• 미생물학회지
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• 제44권1호
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• pp.22-28
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• 2008

본 실험은 생분해가 어려운 절삭유를 단일 균주에 의해 생물학적 처리를 하는 데에 목적이 있다. 절삭유, 절삭폐유로부터 호기 균주 81개를 분리하여 이중 절삭유 분해능이 가장 높은 균주로, 48시간 내에 90.4%를 제거한(초기농도 699.1 mg/L) KS47을 선별하였다. KS47은 형태학적, 생리 화학적, 16S rDNA 염기서열, 그리고 지방산 분석을 통해 Pseudomonas aeruginosa로 동정되었다. P. aeruginosa KS47은 절삭유를 탄소원으로 사용하여 성장 할 수 있었으며, 절삭유 분해시, 최적 분해 조건은 1.5 g/L(wet weight), pH 7.0, $30^{\circ}C$이었다. 최적 조건 하에서 절삭유의 제거능을 본 결과, 1,060 mg/L의 절삭유를 12시간 내에 83.7% 제거함을 확인하였다.

• 한국기계가공학회지
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• 제21권4호
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• pp.23-30
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• 2022

Small-scale production is increasing, and the manufacturing industry is gradually changing into a smart manufacturing industry. Therefore, research on securing optimal cutting conditions for factors affecting machining precision during cutting is very important. Therefore, the purpose of this study is to After machining the inner diameter hole of SCM415 steel with a cermet tool on a CNC automatic lathe, the surface roughness, dimensional accuracy, and dimensional straightness are measured according to the feed rate to analyze the machining characteristics and suggest optimal cutting conditions. The test material was cut using a cermet tool for secondary cutting after a round bar with a diameter of 20 mm was mounted on a CNC automatic lathe. The cutting length was fixed at 0.5 mm, and the cutting speed was fixed at 3200 rpm. When the feed rate was changed to 0.05, 0.1, and 0.15 mm/rev, the respective surface roughness during the 15th test was measured. Consequently, The lower the feed rate, the better is the surface roughness. In addition, the optimum cutting conditions for SCM415 steel were observed to be the most ideal cutting conditions than the condition of 0.05 mm/rev at a cutting speed of 3,200 rpm and a feed rate of 0.1 mm/rev.

• Journal of the Korean Wood Science and Technology
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• 제26권1호
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• pp.38-50
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• 1998

Laser cutting tests were conducted to investigate the laser cutting characteristics of solid woods such as 25mm-thick white oak(Quercus acutissima) and maple(Acer mono), and wood-based panels such as 15mm-thick medium density fiberboard and particleboard. Test variables were laser power, cutting speed, grain direction, and moisture content. Specific cutting energy was measured and the qualities of cut surface were estimated in constant laser power. Specific cutting energy of white oak was larger than that of maple, and specific cutting energy of medium density fiberboard was smaller than that of particleboard. For both white oak and maple, specific cutting energy of green wood was smaller than that of air-dried wood because weight loss of moisture evaporation in green wood was larger than that in air-dried wood. In laser-cut surface, wood cells were not deformed and damaged, but in circular saw-cut surface fibers were pushed out and cut, and wood cells were deformed severely. However, mechanical surface roughness of saw-cut surface was smoother than that of laser-cut surface because of the existence of undeformed cell cavity in laser-cut surface.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.198-203
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• 1992

There are two important variables in machining process control, which are feed and cutting speed. It is possible to improve the machining accuracy and the productivity by maintaining the optimal feed and cutting speed. IN this work, a controller is designed to achieve on-line cutting force control based on the modeling of cutting process dynamics established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and the second is spindle speed control under the constant feed. Finally, both are proved to work properly through simulation and experimentation.

• 한국세라믹학회지
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• 제30권11호
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• pp.979-985
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• 1993

Diamond films were synthesized using CH4-H2-Ar mixture gases by MWCVD, and cutting ability was tested after brazing them onto WC tools. Growth rates were in the range of 0.5~10${\mu}{\textrm}{m}$/hr depending on the deposition conditions, and diamond films with thickness of 100~300${\mu}{\textrm}{m}$ were obtained. Diamond tools brazed by RF induction method showed an enhanced cutting ability in the cutting test of Si single crystal rod.

• 한국생산제조학회지
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• 제7권1호
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• pp.75-81
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• 1998

We have studied internal quality including chemical compositions, microscopic structure and nonmetallic inclusion of test materials. We have analyzed tensile strength value, hardness value, impact value etc. In analyzing internal quality, all of the test materials showed typical ferrite+pearlite structure. But nonmetallic inclusion showed oxide and sulfide inclusions in medium carbon steels, and sulfide inclusion is S-free cutting steels. In ca+ S-free cutting steels, the calcium aluminate and sulfide complex inclusion had low-melting points as deformation of sulfide and oxide inclusion is existed. It was found that tensile strength and hardness give maximum value in medium carbon steels, where as minimum in Ca + -free cutting steels. But values of elongation, reduction of area impact are reverse. Fracture surface of impact specimen is ductile in free cutting steels but brittle in medium cabon steels.

• 한국생산제조학회지
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• 제7권1호
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• pp.89-94
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• 1998

With increasing demands on automatic and high-capability manufacturing, the dynamic performance of machine tools becomes more and more important. In this paper, the correlation between dynamic compliance of the cutting system and the commencing point of chatter vibration in turning is checked by impulse excitation method and cutting tests for some cutting system. The correlation between chucking conditions of workpiece and the commencing point of chatter vibration is clarified, and it is proven that there is a mutual relations between them. Chatter vibration commenced at certain level of dynamic compliance of the cutting system regardless of the kind of the system. It shows the possibility of dynamic performance test of a lathe by means of impulse excitation method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.862-865
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• 2000

The object of this paper is to evaluate the surface roughness using the experimental equation of surface roughness, which is developed in turning by an orthogonal array method. $L_9{3^4}$ orthogonal array method, one of fractional factorial design has been used to study effects of main cutting parameters such as cutting speed, feed rate and depth of cut, on the surface roughness. And the analysis of variance (ANOVA)-test has been used to check the significance of cutting parameters. Using the result of ANOVA-test, the experimental equation of surface roughness, which consists of only significant cutting parameter - feed rate, has been developed. The coefficient of determination of this equation is 0.962.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.279-284
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• 2000

The object of this paper is to evaluate the chip breakability using the experimental equation of surface roughness, which is developed in turning by an orthogonal array method. L$\sub$9/(3$^4$) orthogonal array method, one of fractional factorial design has been used to study effects of main cutting parameters such as cutting speed, feed rate and depth of cut, on the surface roughness. The evaluation of chip breakability is used the chip breaking index(C$\sub$B/), non-dimensional parameter. And the analysis of variance (ANOYA)-test has been used to check the significance of cutting parameters. Using the result of ANOYA-test, the experimental equation of chip breakability, which consists of significant cutting parameters, has been developed. The coefficient of determination of this equation is 0.866.

• 한국정밀공학회지
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• 제16권9호
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• pp.68-74
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• 1999

The influence of surface preparation methods after plasma cutting on the quality of weld zone was investigated. For comparison, three types of welded specimens were prepared by machining (WM), plasma cutting with light regrinding (WPG) and without regrinding (WP), by using three kinds of materials, carbon steel (SM45C), stainless steel (STS304) and aluminum alloy (A6061-T6). Nondestructive examination, hardness test, microstructure examination, and fracture toughness test were performed. The results showed that there was no appreciable reduction in hardness or fracture toughness in WP specimens. But a little difference in heat affected zone size was observed.