• 제목/요약/키워드: Wear Diagnostics

검색결과 8건 처리시간 0.026초

Tribological diagnostics of machinery

  • Myshkin, N.K.
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1990년도 제11회 학술강연회초록집
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    • pp.7-31
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    • 1990
  • Tribologicsl diagnostics as the ensemble of means and methods of continuous monitoring of the state of friction characteristics of moving junctions is playing an ever important part in the development of friction, lubrication, and wear theory end practice. The scheme presenting the main areas of tribological diagnostics is given in Fig. I. This growing part of TD is determined by the general tendency of modern technology, expressed in an attempt to organically combine the functions of measuring, evaluating,and predicting the parameters and characteristics of the processee taking place in the operating device. The logical result of this integration in future is the closed system correcting its operation in accordance with sn established program. Unfortunately, tribotechnicsl devices are still very far from such an ideal system at the present time. While in the friction assemblies with hydrodynamic lubrication it is possible in the first approximation to realize feed-backs in the lubricant circulation system with the aid of monitoring of the pressure, temperature and filtration, in the systems operating without lubrication and with boundary lubricetion even the process of selection of the diagnostic parameters has not been completed.

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엔드밀가공시 복합계측 신호를 이용한 공구 마멸의 카오스적 해석 (Chaotic analysis of tool wear using multi-sensor signal in end-milling process)

  • Kim, J.S.;Kang, M.C.;Ku, S.J.
    • 한국정밀공학회지
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    • 제14권11호
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    • pp.93-101
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    • 1997
  • Ever since the nonlinearity of machine tool dynamics was established, researchers attempted to make use of this fact to devise better monitoring, diagnostics and control system, which were hitherto based on linear models. Theory of chaos which explains many nonlinear phenomena comes handy for furthering the analysis using nonlinear model. In this study, measuring system will be constructed using multi-sensor (Tool Dynamometer, Acoustic Emission) in end milling process. Then, it will be verified that cutting force is low-dimensional chaos by calculating Lyapunov exponents. Fractal dimension, embedding dimension. And it will be investigated that the relation between characteristic parameter calculated from sensor signal and tool wear.

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드릴링 작업의 모델링과 진단법에 관한 연구 (A Study on the Modeling and Diagnostics in Drilling Operation)

  • 윤문철
    • 동력기계공학회지
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    • 제2권2호
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    • pp.73-80
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    • 1998
  • The identification of drilling joint dynamics which consists of drilling and structural dynamics and the on-line time series detection of malfunction process is substantial not only for the investigation of the static and dynamic characteristics but also for the analytic realization of diagnostic and control systems in drilling. Therefore, We have discussed on the comparative assessment of two recursive time series modeling algorithms that can represent the drilling operation and detect the abnormal geometric behaviors in precision roundshape machining such as turning, drilling and boring in precision diemaking. For this purpose, simulation and experimental work were performed to show the malfunctional behaviors for drilling operation. For this purpose, a new two recursive approach (Recursive Extended Instrument Variable Method : REIVM, Recursive Least Square Method : RLSM) may be adopted for the on-line system identification and monitoring of a malfunction behavior of drilling process, such as chipping, wear, chatter and hole lobe waviness.

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ARMA 모델링과 스펙트럼분석법에 의한 가공시스템의 진단에 관한 연구 (A Study on Diagnostics of Machining System with ARMA Modeling and Spectrum Analysis)

  • 윤문철;조현덕;김성근
    • 한국생산제조학회지
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    • 제8권3호
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    • pp.42-51
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    • 1999
  • An experimental modeling of cutting and structural dynamics and the on-line detection of malfunction process is substantial not only for the investigation of the static and dynamic characteristics of cutting process but also for the analytic realization of diagnostic systems. In this regard, We have discussed on the comparative assessment of two recursive time series modeling algorithms that can represent the machining process and detect the abnormal machining behaviors in precision round shape machining such as turning, drilling and boring in mold and die making. In this study, simulation and experimental work were performed to show the malfunctioned behaviors. For this purpose, two new recursive approach (REIVM, RLSM) were adopted fur the on-line system identification and monitoring of a machining process, we can apply these new algorithm in real process for the detection of abnormal machining behaviors such as chipping, chatter, wear and round shape lobe waviness.

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마이크로 드릴비트 연마 시스템 연삭휠의 마모 진단 연구 (A Study on the Wear Condition Diagnosis of Grinding Wheel in Micro Drill-bit Grinding System)

  • 김민섭;허장욱
    • 한국기계가공학회지
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    • 제21권3호
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    • pp.77-85
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    • 2022
  • In this study, to diagnose the grinding state of a micro drill bit, a sensor attachment location was selected through random vibration analysis of the grinding unit of the micro drill-bit grinding system. In addition, the vibration data generated during the drill bit grinding were collected from the grinding unit for the grinding wheels under the steady and worn conditions, and data feature extraction and dimension reduction were performed. The wear of the micro-drill-bit grinding wheel was diagnosed by applying KNN, a machine-learning algorithm. The classification model showed excellent performance, with an accuracy of 99.2%. The precision, recall and f1-score were higher than 99% in both the steady and wear conditions.

엔드밀가공시 복합계측 신호에 의한 공구 마멸의 카오스적 해석 (Chaotic Analysis of Multi-Sensor Signal in End-Milling Process)

  • 구세진;이기용;강명창;김정석
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 춘계학술대회 논문집
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    • pp.817-821
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    • 1997
  • Ever since the nonlinearity of machine tool dynamics was established, researchers attempted to make use of this fact to devise better monitoring, diagnostics and system, which were hitherto based on linear models. Theory of chaos, which explains many nonlinear phenomena comes handy for furthering the analysis using nonlinear model. In this study, measuring system will be constructed using multi-sensor (Tool Dynamometer, Acoustic Emission) in end millingprocess. Then, it will be verified that cutting force is low-dimensional deterministic chaos calculating Lyapunov exponents, Fractal dimension, Embedding dimension. Aen it will be investigated that the relations between characteristic parameter caculated form sensor signal and tool wear.

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Acute-onset respiratory signs in a Labrador Retriever with a positive SARS-CoV-2 rapid antigen test and infection confirmed by RT-PCR analysis: a case report

  • Mark, Gosling;Jessica, Bacon
    • Journal of Veterinary Science
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    • 제23권6호
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    • pp.80.1-80.6
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    • 2022
  • A 10-year-old male neutered Labrador Retriever presented with a history of acute-onset tachypnoea, lethargy and anorexia. The dog was pyrexic, tachypnoeic and dyspnoeic on examination. A rapid antigen test for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was performed on an oropharyngeal swab and yielded a positive result. SARS-CoV-2 infection was subsequently confirmed by reverse transcription polymerase chain reaction (RT-PCR) analysis. Both of the dog's owners had positive rapid antigen test and RT-PCR analysis results for SARS-CoV-2. Additional diagnostics included computed tomography. Resolution of the dog's clinical signs was achieved with symptomatic treatment.

고속철도차량 감속기 결함진단을 위한 진동 파라미터 분석 (Analysis of Vibration Parameters for the Fault Diagnosis of Reduction Unit for High-speed Train)

  • 김재철;지해영;이강호;문경호;서정원
    • 한국정밀공학회지
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    • 제30권7호
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    • pp.679-686
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    • 2013
  • The reduction unit is one of the most important components in railway cars, due to the transmission of torque from the motor to the wheels. Faulty reduction gears in high-speed trains result from excessive wear on the gear or damage to the gear. These types of gear defects have a significant effect on high-speed rail operation and safety; thus, a diagnosis system for the reduction unit is needed. Vibration diagnosis technology is one of the most effective diagnostics. In this paper, the vibration parameters of a reduction unit were evaluated during a driving-gear test and a full-vehicle test, using kurtosis and the crest factor. These tests were performed under normal operating conditions; a specimen tester was used to diagnose problems in defective gears.