• Journal of Korean Institute of Industrial Engineers
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• v.26 no.4
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• pp.325-335
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• 2000

Gouge-free tool-path generation is an important issue in mold & die machining and researches on cutter interference avoidance can be found in many articles. One of the various methods is construction of tool-offset surface of cutter-location (CL) surface on which the cutter-center point (CL-point) locates. Provided that the CL surface is represented in a suitable form, cutter-interference avoidance can be performed without the burden of computing CL data for every cutter-contact (CC) point. In the paper, various methods of constructing a CL surface in the z-map form are presented, where z-map is a special form of discrete nonparametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z[i,j].

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.04a
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• pp.156-156
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• 1999

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.179-184
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• 1995

A new cutting parameter is defined in the spherical part of ball end-mill cutter. A series of slot cutting experiments were carried out to obtain the cutting parameter. The cutter contact area is expressed as the grid posiotion in the cutting plane using Z map. The cutting forces in each grid are calculated and saved as force map, prior to the average cutting forces calculation. The cutting force, in the arbitrary cutting area, can be easily calculated by summing up the cutting forces of the engaged grid in the force map. This model was verified in the inclined surface cutting by cutting test of a cylindrical part.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.35-39
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• 1998

Determination of effective EDM parameters is significant to increase productivity. However, With the complexity of EDM phenomena, a universal selection method of EDM parameters has not been established yet. Moreover, No attempt has been tried before to suggest a logical method in determining essential machining parameters for effective electrical discharge machining. Peak current, one of the most significant factors in EDM, is proportional to EDM area. This paper presents a method that can be Z-map modeling from CMM data, and calculate EDM area using Z-map.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.255-255
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• 2004

일반적으로 10,000 rpm 이상의 고속, 고이송 가공이 수행되는 고속가공에서 절삭력의 급격한 증가는 치명적인 결과를 초래할 수 있다. 따라서 실제 가공에 앞서 NC code에 존재하는 에러 유무를 검출하고, 주어진 절삭 조건의 적합성을 사전에 검사하는 NC 모의 가공 시스템의 중요성이 점점 강조되고 있는 실정이다. 절삭 영역의 탐색에는 일반적으로 Z-map 방식이 사용되고 있다. Z-map 방식은 자료구조의 단순성과 완결성으로 인하여 계산속돈가 라르고 오류 발생의 가능성이 상대적으로 낮기 때문에 상용 CAM 시스템은 대부분 이 방식을 기반으로 하고 있다.(중략)

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.68-75
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• 2005

This paper presents a new method for the optimization of feed rate in sculptured surface machining. A NC verification model based on Z-map was utilized to obtain chip load according to feed per tooth. This optimization method can regenerate a new NC program with respect to the commanded cutting conditions and the NC program that was generated from CAM system. The regenerated NC program has not only the same data of the ex-NC program but also the updated feed rate in every block. The new NC data can reduce the cutting time and produce precision products with almost even chip load to the feed per tooth. This method can also reduce tool chipping and make constant tool wear.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.47-56
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• 2003

Geometric cutting-simulation and verification play an important role in detecting NC machining errors in mold & die manufacturing and thereby reducing correcting time & cost on the shop floor. Current researches in the area may be categorized into view-based, solid-based, and discrete vector-based methods mainly depending on workpiece models. Each methodology has its own strengths and weaknesses in terms of computing speed, representation accuracy, and its ability of numerical inspection. The paper proposes a hybrid modeling scheme for workpiece representation with z-map model and discrete vector model, which performs 3-axis and 5-axis cutting-simulation via tool swept surface construction by connecting a sequence of silhouette curves.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.801-805
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• 2000

This paper presents a new method of tool path optimization. A NC verification model based Z-map was utilized to obtain chip load in feed per tooth. This developed software can regenerate a NC program from cutting condition and the NC program that was generated in CAM. The regenerated NC program has not only all same data of the ex-NC program but also the new feed rates in every block. The new NC data can reduce the cutting time and manufacture precision dies with the same chip load in feed per tooth. This method can also prevent tool chipping and make constant tool wear. This paper considered the effects of acceleration and deceleration in feed rate change.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.725-729
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• 2000

This paper presented a new model of NC verification in ball end milling. The model verifies the over cut the under cut and the surface roughness using NC file generated from CAM and cutting condition. The model uses Z-map model to verify workpiece. In this paper, the model used the velocities of x, y and z direction and obtained a center point of a ball end mill for modeling Z-map of workpiece. To investigate the performance of the model simulation study was carried out. As the results, the model gave geometry accuracy of workpiece, the surface roughness and the chip loads in finish cutting that can predict tool chipping.

• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.537-545
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• 2005

The aim of this paper is to solve the open problem on product properties of digital covering maps raised from [5]. Namely, let us consider the digital images $X_1 {\subset}Z^{n_{0}}$ with $k_0-adjacency$, $Y_1{\subset}Z^{n_{1}}$ with $k_3-adjacency$, $X_2{\subset}Z^{n_{2}}$ with $k_2-adjacency$ and $Y_2{\subset}Z^{n_{3}}$ with $k_3-adjacency$. Then the reasonable $k_4-adjacency$ of the product image $X_1{\times}X_2$ is determined by the $k_0-$ and $k_2-adjacency$ and the suitable k_5-adjacency$ is assumed on $Y_1{\times}Y_2$ via the $k_1-$ and $k_3-adjacency$ [3] such that each of the projection maps is a digitally continuous map, e.g., $p_1\;:\;X_1{\times}X_2{\rightarrow}X_1$ is a digitally ($k_4,\;k_1$)-continuous map and so on. Let us assume $h_1\;:\;X_1{\rightarrow}Y_1$ to be a digital $(k_0, k_1)$-covering map and $h_2\;:\;X_2{\rightarrow}Y_2$ to be a digital $(k_2,\;k_3)$-covering map. Then we show that the product map $h_1{\times}h_2\;:\;X_1{\times}X_2{\rightarrow}Y_1{\times}Y_2$ need not be a digital $(k_4,k_5)$-covering map.