• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.18-24
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• 1999

ThisPaper investigates the feasibility of using acoustic emission signal analysis for the detection of built-up edge during machining. Experiments were conducted on a CNC-lathe using conventional carbide insert tools under various cutting conditions. The cutting forces were also measured for comparisons. Experimental evidence is presented which indicates that the presence of a built-up edge can significantly affect the generation of acoustic emission in metal cutting. It is shown that under conditions in which a built-up edge is generated, the variation of $AE_{rms}$ signal with cutting speed can be quite different from the generally accepted linear, monotonic increase as previously reported. The feasibility of utilizing $AE_{rms}$ in built-up edge sensing is suggested.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.32-38
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• 1998

For the purpose of monitoring the abnormal state in proportion to cutting in automatic production process, the 3 kinds of specimens different from mechanical properties by austempering through temperature variation were manufactured, and the effects of tool wear on thrust and AE RMS was analyzed with sequential drilling in in-process. When the ADI specimens were drilled, the relationship of thrust and AE RMS with flank wear was studied through experiments, and it is confirmed that the reliable wear state is able to be monitored by using these signals. It was shown that thrust and AE RMS increased slowly till flank wear reached to V$_{B}$ = 0.25mm, and they increased steeply over the value. The effective tool exchange time was able to be pre-estimated by using this fact. It was validated that the tool breakage was able to be detected on the real time by monitoring in in-process.s.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.3
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• pp.28-36
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• 1986

This study was investigated the feasibility of AE application on in-process detection of tool fracture and chipping. Carbon steel SM45C workpiece with longitudinal slots was turned interruptedly on a lathe. AE RMS signal at tool fracture was observed and also the tangential force and the feed observed at the time of tool fracture, the levels of tangential force and the feed force at the time of fracture decrease considerably. In chipping, high level AE signal was observed but there were no changes of cutting force. Peak AE RMS squared is proportional to the area of tool fracture and resultant force. Fracture model of tool fracture is proposed as $V_{p}$ = $C_{1}$ $E_{1}$F(.DELTA. A)$_{0.5}$ and peak AE RMS shows strong correlation with the fracture parameter F(.DELTA.A)$^{0.5}$.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.41-46
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• 2003

This paper deals with the possibility of tap breakage detection by AE sensor. AE signals in the tapping were not seldom generated in low speed but reflected the tapping process exactly in high speed. Using AE raw signals sampled in 500kHz, AE RMS and AE count rate was computed in software. When the converting time of AE RMS is less than 10ms, we could distinguish between normal cutting and tap breakage. And AE count rate was more exact when the converting time is greater than 1ms. When two methods were compared to each other, AE count rate was more accurate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.97-101
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• 2000

The AE measurement is one of the most convenient methods for detecting contacts between slider disk. The AE method has been widely used in the investigation of the tribology of sliding interfaces due to the convenience of using AE sensor. In this study, we examined the relationship between the AE signal and the flying height of a slider. We tried to know the influence of the disk velocity on the AE rms signal by using the AE measurement system. The experiment also gives the relationship between the take-off velocity and the disk surface state. To investigate the behavior of the slider further, the variances of the AE signal are analyzed. The results about a subambient pressure slider indicate that the increase in the magnitude of AE rms signal does not necessarily mean the slider/disk contacts.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.9
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• pp.74-85
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• 1995

The purpose of this paper is to evaluate the grade of WA vitrified and resinoid bond grinding wheels by the sue of AE measuring system. When the manufactured 48 kinds of specimens were scratched by the method of OKOSHI'S grade test, the relationship between the amount of bit scratch depth of grinding wheel specimens and the character- istics of AE signals, and the relationship of AE counts and grade were considered as fololws; (1) The higher the grades are AE cumlulative event counts N and AE event count rate n, the smaller the values tend to be. But A $E_{rms}$is in reverse. (2) In the case of same grade, the smaller the grain size is, the higher the value of AE cumulative event counts N and A $E_{rms}$is results of comparison and observation. The grinding wheel with lower elasticity and with higher percentage of pore detected higher value of AE cumula- tive event counts N than with higher elasticity and lower percentage of pore. But A $E_{rms}$ is in reverse. (3) AE cumulative event counts N and bit scratch depth h have normally one to one correspondence. (4) It can be expected that quantitative evaluations of grade by using AE have been carried out by the wave observation of AE signal in line with the relationship between load speed of bit and AE cumulative event counts N & AE event count rate n.' AE event count rate n.ate n.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1391-1399
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• 2001

The AE measurement is one of the most convenient methods for detecting contacts between the slider and the disk. The AE method has been widely used in the investigation of the tribology of sliding interfaces due to its convenience. We examined the relationship between the AE signal and the flying height of a slider. We investigated the influence of the disk linear velocity on the AE rms signal by using the AE measurement system. The experiment also gives the relationship between the take-off velocity and the disk surface conditions. To investigate the behavior of the slider further, the variances of the AE signals are analyzed. The experimental results indicate that the increase in the magnitude of the AE rms signal does not necessarily mean the slider/disk contacts.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.3
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• pp.75-82
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• 1990

Automatic monitoring of the cutting conditions is one of the most improtant technologies in machining. In this study, the feasibility in applying acoustic emission(AE) signals for the in-process detection of endmill wear and fracture has been investigated by performing experimental test on the NC vertical milling machine with SM45C for specimen. As the results of detecting and analyzing AE signals on various cutting conditions, the followings have confirmed. (1) The RMS value of acoustic emission is related sensitively to the cutting velocity, but is not affected largely by feed rate. (2) The burst type AE signals of high level have been observed when removing chips distorderly and discontinuously. (3) When the RMS value grows up rapidly due to the increase of wear the endmill are generally broken or fractured, but when the endmills fracture at the conditions of smooth chip-flow or built-up-edge(BUE) occurred frequently, the rapid change of the RMS arenot found. And it is expected that this technigue will be quite useful for in-process sensing of tool wear and fracture.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.48-57
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• 1998

Abrasive waterjet(AWJ)은 가공시 열에 의한 가공경화가 없기 때문에 유리, 세라믹, 타이타늄및 금속복합재료와 같은 난삭재의 가공기술로 사용이 증가되었다. Acoustic emission(AE)신호에 의한 AWJ 세라믹 drilling가공시 On-Line Monitoring의 가능성이 고찰되었다. 기계 적인 물성이 서로 상이한 3종류의 세라믹이 본 연구에서 사용되었으며, AE신호는 AWJ drilling의 깊이를 monitoring하는데 유용함을 알 수 있었고 또한 세라믹의 material removal mechanisms을 규명하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.906-915
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• 1986

This study reviewed the theory of acoustic emission applying generation of acoustic emission in metal cutting and proposed a relationship between fundamental cutting parameters and the root mean square (RMS) voltage of the acoustic emission on the basis of the mechanics of the orthogonal cutting operation. Experimental results are presented for 6063-T5 Auminum and the validity of this relationship is evaluated by a series of tests varying cutting speed, feed rate and rake angle in orthogonal cutting. The original formula derived theoretically has been modified in order to utilize independent of fundamental cutting parameters. RMS voltage of acoustic emission depends on cutting speed and strain rate, but it is not much affected by feed rate. Applying lubricant, the drop of RMS level has been observed.