• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.289-293
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• 1993

연소가공은 가공에 관계하는 변수가 많기 때문에 트라블 요인을 쉽게 파악하기 힘들다. 트라블의 원인을 탐색해서 처리하는 경우에도 정량적으로 정확한 값을 User에게 제공하기는 어렵다. 따라서 대부분 생산시스템에 활용할때 숙련자가 행하는 것 같이하기 위한 유용한 수단이 엑스퍼트 시스템( Expert System)이다. 본 연구는 연삭가공의 Burning과 Chatter vibration의 진단 . 처리에 대하여 폴트 진단모델 과 계층분석법을 이용하여 Prototype적인 시스템을 구축하였다. 또한, 각 노드에 대한 데이타 분석에 있어, 계층분석법을 이용함으로써 정량적이고 애매한 지식을 객관적으로 처리 하였으며, 각각의 노드에 대하여 중요도를 부여함으로써 데이타 베이스와 추론시간의 성력화를 도모하였다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.122-128
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• 2000

세라믹, 다이야몬드등과 같은 고경질재료에 대한 미소형상의 가공은 대단히 어렵고 일반적인 방법으로는 상당한 시간을 요구한다. 이러한 재료의 고능률 가공을 실현하기 위하여, 메탈본드 다이야몬드휠에 전해 인프로세스 드레싱(Electrolytic In-Process Dressing)을 적용한 연삭을 머시닝센타에서 시도하였다 본 연구에서, 메탈본드 다이야몬드휠은 전기방전에 의하여 고능률로 트루잉(truing)되었다. 알루미나 세라믹의 핀선단($\phi$50$\mu\textrm{m}$)과 로커웰 경도측정기의 다이야몬드 압입자(indenter)($\phi$40$\mu\textrm{m}$)를 ELID연삭에 의하여 창성하였다. 그 결과를 본 논문에서 보고한다.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.61-68
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• 1998

The form accuracy of parts has become an important parameter. Therefore, dimensional tolerance and geometric tolerance are used in the design stage to satisfy required quality and functions of parts. But the informations on the machining conditions, which can satisfy the assigned geometric tolerance in design, are insufficient. The objectives of this research are to study the effects of the grinding parameters such as traverse speed, work speed, depth of cut, and dwell time on the after-ground workpiece shape, and to find out the major parameters among them. The results are as follows, The effects of work speed and depth of cut on workpiece shape are negligible compared with the effect of traverse speed. There is an optimal dwell time depending on the traverse speed. The optimal dwell time is decreasing as the traverse speed is increased.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.1
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• pp.34-44
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• 1997

This study presents the recursive constraint bounding(RCB) method to reduce the cycle time in internal cylindrical plunge grinding process. This method can cope with process noise as well as modeling bias. The main features of RCB method are its utilization of measurements at the end of each cycle and its use of monotonicity analysis for determining the extremes of bias and noise. This method is investigated in simulation and evaluated by experiment in internal cylindrical plunge grinding operation. The results from simulation and experiment show that it is effective in reducing cycle time in spite of modeling uncertainty in the forms of process noise and modeling bias.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.493-498
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• 2013

The present study treats the optimization process for a non-linear grinding system with dual time delay, mainly from the energetic viewpoint. To this end, the stability of the grinding system is investigated first with regard to the grinding wheel rotation speed. The concept of grinding energy density is newly proposed as the primary figure of merit and this quantity is evaluated at various stable and limit cycle conditions. The computational results show that simple monotonic trend in energy density is observed under stable conditions, whilst rather complicated behaviors can appear when the conditions are associated with limit cycle oscillations. Finally, the relations between the vibration amplitude and the energy density and their implications on the engineering decision/compromise are discussed.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.5
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• pp.95-102
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• 2002

The grinding operation is an important machining process for machining of final surface. However, grinding process has inevitable troubles such as loading and glazing for grinding wheel. It is, therefore, an essential research theme to determine the wheel life and the dressing time for efficient grinding. In this study, AE signals (AEavg) generated in the grinding operation were measured and the dressing time was determined from the analysis of the AEavg value. To verify the propriety of the obtained result, the AE signals measured on the grinding and the dressing operation were compared with the grinding force signals and the dressing force which were measured at same time. From the obtained result, it was confirmed that the determination of the wheel life and the dressing tilde by the AE measurement technique proposed in this study can be practically used.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.117-122
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• 2002

The chatter to raise grinding operating is reduce the precision and the quality. In this study, In reply to AE signal and the normal force generated in the grinding operating were measured (1) the amplitude in the mathematical model of the normal force is the form as to transform an exponential (2) the chatter growth is minus point of an exponent. (3) From the observed wheel aspect after the chatter growth, it was to investigated the concern of the chatter growth and the wheel life.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.120-125
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• 1993

The surface roughness of workpiece is reduced during spark-out. The reduction of roughness is a benefit of spark-out, but spark-out lowers productivity. The characteristics of spark-out are different to those of plunge grinding to which feed is applied. This difference is due to overlapping cutting during spark-out. Effect of spark-out is in proportion to volume of grain wear. This phenomenon is due to different overlapping area. Dressing interval can be enlarged by spark-out, when volume of grain wear is large. In this study, the characteristic of spark-out was studied by spark-out obserbation in various grinding conditions. For this purpose thrust force, spark-out time and surface roughness of workpiece were experimentally investigated in various grinding conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.61-67
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• 2017

Research into the selection of suitable materials and the development of fast processing methods for press die manufacturing is absolutely necessary to reduce the production time and cost. In particular, knowledge of its heat properties must be considered whendeveloping a long press die. Generally, as the main component materials of press dies, Cr, W low alloy tool steel, high carbon-high chrome steel, high speed steel, etc., are used as thetooling steel for the cold die. Machine tools and wire-cut electric discharge machining are mainly used for processing the press die parts. There are many differences in the machining time and life cycle of die parts depending on the machining process. The parts produced by milling and grinding have a high manufacturing time and cost with a long life cycle, while thosemade by milling and wire-cut discharge machining have areduced manufacturing time and cost,whereastheir die life cycle is reduced. Therefore, in this study, we will discuss amethod of improving the life cycle of the die parts by using heat treatment as a processing method that reduces the manufacturing time and cost. SEM, EDS analysis and the surface roughness analysis of the surface and center of the workpiece are used for analyzing the specimens produced by three machining methods, viz. milling - grinding, milling - wire cut discharge, and milling - wire cut discharge - heat treatment. A method of making die parts having the same life cycle as those produced by milling - grinding is developed with the milling - wire cut discharge - high temperature tempering method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.6
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• pp.706-713
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• 1985

It is clear that when the amplitude of grinding chatter increases enough the contact between grinding wheel and workpiece cannot be sustained and the loss of contact occurs during a period of grinding chatter. In this paper the behavior of nonlinear grinding chatter due to the loss of contact has been studied. A nonlinear grinding chatter loop is developed where the loss of contact is considered as a nonlinear element of asymmetrical gain. The analysis is carried out in the time domain by numerical simulation and also in the complex domain by use of describing function method. The results show that two typical patterns of nonlinear grinding chatter can originate from the nonlinearity. One is an irregular chatter frequency at starting stage decreases to the natural frequency of grinding structure while the chatter amplitude increases and decreases repeatedly. The other is a limit cycle chatter of which the amplitude and frequency converge to constant and remain. This nonlinear behavior of grinding chatter has been well analyzed by the describing function method and confirmed by the numerical simulation.