• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.52-57
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• 2000

STD11 is one of difficult-to-cut materials and its cutting characteristic data is not built enough. A bad cutting condition of it leads to low productivity of die and mould, so it is necessary to evaluate the machining characteristics of STD11. In this paper, the relations of the geometry of ball-end mill and mechanics of machining with it are studied. The helix angle of ball-end mill varies according to a location of elemental cutting edge in the cutting process are difficult to calculate accurately. To calculate instantaneous cutting forces, it is supposed that the tangential, radial and axial cutting force coefficients are functions of elemental cutting edge location. Elemental cutting forces in the x,y and z direction are calculated by coordinate transformation. The total cutting forces are calculated by integrating the elemental cutting forces of engaged cutting edge elements. This model is verified by slot and side cutting experiments of STD11 workpiece which was heat-treated to HRC45.

• 한국전기전자재료학회논문지
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• 제37권1호
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• pp.36-42
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• 2024

롤투롤 공정은 제조 환경에서 필수적인 위치를 차지하고 있으며, 그 중요성은 수많은 산업에 걸쳐 반향을 일으키고 있다. 이 다목적 기술 플랫폼은 다양한 공정 방법을 포괄하고 광범위한 재료 범주를 수용하여 현대 생산의 초석이 되고 있다. 이 광범위한 영역에서 일반적으로 사용되는 두 가지 코팅 기술인 슬롯 다이와 그라비아 코팅 방식은 완벽한 코팅을 구현하는 정밀도와 효율성으로 각광받고 있다. 또한 건조 공정은 열 건조, 적외선(IR) 건조, 자외선(UV) 건조 방식에 크게 의존하여 재료를 액체 또는 반액체 상태에서 바로 사용할 수 있는 고체 제품으로 신속하게 전환한다. 롤투롤 공정의 중요성은 제조 공정을 간소화하고 비용을 절감하며 제품 품질을 향상시킬 수 있다는 점이 있다. 이 글에서는 이러한 일반적인 롤투롤 공정 방법의 복잡성에 대해 자세히 살펴봄으로써 이러한 중요성의 깊이를 파악하고자 한다. 엄격한 연구와 세심한 데이터 수집을 통해 이러한 기술이 다양한 산업을 형성하고 제조 세계를 발전시키는 데 중추적인 역할을 하는 것을 조명하고자 한다. 롤투롤 공정의 중요성을 이해함으로써 롤투롤 공정의 잠재력을 최대한 활용하고 생산 혁신과 우수성을 위한 기반을 마련할 수 있을 것이다.

• 멤브레인
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• 제34권1호
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• pp.79-86
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• 2024

고분자 분리막의 대표적인 형태 중 하나인 평판형 분리막은 제조가 용이하여 실험실에서 분리막 소재 연구에서부터 실제 상용 분리막 생산에 이르기까지 널리 활용되는 분리막의 형태이다. 정밀여과 및 한외여과 등에 사용되는 평판형의 다공성 고분자 분리막은 주로 상분리 공정을 통해 제조할 수 있으며, 여기에는 비용매 유도 및 증기 유도 상분리 공정이 활용된다. 그러나 상분리 공정 특성상 주변 환경과 실험자에 따라 샘플 간 편차가 쉽게 발생하여 재현성의 확보가 어려운 점이 있다. 따라서 개발된 제조기술을 스케일업 및 재현성 확보를 위해 제어된 환경에서 연속식 대면적 제조가 가능한 롤투롤 제조장치가 필요하며, 본 연구에서는 실험실 스케일의 제조기술을 나이프 및 슬롯다이 롤투롤 공정으로 스케일 업 했을 때 나타나는 제조 환경 차이에 따른 분리막의 특성 변화를 비교하였다. 최종적으로 연속식 제조공정 인자에 대한 최적화를 통해 대면적 제조 시 분리막의 균일성을 확보하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.912-916
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• 2000

The term ‘High Speed Machining’has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry fur the machining of light alloys, notably aluminium. In recent you, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. And the end mill is an important tool in the milling process. A typical examples for the end mill is the milling of pocket and slot in which a lot of material is removed from the workpiece. Therefore the proper selection of cutting parameter fur end milling is one of the important factors affecting the cutting cost. The one of the advantages of HSM is cutting thin-walled part of light alloy like Al(thinkness about 0.1mm). In this paper, firstly, we study characteristics of HSM, and then, we choose the optimal parameters(cutting forces) to cut thin-walled Al part by experiment.

• Progress in Superconductivity
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• 제6권2호
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• pp.142-145
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• 2005

YBCO coated conductors have been fabricated with a newly developed oxide-precursor-based MOD process. The precursor solution was synthesized with low cost YBCO powders as starting materials and YBCO coated conductors have been deposited on IBAD substrate ($CeO_2$/IBAD-YSZ/SS). YBCO coated conductor prepared by dip coating shows transport $I_c$ of 15A/cm-w at 77 K. Microstructural and crystallographic analyses indicate that YBCO layer was grown in epitaxy with substrate and exhibited well-developed dense microstructure. Also discussed are processing and analysis of YBCO coated conductor by slot-die web coating method. It was shown that this oxide-based MOD process provides a low cost route to coated conductor with high $J_c$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.705-706
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• 2008

There has been, in recent years, effort to make cast copper rotors for industrial use of induction motors. Because the incorporation of copper for the conductor bars and end rings of the induction motor in place of aluminum would result in attractive improvements in motor energy efficiency. The purpose of this method is a reducing the copper loss as using higher conductivity of copper. In this paper as the single phase induction motor is studied, the stator slots and coil turn number is designed for adjusting the slot fill factor and improving its efficiency. At this time design is basis on calculation of reducing loss. And finally this paper shows that the before and after result is compared and analyzed.

• Progress in Superconductivity
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• 제8권1호
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• pp.22-26
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• 2006

Total Fluorine content in the precursor solution for MOD processing of YBCO coated conductors can be significantly reduced by synthesizing precursor solution with F-free Y & Cu precursor and Barium trifluoroacetate(TFA). It was shown that crack-free and uniform precursor films were formed after calcinations in humidified oxygen atmosphere. Less than 2 hours are required to finish the calcination process, and XRD measurement shows that $BaF_2,\;CuO,\;and\;Y_2O_3$ are major constituent of calcined precursor films. Film thickness after calcination was measured to be ${\sim}2.8$ um by applying slot-die coating method. In particular, addition of Samarium shows critical current of Ic=226 A/cm-w($Jc=3.4\;MA/cm^2$). Also discussed are recent developments in the reel-to-reel processing using F-free Y & Cu precursor solutions. It is shown that uniform and fast processing route to YBCO coated conductor with high Ic can be provided by employing F-free Y & Cu precursor solutions in MOD process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.19-20
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• 2006

As the Mobile and Display technology are being developed quickly, new wireless devices are released in great numbers. They reduce existing devices' life time and demand a reduction of developing period of portable devices. With these demands, existing film cutting mold used many films of portable devices, especially LCD Display, needs to be more precise, and cheaper. In this research, we have analyzed machining characteristics of cutter shapes, materials, and cutting conditions for application to other films. Cutter edge was machined by slot cutting method and CAD program to select the cutter shape and cutter angle. Also, we have determined the optimal cutting conditions using high speed machining experiments to improve the productivity.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.343-348
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• 2000

The term‘High Speed Machining’has been used for many years to describe end milling with small diameter tools at high rotational speeds. typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent years, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. And the end-mill is an important tool in the milling process. A typical examples for the end mill is the milling of pocket and slot in which a lot of material is removed from the workpiece. Therefore the proper selection of cutting parameters for end milling is one of the important factors affecting the cutting cost. The one of the advantages of HSM is cutting thin-wall part of light alloy like Al (thinkness about 0.3mm). In this paper, firstly, we study characteristics of HSM, and then, we choose the optimal parameters(cutting forces) and investigate various machining strategies to cut thin-wall part by experiment.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.100-104
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• 2019

We have investigated the feasibility of fabricating fine stripes using needle coating for potential applications in solution-processed organic light-emitting diodes (OLEDs). To this end, we have employed an aqueous poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) solution that has been widely used as a hole injection layer (HIL) of OLEDs and performed needle coatings by varying the process parameters such as the coating gap and coating speed. As expected, the stripe width is reduced with increasing coating speed. However, the central thickness of the stripe is rather increased as the coating speed increases, which is different from other coating processes such as slot-die and blade coatings. It is due to the fact that the meniscus formed between the needle tip and the substrate varies depending sensitively on the coating speed. It is also found that the stripe width and thickness are reduced with increasing coating gap. To demonstrate its applicability to OLEDs, we have fabricated a red OLED stripe and obtained light emission with the width of about 90㎛.