• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.882-885
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• 2000

The machinability of material was evaluated using high speed steel drill on hot-rolled high strength steel. Cutting resistance and tool wear were investigated by drilling experimentation. When the steel-board specimens were drilled in industrial condition, the relationship between average of thrust and cutting resistance was random because of slip of chuck and strain of workpiece. The primary objective of this study is to develop the strategy of analysis that can detect drilling states in industrial condition and such strategy is programmed with visual C++. The developed program can analyze thrust of initial rising zone. The result is obtained that thrust of rising zone is closely related to tool wear in despite of industrial condition.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.116-122
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• 2008

In order to establish automation or optimization of the machining process, predictions of the forces in machining are often needed. A new model fur farces in milling with the experimental model based on the specific cutting pressure and the Oxley's predictive machining theory has been developed and is presented in this paper. The specific cutting pressure is calculated according to the definition of the 3 dimensional cutting forces suggested by Oxley and some preliminary milling experiments. Using the model, the average cutting forces and force variation against cutter rotation in milling can be predicted. Milling experimental tests are conducted to verify the model and the predictive results agree well with the experimental results.

• 대한기계학회논문집A
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• 제28권3호
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• pp.222-229
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• 2004

In this paper, the torque of CNC spindle motor during machining is estimated without speed measuring sensor. The CNC spindle system is divided into two parts, the induction spindle motor part and mechanical part. In mechanical part, the variation of the frictional force due to the increment of the cutting torque and the effect of damping coefficient is investigated. Damping coefficient is found to be a function of spindle speed and not influenced by the weight of the load, while frictional force is a function of both the cutting torque and spindle speed. Experimental equations are drawn for damping coefficient and Coulomb friction as a function of spindle speed. Incremental frictional torque Is also obtained as a function of both cutting torque and spindle speed. Graphical programming is used to implement the suggested algorithm to monitor the torque of an induction motor in real time. Torque of the spindle induction motor is estimated well in about average 3% error range under various cutting conditions.

• Current Research on Agriculture and Life Sciences
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• 제22권
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• pp.41-48
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• 2004

본 연구는 예취시 벼 줄기의 절단 저항이 적은 콤바인 예취날 개발에 필요한 기초 자료를 제공하기위하여 예취날의 윗날 내부에 면적 $75mm^2$의 평면 홈을 가공한 개발날과 시중에 판매되는 예취날을 사용하여 절단속도비와 볏짚의 함수율을 인자로 미예취시 예취날의 구동 마찰저항과 예취저항을 측정한 결과는 다음과 같다. 1. 예취날 속도 0.37m/s에서 0.55m/s범위 내에서 단날 구동시의 예취날 구동 마찰저항은 홈 가공을 한 개발 날이 평균 $0.12kg{\cdot}m$로 홈 가공을 하지 않은 기존 날의 평균 $0.16kg{\cdot}m$에 비해 25% 낮게 나타났다. 또한 양날 구동방식에서도 홈 가공을 한 개발말이 기존날에 비해 평균 26%정도 구동 마찰저항이 낮게 나타났다. 2. 절단속도비 10.에서 1.5범위 내에서 홈을 가공한 개발날의 볏짚 예취 저항은 기존 날에 비해 볏짚의 함수율 14.2%, 55.3%, 84.2%에 대해 각각 평균 12%, 15%, 20% 낮게 나타났다. 3. 예취날 구동 방식에 따른 볏짚 예취 저항은 양날구동방식이 $0.20kg{\cdot}m$로 단날 구동방식의 $0.24kg{\cdot}m$에 비해 평균 17%정도 낮게 나타났다. 4. 예취날의 최적 속도비는 볏짚의 함수율 변화에 따라 다르게 나타났으며 함수율 14.2%, 84.2%에 대해 각각 1.2, 1.4로 나타났다.

• 한국정밀공학회지
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• 제19권8호
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• pp.63-70
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• 2002

In end milling process, the undeformed chip section area and cutting forces vary periodically with phase change of the tool. However the real undeformed chip section area deviates from the geometrically ideal one owing to cutter runout and tool shape error. In this study, a method of estimating the real undeformed chip section area which reflects cutter runout and tool shape error was presented in up end milling process using measured cutting forces. The average specific cutting resistance, Ka is defined as the main cutting force component divided by the modified chip section area. Ka value becomes smaller as the helix angle increases from $30^circC \;to\;40\circC$. But it becomes larger as the helix angle increases from $40^\circ$to 50 . On one hand, the Ka value shows a tendency to decrease with increase of the modified chip section area and this tendency becomes distinct with smaller helix angle.

• 한국생산제조학회지
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• 제18권6호
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• pp.629-635
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• 2009

In this research, KP-4, one of the plastic mold steels, was coated with the AlTiN from one layer to four layers by the PVD method in the $\Phi$ 8mm cemented carbide ball end mill. Coated KP-4 was processed with various conditions. For example, slope of $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ the spindle rotation speed was changed from 10,000rpm to 16,000rpm, the tool feeding speed was changed from 1,300mm/min to 1,700mm/min, the depth of cut was also changed from 0.3mm to 0.9mm, and etc. Cutting component force according to the coating layer number, and surface roughness were studied. The cutting component force showed a good agreement better the up ward direction than the down ward direction under all experimental conditions. In case of the condition per the material shape, it was lessen when the tool have larger angle because the average effective diameter of the tool is larger. The surface roughness showed good condition in case of the up ward than the down ward direction. And, in the 3rd layer of AlTiN coating, it showed the most suitable condition.

• 한국정밀공학회지
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• 제19권2호
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• pp.79-86
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• 2002

In end milling process the undeformed chip thickness and the cutting force components vary periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying undeformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting system. According to this analysis, when cutting Inconel 718, 61, 64 and 55% of the total energy is consumed in the shear process with the helix angle 30$^{\circ}$, 40$^{\circ}$ and 50$^{\circ}$ respectively, and the balance is consumed in the friction process. With the helix angle of 40$^{\circ}$ the specific cutting energy consumed is smaller than with the helix angle 30$^{\circ}$ and 50$^{\circ}$.

• Journal of Biosystems Engineering
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• 제28권6호
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• pp.497-504
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• 2003

The objectives of this study were to develop a harvesting gripper for perilla leaves and test its performance, which was a partial work of the automated perilla leaves harvesting system development. The results of this study could be summarized as the followings: The shear forces for harvesting the perilla were measured. The measured results showed that the average shear force required was 12.13N for cutting the petioles attached to the perilla stalks, and the maximum of 17.42N. The inner diameter of air cylinder used was 6mm and the air pressure was maintained as 0.7㎫ during the tests. The time required for cutting perilla leaves could be adjusted by the control program and cutting operation could be done within 1- 10 seconds. The performance tests were conducted to harvest the perilla leaves by the gripper developed. The average success rates of cutting were 72.2％ for the first test, 78.5％ for the second, and 74.2％ for the last. The perilla leaves were not damaged by the gripper The whole system operation could be finished within three seconds except the delay time for dropping harvested leaves.

• 한국CDE학회논문집
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• 제2권1호
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• pp.19-27
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• 1997

This paper presents rough cut tool path planning for the fewer-axis machine consisting of a three-axis CNC machine and a rotary indexing table. In the problem dealt with in this paper, the tool orientation is "intermediately" changed, distinguished from the conventional problem where the tool orientation is assumed to be fixed. The developed rough cut path planning algorithm tries to minimize the number of tool orientation (setup) changes together with tool changes and the machining time for the rough cut by the four procedures: a) decomposition of the machining area based on the possibility of tool interference (via convex hull operation), b) determination of the optimal tool size and orientation (via network graph theory and branch-and bound algorithm), c) generation of tool path for the tool and orientation (based on zig-zag pattern), and d) feedrate adjustment to maintain the cutting force at an operation level (based on average cutting force). The developed algorithms are validated via computer simulations, and can be also used in pure fiveaxis machining environment without modification.

• 터널과지하공간
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• 제33권6호
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• pp.519-533
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• 2023

본 연구에서는 평균 압축강도가 100 MPa 이상인 암석에 대해 픽커터의 선형절삭시험을 실시하였고, 적외선 열화상 카메라를 통해 측정된 픽커터 절삭 시의 발생 온도와 커터 작용력과의 상관관계를 분석하였다. 모든 시험조건에서 최대 온도는 치핑이 발생하는 암석면에서 측정되었고, 암석에 발생한 온도는 픽커터의 작용력과 밀접한 상관관계를 나타내었다. 반면, 픽커터에 발생하는 온도는 대기 온도 대비 최대 36℃ 이내로 상승하였고 커터 작용력과의 상관관계도 뚜렷하지 않았다. 이는 실험실 조건의 짧은 절삭거리와 텅스텐 카바이드 삽입재의 높은 열전도 특성이 원인인 것으로 사료된다. 단, 픽커터의 주요 부위 중에 텅스텐 카바이드 삽입재에 상대적으로 높은 온도가 유지되는 것으로 나타나, 픽커터 절삭 성능의 유지를 위해서는 삽입재와 헤드부 사이에 보강을 실시하거나 픽커터 제작 시에 은납 공정의 품질을 향상시키는 것이 필요할 것으로 판단된다.