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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 15, Issue 12 - Dec 1998
Volume 15, Issue 11 - Nov 1998
Volume 15, Issue 10 - Oct 1998
Volume 15, Issue 9 - Sep 1998
Volume 15, Issue 8 - Aug 1998
Volume 15, Issue 7 - Jul 1998
Volume 15, Issue 6 - Jun 1998
Volume 15, Issue 5 - May 1998
Volume 15, Issue 4 - Apr 1998
Volume 15, Issue 3 - Mar 1998
Volume 15, Issue 2 - Feb 1998
Volume 15, Issue 1 - Jan 1998
Selecting the target year
Development of a Static and Dynamic Analysis System for Motor-Integrated High-Speed Spindle Systems Using Timoshenko Theory and Finite Element Method
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 11~16
Recently, the motor-integrated spindle systems have been used to simplify the machine tool structure, to improve the motion flexibility of machine tool, and to perform the high-speed machining. In this study, a static and dynamic analysis system for motor-integrated high-speed spindle systems is developed based on Timoshenko theory, finite element method and windows programming techniques. Since the system has various analysis modules related to static deformation analysis, modal analysis, frequency response analysis, unbalance response analysis and so on, it is useful in performing systematically the design and evaluation processes of motor-integrated high-speed spindle systems under windows GUI environment.
A Study on Development of Automatic Path Tracking Algorithm for LNG Aluminium Plate and Selection of Process Parameters by Using Artificial Intelligence
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 17~25
Aluminum alloys have low density, relatively high strength and yield strength, good plasticity, good machinability, and high corrosion and acid resistance. Therefore, they are suitable for large containers for the food, chemical and other industries. Large containers are often bodies of revolution consisting of shell courses, stiffening rings, heads and other elements joined by annular welds. Larger containers have longer welds and require greater leak-tightness and higher weld mechanical properties. The LNG tank consists of aluminum plates with various sizes, so its construction should by divided by several sections. Moreover, each section has its own sub-section consisted of several aluminum plates. To guarantee the quality of huge LNG tank, therefore, the precise control of plate dimension should by urgently needed in conjunction with the appropriate selection of process parameters such as cutting speed, depth of cut, rotational speed and so on. In this paper, a manufacturing system was developed to implement automatic circular tracking in height direction and automatic circular interpolation in depth of cut direction. Also, the neural network based on the backpropagation algorithm was used to predict the cutting quality and motor load related with the life time of the developed system. It was revealed that the manufacturing system and the neural network could be effectively applied to the bevelling process and to predict the quality of machined area and the motor load.
Effects of the Surface Grinding Conditions on the Machining Elasticity Parameter
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 26~32
The grinding force generated during the grinding process causes an elastic deformation of the workpiece, grinding wheel, and machine system. Thus, the true depth of cut is always smaller than the apparent depth of cut. This is known as machining elasticity phenomenon. The machining elasticity parameter is defined as a ratio between the true depth of cut and the apparent depth of cut. It is an important factor to understand the material removal mechanism of the grinding process. To increase productivity, the value of this machining elasticity parameter must be large. Therefore, it is essential to know the characteristics of this parameter. The objective of this research is to study the effect of the major grinding conditions, such as table speed and depth of cut, on this parameter experimentally. Through this research, it is found that this parameter value is increasing when the table speed is decreasing or the depth of cut is increasing. Also, this parameter value depends on the grinding mode (up grinding, down grinding).
Development and Tool Life Assessment of TiYN Coated High Speed Steel Tools
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 33~38
TiYN coated high speed steel tools have been developed and their tool lifes were assessed. First yttrium alloyed titanium target was manufactured, then using the arc ion plating(AIP) technique TiYN coating was deposited onto high speed steel substrate. Three kinds of varying thickness of TiYN coated tools were prepared. Cutting tests were carried out with theses tools and for comparison with the commercially available uncoated, TiN, TiCN and TiAlN coated tools. During the cutting tests flank wear width vs. cutting time was measured. It has been revealed that the newly developed TiYN coated tools show superior tool life characteristics to others.
Rapid Tooling (2) : Al Powder Filled Resin Tooling and Its Characteristics
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 39~45
In the previous study. the powder casting was attempted as the rapid tooling. The powder casting was the process to cast dry powder into the casting mold transferred from R/P model and infiltrate the liquid binder to solidify the powder. And then, the melted copper was infiltrated to control the shrinkage rate of the final mold Conseqently, the shrinkage rate was under 0.1% through that process. The mechanical characteristic was also excellent. Generally, in the slurry casting, the alumina powder and the water soluble phenol were mainly used. However, the mechanical property of the phenol was not good enough to apply to molds directly. In this study, aluminium powder filled with epoxy is applicated to the slurry casting to solve these problems. The mechanical and thermal properties are better than phenol because the epoxy is the thermosetting resin. We achieved a successful result that the shrinkage rate is shortened about 0.047%. Futhermore, the manufacturing time and cost savings are significant. Finally, we assume that the developing possibility of this process is very optimistic.
Parametric Shape Design and CNC Tool Path Generation of a Propeller Blade
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 46~59
This paper presents shape design, surface construction, and cutting path generation for the surface of marine ship propeller blades. A propeller blade should be designed to satisfy performance constraints that include operational speed which impacts rotations per minutes, stresses related to deliverable horst power, and the major length of the marine ship which impacts the blade size and shape characteristics. Primary decision variables that affect efficiency in the design of a marine ship propeller blade are the blade diameter and the expanded area ratio. The blade design resulting from these performance constraints typically consists of sculptured surfaces requiring four or five axis contoured machining. In this approach a standard blade geometry description consisting of blade sections with offset nominal points recorded in an offset table is used. From this table the composite Bezier surface geometry of the blade is created. The control vertices of the Hazier surface patches are determined using a chord length fitting procedure from tile offset table data. Cutter contact points and path intervals are calculated to minimize travel distance and production time while maintaining a cusp height within tolerance limits. Long path intervals typically generate short tool paths at the expense of increased however cusp height. Likewise, a minimal tool path results in a shorter production time. Cutting errors including gouging and under-cut, which are common errors in machining sculptured surfaces, are also identified for both convex and concave surfaces. Propeller blade geometry is conducive to gouging. The result is a minimal error free cutting path for machining propeller blades for marine ships.
A Study on Nonlinear Controller of DC Servo-motors with Harmonic Drive Gearing and Its Synchronous Operation
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 60~70
A harmonic drive is compact torque transmission device with no backlash which is widely applied in industrial field to transmit torque precisely. However, one of the disadvantages of harmonic drives is the existence of mechanical flexibility caused by its structural properties, which imposes great limitation on designing precise controller This paper proposes a nonlinear controller for synchronous operation of DC servo-motors with harmonic drive, using Integrator Backstepping method. Furthermore, an alternative algorithm for serial type synchronous operation of multiple DC servo-motors is proposed. Simulation results by SIMULINK for proposed controller shows considerably small error and rapid approach to reference input, which can be adapted to industrial applications.
선형 CCD를 이용한 MTF방법에 의한 카메라 렌즈 초점거리의 출정 및 보정 시스템 개발
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 71~80
A computer aided system has been developed for the focal length measurement/compensation in camera manufacture. Signal data proportional to light intensity is obtained and sampled very rapidly from the line CCD. Based on the measured signal, the MTF performance is calculated, where the MTF is the ratio of magnitude of the output image to the input image. In order to find the optimum MTF performance, an effcient algorithm has been implemented using the least squares technique. The developed system has been applied to a practical camera manufacturing process, and demonstrated high productivity with high precision.
A Study on the High-Speed Machining of Die/Mold Material Using a Spindle-Speeder
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 81~87
High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and molds. In this paper, high-speed machining for HP-4 die material was carried out with a coated tungsten carbide ball endmill. In the high-speed machining, the cutting force and surface roughness of workpiece show various characteristics in different cutting conditions. Especially, the surface roughness of the workpiece depends largely on pick feed and feed-per-revolution of the ball endmill. In the condition where pick feed and feed-per-revolution are equal, better surface roughness is measured. By obtaining good surface roughness at high speed, efficiency of machining can be increased.
Determination factor of Modularization of a product
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 88~101
In this paper, module of a product is determined by the characteristics of a product itself and art assembly process. To analyze the characteristics o( the product, assembly function, structure of subassembly and parts could be considered. Based on the analysis of characteristics of product structure, assembly process and product function, determination criteria of a module could be proposed. For the assembly process, assembly methods, assembly equipment and workers could be considered. For the product structure, constituent object and structural feature could also be considered. To obtain the interrelationship between the product and the assembly process, the matrix table could be used to find the influencing factors that affected the module.
A Study on the Prediction of Laser Spot Weld Shapes of Thin Stainless Steel Sheet
H. S., Kang ; T. O., Jun ; S. J., Na ;
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 102~108
Development of 6-component Load Cell Using Plate Beams
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 109~115
This paper describes the development of a 6-component load cell with plate beams which may be used to measure forces Fx, Fy, Fz and moments Mx, My, Mz simultaneously in industry. We have analyzed the bending strains on the surface of the beams under forces or moments by using Finite Element Method and designed the sensing elements of 6-component load cell. We have also determined the attachment location of strain gages of each load cell and fabricated 6-component load cell. To evaluate the rated strain and interference error of each load cell, we have carried out characteristic test of 6-component load cell.
Prediction and Detection of Tool Wear and Fracture in Machining
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 116~125
In this paper, main target is to select parameters for prediction of tool wear and detection of tool fracture. The research about choosing parameter for prediction of tool wear is done by using force ratios. Also current sensor, tool-dynamometer, and accelerometer are used for researching detection method of tool fracture. Experiment is done using Taguchi's method in medium machining conditions. Parameter which is best for prediction of tool wear and detection of tool fracture by deviation analysis is selected. In this paper, tool wear means flank wear.
Rotational Motion Control Using ER Clutch/Brake Actuators
S. B., Choi ; J. H., Kim ; M. S., Han ;
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 126~134
A Study on Stress Analysis and Fatigue Behaviors of Carbonitried Cr-Mo(SCM415) Steel -About Various Factors Having an Effect on Fatigue Strength-
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 135~144
In this research, the fatigue behaviors of Cr-Mo(SCM415) steel and carbonitrided CrMo(SCM415) steel are examined. The description of experiments in detail as follows. For SCM415 and carbonitried Cr-Mo(SCM415) steel, smooth specimens and hole defected specimens are fabricated and tested under a rotary bending tester, respectively. By performing the rotary bending fatigue test for smooth and hole defected specimens, the characteristics of the fatigue strength are examined for parameters such as tensile strength, hardness at surface, and residual stresses.
Thickness Control of Tandem Cold Mills Using
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 145~155
controller with a roll eccentricity filter is proposed to alleviate the effect of entry thickness variation and roll eccentricity occured in rolling stands themselves of tandem cold mills. A robust controller to the disturbances is designed by H
control techniques, which can reflect the input direction of disturbances and the knowledge of disturbance spectrum in the frequency domain. First, fundamental problems in tandem cold mills such as process transport delay inherent in the exit thickness measurement and the feedforward loading of roll eccentricity signals on the exit thickness be overcome by the roll eccentricity filtering and the compensation for the error of gaugemeter thickness estimator. And non-satndard
control problem caused by the selection of weighting function having poles on the
-axis is discussed. The resultant controller composed by an
controller and an estimator for the roll eccentricity is evaluated through computer simulations. The effectiveness of the proposed control method is compared to that of the conventional LQ controller method and a feedforward controller for the roll eccentricity, which has been already studied.
Development of a Human Interface System for the IMS, - Application of the Teleoperation System -
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 156~164
IMS is a more advanced manufacturing system than FMS. However, IMS do not have sufficient performance for the work in the various and uncertain environment, because of the difficulty of the work and occurrence of the unexpected condition. If IMS is hard to work properly, teleoperation system can support it by using the human's consideration and judgment. The master mechanism is a basic component of the teleoperation system and the development of the useful one is important for efficiency of the work. A master mechanism of exoskeleton type can increase the work efficiency, mobility and harmony between a working robot and an operator. This paper describes an arm-harness of exoskeleton type, which is able to drive a robot according to judgment. This device is applied to a robot system for evaluating the system performance through the experiment.
A Study on Collision Avoidance for Multi-link Intelligent Robots
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 165~173
In this paper, a motion control algorithm is developed by using fuzzy control technique, which makes a robot arm avoid unexpected obstacles when the robot is moving from the start to a goal posture. During the motion, if there exist no obstacles the robot arm moves along the pre-defined path. But if some obstacles are recognized and close to the robot arm, a fuzzy controller is activated to adjust the path of the robot arm. To show the feasibility of the developed algorithm, numerical simulations and experiments are carried out. In the experiments, redundant planar robot arms are considered for the collision avoidance test, and it was proved that the developed algorithm gives good collision avoiding performance.
A CAD/CAM System for Blanking or Piercing of Irregular Shaped-Sheet Metal Products
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 174~182
This paper describes a research work of developing a computer-aided design and machining of irregular shaped-sheet metal product for blanking or piercing operation. An approach to the CAD/CAM system is based on the knowledge-based rules. Knowledge for the CAD/CAM system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD and in customer tool kit on the SmartCAM with a personal computer and is composed of nine modules, which are input and shape treatment, flat pattern-layout, production feasibility check, blank-layout, strip-layout, die-layout, data conversion, modelling, and post-processor module. Based on knowledge-based rules, the system is designed by considering several factors, such as material and thickness of product, complexities of blank geometry and punch profile, diameter and material of a wire, and availability of press. This system is capable of generating NC data automatically according to drawings of die-layout module. Results which are carried out in each module will provide efficiencies to the designer and the manufacturer of blanking or piercing die in this field.
Measurement and Analysis of Back-EMF and Thrust of a Linear Brushless DC Motor
Journal of the Korean Society for Precision Engineering, volume 15, issue 8, 1998, Pages 183~192
In this paper, we measure the back-EMF and the thrust of a linear brushless DC motor along the relative position between coils and magnets in various speed environments in order to obtain the back-EMF and the thrust as a function of a motor position. The measured back-EMF function and thrust function of the position differ from the analytical ones within 5%. The measured back-EMF and thrust function can, then, be employed in controlling the thrust ripple of the linear motor. Furthermore, to minimize the torque ripple of the linear motor, we suggest the design method to shape the back-EMF and thrust function of the linear motor.