• 대한기계학회논문집A
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• 제41권5호
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• pp.391-399
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• 2017

절삭속도 및 이송속도가 평엔드밀로 하향절삭 가공된 측벽 형상에 미치는 영향을 실험을 통하여 알아보고자 한다. 실험은 절삭속도 및 공구 직경, 절삭날 당 이송거리를 변수로 하여 수행하며, 실험 결과로서 배분력과 축방향 형상을 측정한다. 연구 결과, 이송속도를 절삭속도로 나눈 값에 비례하는 날 당 이송거리가 작을수록 축방향 형상정밀도가 높아지는 것이 확인되었다. 아울러, 축방향 형상은 서로 다른 기울기를 갖는 두 직선이 특이점에서 만나는 형태로 단순화 할 수 있다. 그러므로 운전 중 작업자에 의한 형상정밀도의 추정 및 날 당 이송거리 조정에 의한 개선이 용이할 것으로 판단된다.

• 한국공작기계학회논문집
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• 제13권6호
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• pp.17-22
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• 2004

A study for investigating the effects of the cutting conditions (radial depth of cut feed per tooth) and the number of tooth on the side wall of prismatically milled workpiece is described. This study is available not only for understanding the geometrical characteristics of the end milled side wall but also for finding the optimal cutting conditions. In this work, the side wall geometry was characterized by the straightness and the location of maximum peak point. Through this study, it was revealed that the geometrical characteristics of the end milled side wall are strongly related to the material removal per tooth and the number of tooth.

• 한국공작기계학회논문집
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• 제13권5호
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• pp.62-66
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• 2004

A study for investigating the effects of the cutting conditions(feed rate, radial depth of cut, cutting speed) and the tool diameter on the circumferential geometry of the cyl indrically end-mi1led workpiece is described. In this work, the circumferential geometry is characterized by the roundness error. Experimental results show that the circumferential geometry is directly affected by the material removal per tooth,which is defined as a function of the cutting speed, the feed rate and the radial depth of cut. And, the radial depth of cut is revealed to be the most critical condition among them. It is also found that the roundness error decreases when the tool diameter is larger under the same cutting conditions.

• 한국정밀공학회지
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• 제22권4호
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• pp.68-75
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• 2005

This paper presents a new method for the optimization of feed rate in sculptured surface machining. A NC verification model based on Z-map was utilized to obtain chip load according to feed per tooth. This optimization method can regenerate a new NC program with respect to the commanded cutting conditions and the NC program that was generated from CAM system. The regenerated NC program has not only the same data of the ex-NC program but also the updated feed rate in every block. The new NC data can reduce the cutting time and produce precision products with almost even chip load to the feed per tooth. This method can also reduce tool chipping and make constant tool wear.

• 한국정밀공학회지
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• 제23권12호
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• pp.38-45
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• 2006

In this work, optimal finish machining condition considering total time for mold or electrode manufacturing was investigated. First, manual finishing time according to the machining condition was analyzed for the work material. The effect of runout and phase shift of tool path on surface finish was also considered in those analyses. Secondly, optimal manual finishing processes were determined for various machining conditions. Finally, finish machining time and corresponding manual finishing time were taken into account for the estimation of the total time of manufacturing mold. Though small feed per tooth and pick feed reduced the manual finishing time, the finish machining time increased in such conditions. With a machining condition of feed per tooth of 0.2 mm and pick feed of 0.3 mm, the minimum total time of manufacturing mold was achieved in our machining condition.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.801-805
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• 2000

This paper presents a new method of tool path optimization. A NC verification model based Z-map was utilized to obtain chip load in feed per tooth. This developed software can regenerate a NC program from cutting condition and the NC program that was generated in CAM. The regenerated NC program has not only all same data of the ex-NC program but also the new feed rates in every block. The new NC data can reduce the cutting time and manufacture precision dies with the same chip load in feed per tooth. This method can also prevent tool chipping and make constant tool wear. This paper considered the effects of acceleration and deceleration in feed rate change.

• 한국생산제조학회지
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• 제20권1호
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• pp.101-107
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• 2011

Analytical solution of micro-scale milling process is presented in order to suggest available machining conditions. The size effect should be considered to determine cutting characteristics in micro-scale cutting. The feed per tooth is the most dominant cutting parameter related to the size effect in micro-scale milling process. In order to determine the feed per tooth at which chips can be formed, the finite element method is used. The finite element method is employed by utilizing the Johnson-Cook (JC) model as a constitutive model of work material flow stress. Machining experiments are performed to validate the simulation results by using a micro-machining stage. The validation is conducted by observing cutting force signals from a cutting tool and the conditions of the machined surface of the workpiece.

• 한국정밀공학회지
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• 제16권8호
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• pp.178-185
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• 1999

In tool condition monitoring systems, parameters should be set to a certain threshold. In many cases, however, the threshold is dependent on cutting conditions, especially the radial immersion ratio. In this presented is a method of on-line estimation of the radial immersion ratio in face milling. When a tooth finishes sweeping, a sudden drop of cutting force occurs. The force drop is equal to the cutting force that acting on a tooth at the swept angle of cut and can be acquired from cutting force signals in feed and cross-feed directions. Average cutting force per tooth period can also be calculated from cutting force signals in two directions. The ratio to cutting forces in two directions acting on a tooth at a certain swept angle of cut and the ratio of average cutting forces in two directions per tooth period are functions of the swept angle of cut and the ratio of radial to tangential cutting forces. Using these parameters, the radial immersion ratio is estimated. Various experiments are performed to verify the proposed method. The results show that the radial immersion ratio can be estimated by this method regardless of other cutting conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.141-144
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• 2003

This paper proposes an analytical model of off-line feed rate scheduling to obtain an optimum feed rate for high speed machining. Off-line feed rate scheduling is presented as an advanced technology to regulate cutting forces through change of feed per tooth, which directly affects variation of uncut chip thickness. In this paper, the feed rate scheduling model was developed using a mechanistic cutting force model using cutting-condition-independent coefficients. First, it was verified that cutting force coefficients are not changed with respect to cutting speed. Thus, the feed rate scheduling model using the cutting-condition-independent coefficients can be applied to set the proper feed rates for high speed machining as well as normal machining. Experimental results show that the developed fred rate scheduling model makes it possible to maintain the cutting force at a desired level during high speed machining.

• 한국정밀공학회지
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• 제15권5호
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• pp.100-109
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• 1998

In order to increase productivity through unmanned machining in CNC milling process, in-process tool fracture detection is required. In this paper, a new algorithm for tool fracture detection using cutting load variations was developed. For this purpose, developed were tool condition vector which is dimensionless indicator of cutting load and tool fracture index (TFI) which represents magnitude of tool fracture. Through cutting force simulation, tool fracture index was shown to be independent of tool run-outs and cutting condition variations. Using tool fracture index, the ratio of the tool fracture to feed per tooth could be indentified.