• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.166-171
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• 2001

An electric drill is a handy tool used in a machine shop, which consists of motor, gear, bearing, shaft, and case, i.e., a gear driving system. Low level vibration and noise of the electric drill can bring the assurance of the quality and reliability of the machine. The vibration sources of the electric drill should be investigated for the reduction of the vibration and noise of the system. Through the experiments in a laboratory and the various signal processing procedure for the measured vibration and sound signals, the characteristics of the vibration and noise of the electric drill are investigated. And its propagation path is sought using partial coherence technique.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.103-111
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• 2002

Out of all metal-cutting process, the hole-making process is the most widely used. It is estimated to be more than 30% of the total metal-cutting process. It is therefore desirable to monitor and detect drill wear during the hole-drilling process. One important aspect in controlling the drilling process is monitoring drill wear status. There are two systems, Basic system and Online system, to detect the drill wear. Basic system comprised of spindle rotational speed, feed rates, thrust torque and flank wear measured by tool microscope. Outline system comprised of spindle rotational speed feed rates, AE signal, flank wear area measured by computer vision, On-line monitoring system does not need to stop the process to inspect drill wear. Backpropagation neural networks (BPNs) were used for on-line detection of drill wear. The output was the drill wear state which was either usable or failure. This paper deals with an on-line drill wear monitoring system to fit the detection of the abnormal tool state.

• 한국공작기계학회논문집
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• 제12권6호
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• pp.8-13
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• 2003

CFRP composite has a lot of merits such as mechanical characteristic, light weight and thermal resistance. For these merits CFRP is applied to so many industrial area. In order for the composite materials to be used in the aircraft structures or machine elements, accurate surfaces for bearing mounting or joints must be provided, which require precise machining. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48p1ies specimen with the ${\phi}8$, ${\phi}10$, ${\phi}12mm$ cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.213-214
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• 2006

The CAM software for drill grinding has been developed to save time, reduce cost for tool manufacturing and obtain accuracy of tool. In this paper, the developing software for drill will be presented including calculation and simulation of machining processes using 5-axes CNC grinding machine. The algorithm fer helical flute grinding was applied into calculating NC data. The software will generate NC code for machining by using input data of tool geometry, wheel geometry, wheel setting, machine setting. These NC code files will be used in simulator as input file. The simulator provides some functions for simulating machining processes, inspecting and measuring tool geometry.

• 대한산업공학회지
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• 제39권3호
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• pp.149-155
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• 2013

Electric discharging machining (EDM) is commonly adopted to machine the precise and tiny part when it is difficult to meet the productivity and the tolerance by the conventional cutting method. The die-sinking EDM method works well to machine the micro-parts and the perpendicular wall of die and mould, whereas EDM drilling, called super drill, is excellent to machine the deep and narrow hole regardless the material hardness and the hole location. However, the electrode wear is rapid compared to the conventional cutting tool and makes it difficult to control the electrode feeding and to machine precisely. This paper presents an efficient method to estimate the electrode wear using hole pass-through experiment while the stochastic method is used to compensate for the estimation model. To validate the proposed method, the commercial EDM drill machine is used. The experiment result shows that the electrode wear amount can be predicted very precisely.

• 한국공작기계학회논문집
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• 제17권1호
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• pp.77-85
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• 2008

The objective of the study is to construct a sensor fusion system for tool-condition monitoring (TCM) that will lead to a more efficient and economical drill usage. Drill-wear monitoring has an important attribute in the automatic machining processes as it can help preventing the damage of tools and workpieces, and optimizing the drill usage. In this study, we present the architectures of a multi-layer feed-forward neural network with Levenberg-Marquardt training algorithm based on sensor fusion for the monitoring of drill-wear condition. The input features to the neural networks were extracted from AE, vibration and current signals using the wavelet packet transform (WPT) analysis. Training and testing were performed at a moderate range of cutting conditions in the dry drilling of steel plates. The results show good performance in drill- wear monitoring by the proposed method of sensor fusion and neural network analysis.

• 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.

• 대한기계학회논문집 C: 기술과 교육
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• 제1권1호
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• pp.39-47
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• 2013

탑 드라이브 장비는 드릴 비트에 회전력을 전달하여 굴착을 하게하는 장치이며, 1983년 Derrick Drilling Machine의 Kelly Rotary Table로 시작하여, 1984년에 DDM 650 DC가 등장함으로써 본격적으로 개발 되기 시작했다. 이러한 탑 드라이브 장비는 미국의 N사와 노르웨이 A사가 전 세계 시장의 90% 이상을 점유하고 있으며, 이로 인하여 탑 드라이브 장비의 세계시장 진입과 장비에 대한 정보가 제한적일 수 밖에 없다. 따라서 본 논문에서는 제한된 정보를 통하여 신뢰성을 가지는 제품을 개발하기 위한 절차 및 방법에 대하여 소개하고자 한다. 설계 오류 및 신뢰성이 검증된 제품 디자인을 위하여 3D Tool을 사용하였으며, 이를 활용하여 설계오류, 간섭체크, 기능체크, 구조강도 해석 등을 수행하여 제품의 신뢰성을 사전 검증 하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.275-280
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• 2001

Recently, the trends of industrial products grow more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is requested more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multi-layered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. This paper shows the tool monitoring results of micro drill with tool dynamometer. And additionally, microscope with built-in monitor inspection show the relationship between burr in workpiece and chip form of micro drill machining.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.263-268
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• 1999

The most important things to the tube the of the heat exchanger are the precision of t hole position and the quality of the drill face. Nowadays, 6 and 12 spindle multi-drilling machine controlled by CNC or used to drill holes of the tube sheet. The drilling of 12 axes can offer high speover three times as fast as the drilling of axis. However, the drilling of 12 axes h difficulty in controlling many motors to d spindles and assigning a corresponded numbe accurately to each axis. In the past, conventional method to inspect the code the drilling was machining holes on a thin plate previously which resulted in the productivity because it required a h production cost by machining and weldin time. In this thesis, there are two drilling codes different from CNC code. M code is used to control many motors and S code is used to assign a correspondent number for each axis. For increasing the productivity by removing process, this paper is intended to take simulation of the drill machining c including 6 and 12 axis on the persona computer.