• Transactions of Materials Processing
• /
• v.10 no.2
• /
• pp.115-122
• /
• 2001

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup drawing, we set up cushion pressure control system on the hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system. A cushion pressure control experiment was carried out using the NC cushion and it was shown that the proposed system produced good performance. The comparison of drawability of square cups with and without NC cushion showed that the drawability could be greatly improved when S-shaped pressure curve was applied. This paper includes design details of the NC cushion system and experimental analysis of drawability with NC cushion system.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.6
• /
• pp.33-39
• /
• 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 the Society of Naval Architects of Korea
• /
• v.35 no.2
• /
• pp.51-62
• /
• 1998

In this paper, a CAD/CAM system for 5-axis machining of model propeller is introduced. This system has been developed under the environment of personal computer and Windows NT. In order to enhance the productivity, existing text-based design S/W was integrated into this graphic-based system. Non-Uniform Rational B-Spline method is used to represent the sculptured surface of propeller blades and hub using point data, and surface blending between blade and hub is realized in this system. For 5-axis machining of sculptured surface, tool/work collision and interference are checked and inverse kinematic analysis is performed to make NC data. In addition, tool and workpiece are animated on the PC monitor by preparing NC verification module. Finally, optimal cutting conditions are determined empirically and those cutting conditions are integrated into this S/W so that the whole process from design to machining can be done automatically.

• Journal of the Korean Professional Engineers Association
• /
• v.20 no.4
• /
• pp.19-26
• /
• 1987

• Journal of Korea Society of Industrial Information Systems
• /
• v.12 no.1
• /
• pp.46-53
• /
• 2007

NC (Numerical Control) code for the tool path needs to be generated efficiently for machining of free form pockets with arbitrary wall geometry on a three axis CNC machine. The unified rough and finish cut algorithm and the tool motion is graphically simulated in Part 1. In this paper, a grid based 3D navigation algorithm simulated in Part 1 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 experimentally performed and verified.

• Journal of Korea Society of Industrial Information Systems
• /
• v.14 no.4
• /
• pp.1-7
• /
• 2009

This paper presents a process routing (PR) algorithm with multiple objectives. PR determines the optimum sequence of operations for transforming a raw material into a completed part within the available machining resources. In any computer aided process planning (CAPP) system, selection of the machining operation sequence is one of the most critical activities for manufacturing a part and for the technical specification in the part drawing. Here, the goal could be to generate the sequence that optimizes production time, production cost, machine utilization or with multiple these criteria. The Pareto Stratum Niche Cubicle (PS NC) GA has been adopted to find the optimum sequence of operations that optimize two conflicting criteria; production cost and production quality. The numerical analysis shows that the proposed PS NC GA is both effective and efficient to the PR problem.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1991.04a
• /
• pp.270-276
• /
• 1991

가장 대표적인 공작기계인 선반은 가공물에대한 바이트의 이송운동에따라 여러가지 종류의 가공물을 효과적으로 절삭할 수 있기 때문에 절삭 가공에 널리사용된다. 특히, 기계요소로 많이 사용되는 회전체의 절삭에 필요하므로 가장 먼저자동화가 요구되는 분야이다. 그러므로, 보다 효율적인 자동절삭의 목표를 달성하기위한 기초작업으로서 현재의 연구가 수행되었다. 본 연구에서 PC 사용을 전제로 소수의 입력 정보로부터 자동으로 최적의 가공계획 수립을 위한 프로그램의 개발을 목표로 먼저 준비단계로 임의의 외경절삭용 자동 가공계획 시스템을 개발하였다. 개발된 프로그램은 작업자의 자료입력을 최소화 했으며 이 입력자료를 토대로 자동으로 절삭공구의 가공경로 및 절삭에 필요한 자료를 생성하고 가공 전과정을 컴퓨터 그래픽으로 처리하여 사용자의 이해 를 돕도록 하였다. 이러한 기능은 컴퓨터 기억장치를 통하여 저장하고 그장된 자료를 NC code화 하거나 직접 PC로 부터 NC 기계를 구동하면 가공에 관하여 극히 초보자인 경우도 실제 가공을 수 행할 수 있다. 참고로 본 프로그램은 개인용 컴퓨터에서 사용을 전제로 프로그램언어는 Fortran, 그래픽 Library로 Halo를 이용하였고사용자의 이해를 보다 높이기 위하여 EGA Color Monitor를 채택하였다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.280-283
• /
• 1999

Square dies are widely used for hot extrusion processes with high production rate. However the design and manufacture of square dies mainly relies on experience of industrial engineers To overcome such difficulty this study develops a method of automatic generation of NC-codes for the manufacture of extrusion square dies. The result shows that the method can reduce the lead time for the design and manufacture of square dies as well as eliminating engineers ow experience.

• Transactions of Materials Processing
• /
• v.9 no.2
• /
• pp.179-185
• /
• 2000

Square dies are widely used for hot extrusion processes with high production rate, however, the design and manufacture of square dies mainly relies on experience of industrial engineers. To overcome such difficulty, this study presents a method of automatic generation of NC-codes for the manufacture of extrusion square dies. The result shows that the method can reduce the lead-time for the design and manufacture of square dies.

• Journal of the KSME
• /
• v.17 no.3
• /
• pp.183-192
• /
• 1977

우리 나라에서의 NC 공작기계에 관한 현황을 보면 약 100대의 각종 NC 공작기계가 수입되어 사 용되고 있다. NC 공작기계의 국산화는 KIST에서 최초로 시도되었는데 그 개발결과 성능면에서 호평을 받게 되었다. 기계를 국산화함에 있어서 그 구성부품들을 정밀가공하는 것도 중요하지만 그 보다 더 중요한 것은 완성된 기계시스템이 기능면에서 소기의 목적을 달성하는 것이라고 본다 . 본 개발연구에서는 이 점을 중요시하여 Systematic 한 해석과 그에 따른 구성부품의 선택및 제작에 신중을 기하여 소기의 NC 선반을 국산화하였는데 이 과정에서 고려가 되었던 기술적인 제문제와 그에대한 대책등을 소개하기로 한다.