• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.531-535
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• 1996

Computer aided conceptual solution of engineering problems can be effectively implemented by qualitative reasoning based on a physical model. Qualitative reasoning needs modeling paradigm which provides intellignet control of modeling assumptions and robust inferences without quantitative information about the system. We developed reasoning method using new algebra of qualitative mathematics. The method is applied to a conceptual design scheme of anadaptive control system of cutting process. The method identifies differences between proportional and proportional-integral control scheme of cutting process. It is shown that unfeasible investment could be prevented in the early conceptual stage by the qualitative reasoning procedures proposed in this paper.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.161-169
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• 1993

The elimination of chatter vibration is necessary to improve the precision and the productivity of the cutting operation. A new mathematical model of chatter vibration is presented in order to predict the dynamic cutting force from the static cutting data. The dynamic cutting force is analytically expressed by the static cutting coefficient and the dynamic cutting coefficient which can be determined from the cutting mechanics. The stability analysis is carried out by a two degree of freedom system. The chatter experiments are conducted by exciting the cutting tool with an impact hammer during an orthogonal cutting. A good agreement is shown between the stability limits predicted by theory and the critical width of cut determined by experiments.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.3
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• pp.82-91
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• 1995

The purpose of this research is to develop a new real-time process control system. In this paper, a theoretical method for acquiring the control limit of cutting process(cutting surface) according to the required value(geometric tolerance) based on geometrical relations was propsed. In particular, the three following points are amphasized. Firstly, the process control was based on the cutting process, and the control limit was determined from the analysis of geometrical relations. Secondly, AMGD(Actual Measured Geometrical Deviation) was used as a new substitute value in process analysis. Thirdly, fuzzy reasoning was introduced to get the control limit flexibility according to the variations in the required value and general consideration of each measurememnt items.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.28-32
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• 1992

The elimination of chatter vibration is necessary to improve the precision and the productivity of the cutting operation. A new mathematical model of chatter vibration is pressented in order to predict dynamic cutting force from static cutting data. Chatter vibration occurring in the tool structure of lathe is treated theoretically, considering the regenerative effect. The Stability Analysis is carried out by a two degress of freedom system. The dynamic cutting force is analytically expressed by the static cutting coefficient and the dynamic cutting coeccicient which can be determined from the cutting mechanics. The static cutting coefficient controls high speed chatter stability, while the dynamic cutting coefficient dominates low chatter stability. From above considerations, the cirtical width of cut which governs chatter stability was obtained.

• Journal of Welding and Joining
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• v.27 no.6
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• pp.55-61
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• 2009

This study aims for determination of cutting work envelope of an articular robot for H-beam cutting. The robot has its own work envelope. The cutting of piece with groove requires the specific position of the torch which contracts the work envelope. This study suggested the new method to determine the cutting work envelope for this case. The method simplified the problem by use of the combination of inverse kinematics and forward kinematics. The method was used for cutting the H-beam with groove. The cutting work envelope was determined easily. The result was verified by 3D simulation system which implements the articular robot with 6 axes and the H-beam in the virtual shop.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.985-990
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• 1995

Recently, the development of high speed and high precision NC-lathe for piston head machining is needed for the complexity and diversity of the piston head shape used in automobile reciprocating engine. THe piston head has many complex shapes in the aspect of fuel economy, such as ovality, profile, double ovality and recess. Among them, for the maching of the over shape of 0.1~1mm the cutting tool should move periodically symchronized with the rotation of piston workpiece. The cutting tool feeed system must have high positioning accuracy for the precise machining, high speed for the fast maching and high dynamic stiffness for the cutting force. The linear brushless DC motor is used for satisfying these coditions. The ballbush guide and supporting guide using turcite is used for the guidance of the feed drive system. Linear encoder, digital servo ampllifer and controller are used for driving the motor. THis paper presents the design and simulation of the new tool feed system for noncircular machining.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.6
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• pp.113-126
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• 1992

Recently the multi-kind, small-amount manufacturing system has been replacing the mass manufacturing system, and domestic machining inustry also is eager to absorb the new technology because of its high productivity and cost reduction. The optimization of the cutting condition has been a vital problem in the machining industry, which would help increase the productivity and raise the international competitiveness. It is intended in this study to investigate the machining costs per unit time which is essential to the analysis of the optimal cutting condition, to computer the cutting speed that lead to the minimum machining costs and the maximum production to suggest the cutting speed range that enables efficient speed cutting, and to review the machining economy in relation to cutting depth and feed. Also considered are the optimal cutting speed and prodution rated in rrelation with feed. It is found that the minimum-cost cutting speed increases and the efficient cutting speed range is reduced as machining cost per unit time increases since the cutting speed for maximum production remains almost constant. The machining cost is also lowered and the production rate increases as the feed increases, and the feed should be selected to satisfy the required surface roughness. The machining cost and production rate are hardly affected by the cutting depth if the cutting speed stays below 100m/min, however, they are subject to change at larger cutting depth and the high-efficient speed range also is restricted. It can be established an adaptive optimal cutting conditions can be established in workshop by the auto-selection progam for optimal operation. It is expected that this method for choosing the optimal cutting conditions might contribute to the improvement of the productivity and reduced the cost. It is highly recommended to prepare the optimal cutting conditionthus obtained for future use in the programing of G-function of CNC machines. If proper programs that automatically select the optimal cutting conditions should be developed, it would be helpful to the works being done in the machine shops and would result in noticeable production raise and cost reduction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.200-205
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• 1996

Recently, in order to achieve high flexibility of manufacture, monitoring and control strategies cf a new type have been developed. Since the generation of built-up edge on the cutting tool damages the surface finish of the workpiece, the monitoring system of built-up edge is an important process monitoring. In this study, the analyzing methods of cutting force signal to detect the built-up edge during cutting process are described. The cutting force signals are analyzed using the mean, standard deviation and mean to standard deviation of this cutting signals. We can obtain the guide to detect the built-up edge during turning process.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.7
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• pp.67-72
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• 1997

Recently, in order to achieve high flexibility of manufacture, monitoring and control strategies of a new type have been developed. Since the generation of built-up edge on the cutting tool damages the surface finish of the workpiece, the monitoring system of built-up edge is an important process monitoring. In this study, the analyzing methods of cutting force signal to detect the built-up edge during cutting process are described. The cutting force signals are analyzed using the mean, standard deviation and mean to standard deviation of this cutting signals. We can obtain the guide to detect the built-up edge during turning process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.2
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• pp.138-144
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• 1983

To evaluate the dynamic characteristics of machine tool system, the system is modelled as a closed-loop system composed of cutting process and improved machine tool structures. The proposed machine tool structure model is constructed in consideration of energy transfer through the system. A new methodology to identify the machine tool dynamics by adopting impulse response and impulse cutting techniques is also proposed. It is shown that the methodology is successfully applied to a machine tool system to identify its dynamic characteristics employing the improved model.