and CNC milling machine. CAM software is purpose to G-code generation for CNC programming. Then CAM software and CNC milling machine are connect to RS-232-C cable for networking.
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This study is object to program development of fatigue test for universal testing machine. Fatigue program is consist of test simulation, data analysis and print report by control fatigue testing program which expansively applies tension-compression tests with using oil pressure mechanism by Visual Basic software running under windows 98.
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This study is object to structural analysis of continuous casting mold. A two-dimensional finite element model was developed to compute the temperature distribution, stress and strain behavior for continuous casting mold. For structural analysis using thermal analysis result from FEM code. In other to structural analysis of continuous casting mold, many variables such as casting speed, cooling condition, film coefficient, convection and load condition are considered.
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This study is object to thermal analysis of continuous casting nickel-coated mold. A two-dimensional transient finite element model was developed to compute the temperature distribution and stress behavior for continuous casting nickel-coated mold. For thermal analysis using analysis result from FEM code. In other to thermal analysis of continuous casting nickel-coated mold, many variables such as casting speed, cooling condition, film coefficient, convection and load condition are considered.
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To make use of various switches, relays, and control instruments, a connector (jack) is used to link the battery (power) and operating units. A connector must have precision as well as solidity to control the power in a car. To improve productivity, we researched and developed a connector molding by adapting vacuum system and we've made it possible to minimize the incomplete molding and weld-line. As a result, good quality can be warranted with less costs.
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Application of bonded dissimilar materials in various industries are increasing. When these materials are used in structures, it needs to investigate strength evaluation applying fracture mechanics. Al/Epoxy bonded dissimilar materials with an interface crack and an interface crack emanating from an edge semicircular hole were prepared for the static tests so that experiment of fracture toughness were carried out. Stress intensity factors of interface cracks in bonded dissimilar materials were computed with boundary element method(BEM) and the fracture criteria of mixed mode crack were analyzed. From the results, the fracture criteria and the method of strength evaluation by the fracture toughness in Al/ Epoxy bonded dissimilar materials were proposed.
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By using AIP(Arc Ion Plating) of a physical vapor deposition for the first time in Korea a ceramic tool whose surface is coated single layeredly with TiN is developed. In addition, cutting resistance appearing in the process of finishing cut of hardened carbon tool steel, STC3 is studied. The principal and radial components of cutting resistance in those cutting conditions appear to be the same or similar, and the feed component is relatively small. The feed component is found to be in proportion to cutting width, and the radial component in proportion to cutting thickness. Owing to coating the cutting resistance of a TiN coated ceramic tool increases compared with that of a general ceramic tool.
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This paper has been considered on the cutting characteristics such as chip formation and surface roughness for Inconel 690 alloy with difficult-to-cut because of high toughness and strength. We have made efforts solving the problem to difficult-to-cut of Inconel by improvement of tool with TiN coating and the selection of optimum cutting condition. We used the CCD camera and the surface roughness tester to observe the chip formation and the state of machined surface by using the improved tool with diamond coating and various cutting condions. We have found that the chip formation showed the tooth shape of tooth blade and the surface roughness was very poor. but it can be better by selection of optimum cutting condition.
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An absolute type shaft encoder which utilized moire fringe will be presented in this paper. Linear moire fringe is commonly used to measure the displacement of the linear motion. However, an absolute encoder which measure the rotation angle of a shaft is operated usually with a code disk which the gray code pattern is printed on. Such encoder has inherently resolution limit because of the patterning mechanism and sensing mechanism. In order to measure the position of fringes which move as the code disk rotates, neural network was developed in this paper. Formerly fringe position is usually measured by a sophisticated software, which needs a little long calculation time. However, using neural network method can eliminate such calculation time, even though it needs learning job. The proposed method is verified through several experiments.
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Grinding technology in morden industry society is focusing on research & development for grinding stone and machining parts for the purpose of high accuracy and high efficiency of products. But, in order to equip the high technology and high accuracy of micro stone which is one of grinding stone, hardly and continuous effort on R&D is required.In this study, honing processing work of 2-cycle engine cylinder for motorcycle which has open hole is practiced so as to clear how borning that is prior step of honing and hone stone make an influence on accuracy of honing. As the result of analyzing the results of experiments, we came to conclusion that we can secure good conditions of honing by controlling and keeping appropriate cycle-time in the stage of boring of prior step of honing.
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Surface hardening of plain carbon steel (SM$%C) by Laser are usually much finer and stronger than those of the base metals. The present study was undertaken to investigate the wear resistance and a processing parameters such as, power density, pulse width, defocusing distance, and molten depth for surface modification of plain carbon steel. The wear test was carried out under experimental condition using the wear test device, and in which the annular surfaces of wear test specimens as well as mating specimen of alumina ceramics(Al2O3) was rubbed in dry sliding condition. It is shown that molten depth and width depend on defocusing distance. The wear loss on variation of sliding speed was much in lower speed range below 0.2m/sec and in higher speed range above 0.7m/sec, but wear loss was little in intermediate speed range. It depends on oxidation speed and wear speed.
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For the Tailor Welded Blank sheet used for automobile body panel, the characteristics of fatigue strength and crack propagation behavior were studied. The thickness of specimen was machined to be same (0.9mm+0.9mm) and different (0.9mm+2.0mm). As a base test, mechanical properties around welding zone were examined. The results indicated that there were no significant decreases in mechanical properties, but hardness around welding bead is 2.3 times greater than base material. The fatigue strength was the highest when the loading direction was parallel to the welding direction, which was about 85% of tensile strength of base material. It was decreased by 8.5% when the thickness of specimen and base material was different, and it is increased by 25% when pre-strain was applied. The crack propagation rate was noticeable decreased around welding line and rapidly increased as it passed by welding line. Reviewing the shape of the crack propagation, crack width around welding line was wide around the welding zone due to retardation of crack growth, but it became narrow passing welding line due to decreased toughness.
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The effectiveness of software error compensation for thermally induced machine tool errors relies on the prediction accuracy of the pre-established thermal error models. The selection of optimal sensor locations is the most important in establishing these empirical models. In this paper, a methodology for the selection of optimal sensor locations is proposed to establish a robust linear model which is not subjected to collinearity. Correlation coefficient and time delay are used as thermal parameters for optimal sensor location. Firstly, thermal deformation and temperatures are measured with machine tools being excited by sinusoidal heat input. And then, after correlation coefficient and time delays are calculated from the measured data, the optimal sensor location is selected through hard c-means clustering and sequential selection method. The validity of the proposed methodology is verified through the estimation of thermal expansion along Z-axis by spindle rotation.
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In this study, the characteristics of chip formation of the cold drawn Bi-S free machining steels were assessed. And for comparison, those of the cold drawn Pb-S free machining steel, the hot rolled low carbon steel which has MnS as free machining inclusions and the conventional steels were also investigated. During chip formation, the cold drawn free machining steels show relatively little change in thickness and width of chip compare to those of the conventional carbon steels. And a single parameter which indicates the degree of deformation during chip formation, 'chip cross-section area ratio' is introduced. The chip cross-section area. The variational patterns of cross-section area is divided by undeformed chip cross-section area. The variational patterns of the chip cross-section area ratio of the materials cut are similar to those of the shear strain values. The shear stress, however, seems to be dependent on the carbon content of the materials. The cold drawn BiS and Pb-S steels show nearly the same chip forming behaviors and the energy consumed during chip formation is almost same. A low carbon steel without free machining aids shows poor chip breakability due to its high ductility. By introducing a small amount of non-metallic inclusions such as MnS, Bi, Pb or merely increasing carbon content the chip breakability improves significantly.
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Cutting Force Analysis in End Milling Process for High-Speed Machining of Difficult-to-Cut MaterialsDue to rapid growth of die and mould industries, it is urgently required to maximize the productivity and the efficiency of machining. In recent years, owing to the development of new kinds of material, die and mould materials are much harder and it is more difficult to cut. In this study, the workpiece SKD11(HRC45) is cut with TiAlN coated tungsten-carbide cutting tools. To find the general characteristics of difficult-to-cut materials, orthogonal turning test is performed. Orthogonal cutting theory can be expanded to oblique cutting model. The oblique cutting process in the small cutting edge element has been analyzed as orthogonal cutting process in the plane containing the cutting velocity vector and chip-flow vector. Hence, with the orthogonal cutting data obtained from orthogonal turning test, the cutting forces can be analyzed through oblique cutting model. The simulation results have shown a fairy good agreement with the test results.
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SKD11 is one of the most difficult workpiece for machining, so it is necessary to evaluate the machining characteristics of SKD11. The workpiece was made to be the pipe form and heat-treated to HRC45. In this paper, the orthogonal cutting experiment of this material was carried out with TiAlN coated WC cutting tool of 4 kinds of rake angle. After cutting experiment, cutting characteristics of SKD11 were investigated according to variation of cutting speed, feedrate and rake angle.
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Stick-slip friction is present to some degree in almost all actuators and mechanisms and is often responsible for performance limitations. Simulation of stick-slip friction is difficult because of strongly nonlinear behavior in the vicinity of zero velocity. A straightforward method for representing and simulating friction effects is presented. True zero velocity sticking is represented without equation reformulation or the introduction of numerical stiffness problems. Stick-slip motion is investigated experimentally, and the fundamental characteristics of the stick-slip motion are clarified. Based on these experimental results, the characteristics of static in the period of stick and kinetic friction in the period of slip are studied concretely so as to clarify the stick-slip process.
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The experimental investigating is mainly focused on the hole machining characteristics of glass fiber reinforced polyester at different surface conditions, cutting conditions and machining methods. The entrance and exit surface holes of the glass fiber reinforced polyester is observed and the surface photographs of drilled holes is showed. The cutting force is also measured.
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In machining with cutting tool inserts having complex chip groove shape, the flow, curl and breaking patterns of the chip are different than in flat-face type inserts. In the present work, an effort is made to understand the three basic phenomena occurring in a chip since its formation in machining with groove type and pattern type inserts. These are the initial chip flow, the subsequent development of up and side curl and the final chip breaking due to the development of torsional and banding stresses. In this paper, chip flow angle in a groove type and pattern type inserts. The expression for chip flow angle in groove type and pattern type insets is also verified experimentally using high speed filming techniques.
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The micro electronic control technology with developing microcomputers make great contribution to electrohydraulic control systems. The electrohydraulic pulse control simplifies in conjunction with power electronic amplifier and high speed operated solenoid valves. It is necessary to valves to convert electronic pulse signal to hydraulic pulse flow as fast as possible. This study deals with the speed control of an oil hydraulic motor operated by two way high speed solenoid valves. The valves acts as converters of electronic-pulse signals to hydraulic power. By constructing systems in which a hydraulic motor is operated by two solenoid valves, the pulse with modulation method (PWM) has adopted as the speed control of hydraulic motor systems. The static and dynamic characteristics of the systems are investigated by the experiment. It is clarify that a hydraulic motor operated PWM show good performance as a control component, achieving accurate velocity control.
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The temperature dependence of the viscosity was determined for an electrorheological(ER) fluid consisting of 35 weight% zeolite particles in hydraulic oil 46cSt. Thermal activation analysis were performed by changing the ER fluid's temperature from -1
$0^{\circ}C$ to 5$0^{\circ}C$ at fixed electric field. According to the analysis, the activation energy for flow was about 79.64kJ/mole at E=0kV/mm. Generally, the hydraulic oil 46cSt will be operated at the temperature of about 4$0^{\circ}C$ , the ER fluid's electric field dependence of viscosities were investigated at this temperature. also, the influence of adding the dispersant(Carbopl 940) on electrorheological effect of the ER fluid was discussed. -
Electro-rheological(ER) fluids are suspensions which show an abrupt increase in rheological properties under electric fields. The rheological response is very rapid and reversible when the electric field is imposed and/or removed. Therefore, there are many practical applications using the ER fluids. The purpose of the present study is to examine the flow characteristics of electro-rheological fluids. The field-dependent yield stress are obtained from experimental investigation on the Bingham property of the ER fluid. Then the steady relationshup between pressure drop and flow rate of the ERF was two fixed parallel-plates was measured under application of an electric fields. The electrical and rheological properties of zeolite based electro-rheological fluids were reported.
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Hydraulic pipeline between servo valve and actuator affect the dynamic characteristics of electrohydraulic servo systems in serveral ways. This paper deal with the speed control of oil hydraulic gear motor using electrohydraulic servo valve. The frequency and transient response of electrohydraulic servo valve coupled to a gear motor is anlayzed. In particular, the effect of short and long hydraulic pipelines between servo valve and gear motor is investigated. The dynamic characteristics of the speed control systems of gear motor with short pipeline is first described via frequency response experiments with small signal linearized analysis. Loner pipeline is applied distributed parameter pipeline model with consideration of frequency dependent viscous friction.
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The measurement of unsteady flow rate is of vital importance to clarify and improve the dynamic characteristics in pipeline, hydraulic components and system. There is also demand for a real time flow sensor of ability to measure unsteady flow rate with high accuracy and fast response to realize feedback control of flow rate in fluid power systems. In this paper, we propose an approach for estimating unsteady flow rate through a pipeline and components under high pressure condition. In the method, unsteady flow rate is estimated by using hydraulic pipeline dynamics and the measured pressure values at two distant points along the pipeline. The distributed parameter model of hydraulic pipeline is applied with consideration of frequency dependent viscosity friction and unsteady velocity distribution at a cross section of a pipeline. By using the self-checking functions of the method, the validity is investigated by comparison with the measured and estimated pressure waveforms at the halfway section on the pipeline. The results show good agreement between the estimated flow rate waveforms and theroetical those under unsteady laminar flow conditions. the method proposed here is useful in estimating unsteady flow rate through an arbitray cross section in hydraulic pipeline and components without installing an instantaneous flowmeter.
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In this paper, the comparison of the first order approximation schemes such as SLP (sequential linear programming), CONLIN(convex linearization), MMA(method of moving asymptotes) and the second order approximation scheme, SQP(sequential quadratic programming) was accomplished for optimization of and nonlinear structures. It was found that MMA and SQP(sequential quadratic programming) was accomplished for optimization of and nonlinear structures. It was found that MMA and SQP are the most efficient methods for optimization. But the number of function call of SQP is much more than that of MMA. Therefore, when it is considered with the expense of computation, MMA is more efficient than SQP. In order to examine the efficiency of MMA for complex optimization problem, it was applied to the helicopter tail boom considering column buckling and local wall buckling constraints. It is concluded that MMA can be a very efficient approximation scheme from simple problems to complex problems.
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Nowadays development of electric and optical devices needs precision more and more. This study focuses on hydrostatic journal bearing of grinding wheel spindle. It presents theoretical analysis about cylinder type self-controlled restrictor to control flux of oil flowing into pockets around the hydrostatic journal bearing. As a result of this analysis, optimal properties to maximize bearing stiffness such as initial cross distance, supply pressure, diameter of two supply holes, pre-load of spring and clearance between spindle and housing can be obtained. Therefore, by using them it is possible to estimate bearing stiffness and the performance of grinding wheel spindle can be improved.
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In this paper, an off-line programming(OLP) system is presented as the three dimensional graphic simulator and one of the human-robot interface systems for industrial robots. The OLP system has been especially developed to testify robot programs visually using three dimensional geometric modeling and graphics technologies in personal computes. A special feature is its capability of collision detection and of comparing performance of control algorithms. This paper places the focus on the structure and major characteristic of OLP system.
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One of the important technical issues is how to decrease thermal expansion of ballscrew in proportion to the increase of machining speed. When measuring force of stretch of ballscrew, since not only actual expansion and the value of bending have to be considered, it's impossible to definite the exact value of expansion. In addition, support bearings of ballscrew gain considerable force in axial direction. It also generates thermal expansion on the ballscrew, and deteriorates the bearings. In conclusion, it's impossible to give the pretension enough to absorb the all elongation due to thermal expansion generated during machine running. If gave, bed, column and saddle are all bent to change machine accuracy, and the pretension of support bearing of ballscrew in machine tool.
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A study for the roundness of machining center is classified into two ways. one is the way that progresses the roundness amending the parameter of machining center based on the measured value after the measurement of the roundness of machining center by means of a existing measuring device, another is the way that measures the roundness by remodeling the existing measuring device. The former is studied by pack hei jae team in Seoul university, the latter is studied by TSUTSUMI. Especially TSUTSUMI measures the roundness according to circular compensation after the insertion of developed measuring desire using a rotary encoder to the spindle of machining tool. We study how regulation velocity occuring with circular motion of machining center table influences the roundness after measuring the roundness using Circular Test method by a 2 dimention probe and a standard discus in this experiment.
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The recent control system has been changed into the type of PLC(Programmable Logic Controller) control. Up to now, systematic approach of PLC programming or control logic design is not suggested. In this study, the design process of the control logic is systematized and concrete process in each step is suggested. This systematized approach lead developer to be convenient to implement control system. When some error is occurred in the system, this approach enable the developer to analyze the reason of error rapidly and the system is amended according to systematic information of the analysis. The example of control system implementation following this approach is introduced.
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When designing a gerotor, designers determine basic dimensions of a gerotor with transmitted power considering strength, interference and so on. But, designers can not easily obtain the tooth profile generated by dimensions as well as the geometry of generating hob for cutting the tooth profile. In order to resolve these problems, an automatic design system creating not only the solid model of a gerotor but also that of the generating hob using the design parameters of dimensions is developed. Through the developed system, designers can improve the efficiency of design and satisfy the variable requirements of design as well. In this research, the three-dimensional solid model of gerotor is generated considering the design parameters. Besides, that of generating hob with respect to the design parameters of hob is created automatically. The system is developed using Visual Basic and its three-dimensional geometric modeling module is constructed using SolidWorks.
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Recently, the need for designing multi-stage gear drive has been increased as the hear drives are used more in the applications with high-speed and small volume. The design of multi-stage gear drives includes not only dimensional design but also configuration design of various machine elements. Until now, however, the researches on the design of gear drives are mainly focused on the single-stage gear drives and the design practices for multi-stage gear drives, especially in configuration design activity, mainly depend on the experiences and 'sense' of the designer by trial and error. We propose a design algorithm to automate the dimension design and the configuration design of multi-stage gear drives. The design process consists of four steps. The number of stage should be determined in the first step. In second step, the gear ratios of each reduction stage are determined using random search, and the ratios are basic input for the dimension design of gears, which is performed by the exhaustive search in third step. The designs of gears are guaranteed by the pitting resistance and bending strength rating practices by AGMA rating formulas. In configuration design, the positions of gears are determined to minimize the volume of gearbox using simulated annealing algorithm. The effectiveness of the algorithm is assured by the design example of a 4-stage gear drive.
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Recently as the application of gear drive increases in high-speed and high-loading, the concern of designing multi-stage gear drive is being risen. Until now however, the research of gear drive is focused on single-stage gear drive and the design depends on experiences and know-how of designer and is carried out by trial and error. This research automated the basic design and the configuration design for two and three-stage gear drives which consist of cylindrical gears. In basic design, design is executed with two design processes, which minimize the overall volume of gear, and whose results are compared each other. In configuration design, the positions of gears are determined to minimize the volume of gearbox using the result of basic design and simulated annealing algorithm.
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This paper describes a new technique for measurement of the displacement less than one-quarter of the wavelength of ultrasonic wave using ultrasonic pulse-echo method. The technique determines the displacement of a journal bearing from the amplitudes of the total reflected waves from the surface of journal inside the bearing. Vibration of journal bearing can be measured without using a very high frequency ultrasonic transduce over 100MHz which must be used in the conventional techniques for the precision measurement of a small displacement. The method also requires no inversion process to extract the thickness from the waveforms of the reflected waves, so that it makes possible on-line measurement of the vibration of journal bearing.
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A burr is formed in every corner of parts as a result of machining, which produces undesirable edge geometry and influence deeply to surface quality of workpiece. Therefore these burrs must be removed certainly. The cost of removing these burrs is directly proportional to their size. Burrs have been among the most troublesome obstruction to high productivity and automation of machining processes. The proper selection of cutting condition and tool geometry will be helpful to reduce the occurrence of burrs. In paper will observe burr formation along helix angle in end milling and certificate experimentally mechanics relation of helix angle and burr formation.
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Cognition and control of grinding trouble occurring during the grinding process are classified into a quantitative knowledge which depends on experimental data and qualitative knowledge which relies on skillful engineers. Grinding operations include a large number of functional parameters, since there are several ways of coping with grinding trouble. One is the qualitative method which depends on empirical knowledge utilizing the skilful experts from the workshop, the other is the quantitative method which utilizes the experimental data obtained by sensor. But, they are all difficult to accomplish from the grinding trouble-shooting system. The reason is that grinding troubles are not easily controlled in the quantitative method, and therefore, trouble-shooting has mainly relied on the knowledge of skilful engineers. Thus, there is an important issue of how a grinding trouble-shooting system can be designed and what knowledge is utilized among the large amount of grinding trouble information. In this paper, basic strategy to develop the grinding database of rule-based rule, which is strongly depended upon experience and intuition, is described.
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Grinding machine rotating at high speed express the unbalance by the spindle and the weight of grinding wheel. Therefore, the parts requiring a precision processing for grinding machine need acutely to establish of automatic balancer. But the more wheel speed increases the more vibration amplitude increases, surface roughness show the satisfactory according to increase of the wheel speed. Surface roughness of the occasion installing the automatic balancer made better than an occasion no installing the automatic balancer.
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Recently, the miniature of electric products such as notebook, cellular-phone etc. is apparently appeared, due to the smaller size of the semiconductor chips. As the size of chip gets smaller, the circuit could be easily damaged by the slightest influence, so it is important to control the chipping generation in the process of dicing. This paper deals with chipping of the silicon wafer dicing. The relationships between the dicing force and the wafer chipping are investigated. It is confirmed that the wafer chipping increases as the dicing force increases.
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In modern engineering practice, the grinding process is one of the most important and widely used operations for the precision finishing of components. In this paper, machining characteristics of external plunge grinding were investigated by using spindle motor current signal through hall sensor. Grinding experiments were performed in terms of various grinding conditions such as wheel speed, workpiece speed, infeed rate and spark-out time with conventional vitrified bonded WA wheel. The relationship between spindle motor current signal and metal removal rate in terms of infeed rate was induced the by analyzing spindle motor current signal.
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In this study, geometrical similarity conditions for drills of various diameters are discussed. The effect of geometrical similarity on the chip shape and forces of different sized conventional drills has been experimentally confirmed. Drilling tests are carried out for SM45C by using the conventional HSS drills. The torque and thrust forces are measured and compared with those chip forms. Chip shape in drilling are affected by three factors being flow angle, side and up curl of the chip. It is found that the feedrate and drill diameter are more affected than cutting speed on the chip form and cutting forces. The similarity conditions gives easily to estimate the chip shape, the thrust and the torque for drills of different diameters.
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To manufacture alumina products, sintering and grinding process are needed. In Al2O3 grinding, macro/micro surface fracture and cracks are easily occurred on the ground surface because of its high brittleness. In view point of fatigue fracture, surface profile produced by grinding is considered as notches. Therefore, it was reasonable that magnitudes and shapes of surface profiles effects on fatigue strength and life. Particularly, surface finish of Al2O3 which have high hardness and brittleness have an effect on fatigue strength. In this paper, some experiments are carried out to examine influence of grinding conditions to magnitude and shape of surface profile as well as the relationships of Ra, Rmax, Rmax/Ra, and Ku. Through the experimental results, It is found that Ra and Rmax was affected by grinding conditions, but Rmax/Ra and Ku was not. There are linear relations between Ra and Rmax, and between Rmax/Ra and Ku.
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A cone shape drum polisher was developed to make up for the demerits of conventional CMP apparatus. The developed equipment has several superiorities. First of all, it can achieve uniform velocity profile on all the contact line because of its shape and easy to control the amount of slurry at the position of use. The whole area of wafer surface is exposed to the visual area except the contact line between wafer and drum, hence we can detect polishing end point more easily than any other polishing equipments. Also it has additional merits such as small foot print and polishing load. Polishing characteristics were investigated by developed equipment.
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In recently, annealing process of cold rolled sheet tend to change to continuous annealing process for improving quality, saving yield. In the meantime as demand for various kind and small lot of products has been increasing, batch annealing has been appreciated for its small restriction for the operation. So, we tested on the effect for the proper heating temperatures, heating time of cycle, cooling time and total cycle time in this annealing process of hi tensile strength steel for automobile. As a result of several investigation. we confirmed for the following characteristics; In this process, we knew that 68
$0^{\circ}C$ is suitable for this heating temp. cycle heating time of 38 Hr, cooling time of 31 Hr and total cycle time of 70 Hr. Still more, we could know that it is proper for cold rolling before annealing to be managed by 7 pass because of the act on high pressure. -
This paper describes a sweeping path planning algorithm for an autonomous smearing robot on commercial autoCAD system. An automatic planner generates a sweeping path pattern by proposed five basic procedures, (1) interfacing architectural CAD system, (2) off-line obstacle map building, (3) scanning the whole workspace for subgoals of sweeping line, (4) tracking sequence of the subgoals, and (5) obstacle avoiding. A sweeping path is planned by sequentially connecting the tracking points in such a way that (1) the connected line segments should be crossed, (2) the total tracking points should be as short as possible, (3) the tracking line should not pass through the obstacle. Feasibility of the developed techniques has been demonstrated on real architectural CAD draft.
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This study is about development of Feature-based Solid Modeling system in integrated CAD/CAM environment. Parasolid modeling kernel and HOOPS/3D graphics library was used to develop this system in PC level. System feature library was defined using both procedural and declarative approach method. The raw stock is created by boolean operator using design primitives, and a part is designed that pre-defined feature is removed from the raw stock. This method is called "DSG(Destructive Solid Geometry)" and basic constructive operator of this system. This is not complete system and only the first step to develop Feature-based Solid Modeling System using Parasolid. We will add more powerful functionality and flexible GUI in Windows.n Windows.
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The purpose of this study is the machining of texture shapes by the contour fitting data. The hardware of the system comprises PC and scanning system, CO2 laser machine. There are four steps, (1) text image loading using scanning shapes or 2D image files, (2) generation of contour fitting data by the line and arc, cubic Bezier curve, (3) generation of NC code from the contouring fitting data, (4) machining by the DNC system. It is developed a software package, with which can conduct a micro CAM system of CNC laser machine in the PC without economical burden.
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Burr sensing for burr size measurement and deburring process control is one of the essential elements in an automated deburring procedure. This paper presents the implementation of capacitance sensing and acoustic emission (AE) to deburring. The first application is the "on-line" measurement of burrs using a capacitance sensor. A non-contact capacitance gauging sensor is attached to an ultra precision milling machine which was used as a positioning system. The setup is used to measure burr profiles along machined workpiece edges. The proposed scheme is shown to be accurate, easy to setup, and with minor modifications, readily applicable to automatic deburring processes. As the second example, AE signals were sampled and analyzed for the sensor feedback of a precision deburring process - laser deburring -. The results, such as the sensitivity of AE signals to burr shapes and edge detection capability show a clear correlation between physical process parameters and the AE signals. A subsequent control strategy for deburring automation is also briefly discussed.
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In this paper, we developed a windows 95 version Off-Line Programming system which can simulate a Robot model in 3D Graphics space. 4axes SCARA Robot (especially FARA SM5) was adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed program. The interface between users and the OLP system in the Windows 95's GUI environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by silicon Graphics, Inc. were utilized for 3D Graphics.
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In this paper, we propose a new approach to the development of the automatic vision system to examine and repair the steam generator tubes at remote distance. In nuclear power plants, workers are reluctant of works in steam generator because of the high radiation environment and limited working space. It is strongly recommended that the examination and maintenance works be done by an automatic system for the protection of the operator from the radiation exposure. Digital signal processors are used in implementing real time recognition and examination of steam generator tubes in the proposed vision system. Performance of proposed digital vision system is illustrated by simulation and experiment for similar steam generator model.
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The purpose of the present paper are not to develope machine tools of new concepts and advanced mechanisms but to introduce and apply new methods and concepts in the design procedure by using and changing the previously existing technologies. In this paper 3D modeller was proposed for designing machine tools and the design and the better manufacturability checking than 2D one so that design error was dramatically reduced. As designer may easily understand the real shape of a part and assembly object, it's easy to draw the drawings not only in a conceptual design but also in a detailed design. Also, design automation software enabled designer to consider the real important design parameters by reducing time to spend in estimating and calculating the strength of the model by the computer aided automatic calculation instead of a tedious and complex calculation by manual method and help him to easily make the decision for selecting the stocks and design the structure of part or unit of machine tools.
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Due to the development of CNC machining centers and the complexity of machined part geometry, the ball-end milling became the most widely used the cutting process. Generally, the tool runout defined as the eccentricity of a rotating tool set in the holder involved the spindle runout and the problem of tool runout generated to remove the workpiece is a main factor affecting the machining accuracy. In this paper, the relationship of tool runout(zero-to-peak, P-K) and surface shape on the change of cutting conditions is studied and it is proposed the probability of prediction of surface shape from the in-process tool runout measurements with high response displacement sensor in the ball-end milling