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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 16, Issue 12 - Dec 1999
Volume 16, Issue 11 - Nov 1999
Volume 16, Issue 10 - Oct 1999
Volume 16, Issue 9 - Sep 1999
Volume 16, Issue 5 - May 1999
Volume 16, Issue 4 - Apr 1999
Volume 16, Issue 3 - Mar 1999
Volume 16, Issue 2 - Feb 1999
Volume 16, Issue 8 - Jan 1999
Volume 16, Issue 7 - Jan 1999
Volume 16, Issue 6 - Jan 1999
Volume 16, Issue 1 - Jan 1999
Selecting the target year
A Study on the Fatigue Behavior of ARALL and Manufacturing of ARALL Materials
Jang, Jeong-Won ; Sohn, Se-Won ; Lee, Doo-Sung ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 13~18
A Study on the Manufacture and the Performance Evaluation of Stereolithography System
Kang, Won-Joo ; Kim, Jun-An ; Lee, Seok-Hee ; Paik, In-Hwan ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 19~25
This paper addresses a development work of a SLA apparatus on laboratory basis. The SLA test machine is composed of optical, movement, curing and control subsystems. Optical part is performed by a He-Cd laser with mirror combination and mechanical movement is achieved by X-Y table. The developed system is evaluated by several test runs, and shows a good precision capability in forming a basic part. The technique used in this work can be extended to replace the high technology transfer cost of commercial RP machine.
Sensitivity Analysis Using a Symbolic Computation Technique and Optimal Design of Suspension Hard Points
Chun, Hung-Ho ; Tak, Tae-Oh ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 26~36
A general procedure for determining the optimum location of suspension hard points with respect to kinematic design parametes is presented. Suspensions are modeled as connection of rigid bodies by ideal kinematic joints. Constraint equations of the kinematic joints are expressed in terms of the generalized coordinates and hard points. By directly differentiating the constraint equations with respect to the hard points, kinematic sencitivity equations are obtained. In order to cope with algebraic complexity associated with the differentiation process, a symbolic computation technique is used. A performance index is defined in terms of static design parameters such as camber, caster, toe, ect.. Gradient of the performance index can be analytically computed from the kinematic sensitivity equations. Optimization results show the effectiveness and validity of the procedure, which is applicable to any type of suspension if its kinematic configurations are given.
Recognition of Gap between base Plates for Automated Welding of Thick Plates
Yi, Hwa-Cho ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 37~45
Many automated welding equipment are used in the industry. However, there are some problems to get quality welds because of the geometric error, thermal distortion, and incorrect joint fit-up. These factors can make the gap between base plates in case of a thick plate welding. The welding product with the quality welds can not be obtained without consideration of the gap. In this paper, the robot path and welding conditions are modified to get the quality weld by detecting the position and size of the gap. In this work, a low-priced laser range sensor is used. The 3-dimensional information is obtained using the motion of a robot, which holds a laser range sensor. The position and size of the gap is calculated using signal processing of the measured 3-dimensional information of joint profile geometry. The data measured by a laser range sensor is segmented by an iterative end point method. The segmented data is optimized by the least square method. The existence of gap is detected by comparing the data with the segmented shape of template. The effects of robot measuring speed and gap size are also tested. The recognizability fo the gap is verified as good by comparing the real joint profile and the calculated joint profile using the signal processing.
Semi-Actively Controlled Impact System Design
Kim, Dong-Hwan ; Choi, Moon-Chul ; Lee, Kyo-Il ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 46~56
A semi-actively controlled impact system which adjusts an impulse exerted by the external impact is studies. The main control variables are internal pressure difference inside the cylinder and the shock absorber displacement while it travels. Compared to a conventional one so called a passive system with a variable orifice inside the cylinder, a semi-actively controlled system utilizes an external orifice controlled by a highly fast responding electrical proportional valve. This device overcomes the temperature and viscosity change due to continuous operating and keeps the desired pressure difference and displacement in every operation. In this article a new prototype impact system is designed and manufactured based on a semi-actively control system. Through computer simulations and experiments, we verify the possibility of controlling the shock absorber pressure and displacement. After investigating the control performance a modified semi-actively controlled system with better control performance is also proposed.
Evaluation of Analytical Method for Detent Spring Force Correction
Kim, Sun-Ho ; Kwon, Hyuk-Hong ; Park, Kyoung-Taik ; Jung, Yong-Hun ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 57~63
A thin metal plate such as detent spring has the shape deformation due to the phenomenon of spring back after press machining and heat treatment process. This requires the correction of spring shape and force in final inspection process. To do correction of the shape deformation the impact force is manually applied to the bended part of detent spring after measuring the shape deformation and spring force. To develop the automatic spring force correction system, applied force of occurring plastic deformation must be derived from the experimental method. But frequent change of spring shape and material makes it difficult to accomplish the experimental method to be applied. This paper describes the analytical method for detent spring force correction system is to be substituted for the experimental method. FEM(Finite Element Method) is used to find the boundary value between elastic and plastic deformation in the analytical method. To confirm the validity of the analytical method, the result of two methods is compared each other at various applied force conditions. It shows that the simulation result of the analytical method is consistent with the result of the experimental method within the error bound
5%. The result of this paper is useful for development of the automatic spring correction system and reduction of the complicated and tedious processes involved in experimental method.
Study on a Optical Storage Device Based on Multi-beam
Lee, Jeong-Hyeon ; Han, Chang-Su ; Kim, Su-Hyeon ; Gwak, Yun-Geun ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 64~70
A new multi-beam optical system is presented on the grounds of tri-positioning systems in this paper. The system has been developed to improve the data transfer rate for the optical disk system. The actuating system is composed of a tracking and focusing actuating system basically and a newly developed beam rotating actuator. The beam rotating actuator is employed in a multi-beam optical system to trace more than one track simultaneously. The multi-beam optics is established through the optical simulation and several experimental trials. The differential phase tracking method is used in the tracking error signal detection based on the only one beam spot. We also analyze the characteristics of multi-beam optical system. The experimental result shows that the multi-beam positioning system has performance adequate to the multi-beam optical disk system.
A Study on the Optimized Biarc Curve Fitting of Involute Curve
Cho, Seung-Rae ; Lee, Choon-Man ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 71~78
The determination of the optimum biarc curve passing through a given set of points along involute curve is studied. The method adopted is that of finding the optimum number of span and the optimum length of the span such that error between the biarc curve and involute curve minimum. Iterative method is effectively used to find the optimim number and length of the span on involute curve with reduced length of NC-code.
An Influence of Water Ingestion into Engine Cylinder on the Joint Reaction Force of the Connecting Rod
Kim, Hyeong-Hyeon ; Yoon, Hi-Seak ; Seo, Kwon-Hee ; Moon, Young-Deuk ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 79~84
This paper focus on investigating the influence of the amount of water ingestion and the engine speed on the joint reaction force of the connecting rod in engine. The connecting rod was modelled by MSC/PATRAN, the modal informations of it were obtained by the DMAP module in the MSC/NASTRAN, and the dynamic force history was computed through the flexible multibody dynamic simulation in DADS. To analyze the joint reaction force acting on the connecting rod, the 48 cases were investigated. The engine speed varies with 200, 700, 1600, 2400rpm and the volumetric ratio of water to the combustion chamber varies with 0, 10, 20, ..., 90, 95 and 97.5% . As the engine speed decreases and the amount of water ingestion increases, the joint reaction force increase. Especially when the amount of water ingestion exceeds the 70% of the volume of the combution chamber, the joint reaction force acting on the connecting rod is over the design strength.
Machining Cell Control Abstract Machine Tool
Lee, Chang-Ho ; Sheen, Dong-Mok ; Hahn, Hyung-Sang ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 85~94
Reconfiguration, expansion, or new establishment of FMS requires the availability of a shop floor control (SFC) system relevant to the FMS since it is closely related with the hardware component of FMS. Due to the expensive cost of its development, significant research efforts have been made to develop an SFC system that is reusable. This paper presents Abstract Machine Tool (AMT) approach applied to develop an SFC sytem that is reusable without additional programming. The AMT model enables us to design the SFC system independently of the hardware-dependent attributes of euqipment; an AMT models a workstation by abstraction and presents an equipment-independent interface to machining cell controller. Specifically, we describe how we formalize the interfaces among equipment in order to build an AMT and how we design the machining cell control software based on AMT models. We also present MACHINIST the machining cell control system for IAE-FMS plant as an implementation example.
Dynamic Characteristics Analysis of an Escalator Using a Computer Model
Park, Chan-Jong ; Kwon, Yi-Sug ; Park, Tae-Won ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 95~101
In this paper, we propose a dynamic model of an escalator which can be used to build a design database. The model permits to estimate the forces applied to the structure by calculating three primary types of forces; the torque required to operate the escalator, the reaction forces at part interconnection points, and contact forces between parts. These forces can then be used to calculate dynamic stresses in the structure which is required to estimate the durability of the structure. Result of the computer model are compared with testing results. This simulation model is used to construct a design database. So when we design a new escalator, this design database can be used to make a new simulation model which makes it possible for us to do a Knowledge-Based-Design.
Reverse Engineering System Based 3D Digitizer
Choi, Young ; Park, Jin-Pyo ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 102~109
Reverse engineering is a technique that helps designers to quickly generate computer interpretable data from existing physical objects. It can be used for generating CAD data from a mechanical part of high precision, or generating computer animation characters from physical mock-ups. We developed a low precision reverse engineering system that is composed of surface/solid generation software and a contact type commercial 3D digitizer. A unique point sampling procedure has been devised to easily form solid topology from the sampled data. It was also shown that STL data for rapid prototyping was successfully generated from the solid.
The Effects of Molding Conditions on the Surface Gloss of ABS Molding
Jeong, Yeong-Deug ; Hwang, Si-Hyon ; Lee, Mi-Hye ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 110~115
The surface gloss of an injection molded part is one of the most significant point for evaluating the quality of products appearance. The effects of process condition on the gloss of ABS(Acrylonitrile-Butadiene-Styrene) molded part were investigated in this work. The measurements of gloss and morphology on the surface of molded part were carried out with different melt temperature, mold temperature, mold surface roughness, injection pressure and holding pressure. Gloss had a maximum value with melt temperature in the range of 210 to 220
and with mold temperature 40 to 50
and with injection pressure 80~90 MPa, respectively. Melt temperature was shown to have the largest effect on gloss in our work. Gloss was not improved in the region of melt temperature 240
above and of mold temperature 60
above. It was concluded that the variation of gloss was mainly caused by rubber particles migration under shear stress not by their aggregation or necklace.
A Study on the Burr Minimization of Drilling Process by Optimal Velocity Profile Tracking
Park, Min-Suk ; Jeon, Do-Young ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 116~121
At the exit stage of drilling, the burr generates and deburring process is required to remove it. Since the additional process reduces productivity, a burr minimization technique is necessary in the servo system of drilling machines. In this research, cutting force is modelled with tool geometry and the optimal velocity profile with which the desired cutting force maintains is generated to minimize burr. Experiments show that the proposed velocity profile tracking effectively minimizes burr compared to the constant velocity feed.
Three-Dimensional Contact Stress Analysis for Structural Design of Bolted Joint Assembly of Pressure Vessels in Nuclear Power Plants
Lee, Boo-Youn ; Kim, Tae-Woan ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 122~128
Bolted joint assembly for nuclear power plants consists of various components : cover plate, retainer plate, manway flange, gasket and stud bolts/nuts. To guarantee the soundness of the joint, it is important to prevent leakage through the gasket and reduce the stress concentration factor at the thread root. In this paper, Submodeling technique for the finite element method is proposed to accurately compute three dimensional contact stresses which govern the sealing performance and the maximum contact stresses at the threads root. For verification of global solutions used as boundary conditions of submodel solution, the stresses on the cover plate and the manway flange are measured by strain gages when internal pressure is applied to the bolted joint assembly. The numerical results are compared with the experimental results.
A Toolpath Generation for CNC Machining of Free-form Surfaces
Seong, Wan ; Choi, Chong-Ho ; Song, O-Sok ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 129~137
A parametric curve interpolator has been proposed for machining curves instead of a linear interpolator in which curves are approximated by a set of line segment. The parametric curve interpolator is superior to linear interpolator in machining time and contour error and generate exact position commands directly from curve equations. In this paper, a new toolpath generation method is proposed based on the parametric curve interpolator. This method retains all the benefits of parametric curve interpolator and can bound the scallop height within a specified value. By interpolating curves and surfaces directly from the mathematical equations, the amount of data from CAD/CAM system to CNC controller can be significantly reduced. The proposed method was implemented on a CNC controller and was confirmed to give a better result than the other existing method.
Slope Detecting and Walking Algorithm of a Quadruped Robot Using Contact Forces
Lee, Soon-Geul ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 138~147
For autonomous navigation, a legged robot should be able to walk over irregular terrain and adapt itself to variation of supporting surface. Walking through slope is one of the typical tasks for such case. Robot needs not only to change foot trajectory but also to adjust its configuration to the slope angle for maintaining stability against gravity. This paper suggests such adaptation algorithm for stable walking which uses feedback of reaction forces at feet. Adjusting algorithm of foot trajectory was studied with the estimated angel of slope without visual feedback. A concept of virtual slope angle was introduced to adjust body configuration against slope change of the supporting terrain. Regeneration of foot trajectory also used this concept for maintaining its stable walking against unexpected landing point.
Wear of Diamond Dental Burs
Lee, Keun-Sang ; Lim, Young-Ho ; Kwon, Dong-Ho ; So, Eui-Yeorl ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 148~154
This study was carried out to verify grinding performance of dental diamond bur and investigate the possibility of AE application in dentistry field. Workpieces were made of acryl and bovine respectively for the experiments in this study. Grinding test was conducted to get the data of grinding resistance and specific grinding energy of four different types of diamond bur by using tool dynamometer. AE signal was acquired to verify grinding process in the AE measuring system. Tool wear was observed to find parameters about grinding characteristics of diamond bur by means of SEM picture. It was found that the wear of dental diamond bur could be detected with polishing of grinding material, removal of adhesive parts, wear of particles neighboring cutting nose, loss of material and elevation of temperature. The wear of B, C, D type diamond bur is due to wear and fracture of grain size. Abnormal state can be found through the behavior of AE signal in the grinding working. As a result, it is expected that forecast of abnormal state is possible using AE equipments under real time process.
Design of Robust Input Shaping Filter in the Z-domain
Park, Un-Hwan ; Lee, Jae-Won ; Lim, Byoung-Duk ; Joo, Hae-Ho ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 155~162
Input shaping technique has been used as a simple method of controlling the residual vibration of a flexible manipulator. With the conventional methods previously proposed by several authors, the frequency range that shows a good performance is restricted. When the designed frequency being different from the natural frequency of a system, the performance of control degrades remarkably. This paper introduced a new technique that designs input shaping with robustness in the z-domain.
A Study on the Development of Polishing Robot System Attached to Machining Center for Curved Surface Die
Lee, Min-Cheol ; Ha, Deok-Ju ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 163~177
Polishing work for a curved surface die demands simple and repetitive operations and requires much time while it demands also high precision. Therefore it is operated by a skilled worker in handiwork. However the workers avoid gradually a polishing work because of the poor environmental conditions such as dust and noise. In order to reduce the polishing time and to alleviate the problem of shortage of skilled workers, an automatic polishing robot system which is composed of a polishing robot with two degrees of freedom motion and pneumatic system is developed, and it is attached to machining center with three degrees of freedom. The system keeps the polishing tool vertically on the surface of die and maintains constant pneumatic pressure. The polishing robot with DSP(digital signal processor) controller is controlled by sliding mode control. A synchronization between machining center and polishing robot is accomplished by using M code of machining center. A performance experiment for polishing work is executed by the developed automatic polishing robot system. The result shows that the developed automatic polishing robot has a good performance and well polished workpiece surface is obtained.
Various Dynamic Behavior of Three Point Bend Specimens under Rapid Loading
Lee, Ouk-Sub ; Cho, Jae-Ung ; Han, Moon-sik ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 178~188
Path Planning for a Mobile Robot in a Partially Unknown Environment
Chung, Hak-Young ; Kim, Ki-Yong ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 189~196
Study on the Stress Singularity of Interface Crack by using Boundary Element Method
Cho, Chong-Du ; Kwahk, Si-Young ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 197~204
The boundary element method was used for studying singularities of an interface crack with contact zones. The iterative procedure is applied to estimate the contact zone size. Because the contact zone size was extremely small in a tension field, a large number of Gaussian points were used for numerical integration of the Kernels. Stress extrapolation method and J-integral were used ofr determining stress intensity factors. When the interface crack was assumed to have opened tips, oscillatory singularities appear near the tips of the interface crack. But the interface crack with contact zone which Comninou suggested had no oscillatory behavior. The contact zone size under shear loading was much larger than that under tensile. The stress intensity factors computed by stress extrapolation method were close to those of Comninou's solution. And the stress intensity factor evaluated by J-integral was similar to that by stress extrapolation method.
Inverse Kinematic Analysis of a Three Dimensional Binary Robot Manipulator
Ryu, Gil-Ha ; Rhee, Ihn-Seok ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 205~212
A three dimensional binary parallel robot manipulator uses actuators which have only two stable states and its structure is variable geometry truss. As a result, it has a finite number of states and fault tolerant mechanism because of kinematic redundancy. This kind of robot manipulator has some advantages compared to a traditional one. Feedback control is not required, task repeatability can be very high, and finite state actuators are generally inexpensive. Because the number of states of a binary robot manipulator grows exponentially with the number of actuators it is very difficult to solve and inverse kinematic problem. The goal of this paper is to develop an efficient algorithm to solve an inverse kinematic problem of three dimensional binary parallel robot manipulator using a backbone curve when the number of actuators are too much. We first derive the coordinate transformations associated with a three degree of freedom in-parallel actuated robot manipulator. The backbone curve is generated optimally by considering the maximum roll and pitch angles of the robot manipulator configuration and length of link. Then, the robot manipulator is fitted along the backbone curve with some criterion.
A Study on Modeling of LD Movement and Measurement of Mass Center using Piezoelectric Element
Song, Hwa-Seop ; Hong, Jun-Hee ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 213~219
Piezoelectric element is deformed by driving voltage pattern. We developed a device of moving LD(laser disk) to use the rapid deformation of piezoelectric element. If driving voltage is changed very rapidly, the difference of acceleration is accurred between spindle motor and LD. To move LD on turn table is attained by utilizing difference of acceleration. This paper describes theoretical and experimental results about the movement of LD and presents to measure the center of mass LD with unbalance force.
Improvement of the Accuracy in Machining Deep Pocket by Up Milling
Lee, Sang-Kyu ; Ko, Sung-Lim ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 220~228
The machining accuracy has been improved with the development of NC machine tools and cutting tools. However, it is difficult to obtain a high degree of accuracy when machining deep pocket with long end mill, since machining accuracy is mainly dependant on the stiffness of the cutting tool. To improve surface accuracy in machining deep pocket using end mill, the performance by down cut and up cut is compared theoretically and experimentally. To verify usefulness of up milling, various experiments were carried out. As a result, it is found that up milling produce more accurate surface than down milling in machining deep pocket. For effective application of up milling, various values in helix angle, number of teeth, radial depth of cut and axial depth of cut are applied in experiment.
Analysis on the Precision Machining in End Milling Operation by Simulating Surface Generation
Lee, Sang-Kyu ; Ko, Sung-Lim ;
Journal of the Korean Society for Precision Engineering, volume 16, issue 4, 1999, Pages 229~236
The surface, generated by end milling operation, is deteriorated by tool runout, vibration, tool wear and tool deflection, etc. Among them, the effect of tool deflection on surface accuracy is analyzed. Surface generation model for the prediction of the topography of machined srufaces has been developed based on cutting mechanism and cutting tool geometry. This model accounts for not only the ideal geometrical surface, but also the deflection of tool due to cutting force. For the more accurate prediction of cutting force, flexible end mill model is used to simulate cutting process. Computer simulation has shown the feasibility of the surface generation system. Using developed simulation system, the relations between the shape of end mill and cutting conditions are analyzed.