• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1039-1042
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• 1995

In real time application such as motion control, it is hard to find the application of non-causal filtering due to its need for future position data, even though it shows wide usage in off-line digital signal processing. Recently, some of motion control areas such as learning and repetitive control use non-causal filtering technique in their application. these kinds of zero-lag non-causal filter application are very usful not only to reduce the machine vibration, but also to increase control accuracy with comparatively less work. In this paper, genuine method to implement zero-lag non-causal filter in a CNC is introduced. Also the variation of this implementation for the learning operation is suggested to give the NC better control performance for a specific job. By adopting the new NC architecture call Soft-NC, all these implementions are made possible here, and especially large memory requirement which hinders their usage for many years is no longer barrier in their real world application.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.33-39
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• 1998

This paper is related to economic design of tool-resetting period in NC machining. In NC lathe machining, the mean and variance of components dimension fluctuate in slow time and we should reset tool program to compensate the variation from the fluctuation. In this paper. we propose the procedure determining the optimal resetting period based on the total expected operating cost which consists of resetting cost and the quality cost related to dimension variation. As a case study, using experimental data about dimension changes of a lathe machining, we obtain the regression equations of mean and variance of the dimension fluctuation, total expected operating cost, and optimal resetting period.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.1
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• pp.54-59
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• 1995

In this paper, we propose unique CAM system for personal computer that can define the geometric shape in an ease manner and to machine the sculptured surfaces of a mold cavity. In this CAM system, if a user inputs simple initial information such as the control points for a shape definition and a radius of tool etc., all of the procedures for machining will be processed automatically by the CAM system as well as NC commands and simulations. In addition to this, the environment of the CAM system is composed of "C" language for an easy extention of aditional modules. Also, the CAM system with the following characteristics was developed. 1. The optimum tool path satisfying given tolerance limits reduces the time for the high precision machining of sculptured surface in a mold cavity. 2. The generated NC commands can be transmitted to NC directly by the CAM system through RS-232C from PC.C from PC.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.1
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• pp.7-16
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• 2004

The tool path needs to be determined in an efficient manner to generate the final NC (numerical control) code for efficient machining. This is particularly important in machining free form pockets with an arbitrary wall geometry on a three-axis CNC machine. Many CAD/CAM systems use linear interpolation to generate NC tool paths for curved surfaces. However, this needs to be modified to improve the smoothness of the machined bottom surface, reduce machining time and CL (cutter location) file size. Curved machining can be a solution to reduce these problems. The unified rough and finish cut algerian and the tool motion is graphically simulated. In this paper, a grid based 3D navigation algorithm for generating NC tool path data for both linear interpolation and a combination of linear and circular interpolation for three-axis CNC milling of general pockets with sculptured bottom surfaces is developed.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.3
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• pp.139-154
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• 1993

Cutter Interference(or part surface gouging) is one of the most critical problems in NC machining of sculptured surfaces. Presented in this paper is and algorithmic procedure that converts CC data obtained from a compound surface(several surfaces without topological relationship) into interference-free CL data. The interference handling procedure consists of following steps: (1) Z-map model is constructed from input surfaces. (2) Interference sources are detected using local properties of the sources. (3) Interference regions are completely identified based on global tests for neighboring CC points of the interference sources (4) Cutter paths are reconstructed after removing the CC data in interference regions, while avoiding any new interferences.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.1090-1095
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• 1992

This paper describes the systematic control method of process information transfer and machine cell control in FMS implementation. We have constructed an experimental FMS computer network and control system. The system hardware consists of host computer to manage process data and information transfer of machine cells, cell control computers to control machine cells(NC lathe, machining center). On the other hand, software is made up of oredr management module, NC program searching and generation module, NC part program error check module and cell control module. In this study, we could arrive at conclusion as following : The first, each task could be accomplihed by the efficient information transfer in hierachical computer network. The second, data base system of part programs and process control data is needed for the efficint information transfer and production management. Lastly, expansion of FMS control system could be achieved by the hierachical and decentralized computer control system.

• Korean Journal of Computational Design and Engineering
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• v.7 no.4
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• pp.254-261
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• 2002

Small marine propeller is generally machined by 5-axis machining. This paper suggests a method to create geometric model from point array data and 4-axis machining NC data for propeller. With conventional method, the setting posture should be changed, because propeller has front and back surface of wing. The change of setting posture has a bad influence on precision of propeller. So this paper pro-poses a method to machine propeller by single setup for 4-axis machining. The cutter moves to parallel direction of the XY plane. To determine the cutter orientation efficiently, the' tilting guiding line' is proposed. A proposed algorithm is written in C language and successfully applied to the 5-axis milling machine of industrial field.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.279-284
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• 1988

In this paper, NCTOP is an interactive NC auto programming system for two-dimensional machining. NCTOP consists of seven modules, that is pattern form input, free form input, AutoCAD interface, logic processing, postprocessor processing, output, and database upgrade module. The geometry information of a workpiece to be machined is put into NCTOP program. Then it generates NC program which is final output. NCTOP uses the machining dates from the data base.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.1078-1083
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• 1992

Extracting the process planning information from the CAD data is the key issue in integrated CAD/CAM system. In this paper, we develop algorithms for extracting the shape and setup configuration for NC machining of prismatic parts. In determining the workpart shape, the minimum-enclosing condept is applied so that the material waste is minimized. To minimize the number of setups, feature based algorithm is developed considrint the part shape, tool shape, and tool approach direction. The validity and effectiveness of the developed algorithms were tested by computer simulations.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.144-152
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• 2003

The purpose of this paper is to establish an effective inspection system by using OMM (On-Machine Measurement) system based PC-NC. This system can reduce manufacturing lead time because part is inspected each process. Inspection process planning is accomplished by determining the number of measuring points, their location, measuring path using fuzzy logic, Hammersley method, traveling salesperson problem. Inspection with contacted sensor improve quality as inspection feature is developed to based machining feature. This method is tested by simulation and experiment, then analyzed measuring data and geometry tolerance.