• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.72-77
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• 2018

In this study, cutting robot system which could cut lateral protrusion into main pipes at the connection of sewer pipes was developed. In addition, the cutting test of the robot for the lateral protrusions were performed. The test parameters included materials used in the main pipes and diameters of the pipes, and materials used in the protruded pipes. The materials type of the main pipes were concrete and PE, and the diameters of the pipes were 300 and 500 mm. The materials type used in the protruded pipes were PE and PVC, and the diameter of the pipes was 100 mm. Remaining length of each lateral protruded pipe was less than 5 mm which was an target value of cutting performance. It showd that test results were within the target value. Therefore, in the repair of sewer pipes, the lateral protruded pipes can be cut by using the robot system developed in this paper.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1025-1028
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• 2001

In this report, a new method compounding the electrolytic machining with ball end milling process to increase the machining efficiency was introduced. From the experimental result, it was confirmed that effect of cutting force reduction and finer surface roughness can be obtained in a certain condition of ball end milling and electrolytic machining conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.58-63
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• 1995

절삭가공 중에서도 높은 비중을 차지하는 구멍가공은 전자제품, 공작기계 뿐만 아니라 산업 전반에 걸쳐 소형 화, 다양화, 대량생산화 함에 따라 미세화, 고속화하게 되었다. 본 연구에서는 미세드릴 가공시에 발생하는 스러스트를 측정하여 이송, 절삭속도, 피삭재 두께 변화 등 각 절삭조건이 공구수면과 가공확대오차에 미치는 문제점을 해결하기 위한 방안으로 스텝이송 방식을 채택하여 그 효과에 대한 평가를 목적으로 한다.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.231-236
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• 1999

Understanding the exgenous water induced thermomechanical effect on the dental hard tissue by the Q-switched Er:YAG laser (1-$mutextrm{s}$-long pulse width) has an important impact on the further understanding of the free-running Er:YAG laser (250-$mutextrm{s}$-long pulse width) ablation on the dental gard tissue because one macroscopic effect in the free-running laser is an accumulation of microscopic effects we investigated in this study. The Q-switched Er:YAG laser with exogenous water on the tooth enhanced ablation rate compared to the case of no water on the tooth. The frequency of exogenous-water jet on the tooth has affected the ablation rate in such a way that as we dispensed water drops less frequently we could get more enhanced ablation rate. The amplitude of the recoil pressure depends on the tooth surface conditions such that as surfaces wet, and as the volume of the exogenous water drop increased, the amplitude of the recoil pressure increased also. From this study we realized that the 1 $mutextrm{s}$ long pulsed induced thermomechanical effect provides us useful information for the understanding of the free-running Er:YAG laser induced ablation with exogenous water.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.38-45
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• 1997

A new dynamic model for the cutting process inb the end milling process is developed. This model, which describes the dynamic response of the end mill, the chip load geometry including tool runout, the dependence of the cutting forces on the chip load, is used to predict the dynamic cutting force during the end milling process. In order to predict accurately cutting forces and tool vibration, the model which uses instantaneous specific cutting force, inclueds both regenerative effect and penetration effect, The model is verified through comparisons of model predicted cutting force with measured cutting force obtained from machining experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.195-204
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• 2020

To help solve the problems of how to set the optimal sawing force and the optimal controller parameters for different sawing conditions, a mathematical model of a proposed sawing system was established according to the principle of sawing force control. The conventional PID control method was then used for further research of the closed-loop control of the sawing force. Finally, through simulation and experimental research, the influence rule of the controller parameters and sawing load on the control performance and the relationships between the sawing width and controller parameters (proportion coefficient) and the sawing force setting value were obtained, from which a system scheme for intelligent sawing control of a band sawing machine was proposed. The research shows that the sawing efficiency of the intelligent sawing system was 18.1 (48%) higher than that of the original sawing system when sawing a grooved section sawing material, which verifies the good control effect of the proposed scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.995-1000
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• 2000

In this paper. a mechanistic model is first constructed to predict three-dimensional cutting forces, and the uncut chip th thickness is calculated by following the movements of the position of the center of a cutter, which varies with the nominal feed, cutter deflection and runout. For general implementation to a real machining, this paper presents the method that determines constant cutting force coefficients, irrespective of the cutting conditions or cutter rotation angles. In addition, this study presents the approach which estimates runout-related parameters. the runout offset and its location angle, using only one measurement of cutting forces. For more accurate cutting force predictions, the size effect has to be considered in the cutting force model. In this paper, two approximate methods are suggested since the strict approach is practically impossible due to a measurement problem. The size effect is individually considered for narrow and wide cuts.

• The Korean Journal of Applied Statistics
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• v.27 no.6
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• pp.923-932
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• 2014

The Hurdle model can to analyze zero-inflated count data. This model is a mixed model of the logit model for a binary component and a truncated Poisson model of a truncated count component. We propose a new hurdle model with a general heterogeneous random effects covariance matrix to analyze longitudinal zero-inflated count data using modified Cholesky decomposition. This decomposition factors the random effects covariance matrix into generalized autoregressive parameters and innovation variance. The parameters are modeled using (generalized) linear models and estimated with a Bayesian method. We use these methods to carefully analyze a real dataset.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.131-137
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• 1986

Cutting oil cools the chip and a tool as well as lubricates the chip-tool interface, the flank and machined surface. Rehbinder effect has been known as a phenomenon, the reduction of mechanical strength, when the metal is exposed to a polar organic environment or the surface of metal is coated with some polar organic substances. About the cause of Rehbinder effect there have been many different ideas by Rehbinder, Shaw, Barlow, Sakida and etc. In this report, the efect of polar organic substance( $C_{6}$ $H_{5}$C $H_{3}$+ $C_{6}$ $H_{4}$(C $H_{3}$)$_{2}$+ $C_{4}$ $H_{9}$OH+ $C_{6}$ $H_{12}$ $O_{2}$) (magic ink) upon the mechanism of chip formation on the orthogonal cutting of copper and mechanical properties of the work material are experimentally discussed with various rake angles. As expected no lubrication action could be noticed, but the shear angle increased and the cutting force and shear strain on the shear plane decreased, therefore the work material must be embrittled under polar organic substance.substance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2216-2225
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• 1992

In recent years, machining turns to flexible manufacturing. Industry in machining requires to increase machining productivity and to reduce costs. To adapt this trend it is necessary to optimize machining condition. Even though many researches in this are introduced various way to set the optimal condition, still there are not enough. Therefore this research was done to select the optimal cutting condition for industry, and to develope the computer program to select the optimal cutting condition automatically. Also, this program was applied to many companies, and compare costs per minute. The results of this research will contribute to increase machining productivity of various companies with the automatic selection of optimal cutting condition.