• Journal of Powder Materials
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• v.23 no.2
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• pp.149-169
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• 2016

Additive manufacturing (AM) is defined as the manufacture of three-dimensional tangible products by additively consolidating two-dimensional patterns layer by layer. In this review, we introduce four fundamental conceptual pillars that support AM technology: the bottom-up manufacturing factor, computer-aided manufacturing factor, distributed manufacturing factor, and eliminated manufacturing factor. All the conceptual factors work together; however, business strategy and technology optimization will vary according to the main factor that we emphasize. In parallel to the manufacturing paradigm shift toward mass personalization, manufacturing industrial ecology evolves to achieve competitiveness in economics of scope. AM technology is indeed a potent candidate manufacturing technology for satisfying volatile and customized markets. From the viewpoint of the innovation technology adoption cycle, various pros and cons of AM technology themselves prove that it is an innovative technology, in particular a disruptive innovation in manufacturing technology, as powder technology was when ingot metallurgy was dominant. Chasms related to the AM technology adoption cycle and efforts to cross the chasms are considered.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.89-95
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• 2019

In this research, the effect of roughing on tool load through bottom-up machining is investigated through actual machining. Generally, through the use of high-speed machining technology, machining methods, such as general roughing, operate by deepening the cutting depth for as long as the tool is able to withstand it, giving a slower feed rate, less cutting depth, and faster feed. However, when the cutting depth is deep, there is a problem in that the stepped shape of the cutting area is increased (e.g., by the shaking of the tool or the chipping load). However, if the cutting is performed less, the cutting time becomes relatively long. To compensate for these drawbacks and extend the service life of the tool, economic efficiency needs to be secured.

• KIEAE Journal
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• v.12 no.3
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• pp.95-100
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• 2012

Thermal phenomena has caused abnormal weather phenomena due to the lack of urban green spaces To solve these problems, the country of recorded a city business is actively evolving trends. but in all the land, most built-up city's green buildings unless the demolition of the composition is an impossible situation, green space in urban areas, with emphasis on composition. In this study, thermal power plants that occured in the evolution of vegetation by utilizing Bottom Ash was tried to develop a lightweight block. Bottom Ash block to take advantage of vegetation is focused create green space in urban areas Vegetation in the block was carried out manufacturing lightweight, porous, lightweight water ratio suitable for three types of blocks selected according to its kind study on the manufacturing and process. Bottom Ash from this study at the time of disposal of coal ash generated by recycling the landfill shortages, loss of landfill costs, environmental pollution and are trying to solve the same problem at the same time.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.127-133
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• 2005

Manufacturing methods of Nano particles can be distinguished by top-down technology as physical method and bottom-up technology as chemical synthetic method. Top-down technology is a kind of method for making microstructure as like carving after forming a macroscopic structure in advance and its typical methods are ball milling, gas condensation method and so on. Nano Particles synthesized by bottom-up method have got to do dispersing process for using them as actual nano particles because their viscosity are very strong and so easy to shape cohesive substances. Therefore, this study is about a particle separating device which separates a certain constant size of grains processed already in mill and mixer because we mostly use media agitating mill as a device of milling and dispersing and we necessarily use very slight balls as media for manufacturing nano particles in the machine. The centrifugal device has been designed for passing and separating below a certain type of grain size after final process of particles in the mill.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.164-165
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• 2015

Modular construction technique is an adaptation of factory-based mass production concept in ordinary manufacturing industries to construction industry and it assumes that panels, units, etc. are fabricated in factories and assembled in construction sites. Given its structural limitations, modular construction technique is primarily used in low-story buildings whose maximum height is usually five stories, but researchers are actively studying possible adaptation of modular construction technique to high-rise building designs these days as in the case of infill-type modular construction design. Infill-type modular construction technique, most frequently used in high-rise building construction projects, completes frame construction first in reinforced concrete structures and fills unit modules in such structures. However, infill-type modular construction technique leads to longer construction schedule accompanying increase in construction cost, cost overrun due to additional of temporary work, and possible damage to units in the wake of facility construction. Accordingly, this study is performed as a basic study for the development of bottom-up infill-type modular construction technique intended to construct structural frames and fill in units sequentially in a bid to address such drawbacks of current infill-type modular construction technique.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.401-407
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• 2012

The recent manufacturing process in the thin wafers and flat panel necessitate new approaches to reduce handling fragile and surface-sensitive damage of components. This paper presents a new pneumatic levitation for non-contact handling of parts and substrates. This levitation can achieve non-contact handling by blowing air into an air pressure pick-up head with radial passages to generate a negative pressure region. Negative pressure is caused by the radial air flow by nozzle throat and through holes connecting to the bottom region. The numerical analysis deals with the levitational motion with different design factors. The dynamic motion is examined in terms of force balance(dynamic equilibrium) occurring to the flow field between two objects. The stable equilibrium position and the safe separation distance are determined by analyzing the local pressure distribution in the fluid motion. They make considerable design factors consisting the air pressure pick-up head. As a result, in case that the safe separation distance is beyond 0.7mm, the proposed pick-up head can levitate stably at the equilibrium position. Furthermore, it can provide little effect of torque, and obtain more wide picking region according to the head size.

• Journal of Powder Materials
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• v.30 no.2
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• pp.156-168
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• 2023

The semiconductor industry faces physical limitations due to its top-down manufacturing processes. High cost of EUV equipment, time loss during tens or hundreds of photolithography steps, overlay, etch process errors, and contamination issues owing to photolithography still exist and may become more serious with the miniaturization of semiconductor devices. Therefore, a bottom-up approach is required to overcome these issues. The key technology that enables bottom-up semiconductor manufacturing is area-selective atomic layer deposition (ASALD). Here, various ASALD processes for elemental metals, such as Co, Cu, Ir, Ni, Pt, and Ru, are reviewed. Surface treatments using chemical species, such as self-assembled monolayers and small-molecule inhibitors, to control the hydrophilicity of the surface have been introduced. Finally, we discuss the future applications of metal ASALD processes.

• Journal of Powder Materials
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• v.26 no.6
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• pp.528-538
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• 2019

The transition from "More-of-Less" markets (economies of scale) to "Less-of-More" markets (economies of scope) is supported by advances of disruptive manufacturing and reconfigurable-supply-chain management technologies. With the prevalence of cyber-physical manufacturing systems, additive manufacturing technology is of great impact on industry, the economy, and society. Traditionally, backbone structures are built via bottom-up manufacturing with either pre-fabricated building blocks such as bricks or with layer-by-layer concrete casting such as climbing form-work casting. In both cases, the design selection is limited by form-work design and cost. Accordingly, the tool-less building of architecture with high design freedom is attractive. In the present study, we review the technological trends of additive manufacturing for construction-scale additive manufacturing in particular. The rapid tooling of patterns or molds and rapid manufacturing of construction parts or whole structures is extensively explored through uncertainties from technology. The future regulation still has drawbacks in the adoption of additive manufacturing in construction industries.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.389-395
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• 2005

The etching technology of the high aspect ratio contact(HARC) is necessary at the critical contact processes of semiconductor devices. Etching the $SiO_{2}$ contact hole with the sub-micron design rule in manufacturing VLSI devices, the unexpected phenomenon of 'profile tilting' or 'bottom distortion' is often observed. This makes a short circuit between neighboring contact holes, which causes to drop seriously the device yield. As the aspect ratio of contact holes increases, the high C/F ratio gases, $C_{4}F_{6}$, $C_{4}F_{8}$ and $C_{5}F_{8}$, become widely used in order to minimize the mask layer loss during the etching process. These gases provide abundant fluorocarbon polymer as well as high selectivity to the mask layer, and the polymer with high sticking yield accumulates at the top-wall of the contact hole. During the etch process, many electrons are accumulated around the asymmetric hole mouth to distort the electric field, and this distorts the ion trajectory arriving at the hole bottom. These ions with the distorted trajectory induce the deformation of the hole bottom, which is called 'profile tilting' or 'bottom distortion'. To prevent this phenomenon, three methods are suggested here. 1) Using lower C/F ratio gases, $CF_{4}$ or $C_{3}F_{8}$, the amount of the Polymer at the hole mouth is reduced to minimize the asymmetry of the hole top. 2) The number of the neighboring holes with equal distance is maximized to get the more symmetry of the oxygen distribution around the hole. 3) The dual frequency plasma source is used to release the excessive charge build-up at the hole mouth. From the suggested methods, we have obtained the nearly circular hole bottom, which Implies that the ion trajectory Incident on the hole bottom is symmetry.

• 전기의세계
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• v.43 no.3
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• pp.10-17
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• 1994

패트리네트는 시스템의 관계를 시작적으로 보여주어 시스템의 모델링을 쉽게 만든다. 시스템의 각 부분에 관한 정보를 가지고 전체와 부분에 대하여 하향식(top-down)과 상향식(bottom-up) 설계를 할 수 있게 해준다. 패트리네트는 그래프 표현이므로 FMS(flexible manufacturing systems)등과 같은 실시간 제어(real-time control)의 구현에 사용될 수 있으며 토큰 정보로부터 시스템의 각 부분의 상태를 실시간 감시(monitoring)할 수 있다. 패트리네트는 PLC(programmable logic controller)와 같이 여러 요소시스템(subsystem)을 순서대로 동작시키고 조정한다. 시스테메 대한 페트리네트 모델로부터 시뮬레이션(simulation)을 할 수 있고, 이로부터 성능 평가를 할 수 있다.