• 제목/요약/키워드: Milling operation

검색결과 143건 처리시간 0.027초

밀링가공에서 효과적인 채터진동 판별을 위한 신호 획득 (Signal Acquisition for Effective Prediction of Chatter Vibration in Milling Processes)

  • 조문호;김혁;구준영;이종환;김정석
    • 한국생산제조학회지
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    • 제23권4호
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    • pp.325-329
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    • 2014
  • This paper proposes a method to predict chatter vibration generated in milling processes and to enhance machining quality and surface finish. Chatter vibration is a common problem in the milling of thin walls and floors. It causes a poor surface finish, or even marks, to appear on the final machined surface. Therefore, an effective method is necessary to predict chatter vibration in machine tools. In this investigation, chatter vibration is measured by an accelerometer, microphone, and Acoustic Emission (AE) sensor in a machining operation. Based on the results of the experiment, a microphone can be applied for the prediction of chatter vibration in milling processes.

기계적 합금화에 의한 나노구조 Fe-Co 합금분말의 제조 및 자성특성 (Fabrication of Nanostructured Fe-Co powders by Mechanical Alloying and Their Magnetic Properties)

  • 정진영
    • 한국분말재료학회지
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    • 제6권1호
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    • pp.27-35
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    • 1999
  • A study was made on the fabrication of nanostructured Fe-Co powders by mechanical alloying and their magnetic properties. Microstrural development during the process of MA was inverstigated by means of X-ray diffraction, differential thermal analyzer, scanning electron microscopy and transmission electron microscopy. The magnetic properties of NS Fe-Co powders were evaluated through the measurements of the saturation magnetization $(M_s)$ as well as the coercivity $(H_c)$. The average grain size calculated from line braodening in XRD peak was about 10nm or less and confirmed by TEM. In this experiment, two different milling methods (cycle opertion and conventional milling) were used. Cycle operation had an advantage over the conventional milling method in that more refined powders can be obtained. Solid state alloying of the components was confirmed from both the change of the saturation magnetization and the change of lattice parameter with Co contentration. Maxium $M_s$ was obtained at the composition of 30at.%Co. Relatively high coercivities of 10~150e were obtained for the compositions investigated, and this seems to be due to the high amount of internal strain introduced during milling.

불균일도정이 저장 중 쌀의 품질에 미치는 영향 (Effect of Non-Uniform Milling on Quality of Milled Rice during Storage)

  • 김훈;이현정;김의웅;이세은;윤두현
    • 한국식품저장유통학회지
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    • 제13권6호
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    • pp.675-680
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    • 2006
  • 본 연구에서는 쌀의 불균일도정 조건이 저장중 품질에 미치는 영향을 구명하기 위하여 불균일도정 2수준, 균일도 정 1수준에 대하여 저장온도 5, $25^{\circ}C$ 수준에서 8주간 저장하면서 함수율, 중량, 지방산가, 동할율, 백도, b값 등 품질특성과 관능검사를 수행하였다. 도정과정에서 불균일도정은 과도정이 발생하면서 균일도정에 비해 함수율 차이가 발생하였으며, 저장과정에서 함수율 변화의 차이는 나타나지 않았지만 초기함수율 차이가 지속적으로 유지되었다. 또한, 저장온도가 높을수록 함수율 및 중량감소가 크게 나타났다. 저장온도가 높거나 불균일도정이 심할수록 지방산가는 크게 증가하여 품질에 영향을 미치는 것으로 나타났다. 동할증가율은 저장온도 및 불균일도정에 따라 다소 차이가 나타났다. 저장온도가 높고 불균일도정이 발생할수록 저장기간이 증가하면서 백도는 감소하고 b값은 다소 증가하는 경향을 보였다. 불균일도정 정도가 가장심한 불균일도정 I의 경우저장 전 관능검사에서 균일도정 및 불균일도정II에 비해 낮은 수준에서 유의적인 차이가 나타났으며, 저장기간이 증가하여도 동일한 결과이었다.

Elucidating Energy Requirements in Alternative Methods of Robo Production

  • Akinoso, Rahman;Are, Oluwayemisi Teslima
    • Journal of Biosystems Engineering
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    • 제43권2호
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    • pp.128-137
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    • 2018
  • Purpose: This study was designed to elucidate the energy-utilization patterns for five methods of robo production. Methods: Robo (fried melon cake) was produced using five different methods, and the energy used for each unit operation was calculated using standard equations. The sensory attributes of the products were determined by panelists. Data were analyzed using descriptive analysis and analysis of variance at p < 0.05. Results: The energy demands for processing 2.84 kg of melon seed into robo (fried melon cake) using processes 1 (traditional method), 2, 3, 4, and 5 (improved methods) were 50,599.5, 21,793.6, 20,379.7, 21,842.9, and 20,429.3 kJ, respectively. These are equivalent to energy intensities of 1,7816.7, 7,673.8, 7,175.9, 7,691.2, and 7,193.4 kJ/kg, respectively. For the traditional process, the frying operation consumed the highest energy (21,412.0 kJ), and the mixing operation consumed the lowest energy (675.0 kJ). For the semi-mechanized processes, the molding operation consumed the highest energy (6,120.0 kJ), and the dry milling consumed the lowest energy (14.4 kJ). Conclusions: The energy-consumption patterns were functions of the type of unit operation, the technology involved in the operations, and the size of the equipment used in the whole processing operation. Robo produced via the milling of dried melon seed before oil expression was rated highest with regard to the aroma and taste quality, as well as the overall acceptability of the sensory evaluation, and required the lowest energy consumption. Full mechanization of the process line has potential for further reduction of the energy demand.

Cutting simulation을 이용한 End-milling cutter의 모델링 및 제작에 관한 연구 (End-mill Modeling and Manufacturing Methodology via Cutting simulation)

  • 김재현;박수정;김종한;박정환;고태조;김희술
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 추계학술대회 논문집
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    • pp.456-463
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    • 2005
  • This paper describes a design process of end-milling cutters: solid model of the designed cutter is constructed along with computation of cutter geometry, and the wheel geometry as well as wheel positioning data fur fabricating end-mills with required cutter geometry is calculated. In the process, the main idea is to use the cutting simulation method by which the machined shape of an end-milling cutter is obtained via Boolean operation between a given grinding wheel and a cylindrical workpiece (raw stock). Major design parameters of a cutter such as rake angle, inner radius can be verified by interrogating the section profile of its solid model. We studied relations between various dimensional parameters and proposed an iterative approach to obtain the required geometry of a grinding wheel and the CL data fer machining an end-milling cutter satisfying the design parameters. This research has been implemented on a commercial CAD system by use of the API function programming, and is currently used by a tool maker in Korea. It can eliminate producing a physical prototype during the design stage, and it can be used fur virtual cutting test and analysis as well.

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무증자 전분당화용 분쇄마찰매체 함유 효소반응기의 조작조건과 동력소모의 검토 (Evaluation of Operational Conditions and Power Consumption of a Bioattritor for Enzymatic Saccharification of Uncooked Starch)

  • 이용현;박진서
    • 한국미생물·생명공학회지
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    • 제17권4호
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    • pp.349-357
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    • 1989
  • 전분질을 당화시킬 때 유리구와 같은 분쇄마찰매체 (attrition-milling media)를 첨가하여 교반함으로써 생전분질 -효소 현탄액에 분쇄마찰효과를 주어 전분입자를 구조적으로 변화시켜 당화를 현저히 촉진시키는 적절한 무증자 당화법을 연구해오고 있다. 본 연구는 전분질의 무증자 당화에 적합한 고효율 및 저에너지 소모형 분쇄마찰매체 함유 효소반응기의 개발을 목포로, impeller를 갖춘 agitated bead type bloattritor를 설계 제작하여 그 효용성을 검토하였다. 무증자 옥수수전분을 기질로 당화에 적합한 bioattritor의 최적 조작조건을 검토하였고, 일정한 탄성계수를 지닌 spiral spring coil을 내장한 torque 측정장치를 개발하여 부하되는 torque 및 분쇄마찰 매체의 교반에 소요되는 energy를 측정하였고 중요 변수의 영향을 검토하였다. 또한 energy 소모와 생 전분의 효소당화 촉진효과와의 상관관계를 규명하였으며, bioattritor의 경제성을 전망하였다. 전분질의 최적 당화조건에서 분쇄마찰매체의 교반에 소요되는 동력은 1.53watt/ι로서 매우 적었다. 분쇄마찰매체 함유 효소반응계는 에너지 절약형 공정으로 사료되며, 이를 이용한 무증자 전분 효소당화공정의 산업적 활용 전망이 예상된다.

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복합형상 및 다중경로에 대한 Exit Burr 판별 알고리듬의 개발- 스플라인을 포함한 Exit Burr의 해석 - (Development of Exit Burr Identification Algorithm on Multiple Feature Workpiece and Multiple Tool Path)

  • 김지환;이장범;김영진
    • 산업공학
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    • 제18권3호
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    • pp.247-252
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    • 2005
  • In the automated production environment in the present days, the minimization of manual operation becomes a very important factor in increasing the efficiency of the production system. The exit burr produced through the milling operation on the edge of workpiece usually requires manual deburring process to enhance the level of precision of the resulting product. So far, researchers have developed various methods to understand the formation of exit burr in cutting process. One method to analytically identify the formation of exit burr was to use the geometrical information of CAD and CAM data used in automated machining. This method, in turn, generated the information resulting from the analysis such as burr type, cutting region, and exit angle. Up to now, the geometrical data were restricted to the single feature and single path. In this paper, a method to deal with the complicated geometric features such as line segment, arc, hole, and spline will be presented and validated using the field data. This method also deals with the complex workpiece shape which is a combination of multiple features. As for the cutting path, multiple tool path is analyzed in order to simulate the real cutting process. All this analysis is combined into a Windows based software and real data are used to validate the program in the conclusion.

표면노조 모델을 이용한 졍면밀링에서의 최적 이송속도 선정 (Determination of the Optimum Feed Rate by a Surface Roughness Model in a Face Milling Operation)

  • 백대균;고태조;김희술
    • 대한기계학회논문집A
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    • 제20권8호
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    • pp.2508-2515
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    • 1996
  • Determination of an optimal feed rate is valuable in the sense of the precision and efficient machining. In this regard, a new surface roughness model for the face milling operation that considered the radial and axal runouts of the inserts in the cutter body was developed. The validity of the model was proved through the cutting experiments, and the model is able to predict the real machined surface roughness exactly with the information of the insert runouts and the cutting conditions. From the estimated surface roughness value, the maximum feed rate that obtains a maximum naterial removal rate under the given surface roughness constraint can be selected by using a bisection method. Therefore, this mehod for optimizing the feed rate can be well applied to the using a bisection method. Therefore, this method for optimizing the feed rate can be well applied to the using selsction of the cutting condition during the NC data generation in CAM.

Statistical analysis and modelization of tool life and vibration in dry face milling of AISI 52100 STEEL in annealed and hardened conditions

  • Benghersallah, Mohieddine;Medjber, Ali;Zahaf, Mohamed Zakaria;Tibakh, Idriss;Amirat, Abdelaziz
    • Advances in materials Research
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    • 제9권3호
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    • pp.189-202
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    • 2020
  • The objective of the present work is to investigate the effect of cutting parameters (Vc, fz and ap) on tool life and the level of vibrations velocity in the machined part during face milling operation of hardened AISI 52100 steel. Dry-face milling has been achieved in the annealed (28 HRc) and quenched (55 HRc) conditions using multi-layer coating micro-grain carbide inserts. Statistical analysis based on the Response surface methodology (RSM) and ANOVA analysis have been conducted through a plan of experiments methodology using a reduced Taguchi table (L9) in order to obtain engineering models for tool life and vibration velocity in the workpiece for both heat treatment conditions. The results show that the cutting speed has a dominant influence on tool life for both soft and hard part. Cutting speed and feed per tooth is the most significant parameters for vibration levels. Comparing the experimental values with those predicted by the developed engineering models of tool life and levels of vibrations velocity, a good correlation has been obtained (between 97% and 99%) in annealed and hard conditions.

밀링작업에서 가공 안전성을 고려한 가공조건의 결정 (Determination of Cutting Parameters Considering Machining Safety in Milling Operation)

  • 박병태
    • 한국안전학회지
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    • 제21권6호
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    • pp.116-121
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    • 2006
  • 절삭가공에서 가공조건은 가공비용의 감소와 제품 품질의 향상에 영향을 주는 주요 요인 중의 하나이다. 일반적으로 공정설계자는 제품의 목표 품질을 만족하는 범위 내에서 비용을 줄일 수 있는 가공조건을 결정하기 위하여, 가공조건 핸드북 등에서 제공하는 표준 가공조건을 세부 공정별 요구 사항이 만족되도록 경험을 기반으로 수정한 후 작업자의 안전에 문제가 없는 지 검토한다. 본 논문에서는 공정설계자의 경험에 의해 수행되는 일련의 과정을 신경회로망 모델과 규칙에 의해 모델링한 작업설계시스템을 소개한다. 개발된 시스템은 각주형 부품의 밀링 작업에서 (1) 표준 가공조건을 세부 공정별 요구 사항이 만족되도록 신경회로망 모텔에 의해 수정하고, (2) 다음으로 작업자의 안전을 만족하도록 수정된 가공 조건을 필터링하는 모듈로 구성된다. 본 논문에서는 우선 개발된 밀링 작업설계시스템의 전반적인 기능을 간략히 소개한 후, 제안된 방법론에 의한 의사결정 과정을 자세히 기술한다. 마 지막으로 실제 적용 예를 통하여 개발된 시스템의 성능을 예시하도록 한다.