• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.471-472
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• 2009

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.578-583
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• 2001

Chattering phenomenon is an abrupt relative vibration between the strip and rolls of rolling machine in working. It inevitably results from the progress of the degeneration in the mill facilities. This research was carried out in order to analyze the characteristic and find the cause of chatter mark in finishing mill and it was founded that major causes are facility character of driving part and special condition in case of excessive roll force.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1854-1858
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• 2000

Chattering phenomenon is an abrupt relative vibration between the strip and rolls of rolling machine in working. It inevitably results from the progress of the degeneration in the mill facilities. This research was carried out in order to analyze the characteristic and find the cause of chatter mark in finishing mill and it was founded that one of major cause is appearance of dead zone at pinion stand in case of excessive roll force.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.9-14
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• 1996

The deflection of an end mill is very important in machining process and cutting simulation because it affects directly workpiece accuracy, cutting force, and chattering. In this study, the deflection of the end mill was studied both experimentally and by using finite element analysis. And the moment of inertia of radial cross sections of tile helical end mill is calculated for the determination of the relation between cross section and rigidity of tile tools. Using tile Bernoulli-Euler beam and and the concept of equivalent diameter, a deflection model is established, which includes most influence from tool geomety parameters. It was found that helix angle attenuates the rigidity of the end mill.

• 소음진동
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• 제4권1호
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• pp.43-50
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• 1994

Chatter vibration of a rolling machine in steel plants has a significant effect on thickness quality of the products. The cause and mechanism of the mill chattering is addressed through measurement of vibration and dynamic torque. An FFT system and an FM telemetry system are employed to collect data at several locations of possible damages. The results reveal the followings as sources of the mill vibration. The first is defects in roller bearings of a work roll chock. The second is instability of an oil film bearing in a backup roll chock, which has been investigated with a theoretical model describing the phenomenon. Dynamic torque is not the direct cause of mill vibration but rather influenced by the vibration. Appropriate treatment methods are suggested to address each of the above sources.

• 한국정밀공학회지
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• 제14권12호
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• pp.143-152
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• 1997

The deflection of an end mill is very important in machining process and cutting simulation because it affects directly workpiece accuracy, cutting force, and chattering. In this study, the deflection of the end mill was studied both experimentally and by using finite element analysis. And the moment of inertia of cross sections of the helical end mill is calculated for the determination of the relation between geometry of radial cross section and rigidity of the tools. Using the Bernoulli-Euler beam theory and the concept of equivalent diameter, a deflection model is established, which includes most influences from tool geomety parameters. It was found that helix angle attenuates the rigidity of the end mill by the finite element analysis. As a result, the equivalent diameter is determined by tooth number, inscribed diameter ratio, cross sectional geometry and helix angle. Because the relation betweem equivalent diameter and each factor is nonlinear, neural network is used to decide the equivalent diameter. Input patterns and desired outputs for the neural network are obtained by FEM analysis in several case of end milling operations.

• 한국기계가공학회지
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• 제12권6호
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• pp.159-166
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• 2013

In order to develop the optimum shape of an MQL carbide end-mill suitable for high speed machining of wing ribs which are a detailed part of larger wing structures, using a new material Al-Li alloy, a new MQL carbide end-mill is created that has various quantities of holes, hole sizes, and hole locations. A theoretical machining graph is generated using the hammer test and FRF simulation, and a machining test is performed in order to verify the machining stability in the high speed machining area. The optimum configuration of the MQL carbide end-mill is also presented through comparing the chattering, machining noise and cutting conditions, including the maximum cutting depth, rpm, and feed rate per teeth, for each cutter.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.292-296
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• 2002

In the present investigation, the improvement of processing efficiency in the high speed machining of GC250 is explored. This study is to evaluate the tool performance in difficult-to-material using the new developed tool. Tool performance evaluation are conducted by tool wear, surface roughness, chattering in machined surface. The tool wear of A type was smaller than B type. In type B tool the chatter mark was observed in machined surface. The good surface roughness was obtained in type A tool. Consequently, the tool performance of A type is better than B type.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1343-1346
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• 2005

In the cold rolling mill, coil breakage that generated in rolling process makes the various types of troubles such as the degradation of productivity and the damage of equipment. Recent researches were done by the mechanical analysis such as the analysis of roll chattering or strip inclining and the prevention of breakage that detects the crack of coil. But they could cover some kind of breakages. The prediction of Coil breakage was very complicated and occurred rarely. We propose to build effective prediction modes for coil breakage in rolling process, based on data mining model. We proposed three prediction models for coil breakage: (1) decision tree based model, (2) regression based model and (3) neural network based model. To reduce model parameters, we selected important variables related to the occurrence of coil breakage from the attributes of coil setup by using the methods such as decision tree, variable selection and the choice of domain experts. We developed these prediction models and chose the best model among them using SEMMA process that proposed in SAS E-miner environment. We estimated model accuracy by scoring the prediction model with the posterior probability. We also have developed a software tool to analyze the data and generate the proposed prediction models either automatically and in a user-driven manner. It also has an effective visualization feature that is based on PCA (Principle Component Analysis).

• 대한기계학회논문집
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• 제16권7호
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• pp.1363-1372
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• 1992

본 연구에서는 고속 냉간 압연유를 개발하기 위한 기초 연구로써 압연유의 기본이 되는 기유의 종류와 압연유에 첨가되는 각종 첨가제중 고속, 고압하 압연에서 가장 문제가 되는 히트 스크래치를 방지하는 역할을 하는 극압제의 종류 및 함량이 압연유의 윤활성과 내소부성에 어떠한 영향을 주는가를 소다식 진자형 마찰계수 시험 기, Falex 시험기 그리고 Four Ball 시험기와 같은 실험실적 평가방법과는 달리 실제 롤과 스트립 사이의 접촉조건이 상사한 시험압연기를 사용한 윤활성 및 내소부성 평가 실험을 통하여 검토하였다. 본 평가 실험에 사용된 시험압연기는 압하배분, 압연 채 터링(chattering), 장력 제어, 압연윤활 특성, 압연재 형상 제어, 이주속 압연특성 등 을 시험할 수 있는 다목적 냉간압연기로써 그 구조와 제원을 Fig.1과 Table 1에 나타 내었다. 또한 극압제를 함우하고 있는 압연유와 스트립 표면간의 화학반응에 의한 극압막의 존재여부를 확인하기 위하여 EDS(energy dispersive spectrometer) 분석법과 ESCA (electron spectroscopy for chemical analysis) 분석법을 이용하여 분석하였다.