• 대한기계학회논문집
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• 제13권4호
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• pp.611-617
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• 1989

본 연구에서는 제트 분사 시스템을 제작하여 절단 성능에 관게하는 여러 변수중 고압수의 압력, 연마제의 크기 및 공급량, 그리고 공작물의 이송속도의 영향을 실험적으로 연구하였다.

• 한국기계가공학회지
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• 제18권10호
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• pp.75-82
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• 2019

Few studies have been conducted regarding theoretical turning force modelling while considering cutting constant. In this paper, a new cutting force modelling technique was suggested which considers the specific cutting force coefficients for turning. The specific cutting force is the multiplication of the cutting force coefficient and uncut chip thickness. This parameter was used for experimental modelling and prediction of theoretical cutting force. These coefficients, which can be obtained by fitting measured average forces in several conditions, were used for the formulation of three theoretical cutting forces for turning. The cutting force mechanism was verified in this research and its results were compared with each of the experimental and theoretical forces. The deviation of force was incurred by a small amount in this model and the predicted force considering feed rate, nose radius, and radial depth shows a physical behavior in main force, normal force, and feeding force, respectively. Therefore, this modelling technique can be used to effectively predict three turning forces with different tool geometries considering cutting force coefficients.

• 센서학회지
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• 제31권1호
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• pp.57-63
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• 2022

This study describes a system that monitors the tool and cutting state of automatic beveling operation in real time. As a signal for cutting state monitoring, a motor current detected from the spindle drive system of the automatic beveling machine is used to monitor abnormal state. Because automatic beveling is processed using a face milling cutter, the cutting force mechanism is the same as the milling process. The predicted cutting torque is obtained using a cutting force model based on specific cutting resistance. Then, the predicted cutting torque is converted into the spindle motor current value, and cutting state stability is diagnosed by comparing it with the motor current value detected during beveling operation. The experimental results show that the spindle motor current can detect abnormal cutting state such as overload and tool wear during beveling operation, and can diagnose the cutting stability using the proposed equip-current line diagram.

• 터널과지하공간
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• 제13권6호
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• pp.413-420
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• 2003

본 논문에서는 터널 및 지하공간의 기계화 시공에 있어서 굴진성능을 예측하는 모델링 기법을 고찰하였다. 첫 번째로 세계적으로 가장 잘 알려져 있는 두 가지 모델, 즉 이론적 접근을 기본으로 하고 있는 CSM 모델과 경험적 접근을 기본으로 하고 있는 NTH 모델의 비교를 수행하였다. 두 번째로는, 특별히 Constant Cross Section 커터를 사용하는 경우의 암석 굴삭 원리를 알아보고, 이 원리를 기본으로 하는 이론적 모델을 전개하여 암석특성과 커터 제원만으로 유도되는 절삭력을 구하는 관계식을 고찰하였다. 세 번째로는 기계화 시공에 있어서 굴진성능을 예측하기 위한 일반적인 모델링 기법을 제시하였다. 마지막으로 미국 Colorado School of Mines의 Earth Mechanics Institute(EMI)에서 개발한 CSM 컴퓨터 모델을 소개하고, 이 모델을 TBM 설계에 적용한 사례를 제시하였다.

• 한국안전학회지
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• 제16권1호
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• pp.88-93
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• 2001

본 연구에서는 복합소재인 GFRP(Glass Fiber Reinforced Polyester)의 2차원 절삭공정에서 절삭 메커니즘과 소재의 신뢰도 및 안전성과 밀접한 관련이 있는 표면정도를 중심으로 한 공정의 특성화를 시도하고, 주파수 분석에 관하여도 논의한다. 구체적으로는, 공정중 발생하는 절삭력 신호를 AR(Autoregressive) 모델링하여 해석에 사용한다. 특히, 특징추출과정을 통해 AR계수로 이루어진 패턴벡터 중 다양한 절삭 메카니즘에 민감한 계수만 선택할 수 있다. 이들 계수와 절삭 메커니즘과의 실험적 관계를 설정함으로써 섬유경사각(Fiber orientation angle), 절삭 변수 그리고 공구형상이 절삭 메커니즘에 미치는 영향을 평가하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1352-1355
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surface. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamometer. Based on the parameter estimation of cutting dynamics and the admittance model-based nanodynamic control scheme, simulation results are shown.

• 한국구조물진단유지관리공학회 논문집
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• 제12권4호
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• pp.107-114
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• 2008

현재 각 관리 주체별로 절토사면에 대한 유지관리를 시행하고 있으나 평가항목 및 평가모형이 다양하고 접근방법이 상호보완적이지 못하므로 보편성 및 객관성이 부족한 실정이다. 따라서, 본 연구는 기존 절토사면 평가기법에 대한 분석을 통하여 합리적인 모형개발을 위한 접근을 시도하고 붕괴사례 분석을 통하여 붕괴 주요원인 및 인자를 발굴하고 이를 계층분석기법(AHP)을 이용하여 기존 절토사면의 조사 평가단계에서 조사우선순위를 결정하기 위한 평가표를 작성하였다.

• 대한조선학회논문집
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• 제42권1호
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• pp.64-72
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• 2005

Digital manufacturing is a technology to simulate the real manufacturing process using the virtual model representing the physical schema and the behavior of the real manufacturing system including resources, processes and product information. Therefore, it can optimize the manufacturing system or prevent the bottleneck processes through the simulation before the manufacturing plan is executed. This study presents a method to apply the digital manufacturing technology for the steel cutting process in shipyard. The system modeling of cutting shop is carried out using the IDEF and UML which is a visual modeling language to document the artifacts of a complex system. Also, virtual NC simulators of the cutting machines are constructed to emulate the real operation of cutting machines and NC codes. The simulators are able to verify the cutting shape and estimate the precise cycle time of the planned NC codes. The validity of the virtual model is checked by comparing the real cutting time and shape with the simulated results. It is expected that the virtual NC simulators can be used for accurate estimation of the cutting time and shape in advance of real cutting work.

• 산업기술연구
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• 제17권
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• pp.11-20
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• 1997

This paper deals with the study on the cutting characteristics in ball endmilling process. First of all, the effects of the geometric cutting conditions such as the cutting speed, feedrates and the path interval on the surface integrity were evaluated by the analytical and the experimental approaches. Secondly, the cutting mechanism model was developed to predict the cutting force accurately. Prediction of cutting force make it possible to predict the shape error, estimate system stability and build the reliable adaptive control system. A large amount of experimental set are performed to show the validities of the proposed theories and to investigate the effect of cutting geometry such as rubbing effects, burr effects and etc.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1133-1136
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• 2004

The structures of airplane consist of sheet metal part, heavy machined part, and so on, which generate enormous amounts of cutting chip when these parts are machined. The cutting chip detoriorates the part quality and production efficiency. Therefore, cutting chip collecting apparatus is necessary for better quality and efficiency. In this study, blowing type cutting chip collecting apparatus was newly proposed and the concept design of the apparatus was examined through numerical analysis. Computations using the mass-averaged implicit 2D Navier-Stokes equations are applied to predict the nozzle flow field. The standard k-e turbulent model are employed to close the governing equations. Consequently, this study shows that the suggested blowing type cutting chip collecting apparatus can be alternative to existing expensive chip collecting apparatus.