• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.23.2-23.2
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• 2010

Researches on the drying of particle/polymer suspensions receive attentions in technical applications such as manufacturing display and batteries. In this study, the effect of polymers on drying behavior of silica/poly(vinyl alcohol) suspension was investigated in terms of suspension stability and stress development during drying. The effect of polymer adsorption was studied by changing pH. More strongly flocculated suspension with lower pH became more dispersed and close-packed film after drying. Evaluation of potential energy allows us to suggest that the adsorbed polymers which bridge the particles introduce steric repulsion and lead flocculated suspension to dispersed film. When the effect of adsorption kinetics was studied by changing the mixing time, the adsorption amount, characteristic stress and dried film density showed a similar behavior in the form of with a single characteristic time. It implies that the drying process can be determined by simple characteristic equation with a single time constant.

• IE interfaces
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• v.12 no.1
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• pp.121-131
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• 1999

In this article, a simulation model of a microwave oven assembly line is developed to identify system parameters to improve the system performances such as work-in-process inventories, production lead time, mean earliness, mean tardiness and in-time completion rate. System parameters investigated include dispatching rules, lot sizing, setup time reduction, demand increase, productivity improvement, production scheduling, hardware characteristics, etc. The model has been developed using SIMAN simulation language which has been demonstrated to be a powerful tool to simulate complex manufacturing systems. We have suggested the results obtained to improve the system performances of an existing production line.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.235-242
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• 2016

The purpose of this study is an attempt to improve the functionality of a conventional Fused Deposition Modeling (FDM) process using the Automatic Tool Changer (ATC) to perform multimaterial production and post-processing. Hybrid-FDM means a fusion of an Additive Manufacturing process and grinding process using the ATC system. In order to enhance the potentiality of production capacity for multi-material fabrication and surface roughness improvement, two extrusion tools and one grinding tool system are suggested. A pneumatic chuck is attached on a moving platform in the XY axes plane and an extrusion head and grinding head are placed in a docking station, allowing for a quick changeover with each other. Therefore, the manufacturing lead time can be reduced efficiently for the fabrication of a product.

• Industrial Engineering and Management Systems
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• v.4 no.2
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• pp.145-157
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• 2005

There are a lot of raw materials, work-in-processes and finished goods in manufacturing industry. Here, the less stock of materials and work-in-processes manufacturing industry has, the worse the rate of the production is. Inversely, the more manufacturing industry has, the more expensive the cost to support them is. Thus, it is important for us to balance them efficiently. In general, inventory problems are to decide appropriate times to produce goods and to determine appropriate quantities of goods. Therefore, inventory problems require as more useful information as possible. For example, there are demand, lead time, ordering point and so on. In this paper, we deal with an optimal ordering policy on both way substitutable two-commodity inventory control system. That is, there is a problem of how to allocate the produced two kinds of goods in a factory to m areas so as to minimize the total expected inventory cost. The demand of each area is probabilistic, and we adopt the exponential distribution as a probability density function of demand. Moreover, we provide numerical examples of the problem.

• Journal of Ocean Engineering and Technology
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• v.24 no.4
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• pp.86-93
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• 2010

RFID has been used as an identification tool that substitutes for bar codes. Its areas of application are increasing due to its suitability in ubiquitous environment. In this paper, first, we review various aspects of RFID, including standards, characteristics, and relationships with wireless sensor networks. Then, we review the technical aspects of RFID and its areas of application, e.g., supply chain management (SCM) and manufacturing since 2005. SCM, in which RFIDs can shorten lead time and ensure the quality of products, is one of the most active application areas. Manufacturing is a relatively new area for RFID applications, but it is believed that it can enhance the productivity and the reliability of the products. Also, the authors suggest research issues and limitations of RFID, as well as possible application areas related to marine engineering.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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• pp.51-56
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• 2003

Generally, the build-up printed circuit board manufactured by a sequential process involving etching, plating, drilling, etc, which requires many types of equipments and long lead time. Etching process is suitable for mass production, however, it is not adequate for manufacturing a prototype in the development stage. In this study, we introduce a screen printing technology for prototyping a build-up printed circuit board. As for the material, photo/thermal curable resin and conductive paste are used for the formation of dielectric and conductor. The build-up structure is made by subsequent processes such as formation of a liquid resin thin layer, solidification by a UV/IR light, and via hole filling with a conductive paste. By use of photo curable resin, productivity is greatly enhanced compared with thermal curable resin. Finally, the basic concept and the possibility of build-up printed circuit board prototyping are proposed in comparison with the conventional process.

• Journal of Dairy Science and Biotechnology
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• v.26 no.2
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• pp.45-49
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• 2008

We studied the feasibility of monitoring and controlling the manufacturing process of an infant formula with rice starch by testing in-process samples using rheology. We used DSC to first determine the gelatinization temperature of the rice starch, a key ingredient of this product. With this characteristic temperature and the process design known, rheological measurements were conducted on the in-process samples for detecting the presence and extent of gelatinization and retrogradation of rice starch; in-process samples were collected from the carbohydrate tank, after the homogenizer, and the finished product tank. The correlation between the rheological measurements on these samples and manufacturing performance proved that rheology is a very sensitive tool for monitoring the structural development of this infant formula during main process, and their influence on sterilization efficiency. We observed that the lower degree of gelatinization during main process, a shorter residence time in the finished product tank, and using caustic flush rather than clean-in-place additively lead to higher sterilization efficiency. These findings can be utilized for a rational design and analysis of the manufacturing process for infant formulas containing rice starch.

• Industrial Engineering and Management Systems
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• v.9 no.3
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• pp.227-241
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• 2010

A memory module industry's supply chain usually consists of multiple manufacturing sites and multiple distribution centers. In order to fulfill the variety of demands from downstream customers, production planners need not only to decide the order allocation among multiple manufacturing sites but also to consider memory module industrial characteristics and supply chain constraints, such as multiple material substitution relationships, capacity, and transportation lead time, fluctuation of component purchasing prices and available supply quantities of critical materials (e.g., DRAM, chip), based on human experience. In this research, a directed graph-based supply network planning (DGSNP) model is developed for memory module industry. In addition to multi-site order allocation, the DGSNP model explicitly considers production planning for each manufacturing site, and purchasing planning from each supplier. First, the research formulates the supply network's structure and constraints in a directed-graph form. Then, a proposed genetic algorithm (GA) solves the matrix form which is transformed from the directed-graph model. Finally, the final matrix, with a calculated maximum profit, can be transformed back to a directed-graph based supply network plan as a reference for planners. The results of the illustrative experiments show that the DGSNP model, compared to current memory module industry practices, determines a convincing supply network planning solution, as measured by total profit.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.175-181
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• 2013

The primary element of machining automation is to maximize the utilization of machine tools, which determines the output and lead-time. In particular, 95% of raw materials for wing ribs are cut into chips and 0.6 ton of chips are generated every hour from each machine tool. In order to verify the chip recycling system that controls the chips from the machines in five-axis FMS line, a simulation of the virtual model is constructed using the QUEST simulation program. The optimum speed of the chip conveyor and its operating conditions that directly affect the efficiency of the FMS line are presented including the chip conveyor speed, the maximum capacity of the hopper, and the number of chip compressors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.239-244
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• 2019

Traditional casting methods require long production lead time and high cost while not accommodating design changes easily. One of the technological alternatives to improve casting method to meet diversifying needs is Additive Manufacturing (AM). Among the 7 AM techniques, Powder Bed Fusion (PBF) is deemed most appropriate for casting applications. Currently, most AM machines are imported; therefore limiting the scope of available services and applications. This paper explores the domestic development of AM machines as well as the applications in casting. Each chapter describes development phases of PBF machines, applicable materials and parameter settings, while the last chapter illustrates a successful case of additive manufacturing industrial casting cores.