• 한국CDE학회논문집
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• 제21권2호
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• pp.122-129
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• 2016

4D printing is a method that manufactures a programmed transformable 3d printed components that can be transformed in a pre-designed environment. We propose a service-oriented web architecture for supporting 4D printing system. Service model is classified under four kinds of functions: design, sharing, application and production. We designed RESTful web APIs for these functions. Some preliminary designs about the web API architecture and data modeling is discussed.

• 한국기계가공학회지
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• 제17권5호
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• pp.143-148
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• 2018

3D printing has been expanding beyond the bio/nano field to the automobile and aviation industries. 3D-printing technology has to overcome real problems to have economic value compared to its unlimited usability. Typically, the difference in mechanical strength along the lamination direction requires sufficient research to ensure reliability. In this paper, we study the anisotropic properties of ABS based on the stacking method of FDM 3D printing. Specifically, the mechanical properties of ABS material are determined through a tensile test and 3-point bending test, and the in-plane orthotropic properties are ascertained.

• 한국재료학회지
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• 제12권6호
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• pp.499-507
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• 2002

The carbon nanotube emitters for field emission displays were fabricated by using screen printing techniques. The pastes for screen printing are composed of organic binders, carbon nanotubes (multiwalled or singlewalled), and some additive materials. The pastes were printed on Cr-coated/Ag-printed soda-lime glass substrates. From the I-V characteristics, the turn-on field of SWNT was lower than that of MWNT. The decrease in the mesh size of screen masks (i.e. increase in the opening size of the screen mesh) resulted in decreasing the turn-on field and increasing the electron emission current. When the carbon nanotubes were mixed with silver pastes, silver powders appeared to contribute to the vertically aligning of carbon nanotubes on a glass.

• 한국기계가공학회지
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• 제17권5호
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• pp.117-122
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• 2018

3D printing technology and its applications have grown rapidly in academia and industry. We consider a 3D printing system designed for the selective laser sintering (SLS) method, which is one of the powder bed fusion (PBF) techniques to build up the final product by layering sintered powder slices. Thermal distortion of printing products is a critical challenge in 3D printing. This study investigates temperature-dependent conformational behaviors of 3D printed samples of sintered poly-ether-ether-ketone (PEEK) powders using molecular dynamics simulations. The wear and chemical resistance properties of PEEK are understood, as it is a well-known biocompatible material used for implants. However, studies on physical phenomena at nanoscale in PEEK are rarely published in public. We simulate dissipative particle dynamics to elucidate how a cavity regime forms in PEEK at different system temperatures. We demonstrate how PEEK structures deform subject to the system temperature distribution.

• 동력기계공학회지
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• 제9권4호
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• pp.162-167
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• 2005

The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that are cost less and faster than previous semiconductor processes have been developed for the production of electric paper and RFID(Radio Frequency IDentification). The system proposed in this study prints by spraying the molten metal. And this system consist of a nozzle, heating furnace, operating actuator and an XYZ 3-axis stage. As an operating system, the piezoelectric(PZT) actuator is a very useful tool for position control of the metal printing system. However, the PZT actuator has a hysteresis nonlinearity due to the ferroelectric characteristics of the PZT element. This hysteresis causes problem position control characteristics in the system and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. In order to reduce the hysteresis nonlinearity of the PZT actuator, this proposed a inverse hysteresis model and a mathematic modeling method that can express the geometric relationship between voltage and displacement. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good tracking performance.

• 대한기계학회논문집A
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• 제36권12호
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• pp.1563-1568
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• 2012

인쇄전자는 RFID 나 유연 디스플레이 등의 전자회로나 소자를 인쇄방식으로 제작하는 공정이다. 특히 롤투롤과 같은 웹 이송방식 프린팅은 얇은 필름형태의 웹(Web)에 그라비아 인쇄나 고속 잉크젯과 같은 방법으로 이송중인 웹 상에 회로를 형성하는 공법이다. 이 공정은 생산단가가 저렴하고 고속생산이 가능하다는 이점이 있다. 다층구조를 가지는 회로나 디바이스를 생산할 때, 층과 층을 얼마나 정확하게 중첩시켜 인쇄하는가 하는 것은 인쇄된 전자회로의 집적도와 성능을 결정짓는 중요한 요소이다. 인쇄전자공법을 상용화하기 위해서 높은 중첩정밀도 구현이 선행되어야 한다. 본 연구에서는 롤투롤 인쇄방식에서 중첩정밀도의 향상을 위한 위치측정 시스템을 제안하고 신뢰성을 확인하였다. 또한 웹이 변형되었을 때의 측정 강인성도 실험적으로 확인하였다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.25-28
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• 2003

최근 생활수준의 향상과 함께 고기능성, 고감성의 제품이 요구되고 또한 소비패턴의 고급화, 다양화, 개성화와 함께 단시간의 유행변화에 신속하게 대응하기 위하여 섬유날염면에서도 다양한 색상과 디자인이 요구되고 있다. 그러나 기존의 rotary printing system에 의한 날염기술은 이러한 요구에 다양하고 신속한 대응을 할 수 없으므로 새로운 날염기술의 개발이 요구되었고 이에 xerography printing에 의한 직물날염이 주목받게 되었다. (중략)

• 산업경영시스템학회지
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• 제27권1호
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• pp.32-37
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• 2004

A new display device is required, which has concepts of flatness and slimness. FED can be one of the solutions. When we use flat panel, we can save the raw material and reduce the production time by eliminating the printing process, drying process, and washing process. In this case, good panel flatness and consistency with panel flatness and black matrix is the precondition. Therefor, we analyzed process capability of panel flatness and regression between panel flatness and BM position by experiments.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.209.1-209.1
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• 2005

• 한국인쇄학회지
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• 제12권1호
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• pp.57-68
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• 1994

In the last decade, digital image processing technics have been rapidly developed according to the advancement of electronic technique, and total scanner and DTP system were developed. Specially, there is need to retouch the color and image on the CRT. In this paper, we described a method to display surface color of printing on the CRT, and an algorithm to simulate the color reproduction by offset printing. The experimental results show that the described method and algorithm are useful and valid on the computer simulation of the multi-color printing adapted process ink characteristics.