• Korean Journal of Computational Design and Engineering
• /
• v.4 no.4
• /
• pp.355-359
• /
• 1999

This paper presents a method for determining machining parameters in electrical discharge machining process (EDM) based on discharge area. The parameters are the peak value of currents, the pulse-on time, and the pulse-off time, on which the EDM performance depends chiefly. The optimal machining parameters are closely related on discharge area, which can be calculated from a tool electrode and a discharge height. In the paper the discharge area is obtained from NC code for machining the tool electrode instead of its geometric model. The method consists of following three steps. First a Z-Map model is constructed from the NC code. Secondly, the discharge area is obtained from the Z-Map model and a Z-height. Finally, the machining parameters are calculated from the discharge area. An introduced example shows that the machining parameters are calculated by the using a Z-map model obtained from the machining data for a tool electrode.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.534-537
• /
• 1996

As consumer electronics, information, and aero-space industry grow, the demand for aspheric lens increases higher. To enhance the precision and productivity of aspheric surface, a CAM system for ultra-precision aspheric surface needs to be realized. In this study, the developed CAM system can generate NC code for various aspheric surfaces fast and precisely by Tri-arc interpolation method that the location of maximum error is fixed. The cutting condition input module and the NC code verification module are adequate to ultra-precision machining, so that a operator can obtain products fast and easily.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.10a
• /
• pp.176-176
• /
• 2003

• The Journal of Society for e-Business Studies
• /
• v.5 no.1
• /
• pp.55-73
• /
• 2000

Recently; EC(Electronic Commerce) is increasing with high speed based on the expansion of Internet. EC which is done on the cyber space through Internet has strong point like independence from time and space. On the contrary, it also has weak point like security problem because anybody can access easily to the system due to open network attribute of Internet. Therefore, we need the solutions that protect the security problem for safe and useful EC activity. One of these solutions is the implementation of strong cipher algorithm. NC(Nonpolynomial Complete) cipher algorithm proposed in this paper is good for the security and it overcome the limit of current 64bits cipher algorithm using 128bits key length for input, output and encryption key, Moreover, it is designed for the increase of calculation complexity and probability calculation by adapting more complex design for subkey generation regarded as one of important element effected to encryption. The result of simulation by the comparison with other cipher algorithm for capacity evaluation of proposed NC cipher algorithm is that the speed of encryption and decryption is 7.63 Mbps per block and the speed of subkey generation is 2,42 μ sec per block. So, prosed NC cipher algorithm is regarded as proper level for encryption. Furthermore, speed of subkey generation shows that NC cipher algorithm has the probability used to MAC(Message Authentication Code) and block implementation of Hash function.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.529-533
• /
• 1996

Recently, manufacturing industries are doing their best to increase productivity and to reduce production time. One of tile efforts is to develop user-friendly and effective CAM systems. For this purpose, a CAM system for turning was developed. In the developed system. user interacts with tile CAM system using graphical user interface (GUI) and manufacturing support functions to make NC programs effectively. Manufacturing support functions include cycle decoder. interference check be ween tool and workpicce. bar turning without air cut and dynamic/wireframe simulation. In the cycle decoder. basic options are provided to novices for their convenience. and advanced options are provided to help expert to modify the program using their knowledge. Interference check has been nil issue in tile CAM system for tuning. In this paper. when a user selects a tool. interference check between selected tools and workpieces is done automatically. Moreover. remaining shapes are calculated automatically. Then, tile CAM system requests user to input all additional tool and generates NC codes to cut tile remaining shapes. In bar turning of forged raw material, air cut should be prevented for effective machining. For this purpose, a new algorithm for bar turning was developed. Dynamic and wireframe simulation was used to verify the generated NC code.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2011.09a
• /
• pp.101-105
• /
• 2011

In most shipbuilding company, cutting procedure is proceed by cutting machine which run by CNC(Computer Numerical Code) data. In our cutting process, all CNC data is created by our nesting post processor system automatically. Among them, in case that cutting piece in the remnant plate, our system creates only one piece CNC data. Because remnant plate is not typical shape, and ship designers don't know remnant plate shape and quantity. In can happen some merit and good point if we modify 1:1 piece NC data by shorten cutting path, reducing cutting time or re-arrangement piece. For modifying cutting data, outside workers have to call to ship designer or have to go to NC control room where control the CNC system and cutting machine. It makes stop work process, and it waste time. In this paper, we introduce a program that can modify and replace 1:1 NC data with continuous or common NC data automatically.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.305-311
• /
• 1993

In recent years, it has been variously developed for testing the accuracy of circular motion of NC machine tools, for example Telescoping Ball Bar Method by Bryan,Circular Test Method by Knapp and r $_{- \theta}$ Mathod by Tsutsumi etc., but it is not yet settled in the code of measuring methods of motion errors of NC machine tools, because of errors of measuring units and sensors, and also especially the difficulties of centering of measuring units. In this paper, in use of magnetic type linear scale with resolution of 0.5 .mu. m and tick pulses come out from computer, it has become possible for detecting of linear displacement of radial errors and measuring of revolution angle of circular motion of NC machine tools.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1992.04b
• /
• pp.545-554
• /
• 1992

본 논문에서는 복합형상의 금형을 가공하기 위하여 필요한 공구와 가공경로를 자동으로 생성해 주는 자동공정계획(CAPP)방법을 제시한다. 금형곡면은 일반적으로 복잡한 형상의 자유곡면들의 조합으로 이루어 지는데 육면체 형상의 소재로부터 원하는 금형곡면을 가공하는데는 수십시간의 기계가공 시간이 소요되며 또한 NC Code를 준비하는데도 같은정도의 시간이 소요된다. 금형곡면의 NC가공에 있어서 또다른 어려움은 공구의 과부하와 공구간섭이 빈번하게 발생할 수 있다는 점이다. 제안하는 자동공정계획방법은 전처리, 공정계획, 공구경로 생성의 3단계로 구성된다. 자동공정계획시스템의 입력정보는 1) 생성될 곡면형상 2) 가공할 소재형상 3) 가공공구 셀(드릴, 볼 엔드밀, 플렛 엔드밀), 절삭성 데이타등이다. 전처리 단계에서는 곡면모델러로부터 생성된 입력 형상을 Z-map이라 부르는 자료구조로 변환한다. 두번째 단계에서는 절삭 가공작업의 순서가 사용되는 공구와 함께 후방순환법에 의하여 결정된다. 그리고 실제 가공될 NC공구경로가 마지막 세번째 단계에서 생성된다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.869-872
• /
• 2003

This paper presents a geometric machining simulation algorithm to enhance the reliability and user-friendliness of a comprehensive computer aided process planning (CAPP) system by verifying generated NC data. In order to represent the complex machining geometry with high accuracy, the proposed algorithm is developed based on a boundary representative (B-rep) solid modelling kernel. Solid models are used to represent the part geometry. tool swept volume and material removal volume by Boolean unite and subtract operations. By integrating a machining simulation procedure into the CAPP system, the systematic analysis of the tool path can be implemented synthetically. To demonstrate and check the validity of suggested system, a simple example of simulation is represented and the result is discussed.

• 연구논문집
• /
• s.22
• /
• pp.47-54
• /
• 1992

A problem of relevant interest to some industries is that of optimum two-dimensional layout. The objective of this work is to allocate the shapes on a sheet in such a way to minimize the amount of waste. A nesting software has been developed to help user arrange the 2D parts effectively. It provides various functions, e.g., transformation, distance-check, NC post-processor, etc. This software is developed in X window system with C langusge. Final goal of this software is generating NC code data of the 2D parts on the sheet that can be directly used in NC machines.