• Biotechnology and Bioprocess Engineering:BBE
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• 제5권2호
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• pp.118-122
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• 2000

A comlementary call line CR2 is curretly used to propagte the Disabled Infectious Single Cycle Herpes Simplex Virus Typee2 (DISC HSV-2) on a small Iaboratory scale upto 15 L. These cultures are initiated by passaging the cells from roller bottle cultures. Whilst this is suitable for the laboratory scale it is totally impractical for use in seeding an industrial manufacturing scaled version of the culture. It is paramount to have a robust system for passaging cells from a small microcarrierier culture system to a larger one by a serial subculturing regime. Here we report on the successes we have had in our laboratory in scaling up out production system for the DISC HSV-2 from small 1-L cultures to a 50-L vessel with the maintenance of the viral productivity. Ease of use, reproducibility and the need to minimise overall production time were factors which were taken into consideration whils developing our procedures. We were aware of the need to keep a production train simple and as short as possible as this was the amall scale study for an envisaged manufacturing process.

• 한국생산제조학회지
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• 제21권3호
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• pp.516-524
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• 2012

Selective Laser Sintering(SLS) system consists of various element technologies. Main components of the system include a position control system, a speed control system of the roller, and nitrogen atmosphere furtherance for the powdered sintering. Other systems which make the core of the SLS system are build room and the feed room for powder epitaxial, a temperature control system, and a scan path generator for the laser. The powder material for laser sintering is necessary to produce prototypes in Solid Freeform Fabrication(SFF) based on SLS process. This powder material is sintered in powder room using $CO_2$ laser after spreading evenly using roller to reproduce mold via SFF. This study addresses an SFF system by using the SLS process which applies single laser system to enable manufacturing of 3D shape. And to evaluate applicability of the single laser system, experiments were conducted with optimal fabricating process.

• 한국기계가공학회지
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• 제18권10호
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• pp.93-98
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• 2019

Recently, with the development of the aerospace and automotive industries, the demand for high-melting-point materials has increased. However, high-melting-point materials are difficult to cut through conventional machining methods. Thermally assisted machining (TAM) is a method for improving the machinability by preheating the materials. A laser, the most commonly used device for TAM, has high efficiency through local preheating but is not sufficient for maintaining a high preheating temperature due to rapid cooling. However, the use of multi-heat sources can supplement the disadvantage of a single heat source. The high preheating temperature can be maintained with a wide and deep heat-affected zone (HAZ) by multi-heat sources. The purpose of this study is to analyze the preheating effects of multi-heat sources using laser plasma. Thermal analysis and preheating experiments were carried out. As a result, the high preheating effect of multi-heat sources compared with a single heat source was verified.

• 한국생산제조학회지
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• 제7권1호
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• pp.58-68
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• 1998

Advantages of adhesively bonded joints and techniques of weight reduction have led to increasing use of structural adhesives such as LSI(large scale integration) package, automobile, aircraft in the various industries. In spite of such wide applications of adhesively bonded joints, the evaluation method of bonding strength has not been established. Stress singularity occurs at the interface edges of adhesively bonded joints and it is required to analyze it. In this paper, the stress singularity using 2-dimensional elastic boundary element method (BEM) with the changes of the lap length and adhesive for single lap joint was analyzed, and experiments of strength evaluation were carried out. As the results, the evaluating method of bonding strength considering stress singularity at interface edges of adhesively bonded joints and stress intensity factor of interface crack have been proposed in static and fatigue test.

• 한국기계가공학회지
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• 제10권1호
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• pp.47-53
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• 2011

From recent research, it has revealed that Electroacitve polymer(EAP) has a physical limitation. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. In this paper, we suggest the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. Using mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we disperse Single-walled carbon nanotubes(SWCNT). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. In the result, we fabricated a disperse SWCNT/Nafion composite uniformly.

• 대한안전경영과학회지
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• 제2권4호
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• pp.103-112
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• 2000

This research aims at the improvement of the manufacturing productivity of . kitchen furniture industry. W company deals with the orders of 2 types - the one is the batch order for mass production, and the other is the order of a customized single set. But, because the company has a single manufacturing system appropriate to mass production despite of the above 2 types-orders, the problems of increasing work-in-process, throughput time and material handling time were resulted in, and the overall productivity was generally low. We proposed a new material handling method to substitute the traditional one, the rearrangement of facility layout, and the introduction of a proper outsourcing method. This research results in about 80% increase in production quantity in the same period.

• 한국기계가공학회지
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• 제11권5호
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• pp.76-81
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• 2012

The continuing demand for increasingly slimmer and brighter liquid crystal display(LCD) panels has led to an increased focus on the role of the light guide panels(LGPs) or optical films that are used to obtain diffuse, uniform light from the backlight unit(BLU). And the most basic process in the production of such BLU components is the micromachining. LCD BLUs comprise various optical elements such as a LGP, diffuser sheet, prism sheet, and protector sheet with micro patterns. High aspect ratio patterns are required to reduce the number of sheets and enhance light efficiency, but there is a limit to the aspect ratio achievable for a given material and cutting tool. Therefore, this study comprised a series of experimental evaluations conducted to determine the machining feasibility in microcutting various aspect ratio patterns on electroless nickel plated die materials when using single-crystal diamond tools. Cutting performance was evaluated at various cutting speeds and depths of cut using different machining methods and machine tools.

• 대한산업공학회지
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• 제37권4호
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• pp.279-288
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• 2011

The past researches focused on the supply chain network that consists of factories, distribution centers and retailers for single product type. This research is required because the factory for single product type is advanced to reconfigurable type in order to produce various products, according to customers' various purchase forms and time. This research is also required because in the past researches, the material flows from factories to distribution centers and from distribution centers to retailers, but recently, there are material flows between distribution centers. The supply chain network in this research consists of reconfigurable manufacturing system, multi-layered distribution centers, and retailers. A simulator is developed to analyze the material flow on the supply chain network. The developed simulator is web-based designed by using Java Server Page and MS-SQL, so as to maximize the convenience for users.

• 한국생산제조학회지
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• 제19권6호
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• pp.731-738
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• 2010

Cavitation is described by formation and collapse of the bubbles in a liquid when the ambient pressure decreases. Formed bubbles grow and collapse by change of pressure, and when they collapse, shockwave by high pressure is generated. In general, bubble behavior can be described by Rayleigh-Plesset equation under adiabatic or isothermal condition and hence, phase shift by the pressure change in a bubble cannot be considered in the equation. In our study, a numerical model is developed from the mathematical model considering the phase shift from the previous study. In the developed numerical model, size of single spherical bubble is calculated by the change of mass calculated from the change of the ambient pressure in a liquid. The developed numerical model is verified by a case of liquid flow in a narrow channel.

• 한국기계가공학회지
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• 제10권2호
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• pp.90-95
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• 2011

This paper presents the study on the contact stress analysis of a pair of mating helical gears for turbo blower during rotation. Turbo blowers need high speed rotation of impeller in structure and high rate gear ratio. The use of helical gear indicated that noise was an important problem when the application involves high speeds and large power transmission. An example is presented to investigate the variation of contact stress on a pair of mating gears with contact positions. The variation of contact stress during rotation is compared with the contact stress at the lowest point of single tooth contact(LPSTC) and AGMA Equation for contact stress. In this study, the gear design considering the contact stress on a pair of mating gear is more severe than that of AGMA standard.