• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.14-19
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• 2000

A machine tool has some serous stability problem in the from of tool chatter during the cutting process. Chatter vibration deteriorates the surface finish, reduce tool and machine life, accelerate machine tool system component wear, and may lead to an unacceptable noise sound in the working environment. In this study, in order to moni색 of the chatter vibration on the cutting process, the behavior of spectral density of AE signal and principal cutting force signal has been investigated. Furthermore, its reliability from obtained the results has been studied to evaluate and confirm the proposed method with the application procedure and the experimental results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.261-264
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• 2004

This paper presents the design and test of elliptical vibration assisted cutting tool post. It is actuated by two piezoelectric actuators which are connected to the moving part through the elastic hinge with its role of imposing the preliminary pressures. These two actuators are located at right angles so that the resulting tool tip moves like a two-dimensional ellipse. Also, the tool post is activated within the region of linear actuation in order to overcome the distorted elliptical motion. For the precise measurement of the displacement of the tool tip, three-dimensional experimental apparatus was designed and the strokes of the tool post in major and minor axes were measured. The results show that the tool post can produce the variety of vibration locus from a circle with a radius of 5 ${\mu}{\textrm}{m}$ to an ellipse with a major axis, a =10 ${\mu}{\textrm}{m}$, and a minor axis, b =2.5 ${\mu}{\textrm}{m}$

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.689-694
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• 2004

To increase accurateness and reliability of the evaluation of power tool vibration transmitted to an operator, it is necessary to measure grip and feed forces during the measurement of hand-transmitted vibration. In the study a system was invented to measure the vibration and the grip and/or feed force, which consists of a measurement handle and a PC with data acquisition system and the software. Strain gauges and an accelerometer were mounted on the handle for the simultaneous measurement of the forces and the vibration. The program in the system makes it possible to monitor the grip and feed force during the tool operation so that the operator keeps the applying forces within the pre-determined range. Investigating the vibration total values, frequency-weighted root mean square accelerations at the handle, obtained at various conditions with control of the grip and feed force showed more consistency than those measured without force control. By using the system the experimenter can reduce uncertainty of the measured vibration.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.4790-4795
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• 2014

공작기계는 기계산업의 생산 및 시제품가공 등에 널리 적용되고 있다. 폭발시 발생하는 지반진동은 인근 구조물의 손상이나 시설에 많은 영향을 미친다. 본 논문은 발파진동이 공작기계의 가공정밀도에 미치는 영향을 고찰하였다. 발파진동과 발파시 공작기계의 진동을 측정하였고, 진동허용치를 기준으로 평가하였다. 공작기계의 진동허용치를 기준으로 할 경우 본 연구에 사용된 공작기계의 발파시 진동허용치는 SLIGHTLY ROUGH~ROUGH에 해당된다. 발파진동이 반복될 경우 정밀도가 저하될 가능성이 많다.

• 한국생산제조학회지
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• 제20권3호
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• pp.268-273
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• 2011

In light guide panels, the PMMA sheet that is used in liquid crystal displays plays an important role in scattering the incident light and requires very fine machining as the sheet is directly related to the optical characteristics of the panels. High speed end milling(HSE) and high speed shaping(HSS) processes that are widely adopted and applied to the precise machining of light incident plane through vibration-assisted HSS for increasing the optical quality by minimizing the above-mentioned problems. The cutting tool and the tool post presented in this paper are designed by the authors to increase the magnitude of the cutting stroke by adopting the resonant frequency without weakening the stiffness and to reduce vibrations during even high speed feeding. The dynamic haracteristics of thecutting tool and the tool post are evaluated through simulation and experiment as well. The results reveal very appropriate dynamic characteristics for vibration-assisted HSS.

• Structural Engineering and Mechanics
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• 제70권4호
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• pp.395-405
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• 2019

In the present work, the effects of cutting parameters on surface roughness parameters (Ra), tool wear parameters (VBmax), tool vibration (Vy) and material removal rate (MRR) during hard turning of AISI 4140 steel using coated carbide tool have been evaluated. The relationships between machining parameters and output variables were modeled using response surface methodology (RSM). Analysis of variance (ANOVA) was performed to quantify the effect of cutting parameters on the studied machining parameters and to check the adequacy of the mathematical model. Additionally, Multi-objective optimization based desirability function was performed to find optimal cutting parameters to minimize surface roughness, and maximize productivity. The experiments were planned as Box Behnken Design (BBD). The results show that feed rate influenced the surface roughness; the cutting speed influenced the tool wear; the feed rate influenced the tool vibration predominantly. According to the microscopic imagery, it was observed that adhesion and abrasion as the major wear mechanism.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.28-33
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• 2000

The monitoring of the chatter vibration is necessarily required to do automatic manufacturing system. To this study, we constructed a sensing system using tool dynamometer in order to the chatter vibration on cutting process. And a approach to a neural network using the feature of principal cutting force signals is proposed. with the error back propagation training process, the neural network memorized and classified the feature of principal cutting force signals. As a result, it is shown by neural network that the chatter vibration can be monitored effectively.

• Composites Research
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• 제33권5호
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• pp.262-267
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• 2020

고속 가공과 저중량 설계에 대한 수요가 증가함에 따라, 공작기계 주축의 진동 발생 가능성이 증가하고 있다. 또한 초정밀 가공에서 주축의 진동은 공작물 표면 형상에 큰 영향을 끼치게 된다. 다양한 가공 공정의 가공 정밀도를 향상시키기 위해, 공작기계 주축 진동 문제를 해결하여야 한다. 이 논문에서, 공작기계 주축의 진동 억제를 위해 TiC-SKH51 금속 기지 복합재가 사용되었다. TiC-SKH51 복합재의 동적 특성을 확인하기 위해 충격 망치 시험을 수행하였다. FEA의 모드 분석 결과와 충격 망치 시험 결과를 비교하여 FEA의 신뢰성을 확인한 후, 공작기계 주축 모델의 해석이 실행되었다. FEA 결과로부터 진동 발생 억제를 위해 TiC-SKH51 복합재를 적용한 공작기계 주축이 사용될 수 있음을 확인하였다.

• 한국생산제조학회지
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• 제21권1호
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• pp.33-39
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• 2012

The tool wear and failure in automatic production system directly influences the quality and productivity of a product, thus it is essential to monitor the tool state in real time. For such purpose, an ART2-based remote monitoring system has been developed to predict the appropriate tool change time in accordance with the tool wear, and this study aims to experimently find the relationship between the tool wear and the monitoring signals in cutting processes. Also, the roughness of workpiece according to the wool wear is examined. Here, the tool wear is indirectly monitored by signals from a vibration senor attached to a machining center. and the wear dimension is measured by a microscope at the start, midways and the end of a cutting process. A series of experiments are carried out with various feedrates and spindle speeds, and the results show that the sensor signal properly represents the degree of wear of a tool being used, and the roughnesses measured has direct relation with the tool wear dimension. Thus, it is concluded that the monitoring signals from the vibration sensor can be used as a useful measure for the tool wear monitoring.

• 한국정밀공학회지
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• 제25권3호
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• pp.56-62
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• 2008

The biocompatibility and the fatigue strength of Co-Cr-Mo alloy are excellent, so it is used well for the material of artificial joints. The head of artificial joint needs mirror surface for reduction of abrasive resistance. Mirror finishing of Co-Cr-Mo alloy with geometrically defined single crystal diamond cutting tools is handicapped by micro chipping of tool edge. In general, it is said that the micro chipping of diamond tool is caused by work hardening of Co-Cr-Mo alloy for the cut. In the present research, mirror finishing of Co-Cr-Mo alloy by applying ultrasonic elliptical vibration cutting was carried out. The experimental results show that the micro chipping of diamond tool was suppressed and the tool wear was remarkably reduced as compared with the ordinary diamond cutting without elliptical vibration motion. It was confirmed that the good mirror surface of maximum surface roughness of 25 nmP-V was obtained for the cutting length of about 14 m. It is expected that mirror finishing of Co-Cr-Mo alloy can be achieved by applying ultrasonic elliptical vibration cutting practically.