• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.9-20
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• 1998

In recent manufacturing process, the increase of productivity has been attempted by reducing machining time with the increase of cutting force. However, the excessive increase of cutting force can cause tool breakage and have a bad effect on both manufacturing machine and workpiece. Thus, it is necessary to estimate and control the cutting force in real time during the process. In this study, use of disturbance observer is proposed for the indirect cutting force estimation. The estimated cutting force is used for the real-time control of feedrate, making the actual cutting force follow the reference force command. Since the suggested method does not need an expensive sensor like a dynamometer, the method is expected to be used practically. Since the actual cutting force follow the reference force, resulting the reducing of the machining time the increase of productivity are also expected, and the quality of cutting surface has been improved due to the adjusted feedrate. Besides, an actual constant cutting force guarantees the prevention of tool breakage. To show the effectiveness of the suggested cutting force control method, an experimental setup has been made without sensor and applied to several workpieces. Experiments show that the suggested method is effective to cutting force control of a CNC machining center.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.809-813
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• 2000

In this study, screw machining system by use of a rotational tool such as an end-mill or a face cutter with Y axis off-set on a CNC turing center was developed for quick machining. In this system, It was possible to use different tools for different processes, and by off-setting the tool in Y direction by calculated amount it was possible to avoid tool interference problem which could occur within the central area at the end of a tool. In addition, machining a screw with a helix of up to 3 different leads combined and with tapered minor diameter was possible.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.399-404
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• 2001

In CNC machining, a 3D(3-dimension) linear segment and a 2D(2-dimension) circular arc are general forms given by CAD/CAM system. Generally, the 2D circular arc machining is processed using dividing into some linear segments. A 3D circular arc also don't exist in the standard form of NC data. This paper present a algorithm and method for real-time machining of a circular arc(not only the 2D one, but also the 3D one). The 3D circular arc machining is based on the 2D circular arc machining. It only needs making a new coordinate system, converting given 3D points(a start point, a end point, and a center point of a 3D circular arc) into points of the new coordinate system, and processing a inverse transformation about a interpolated point. The proposed algorithm was implemented and simulated on PC system. It was confirmed to give a gcod result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.977-980
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• 1995

This paper proposes the look ahead algorithm with the trapezoidal velocity trajectory in each G-code block. The algorithm requires the information on the length of next trajectories and the connecting angle between each trajectiories. A method of generating the maximum corner velocity upon the connecting angle within the machining tolerance is developed and applied to the look ahead algorithm. Simulations and experiments witha machining center show the effectiveness of the methodology.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1173-1182
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• 2001

Recent noticeable advances of CNC machine tools have considerably improved productivity and precision in manufacturing processes. However, in the respect of productivity some defects still remain because selection of machining conditions entirely depends on the experiences of programmers. Usually, machining conditions such as feed rate and spindle speed have been selected conservatively by considering the worst cases, and it has brought the loss of machining efficiency. Thus, the improvement of cutting force controller has been done to regulate cutting force constantly and to maximize feedrate simultaneously in case that machining conditions change variously. In this study, sliding mode control with boundary layer is applied to milling process for cutting force regulation and in a commercial CNC machining center data transfer between PC and PMC (programmable machine controller) of CNC machine is done using a standard interface method. And in the cutting force measurement, an indirect cutting force measuring system using current signal of AC servo is adopted in order not to use high-priced equipment like tool dynamometer. The purpose of this study is to maximize the productivity in milling process, thus its results can be applied to cases such as rough cutting process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.68-72
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• 2012

Al2017 is typical Duralumin of self-hardening aluminum alloy. It is lightweight, formability and machinability so throughout the industries have widely used automobile, electronics, semiconductor and aircraft as material. A variety of CNC machine tool processing technology, scientific principles and experience have been studied in order to increase accuracy and productivity. Using a machining center is to constant amount of side step and cutting characteristics studied changing depth of cut, revolution per minute and feed rate.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.4
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• pp.21-31
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• 1989

역사적으로 CNC기술이 생산성향상에 기여한바는 매우 크다. 최근에는 고도의 생산성을 추구하는 CNC공작기계는 수요자들의 요구에 부응하여 관련업계는 CNC 기술의 발전을 더욱 가속화 시키고 있다. 오늘날의 CNC는 더욱 향상된 Computer Architecture에 적합한 Software System과 고속, 고집적의 소자기술을 결합한 것이라 볼 수 있으며, 그 결과는 생산을 자동화 하고 전체를 하나의 system화 하려는 요구에 부응하고 유연(Flexible)하며, 사용하기에 편리하고(User-friend- ly), 신뢰성과 높은 생산성을 갖추고 있다. 새로운 CNC 기술이 요구되는 응용분야는 고도로 자동 화 되고 결합 된 FMS에서 부터 단축제어용에 이르기까지 매우 광범위하다. 3축의 Milling, 6축 Machining Center, 전용기 등 Stand-alone 기계들을 위주로한 중소형기계 공장에 적합한 CNC 기술이 개발되고 있는 동시에 CELL LEVEL, 좀더 큰 규모의 FMS 또는 그 이상으로 자동화된 system을 구성하 기 위하여 많은 새로운 기능이 요구되고 종래의 CNC와는 다른 역할의 변화가 필요하다. 실제로는 많은 경우에 이러한 두가지의 응용이 공존하고 있으며, CNC의 기능이나 성능을 희생하지 않고 동일한 Hardware로 여러가지의 응용을 만족시켜야 한다. 생산공정과 생산기술의 변화가 반영되어야 하며, Control 기술도 변화하고 있다. 유연하고 확장가능한 Software, Hardware 구조의 CNC가 실제적으로 가장 Cost-effective한 해결책이다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.57-62
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• 2021

CNC machining is used to fabricate various components. This has led to the development of processing-based industries for the production of automobile, appliances, semiconductors, and rockets. Additionally, this machining has enabled economical mass production of high-quality products in industries. Magnesium alloy with a hexagonal closed packed configuration is prone to difficulties during plastic machining, has a high oxygen affinity, and exhibits poor corrosion resistance to seawater and the atmosphere. In this research, Al alloy A5083 was used to investigate and analyze the surface roughness with a certain depth of cut fixed by the machining center (DVM-500II) and various feed rates, speeds, and processing methods after modeling and simulated machining with Gibbs CAM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.225-226
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• 2007

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.73-79
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• 2020

Although engineering plastics that are light-weight and have excellent mechanical performance have been widely applied in various industries in place of steel structures to reduce the burden of cost and time, there have been few studies related to their surface roughness. This study aims to evaluate the optimal effects of feed rate, cutting speed, and depth of cut as cutting parameters as well as nose angle on the surface characteristics of MC nylon in CNC lathe machining. To determine the best conditions under different nose radii, the experiments were performed based on the Taguchi L9(34) orthogonal array method, in which the resulting data was analyzed using the S/N ratio and ANOVA. Results indicate that the most significant contribution was feed rate followed by nose angle and cutting speed, whereas the depth of cut did not influence the performance. This study demonstrates that the suggested method for improving the surface finishing of MC nylon is efficient compared with results obtained from experimentation and prediction.