• 한국정밀공학회지
• /
• 제17권12호
• /
• pp.94-100
• /
• 2000

This paper presents a methodology for In-Process monitoring of tool wear by using ultrasonic sensor in turning operation. An integrated single ultrasonic transducer operation at a frequency of 10MHz is placed in contact with the insert tip. The change in amount of the reflected energy from the nose and flank of the tool can be related to the level of tool wear and the mechanical integrity of the tool. As the results, the tool wear monitoring system based on the ultrasonic pulse-echo method was proposed, it is useful to determine a tool life and tool change time.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 춘계학술대회 논문집
• /
• pp.852-856
• /
• 1997

This paper describes a ultrasonic method for direct measurement of tool wear in turning operations. An integrated single ultrasonic transducer operating at a frequency of 10MHz is placed in contact with the insert tip. The change in amount of the reflected energy form the nose and flanks of the tool can be related to the level of tool wear and thr mechanical integrity of the tool. As a results, a correlation exists between the untrasonic measurement and tool wear and that it is tool dependent.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.851-856
• /
• 1997

This study is on the estimation of the tool temperature for different tool nose radius and cutting conditions in turning. The experiment has been performed in different cutting conditions such as cutting speed, feed rate, and depth of cut for the tool nose radius, 0.4R, 0.8R using SMC workpiece materials. Tool temperature is measured using thermo-couple which is embedded in the insert tip. Using a multiple linear regression method, the tool temperature can be determined as an exponential equation with cutting variables and tool nose diameters for different tool materials. The equations determined in this study show a good correlation for the cutting conditions and can be used for the tool temperature estimation. The result indicates that the tool temperature decreases for ~ncreasing the tool nose radius in general. Also, nose radius hardly influences on the tool temperature compared with cutting speed, feed rate and depth of cut.

• 한국정밀공학회지
• /
• 제12권10호
• /
• pp.50-56
• /
• 1995

Chatter Vibration is an unwanted phenomenon in metal cutting and it always affects surface finish, tool life, machine life and the productivity of machining process. The real-time detection of the chatter vibration is is necessarily required to automation system. In this study, we constructed the multi-sensing system using Tool Dynamometer, Accelermeter and AE sensor. Especially, Acoustic Emission(AE) generated during turning was investigated the possibility for real-time detection of chatter vibration. Turning experiments were performed using carbide insert tip under realistic cutting conditions and tapered workpiece of SM45C. Consquently, the real-time detection using multi-sensing system can be used for Inprocess monitoring of chatter vibration.

• 대한기계학회논문집
• /
• 제7권1호
• /
• pp.1-10
• /
• 1983

The photoelastic determination of S.I.F. in Fracture mechanics has been regarded as one of the most effective and practical experimental methods in which stresses are read directly, except a few shortcomings involved in the process of experiment; the difficulties of making a sharp crack tip similar to the practical one and nearly impossibilities of carving an arbitrarily shaped crack on the test plate, etc. To eliminate flaws mentioned above, recently, Kitagawa and Watanabe of Tokyo Univ.developed a new method named"Teflon Insert Method". which has improved experimental accuracy to a considerable extent byt remaining still room for further improvement, that is, the elimination of bonding boundary scars which render photoelastic fringes obscure. In this paper, a newly exploited"Teflon Molding Method" was attempted for the completion of teflon-epoxy experimental method. The experimental results obtained by this method are compared with existent theoretical and experimental values to evaluate its accuracy. As result, 1-6% of margin of errors were appeared in a series of photoelastic experiments which defied any other conventional method in terms of experimental accuracy.perimental accuracy.

• 한국생산제조학회지
• /
• 제8권5호
• /
• pp.102-107
• /
• 1999

In this paper hardened SCM440 material and annealed SCM440 material are for cutting experiments by the cutting con-dition which is chosen respectively by tool three components of cutting force are recorded using multicorder, Then the surface roughness for various force are measured by Roughness Tester. The results of the experiment are summarized as follow. The hardened material cut by ceramic tool(BX20) gives the highest radial component values among the cutting resistance radial components is increased higher for the higher cutting speed even though vertical component and axial component tend to decrease. But when the annealed material was cut increase in cutting speed results in the increase of three component forces. Since ceramic insert tip used the experiment hardly affect Built-up Edge and heat the cutting resistance decrease slightly regardless of the increased of cutting speed. The hardened material has higher three compo-nent force value than the annealed material because the material of high hardness is increased cutting resistance. The low-est cutting forces for hardened material and annealed material are shown in the cutting speed of 60m/min and 180m/min. respectively.

• 한국정밀공학회지
• /
• 제19권11호
• /
• pp.96-102
• /
• 2002

This study is on the estimation method of toot temperature for different tool nose radius and cutting conditions in turning. Experimental analysis has been performed in different cutting conditions such as cutting speed, feed rate, and depth of cut for the tool nose radius, 0.4R, 0.8R using SMC workpiece materials. Tool temperature is measured using a thermo-couple which is embedded in the insert tip. Using multiple linear regression method, the tool temperature can be determined as an exponential equation with cutting variables and tool nose diameters for the different tool materials. The equations determined in this study show a good correlation for the cutting conditions and can be used for a tool temperature estimation technique. The result indicates that the tool temperature decreases for increasing the tool nose radius in general. Also, nose radius hardly influences on the tool temperature compared with cutting speed, feed rate and depth of cut. This method will be useful for the estimation of tool life and temperature using limited experimental data for given cutting conditions.

• 한국정밀공학회지
• /
• 제11권6호
• /
• pp.185-199
• /
• 1994

This study has been performed to present a new automatic tool wear measurement by digital image processing. The purpose of this paper is to develop an automatic tool wear measuring system based on the image processing which can be applied to the quasi-real time measurement of the characteristics of insert tip in turning. Tool wear monitoring is one of the key-problems, for the development of control systems of modern unmanned factory which are not completely solved now. In oredr words at present complete qualitative and quantitative information on tool wear morphology is required, at least on the following aspects : flank wear, its dimensions and distribution on the maximum and mean values on VB pqrqmeter in the various zones of the wearland. crater wear, its main dimensions and values of KT parameters. This research has been performed to this technique made possible by designing a proper lighting system to the worn tool with following features : The flank wear is measured by observing the active cutting part from a proper direction and by lighting the wearland by a diffuser optic system. The crater wear is visualized by lighting the tool by a He-Ne gas laser system developed in this study. By means of this system it is research to evaluate classical parameters of tool wear and to have complete information about tool wear morphology.

• 방송공학회논문지
• /
• 제6권1호
• /
• pp.13-20
• /
• 2001

본 논문에서는 켑스트럼 영역에서의 오디오 워터마킹 방법을 제안한다. 광대역 채널에 협대역 신호를 숨기는 대역확산(spread spectrum) 통신과 유사한 방법을 이용하여 워터마크 신호를 오디오 신호의 켑스트럼 성분에 삽입한다. 의사잡음 시퀸스 (pseudo-random sequence)를 이용하여 오디오 신호에 삽입할 워터마크 신호를 발생시킨다 켑스트럼 계수들의 분포와 인간 청각 시스템(Human Auditory System, HAS)의 주파수 마스킹 특성을 고려하여 결정한 가중치를 곱해서 얻은 워터마크 신호는 사람 의 귀로 감지할 수 없을 정도의 크기를 갖는다. 본 논문의 실험 결과에서 보인 것처럼. 오디오 신호의 사용 권한이 없는 사용자들 은 삽입된 워터마크 신호를 검출하기가 통계적으로 거의 불가능하며, 다중 워터마크, MPEG 오디오 부호화. 부가잡음과 같은 다양한 공격에도 소유자에 의해서는 워터마크 신호의 검출이 가능하다.

• 한국생산제조학회지
• /
• 제18권5호
• /
• pp.514-520
• /
• 2009

Titanium is one of the most attractive materials due to their superior properties of high specific strength and excellent corrosion resistance. The applications in aerospace and medical industries demand machining process more frequently to obtain more precise products. Machining of titanium is faced with strong challenges such as increased component complexity i.e. airframe components manufacturing processes. The machining cost on titanium have traditionally demanded high cutting tool consumable cost and slow machining cycle times. Similarly, the high wear of the cutting tools restricts the cutting process capabilities. Titanium screws applied to fasten parts In the several corrosion environment. In the thread cutting of titanium alloys, the key point for successful work is to select proper cutting methods and tool materials. This study suggests a guidance fur selecting the cutting methods and the tool materials to improve thread quality and productivity. Some experiments investigate surface roughnesses, cutting forces and tool wear with change of various cutting parameters including tool materials, cutting methods, cutting speed. As the results, the P10 type insert tip was assured of the best for thread cutting of Ti-6Al-4V titanium alloy. Also the initial depth of infeed was desirable to use the value below 0.5mm as the uniform cutting area method is applied.