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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
Journal Basic Information
Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 9, Issue 4 - Dec 1992
Volume 9, Issue 3 - Sep 1992
Volume 9, Issue 2 - Jun 1992
Volume 9, Issue 1 - Mar 1992
Selecting the target year
한국 공작기계 산업의 현황과 전망
Kim, Seong-Ung ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 7~12
INTERNATIONAL STANDARDISATION-MOVES TO COMPLETE THE MACHINE CALIBRATION PACKAGE
M. Blackshaw ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 13~21
Standards concerning the determination of positioning accuracy and repeatability of numerically controlled(NC) machine tools have been published relentlessly over the last 20 years. Since the publication in 1988 of the International Standard 230-2 there has been a pronounced move, both at national and international standards level, to embrace further test procedures for a complete machine tool performance assessment. For example, measurements of angular (pitch, roll, and yaw) and straightness errors along linear axes are now commonplace and complement the existing positioning accuracy and repeatablity tests. More recently the subject of circularity evalutaion has also gained considerable interest. Here dynamic tests, using a kinematic ballbar or circular masterpiece, give an instant overview of the contouring ability of the machine in two axes at specific feedrates. This information is extremely important in optimising machining accuracy. This paper describes moves to complete the machine calibration package in national and international standardis- ation for the assessment of machine tool performance.
A Study on Intelligent On-line Tool Conditon Monitoring System for Turning Operations
Choe, Gi-Hong ; Choe, Gi-Sang ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 22~35
In highly automated machining centers, intelligent sensor fddeback systems are indispensable on order to monitor their operations, to ensure efficient metal removal, and to initate remedial action in the event of accident. In this study, an on-line tool wear detection system for thrning operations is developed, and experimentally evaluated. The system employs multiple sensors and the signals from these sensors are processed using a multichannel autoegressive (AR) series model. The resulting output from the signal processing block is then fed to a previously tranied artificial neural network (multiayered perceptron) to make a final decision on the state of the cutting tool. To learn the necessary input/output mapping for tool wear detection, the weithts and thresholds of the network are adjusted according to the back propagation (BP) method during off-line training. The results of experimental evaluation show that the system works well over a wide range of cutting conditions, and the ability of the system to detect tool wear is improved due to the generalization, fault-tolearant and self-ofganizing properties of the neural network.
A Study on the Hierarchical Real-time Operation Control and Monitoring for an Flexible Manufacturing System
Kim, Jong-Won ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 36~43
This paper presents a hierarchical real-time operation control and monitoring scheme of the FMS/CIM center which has been implemented at the Automation and Systems Research Institute of Seoul National University. The hierarchical structure of the whole scheme consists of three lavers. The upper layer is in charge of on-line scheduling, computer network control, shop-floor monitoring and command generation for AGV dispatching, machining, assembly, inspection, set-up, etc. The middle layer has six modules, which are installed in the FMS host computer with the upper layer and run on the multi-tasking basis. Each module is connected to one of six cell controllers distributed in the FMS model plant and transfers operation command down to each cell controller through the Ethernet/TCP-IP local area network. The lower layer is comprised of six cell control software modules for machining cell, assembly cell, inspection cell, set-up stations. AS/RS and AGV. Each cell controller reports the status of the manufacturing facilites to the middle layer as well as ecxecuting the appropriate sequence control of the manufacturing processes.
Thermal Expansion Analysis of the Ball Screw System by Finite Difference Methods
Jeong, Seong-Jong ; Park, Jeong-Gyun ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 44~57
Ball screw systems have been used for positioning elements of machine tools and precision tables. In order to maintain the high rigidity and accuracy, a certain amount of preload is applied between the nut and the screw of ball screw systems. However, large amount of the preload oncreases the frictional heat. The temperature rises remarkably at the high speed motion, and the thermal expansion degrades the positioning accuracy. In this paper, a finite difference method is applied to analyse temperature distributions and thermal expansions of the ball screw system according to preload conditions and rotational speeds. Some simulation results show that the developed methodology is appropriate to study the thermal expansion characteristics of ball screw systems.
A Study on the Hybrid Position Control of the Liquid-Slop System
Ju, Hae-Ho ; Lee, Jae-Won ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 58~64
Development of an Efficient Algorithm for the Intersection Calculations in a Simulated Radiograph
O, Jae-Yun ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 65~71
This paper develops an algorithm for efficiently computing the intersection points between rays and an object in a simulated radiograph. This algorithm allows interactive calculation of simulated radiographs for very complex parts. It needs a geometric model of a part which is approximated by a bounding surface made up of flat triangular polygons. Since rays have a point source, a perspective transformation is applied to convert the point source problem to one that has parallel rays. This permits to use a scan-line algorithm which utilizes the coherence of the grid of rays for the intersection calculations. The efficiency of the algorithm is shown by comparing compute time of the intersection calculations to a commercial software that computes each ray intersection independently.
An Estimation of Tool Failure by Means of AE Signal and Surface Roughess in Turning Machining
Han, Eung-Gyo ; Lee, Beom-Seong ; Park, Jun-Seo ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 72~77
In this study, using in-process tool failure detecting system by AE method in turning machining, we measured AE signal from the tool, and the surface roughness of workpiece and then compared it with tool wear. As a result, we found that tool failure can be predicted by means of surface roughness of the workpiece and it can be predicted more precisely by the arithmetical average roughness (Ra) than by the maximum height of irregularities (Rmax) of the workpiece. Also, we found that we could judge whether it was sudden failure or the wear by means of the shape of AE signal and the range distri- bution of power spectrum frequency when tool danage was happened.
A Study on the Analysis of Transmission Errors of Spiral Bevel Gears
Shin, Gwe-Su ; Lee, Kee-Hyung ; Chae, Hee-Chang ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 78~89
The most important criteria of quality of meshing and contact of gears are the low level of noise and the sufficient dimensions and location of the contact. A new approach for determination of machine-tool settings for spiral bevel gears is proposed. The proposed settings provide a function of transmission errors, the desired location and orientation of contact. The function is able to absorb piece-wise linear functions of transmission errors that are caused by the gear misalignment and to reduce the gear noise. The determination of pinion machine-tool settings is based on the local synthesis of gears. A computer program for simulation of meshing bearing contact and determination of transmission errors for misaligned has been developed.
Measurement of Thermal Coefficient at High Temperature by CW-Laser Speckle Photography and Image Processing
Kim, Gyeong-Seok ; Choe, Jeong-Seok ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 90~99
In resent year Laser Speckle and its development have enabled surface deformation of engineering components and materials to be interferometrically examined. Laser Speckle- Pettern Interferometry Method is a very useful method for measuring In-plane components of displacement. In measuring thermal expansion coefficient, the various problems generated were established, and the measuring limitation examined. Metarial INCONEL 601 was used in experiments. Specimen was heated to the high temperature(100
) by diong current to the direct two specimen. Then, those problems appear to the influence of back-ground radiation by the heated specimen, the influence by air turbulence, the oxidation of specimen. The color monitor and interference filter prevented the back-ground radiation by rad heat. The oxidation occuring in specimen itself was not generated by the being acid-proof excellence of material INCONEL 601. Yet, in this experiments, the serious problems are the oxidation of specimen and influence by air turbulence. By more reserching these problems forward, it is helpful that the thermal expansion coefficient of many materials is directly measured under high temperature.
Stability Analysis of the Adaptive Input-Output Linearizing Controller
Lee, Man-Hyung ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 100~108
In this study, the technique of adaptive control based on certainty equivalence for the input-output linearization of nonlinear system is investigated. It is shown that the upper bound of the parameter estimation error can be represented more explicitly than Teel et al's works. Another direct approach, which stows that the adaptive input-output linearing control laws using the normalized identifier yield bounded tracing, is also presented.
A Study on Mixing for Injection Molding of Ceramic Turbo-charger Rotor for Automobile Engine.
Jang, In-Cheol ; Go, Jin ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 109~117
Mixing of ceramic-binder system was investigated experimentally and theoretically for application to Ceramic Injection Molding. Polypropylene, stearic acid, and paraffin wax were selected as the binder system, and silicon nitride fine powders were selected as the ceramic material. Single screw ectruder was employed as the mixing equipment. Theoretical analysis was performed to investigate the mixedness of mixture quantitatively. The analysis predicted average residence time average total strain, and average shear stress as a function of screw speed for mixtures of different volume fraction. Qualitative mixedness of mixture and characteristics of mixing were investigated by using SEM and EPMA. In addition, rheological properties of the mixture were investigated by using a capillary rheometer to examine possibility of injection molding.
Stress Analysis of a Hydrostatically Pressurized Frustum of Axisymmetric Conical Pressure Vessel
Baek, Tae-Hyun ; Chung, Tae-Jin ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 118~125
Theoretical equations for hoop stress, longitudinal or meridian stress and Von Mises stress of an axismmetric conical pressure vessel and a frustum of conical pressure velle, both of which are pressuized by hydrostatic loading, are derived from equilibrium equations. The membrane stresses conputed by theoretical equations for a conical pressure vessel and a frustum of conical pressure vessel are compared with the values obtained from finite elelment method. Based on the fact that the computational values by theoretical equations are well agreed with the finite element results, derived equations are proved to be valid and it is possible for those equations to be conveniently used for structural analysis or design of frustum of conical pressure vessel which is a part of silo body.
A Study on the Position Control of Electro-hydraulic Sevosystem using PID Sliding Mode
Ha, Seok-Hong ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 126~135
Up to now, there has been a lot of researches on the sliding mode control which has the insensitive characteristics to the variations of plant parameters, nonlinearities and external disturbances. One difficulty in applying the sliding mode control is the need for the knowledge of the full-state vector. The use of state observer is a natural step towards the relaxation of this condition. However, the exact plant-modeling is assumed to be known. Recently, there has been a remarkable advance in the microprocessor and one can construct the controller which could not realize due to hardware restriction in the past. Therefore in this paper, the PID sliding mode controller which has only one output feedback signal is suggested by means of microprocessor and the performance of electro-hydraulic servosystem compensated with this controller is proved.
The End-Point Position Control of a Translational Flexible Arm by Inverse Dynamics
Lee, Seong-Cheol ; Bang, Du-Yeol ; S. Chonan ; H. Inooka ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 136~146
This paper provides the end-point positioning of a single-link flexible robot arm by inverse dynamics. The system is composed of a flexible arm, the mobile ballscrew stage as an arm base, a DC servomotor as an actuator, and a computer. Actuator voltages required for the model of a flexible arm to follow a given tip trajectory are formulated on the basis of the Bermoullie-Euler beam theory and solved by applying the Laplace transform method, and computed by the numerical inversion method proposed by Weeks. The mobile stage as the arm base is shifted so that the end-point follows the desired trajectories. Then the trajectory of end-point is measured by the laser displacement sensor. Here, two kinds of functions are chosen for the given tip trajectories. One is what is called the bang-bang acceleration profile and the other is the Gaussian velocity profile.
The Study on the Cutting Behavior of Super Duralumin(A2024-T3)
Jun, Tae-Ok ; Park, Heung-Sik ; Ye, Guoo-Hyeon ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 147~153
This study was undertaken to investigate the cutting behaviour of super duralumin (A2024-T3) with sintered carbide tool(P20). The cutting test was carried out under different conditions such as cutting speed, cutting depth and rake angle, etc. The specific cutting force Kc and Kt of vertical and radial forces decreases as cutting speed increases, especially the decrease rate of Kt becomes larger than of Kc as cutting speed increases. Kc and Kt in small cutting depth are much affected by work-hardening of surface layer. The chip width and shear angle become layer as cutting depth increases, especially chip width at feed of 0.1mm almost approaches cutting width. Relation between the friction coefficient of chip side and tool rake angle side can make the modelization studying the built-up edge size. The shear angle model equation of super duralumin generally agree with theory of Ernst-Merchant.
Design of the Position Control System for a Nonlinear Multivariable Launcher
Kim, Jong-Shik ; Han, Seong-Ik ; Sim, Woo-Jeon ;
Journal of the Korean Society for Precision Engineering, volume 9, issue 4, 1992, Pages 154~166
A kinematic nonlinear multivariable launcher is modeled of which the azimuth and elevation axes are drived simultaneously and position control systems are designed for this system by the PD and LQG/LTR control methods. Also, the suitable command input fonction is suggested for the desired command following performance and the two control systems with disturbances and load variation are evaluated for the entire operating range by computer simulation. It is found that the two linear controllers can be used for the kinematic nonlinear multivariable launcher in the entire operating range and LQG/LTR controller is more effective for disturbance rejection.