• Journal of the Korean Society for Precision Engineering
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• v.7 no.2
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• pp.85-94
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• 1990

In automatic metal cuttings, the chip control is one of the serious problems. So the automatic detection of chip forms is essential to the chip control in automatic metal cuttings. Cutting experiments were carried out under the variety of cutting conditions (cutting speed, feed, depth of cut and tool geometry) and with workpiece made of steel (S45C), and cutting forces were measured in-processing by using a piezoelectric type Tool Dynamometer. In this report, the frequency analysis of dynamic components, the upper frequency distributions, the ratio of RMS values, the numbers of null point and the probability density were calculated from the dynamic componeents of cutting forces filtered through various band pass filters. Experimental results showed that computer chip form monitoring system based on the cutting forces was designed and simulated and that 6 type of chip forms could be detected while in-process machining.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.5
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• pp.189-198
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• 1994

The achievable machining accuracy depends upon the level of the micro-engineering, and the today's accuracy targets are dimensional tolerances in the order of 10nm and surface roughness in the order of 1nm. Such requirements cannot be satisfied by the conventional machining processes. Single point diamond turning is the one of new techniques which can produce the parts with such accuracy limits. The aims of this thesis are to get a better understanding of the complex cutting process with a diamond tool and, consequently, to develope a predicting model of a turned surface profile. In order to predict the turned surface profile, a numerical model has been developed. By means of this model, the influence of the operational settings-the material properties of the workpiece, the geometry of the cutting tool and the dynamic behaviour of the lathe-and their influences via the cutting forces upon the surface roughness have been estimated.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1493-1498
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• 2007

Silicon Nitride ($Si_3N_4$), which is widely used in a variety of applications, is hard-to-machine due to its high hardness. At high temperature (e.g. above $1000^{\circ}C$), however, the machinability can be greatly improved. In this work, we used a $CO_2$ laser with a high absorptivity to $Si_3N_4$ of 0.9 to preheat the surface of a rothting $Si_3N_4$ rod. Preheating and turning of $Si_3N_4$ was executed at the same time. The result of machining was MRR of $8.0mm^3/s$ that is four times faster than normal grinding. Continuous chip formation was observed by a microscope.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1338-1343
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• 2007

High-efficient machining, which means cutting a part in the least amount of time, is the most effective tool to improve productivity. In this study, a new feed optimization method based on the cutting power regulation was proposed to realize the high-efficient machining in turning process. The cutting area was evaluated by using the Boolean intersection operation between the cutting tool and workpiece. And the cutting force and power were predicted from the cutting parameters such as feed, depth of cut, spindle speed, specific cutting force, and so on. Especially, the reliability of the proposed optimization method was validated by comparing the predicted and measured cutting forces. The simulation results showed that the proposed optimization method could effectively enhance the productivity in turning process.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.357-362
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• 2003

Recently, the demand for advanced technology of high precision and high efficiency processing of hard materials such as inconel is increasing with progress of industrial goods. However, the machinability of inconel is very inferior to the other conventional industrial materials and the machining technology for inconel involves many problems to be solved in machining accuracy, machining efficiency, etc. Therefore it is needs to establish the machining technology. The purpose of this study is to develop an advanced ultrasonic vibration machining technology for inconel, using the 60KHz and 75KHz high frequency, amplitude about 8${\mu}{\textrm}{m}$ and 4${\mu}{\textrm}{m}$, respectively. As the result, this new ultrasonic vibration machining is reasonable and suitable for the high efficient. accuracy machining method of inconel.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.186-194
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• 2000

The purpose of this study is to investigate the difference in cutting characteristics of cermet, carbide and coated carbide tools in the similar application range via turning test of various conditions. The cermet and carbide tools in the range of ISO P10 grade were developed using optimum compositions with a view to obtaining a high toughness and hardness by PM process. First mechanical properties were characterized on these tools. Experimental results of wear behaviour and resistance to fracturing were presented and discussed in the turning of gray cast iron and alloy steels by cermet, carbide and coated carbide tools. The coated carbide tool shows similar cutting performance compared to the cermet, while the cermet has better combination of wear resistance and toughness of high speed (V=500m/min) cutting in comparison with carbide and coated carbide tools, and also shows a potentiality for cast iron cutting. Fe adhesive behaviour on the tools and surface roughness of workpieces were explained by chemical affinity between tools and workpieces.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.80-87
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• 1995

An experimental study of hot machining has performed to improve themachinability of Inconel 718. This experiment used plasma arc for heating materials and Whisker-reinforced aluminum oxide ceramic tool insert. An assembled plasma heating system are described and experimental results obtained from bothconventional and plasma hot machining of Iconel 718 are compared. Turning experiments with plasma heating demonstrated the following effectiveness. 1) The cutting force was reduced with increasing surface temperature of workpiece from 450 .deg. C up to 720 .deg. C as much as approximately from 20 to 40%. 2) Surface roughness(Ra) was improved by as much as a factor 2 in case of one pass cutting with new ceramic tool inserts. 3) The depth of cut notchwear at primarycutting tool was singificantly reduced.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.75-84
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• 1994

기계가공프로세스에서 절삭공구의 마멸과 채터진동은 공작기계의 가동율과 생산성을 크게 저해하는 요인이 되고 있다. 본 연구에서는 공구마멸과 채터현상이 혼재하는 상황에서, 이들 두 현상을 동시에 검출하는데, AE 및 가속도센서에서 검출된 신호와 AR계수 및 주파수대역 평균에너지를 특징입력으로 하는 인공신경회로망을 이용하였다. 그 결과, 공구마멸과 채터현상에 대응하는 서로 다른 신호특징의 차이를 동시에 식별하는 데 인공신경 회로망의 유용성을 입증하였으며, 시계열모델의 AR계수(70 .approx. 90%)보다는 주파수대역에너지법의 평균에너지 (80 .approx. 100%)를 신경회로망의 특징입력으로 하는 경우가 높은 성공률을 나타내었다.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.49-55
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• 2011

Recently, various efforts to make more speedy and precision machine tool to improve productivity and also various efforts to solve environmental problem are going on, so that dry cutting in manufacturing industry, which needs environmental conscious design and development of manufacturing technique, is becoming a very important assignment to solve. Because dry cutting does not use cutting fluid, we need other methods that can be used instead of cutting fluid, which does cooling, lubricating, chip washing, and anti-corrosion. Especially, because turning is a continuous work, the consideration of tool life and surface roughness due to continuous heat and poor lubrication is important. The purposes of this paper are the consideration of how well the compressed air can work instead of cutting fluid, and also the development of the method to select the optimum machining condition by the minimum numbers of experiments through the Taguchi method.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.122-130
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• 1996

In this study, machinability of some aluminum-magnesium alloy are experimentally investigated using polycrystalline diamond tool with turning, and evaluated some independent cutting variables affected micrometal cutting characteristics as cutting force, specific cutting resistance, shear angles. To know the effect of cutting parameters of single point diamond machining, experiments were performed to measure cutting forces for high speed turning of aluminum alloy 6061-T6, SM45C and FC20 with poly- crystalline diamond and coated cemented carbide tool. Independent cutting variables were changed to a variety of cutting speed, feed rate, rake angles, material properties of workpiece and tool. Futhermore. Some useful informations are obtained in this study can guide micro metal cutting of aluminum alloy with diamond tool.