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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 11, Issue 6 - Dec 1994
Volume 11, Issue 5 - Oct 1994
Volume 11, Issue 4 - Aug 1994
Volume 11, Issue 3 - Jun 1994
Volume 11, Issue 2 - Apr 1994
Volume 11, Issue 1 - Feb 1994
Selecting the target year
Monitoring and Diagnosis for Abnormal States of Machine Tools
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 5~16
Intelligent Simulation Technology for Production Planning and Control in Automated Manufacturing System
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 17~22
A study on the digital signal processing by shear horizontal-electro magnetic acoustic transducer
Kim, J.Y. ; Park, H.I. ; Y.T. Cho ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 32~40
In this study by using EMAT(electro magnetic acoustic transducer)the artificial slit is installed on 12B-SUS pipe test piece. By making 4 cycle SH-burst (EMA) incidence to 45 .deg. angle, the signal data of pulse, received from EMAT are translated into digital-signal-processing- method SSP(Split Spectrum Processing) and Deconvolution method. The main conclusions obtained are as follows; (1) the signal data received from EMAT are translated with digital signal proc- essing of SSP-method and Deconvolution-method and this method shows exellent results more than Ultrasonic testing method does; (2) noise can well be removed by SSP with signal data, and resolution and S/N ratio are advanced; (3) when used with Ultrasonic wave general stainless steel has proporties of multiscattering and reflection phenomena, but resolution is progressed by using Deconvolution method;and (4) as addition-averaging-processing mumber is increasing, the resolution and S/N ratio are improved and the satisfactory signal is obtained.
A study on the heat flow in laser welding of steel sheet of the different thickness
Y.S. Yang ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 41~49
Laser welded blanks are finding increased usage in many industrial applications, which are made of different sheet thickness or different material strengths joined together. In this study the heat flow problem in laser welding of the different steel sheet thickness was solved by using a finite element method, and a series of experiments wers carried out to confirm the validity of the numerical method.
A stydy on the precision machining in ball end milling system
M.Y. Yang ; C.G. Sim ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 50~64
Cutter deflections in the ball-end milling process is one of the main causes of the machining errors on a free-form surface. In order to avoid machining errors in this process, a methodology avoiding these machining errors on the free-form surfaces has been developed. In this method, feedrates in the finish cuts are adjusted for the prevention of machining errors. A model for the prediction of machining errors on the free-form surface is analytically derived as a function of feed and normal vector at the surface of contact point by the cutter. This model is applied to the dertermination of the adjusted feedrates which satisfy the machining tolerance of the surface. In the finish cuts of a simple curved surface, the suggested model is examined by the measurements of the generated machining error on this surface. And also, this surface is machined with the adjusted feedrates for the given machining tolerance. The measured machining errors on this surface are compared with the given tolerance. In this comparisons, it is shown that the predicted errors are fairly good agreement with the test results.
Ddsign of a backcap system for remote control of hydraulic valves
Lee, J.G. ; J.S. Myung ; Kim, O.H. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 65~74
Backcap is an electric remote control system for the operation of directional flow control valves. This paper presents a new type of basckcap system which is characterized by its simple construction. The backcap is essentially a hydraulic cylinder of which the piston is connected to a spool of hydraulic valve and controlled by input current. An inherent feedback is imposed on its mechanism so that no artificial noe is needed. Characteristics of the backcap is verified by stability analysis, transient motion and steady state positioning for step inputs. Design parameter analyses have been executer by some analytical approaches and computer simulations, which lead to their optimal valves. These results contributed to an effective new backcap system and its design strategy.
Tool Wear and Chatter Detection in Turning via Time-Series Modeling and Frequency Band Averaging
;Y.S. Chiou;S.Y. Liang;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 75~84
An analysis of cutting process with ultrasonic vibration by ARMA model
I.H. Choe ; Kim, J.D. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 85~94
The cutting mechanism of ultrasonic vibration machining is characterized as two phases, that is, an impact at the cutting edge and a reduction of cutting force due to non-contact interval between tool and workpiece. In this paper, in order to identify cutting dynamics of a system with ultrasonically vibrated cutting tool, an ARMA modeling is performed on experimental cutting force signals which have a dominant effect on cutting dynamics. The aim of this study is, through Dynamic Date System methodology, to find the inherent characteristics of an ultrasonic vibration cutting process by considering natural frequency and damping coefficient. Surface roughness and stability of cutting process under ultrasonic vibration are also considered
Equivalence of the times of flight by ultrasonic energy and phase velocities and determination of the elastic constants of anisotropic materials
H.J. Jeong ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 95~103
The purpose of this paper is to provide the experimenters who use the oblique incidence ultrasonic method for anisotropic elastic constants measurement eith some useful relations. In particular, the equivalence of the times of flight by the energy ad phase velocities, which is key to the oblique incidence method, is proved explicitly. This equivalence greatly simplifies the analysis of immersion measurement results. In oredr to correctly measure the transit time of an immersed sample using the oblique incidence, the receiving transducer should be shifted laterally, and an expression in given for this shift. A method for determining all nine elastic constants of an orthotropic material is briefly described and the measurement results are listed for SiC particulate reinforced A1 matrix composites.
Computer-Aided Process Planning and Die Design for Hot Forging of H-Shaped Plane Strain Components
Park, J.C. ; Kim, B.M. ; Kim, S.W. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 104~109
This research describes some developments of computer-aided process planning and die design for hot forging products of H-shaped plane strain produced by the press. The system is composed of three main modules(process planning module, die design module and simulation module) which are used independently or in all. Systm capabilities include as follows: 1. In die design module, using the results of process planning module, the shape and size of bolcker and finish die in each operation are determined and the ouput id generated in graphic form for manufacturing drawing. 3. In simulation module, the flow pattern of workpiece and the load/stroke curve are approximately predicted. Design rules for process planning and die design are extracted from plasticity theories, handbooks, relevant references and empirical know-how of field experts in hot forging companies. The developed system provides poweful capabilities for process planning and die design of hot forging products.
Robust controller design and performance analysis of seeker scan-loop
Lee, Ho-Pyeong ; Hwang, Hong-Yeon ; Song, Chang-Seop ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 110~119
The Robust Controller for scan-loop is designed using LQG/LTR Methodology. The design and analysis of spiral, rosette and conical scan patterns are discussed. The perfermance and robustness of the LQG/LTR controller are analyzed through experiments and cpmpared with those of the P-controller. Especially to improve the scan performance at large look angle, the cage coil output is linearized using a binomial equation. It is demonstrated that the scan-loop system by the LQG/LTR control is very robust to phase uncertainties.
An Integrated Expert System for Automated Data Reduction in High-speed Holographic Interferometry
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 120~133
Relation between J and CMOD in dynamic loaded 3-point bend specimens
O.S. Lim ; I.N. Cha ; J.U. Cho ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 134~140
Numerical caiculations are made in order to find a possible relation between the J-integral and the crack mouth opening displacement(CMOD) in dynamic nonlinear fracture experiments. Both elastic-plastic and elastic-viscoplastic materials are considered at different impact velocities. The J-integral may be estimated from the crack mouth opening displacement which can be measured directiy from photographs taken during dynamic experiments.
Intercomparison of Force Standards between Korea and Germany
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 141~148
A Study on the optical aspects of machine vision based dimensional measurement system
Lee, E.H. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 149~163
A novel method of dimensional measurement using machine vision, which is called Landmark Tracking System, has been developed. Its advantages come form tracking only the bright, standard shaped "landmarks" which are made from retroreflective sheets. In the design of the LTS, it is essential to know the relationship between optical parameters and their influence on system performance. Such optical parameters include the brightness of landmark image, the illumination system design, and the choice of imaging optics. And the performance of retroreflective material also plays important role in the LTS performances. Influences of such optical parameters on LTS's dimensional measurement characteristics are investigated, with respect to the retroreflective material, the imaging optics, and the illumination system. Measuremtn errors due to parameter variations are also analyzed. Experiments are performed with a LTS prototype. Retroreflective characteristics are verified, and the LTS's measurement performances are measured in the form of repeatability and accuracy. Experimental results shgow that the LTS has repeatability better than 1/30,000 of a field of view(30 degrees), and accuracy better tha 1/3,000 of a field fo view.d fo view.
The analysis of the dynamic characteristics of the tension arm in tape transporting system
Kim, J.B. ; D.H. Ryu ; Park, Y.P. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 164~172
The purposes of the study are to formulate a mathematical model of mechanical tension arm system including supply reel and capstan system, and to simulate dynamic reponse according to parameter variations of the componests in tension arm system. Experiments were carried out in order to prove the validity of the mathematical model. From the results of simulations and experiments, dynamic responses of tape tension and displacement of tension post were analyzed during entire playing mode and they showed the basic characteristics of the tension arm system.
A study on coil temperature bariation in 75% hydrogen batch annealing furnace
E.C. Jeon ; Kim, S.K. ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 173~181
A Cold spot temperature control system for the batch annealing furnace has been estabilished in order to reduce energy consumption to improve productivity and stabilize the propertics of products. Therefore we confirmed a relation between annealing cycle time and atmospheric gas, variation of coil cold spot temperature with time during heating and actual temperature measurements at mid-width of each coil during heating and actual temperature measurements at mid-width of each coil during soaking. The results of the tempaeature variation effect on the batch annealing are as follows. 1) Heating time is reduced to one half with increasing atmospheric gas flow rate and changing of atmospheric gas component from HNx to Ax gas, and annealing cycle time is reduced to 2.7 times. 2) In case of short time healing, the slowest heating part is the center of B coil, in case of long time heating, the low temperature point moves from the center of coil to inside coil. And the temperature in this part is higher than other parts when cooling. When finished heating, the cold spot is located 1/3 of coil inside in case of HNx atmospheric gas. But center of coil in case of Ax atmospheric gas. 3) The outside of top coil is the highest temperature point when heating, which becomes the lowest temperature point when cooling. So, this point becomes high temperature zone at heating and low temperature zone at cooling, It has relation according to atmospheric gas component and flow rate. 4) Soaking time at batch annealing cycle determination is made a decision by the input coil width, and soaking time for quality homogenization of 1214mm width coil must be 2.5 hours longer than that of 914mm width coil for the same ciol weight. 5) Annealing cycle time with Ax atmospheric gas is extended 1 hour in of slow cooling during 5 hours in order to avoid rapid cooling.
A study on the cutting characteristics of SUS304 by flank wear
K.H. Yu ; C.Y. Cheong ; N.S. Seo ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 182~188
This expermintal study is intended to investigate he development of flank wear in turning os SUS304 which is used in industrial applications and is acknowledged as a machining difficult material. In cutting process, change of velocity, change of feed, and change of depth of cut were investigated about the effect of flank wear, and slenderness ratio is also investigated. The variations of unit cutting force with the change of rake angle and the change of uncut chip area are observed. The friction angles are calculated for the change friction force and observed. The friction angles are calculated for the change friction force and normal forcd on the different rake angles. From this experimental study, the following results can be said. 1. Under the high cutting speed condition, the flaank wear is affected by the feed and depth of cut, but the influence of feed and depth of cut to the flank wear is reduced when the velocity is low. 2. The smaller slenderness ratio is, the shorter the tool life results in high cutting speed, and the lower cutting speed is, the lower the effect of slenderness ratio to the flank wear is. 3. Using the characteristics of force-RMS, the flank wear of a tool can be detected. There are almost no differences between the RMS characteristics of cutting force and feed force.
Quality characteristics and the process control of high-strength frictional bolt-sets
S.Y. Son ; D.H. Shin ;
Journal of the Korean Society for Precision Engineering, volume 11, issue 2, 1994, Pages 189~196
Quality assurance in the process of manufacturing high strengh bolt sets used in the frictional joints of structures in one of important concern to users as well as to manufactures. In case of occurrences of either defective or low-quality products, even if they are quite rare, some systematic means of localizing the cause-characteristics and matching to corresponding production process is necessary. Control chart of torque factor is the primary indicatir in finding defectiveness of the products. Use of correlation diagrams ofnhardness of the bolt set presents in part a way of screening the cause. Retest data of the bolt set provide additional ideas of localizing the cause, for which theoretical background is presented in this regard. A process-characteristics matrix relating the causes of low quality to the corresponding process of manufacturing, which is of prime importance for the feedback control of production, is also proposed. Finally general features of control to assure quality of the set is described.