Additive manufacturing is a new approach to design and production. This applies in particular to processes such as repair and rework of selected components. Additive manufacturing can produce almost any shape, and from an MRO part perspective, additive manufacturing offers tremendous advantages. The special feature of additive manufacturing is that it is particularly economical for small-volume production as the number of units is irrelevant compared to the existing manufacturing process. The purpose of this study was started from the MRO point of view, and it Identify changes and respond to the Blisk It is a study on the effect of changing the conditions on the path of the toolpath and the CAM during additive manufacturing using CAM after finding suitable conditions. metal powder.The metal powder withstands various corrosive environments and age hardening occurs very slowly. Inconel 718, which can be used in various applications such as nuclear facility-related parts, aerospace, oil facilities, turbines, and valves, was used. This is SUS 316L with good high temperature strength. The variable of the laser used in the study is the laser power, and the variables on the CAM are Operation, Stepover, Pattern, etc. In the relation between laser power and feed, when feed is specified as 500mm/min, laser power of 700W was most suitable. As for the conditions on NX CAM, ADDITIVE PROFILE Stepover was 0.8mm for Operation, and Infills and Finish for Pattern. When stacking, each layer should be overlapped with the result. Therefore, the stepover should be smaller than the laser spot size and reprocessing should be done in terms of repair, so infills and finish were applied to work larger than the actual product shape.
The process optimization of directed energy deposition (DED) has become imperative in the manufacture of reliable products. However, an energy-density-based approach without a sufficient powder feed rate hinders the attainment of an appropriate processing window for DED-processed materials. Optimizing the processing of DEDprocessed Ti-6Al- 4V alloys using energy per unit area (Eeff) and powder deposition density (PDDeff) as parameters helps overcome this problem in the present work. The experimental results show a lack of fusion, complete melting, and overmelting regions, which can be differentiated using energy per unit mass as a measure. Moreover, the optimized processing window (Eeff = 44~47 J/mm2 and PDDeff = 0.002~0.0025 g/mm2) is located within the complete melting region. This result shows that the Eeff and PDDeff-based processing optimization methodology is effective for estimating the properties of DED-processed materials.
본 연구에서는 전처리 방법별 건조 단호박의 이화학적 특성을 비교 분석하고 반응표면분석법을 이용하여 단호박 말랭이의 최적 건조 조건을 설정하였다. 단호박의 이취 제거와 가공적성을 위한 건열(굽기), 습열(증자), 마이크로웨 이브 처리의 전처리 방법을 비교하고자 호화 점도를 측정 하여 전처리 시간을 설정하였다. 각 전처리 방법별 열풍 건조 전후의 단호박 품질특성을 비교한 결과, 마이크로웨이브 처리에서 가용성 고형분, 과당, 포도당, 자당 함량이 건열과 습열 처리보다 높았고, 수분 함량, 강도 및 경도가 낮게 나타나 마이크로웨이브 처리를 단호박 열풍 건조를 위한 최적의 전처리 방법으로 설정하였고 반응표면분석법을 이용하여 최적의 열풍 건조 조건을 확인하였다. 반응표면분석은 중심합성 계획법으로 실험을 디자인하여 독립변수로서 건조 온도(30, 40, 50oC, X1)와 건조 시간(4, 6, 8 h, X2)을 설정하고, 종속변수로는 건조 단호박의 수분 함량, 수분활성도, 가용성 고형분, 강도, 경도, 과당, 포도당, 자당 함량, 색도(L*, a*, b*)를 측정하여 건조 조건을 최적화하였다. 최적화 변수로는 적합성 결여 검증에서 Pr> F 값이 0.05 이상인 수분 함량, 수분활성도, 가용성 고형분을 최적화 변수로 설정하였으며, 최적화 결과 43oC의 온도와 7.2시간이 최적 건조 조건으로 확인되었고, 예측값과 실험 값을 비교한 결과 90% 이상의 최적 비율을 보였으며, 해당하는 값이 95% 신뢰구간과 예측구간 범위에 들어 실험 디자인과 모델의 적합성 또한 검증되었다.
Forged part made of Cold heading quality wire materials are used for automotive brake systems. The cost reduction of forged products is a major issue because of the strict shape change. A series of studies were conducted to minimize the cost of EPB spindle process among brake parts. In order to reduce the material cost, heat treatment-abbreviated material was applied and the formability on the processes was verified by the ductile fracture theory. In addition, the causes of shape fixation and die life degradation were analyzed using the numerical simulation. The process cost has been minimized by re-designing process, changing the product shape, and the die material.
The purpose of this study was to optimize the mandarin dry chip manufacturing using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the drying temperature (X1, 50-90oC), drying time (X2, 12-36 hours), and microwave pretreat time (X3, 0-4 minutes). The results of appearance (Y5), color (Y6), taste (Y8) and overall acceptance (Y10) were fitted to the response surface methodology model (R2=0.86, 0.88, 0.89, and 0.84, respectively). Increasing the drying temperature and microwave treatment time were negatively evaluated for consumer acceptance. On the other hand, a high value of consumer acceptance was evaluated when the drying time was more than 24 hr. Therefore, the optimal conditions of X1, X2, and X3 were 52.989oC, 24 hr, and 1 min, respectively. Under these optimal conditions, the predicted values of Y5, Y6, Y8, and Y10 were 5.066, 5.338, 5.063, and 5.339, respectively.
A사는 발전 플랜트, 오수처리장, 취수, 정수, 배수장, Oil Plant 등 국가 기간 산업현장에서 사용되는 전동 액추에이터를 제조하고 있다. A사가 각 수요처별로 각기 다른 기능을 필요로 하는 Order에 대응하여 제품을 생산하고자 기존의 A사가 적용하고 있는 생산방식인 라인로트생산방식이 가지고 있는 문제점을 파악하여 개선하고자 한다. 본 연구를 통해 시장과 고객의 요구에 유연하게 대응할 수 있도록 다품종 소량생산에 적합한 셀 생산방식으로 변경을 통하여 생산유연화와 생산성향상을 이룰 수 있었다. 이러한 개선을 통하여 다변화하는 고객의 요구에 실시간으로 대응 할 수 있음은 물론이고 생산성향상과 그에 따른 이익창출을 이뤄낼 수 있는 계기가 될 것이다. 또한 A사의 생산 작업자의 업무 능력배양에 긍정적으로 작용하여 일을 하는 재미와 이에 따른 보상의 기대치를 높일 수 있는 계기로 작용하였다.
This paper deals with the production plan for the foaming process, the core part of the refrigerator manufacturing process. In accordance with this change, the refrigerator manufacturing process has also been converted into the mixed-model production system and it is necessary to optimize the production release pattern for the foaming process. The pattern optimization is to create a mixed-model combination which can minimize the number of setup operations and maintain mixed-model production. The existing method is a simple heuristic that depends on the demand priority. Its disadvantages are low mixed-model configuration rate and high setup frequency. Therefore, demand partitioning occurs frequently. In this study, we introduce the tolerance concept and propose a new pattern optimization algorithm based the large neighborhood search (LNS). The proposed algorithm was applied to a refrigerator plant and it was found that mixed-model configuration rate can be improved without demand partitioning.
A study was conducted for optimization of the process for the manufacture of raw noodle added with leaf powderof Cirsium setidens Nakai, which is rich in various minerals and dietary fibers along with intrinsic antioxidativeproperties. The level of leaf powder, water content, and kneading time of the dough were selected as three majorfactors affecting quality of the product. Quality parameters of the product such as color, texture, water absorptionratio, volume, turbidity of cooking water, and sensory evaluation result were analyzed as dependent variables. D-optimum design of the complete RSM analyses was adopted for designing the optimum noodle manufacturing pro-cedure. Ranges of the independent variables as determined through preliminary experimental work were level of leafpowder, 2-9% (w/w, wheat flour); moisture content, 40-50%; and kneading time, 7-20 min. Within the given rangesof these independent variables, 18 experimental points included in four repetitive runs were obtained for the anal-yses. The optimum conditions that together satisfy the quality parameters of the raw noodle, as based on the numer-ical and graphical statistical analyses, were amount of leaf powder, 5.76%; water content, 42.52%; and kneadingtime 13.86 min. The complete RSM analysis for manufacture of the high quality raw noodle with an added ingre-dient is suitable for similar application to other products in the industry.
In this paper, we optimize simulation model of a manufacturing system using the real-coded genetic algorithm. Because the manufacturing system expressed by simulation model has stochastic process, the objective functions such as the throughput of a manufa
시뮬레이션은 분석적인 방법으로 해결할 수 없거나 표현하기가 어려운 문제를 현실 세계와 최대한 비슷하게 컴퓨터상에서 모델링하고, 결정 변수에 대한 시뮬레이션을 수행하여 수행도 결과를 주는 방법이다. 그러나 시뮬레이션은 시스템 수행도를 최적화할 수 있는 결정 변수의 값을 찾아주지 못하는 단점이 있다. 이러한 시뮬레이션 기법의 문제점을 해결하고자 최적화 기법을 시뮬레이션에 적용하여 사용하는 것이 일반적인 방법이다. 그러므로 본 논문에서는 최적해를 탐색시에 개체군을 사용하기 때문에 전역적 해를 찾을 확률이 다른 기법들보다 높은 유전자 알고리즘을 시뮬레이션에 적용시킨다.
본 연구에서는 제약 조건을 갖는 문제에서는 이진 코딩 유전자 알고리즘 보다 효과적이라고 알려진 실수 코딩 유전자 알고리즘을 생산 시스템의 시뮬레이션 최적화에 적용한다. 실수 코딩 유전자 알고리즘의 적용시에 재생산 연산자는 교체를 수반한 잔여확률분포 선택 기법을 사용하고, 교배 연산자는 단순 교배 기법을 사용한다. 돌연변이 연산자는 세대에 따라 탐색 영역을 조절해 줄 수 있는 동적 돌연변이 기법을 사용한다.
The catalytic activity of Ni-0.2%YSZ (Yttria-Stabilized Zirconia) with different promoters was evaluated for CO2 methanation. The catalysts were weighed for mixing and they were dried at 110 for molding into disks. The concentration of CO2 and CH4 for conducting of CO2 methanation were analyzed by gas chromatography and the physical characteristics of the disk-type catalyst formed were analyzed by X-ray diffraction, scanning electron microscope and energy dispersive x-ray spectrometer. The addition of CeO2 as a promoter for Ni-0.2%YSZ (denoted as Ni-5%Ce-0.2%YSZ) resulted in the highest CO2 methanation. It also showed catalytic activity at a low temperature(200°C). Following this, ZrO2, SiO2, Al2O3 and TiO2 were added to Ni-5%Ce-0.2%YSZ to compare the CO2 methanation, and the highest efficiency was found for. Ni-1%Ti-5%Ce -0.2%YSZ Then, the concentration of Ti was increased to 10% and the catalytic activity was estimated using seven different types of commercial TiO2. In conclusion, ST-01 TiO2 showed the highest efficiency for CO2 methanation.
뜰보리수를 이용한 가공식품을 개발하기 위한 연구의 일환으로 뜰보리수 추출물과 현미식초를 혼합한 음료를 개발하기 위하여 혼합비에 따른 이화학적 품질 특성을 분석하여 혼합조건을 최적화 하고자 하였다. 중심합성계획법에 의하여 설계된 실험조건에 따라 제조된 혼합음료의 당도는 9.77-11.5 , pH 는 3.0정도 이었다. 음료의 색도는 뜰보리수의 추출물의 함량에 따라 약간 증가하였으며, 총산의 함량은 현미식초의 혼합정도에 따라 증가하였다. 총페놀성 물
뜰보리수의 부가가치 향상과 새로운 식품자원의 개발을 위한 뜰보리수 추출물과 현미식초의 혼합음료를 개발하고자 혼합조건에 따른 관능적 품질특성을 분석하여 제조조건을 최적화 하고자 차였다. 음료의 색, 풍미, 맛 그리고 기호도는 뜰보리수 추출물의 함량이 낮을 경우 유의성이 있게 가장 높은 기호도를 보였다. 풍미는 현미식초의 함량이 적을수록 높았으며, 맛은 색도와 같이 뜰보리수의 함량이 낮은 혼합구에서 가장 높았다. 음료의 기호도는 뜰보리수 추출물의 함량이 낮