• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.179-185
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• 2012

When manufacturing die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimize casting design of an automobile part (Gear Box) Computer Aided Engineering (CAE) was performed by using the simulation software (Z Cast). The simulation results were analyzed and compared with experimental results. During the mold filling, internal porosities caused by air entrap were predicted and reduced remarkably by the modification of the gate system and the configuration of overflow. With the solidification analysis, internal porosities caused by the solidification shrinkage were predicted and reduced by the modification of the gate system. For making a better production die casting tool, cooling systems on several thick areas are proposed in order to reduce internal porosities caused by the solidification shrinkage.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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• pp.287-293
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• 1993

This study was carried out to investigate the influences of cultural conditions of koji on the production of organic acid during rice-koji making by Aspergillus awamori var. kawachii which is now widely used as koji-mold in brewing Takju and Yakju in Korea. The optimum temperature for the germination of the conidia of the mold was 35'8, and the time required for germination at this temperature was 8 hours. Rapid germination occurred when the water content of steamed rice was above 40%, but germination retardation occurred markedly below 35%. The optimum cultural temperature for the production of organic acid was 32$^{\circ}C$, and the production of organic acid was markedly restricted at 36$^{\circ}C$ and 4$0^{\circ}C$. It was effective for the high production of both saccharogenic amylase and organic acid to shift the cultural temperature from initial 36$^{\circ}C$ to 32$^{\circ}C$ after 20~25 hours of cultivation. Initial water content suitable to the production of organic acid was 40% in steamed rice, but its production was markedly restricted below 30% of water content. When the quantity of conidial inoculation was too small, the production of organic acid was low in initial phase, but it was retrived at later period. Acid production was markedly restricted together with the increase in koji thickness.

• Korean Journal of Metals and Materials
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• v.46 no.10
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• pp.662-671
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• 2008

The behavior of hydrogen in the steel making process was investigated. The relation between the composition of ladle slag and hydrogen concentration in molten steel was considered. The hydrogen distribution ratio between ladle slag and molten steel was increased with increasing basicity of the slag; it was about 20 when the basicity of slag was 15. Hydroxyl capacity measured from the hydrogen distribution ratio between slag and the molten steel was comparatively corresponding to the value of hydroxyl capacity measured by the equilibrium reaction of slag and $H_2O$ gas. However, it is considerably different from the value calculated by regular solution model. The influence of hydrogen on a sticking type breakout is considered. The effect of hydrogen and $H_2O$ gas on the crystallization behavior of mold powder was investigated by DHTT (Dual hot thermocouple technique). As a result, it was proved that mold powder could be crystallized by $H_2O$ gas in the atmosphere. Therefore, it is concluded that $H_2O$ gas in the atmosphere can be a possible cause of the sticking type breakout that occasionally occurs in the continuous casting process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.1-8
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• 2019

In this study, we design the feed system and process conditions for a lamp garnish lens of an automobile. For this purpose, four design alternatives are presented and injection molding simulation analyses are performed. The optimal feed system is selected by considering the formability of the product and the cost of mold manufacture. The product formability is assessed by the weld line, warpage, sink mark and the maximum injection pressure, whereas the mold-making cost is estimated by the number of valve gates in the hot runner system. To improve the product formability, process conditions are optimized using an experimental design approach named one-factor-at-a-time. No weld line is generated as a result of the optimization. In addition, it is found the warpage and sink mark are reduced while the maximum injection pressure is increased, compared with those before the optimization.

• Design & Manufacturing
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• v.15 no.3
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• pp.32-38
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• 2021

Plate-shaped works are one of the materials that can be applied to the entire industry due to their various shapes and sizes. Plate-shaped parts workpieces are thin and wide, and when processing is completed, they are often bent or deformed in various directions, making it difficult to produce normal products. In particular, this study intends to study the processing deformation and distortion of plate-shaped parts fastened to the jig during milling processing. In this study, a method for preventing deformation occurring in plate-shaped parts was derived through jig element change and CAE analysis, and this was applied to actual processing to produce products with stable dimensions. Through a finite element analysis experiment, it was found that installing two supports on the back of the plate-shaped part results in minimal deformation and the optimal distance between the two supports is 150 mm. Through this experiment, when processing a thin plate product, a support was installed in a direction opposite to the cutting force applied to the thin plate to prevent deformation of the product, thereby improving defects.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1237-1241
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• 2009

With the average life expectancy increasing thanks to better standards of living and medical technology, the number of elderly construction workers in construction sites rises every year to surpass the 450 thousand people in the construction industry (24.7% of all employees in the construction industry). Similarly, the percentage of fatal accidents involving elderly workers has stood at 41~46 percent for the past five years; note that this is significantly higher than the other age groups, making safety measures for dealing with this issue a matter of urgency. This study sought to propose appropriate safety guidelines for elderly construction workers aged 50 years and over by examining the changes in their physical and psychological functions and through the subsequent analysis of the current status and causes of fatal accidents involving them. The guidelines targeted ferroconcrete construction where accidents occur quite often; construction was classified into mold construction, reinforcing rod construction, and concrete construction. Mold construction was further classified into preparation, carry-in, processing, assembly, and disassembly, and reinforcing rod construction, into preparation/transport and processing/assembly. Safety guidelines for each process were presented by dividing them into three aspects considering the changes in the physical and psychological functions according to their ages and type of accident causes: work environment improvement, machinery and equipment improvement, and work method improvement.

• Design & Manufacturing
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• v.18 no.2
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• pp.23-28
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• 2024

The automobile industry is a wide range of related industries, including parts manufacturing and vehicle assembly, press processing is an essential element in making automobiles. Press processing is a processing method for metal sheets that has relatively high dimensional and shape precision and is suitable for mass production. It refers to processing by attaching a special tool, a mold, to a press machine. Recently, the automobile industry is attempting to reduce the weight of automobiles in order to reduce carbon emissions due to global warming, and the use of high-strength steel sheets, which are lighter than general structural steel sheets, is a natural trend. Shear processing is required to use high-strength steel, and the shape of the shear surface created by shear processing has a significant impact on the quality of the automobile. Therefore, various methods are being attempted to improve the share surface during shear processing. Among them, shaving processing is a method of shearing the primary shearing area again, and it is difficult to obtain an accurate answer because complex deformation occurs in the microscopic shear area. Therefore, in this study, the effect of machining allowance on shaving processing was analyzed using the finite element method using high-strength steel plate (SPFH590), and the differences were compared and examined through actual experiments under the same conditions.

• The Journal of Society for e-Business Studies
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• v.8 no.3
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• pp.37-52
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• 2003

ISO 13584 Parts Library (PLIB) standard is making its way into e-business as a norm for classifying products and their characteristics. PLIB is a multi-parts standard, and the Part 42: Methodology for structuring Parts families Provides the information model and design Principles for the data dictionary of parts library or e-catalog. If e-catalog systems are built using a data dictionary that is constructed based on PLIB dictionary data model, many different e-catalog systems can be easily integrated and interoperated. This paper studies the roles and requirements of the data dictionary in e-catalog, and applies the data model and design principles of PLIB Part 42 to construct a data dictionary from the viewpoint of ontology Based on the analysis results, we propose a data dictionary of die and mold parts, and implementat the B2B e-catalog system.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.2 s.120
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• pp.68-77
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• 2007

It is necessary to recognize philosophical and scientific depth, contained in traditional culture in a correct fashion, in order to succeed and develop our excellent traditional culture. Some studies on storage, circulation, and package design of traditional food will multiple the added value of traditional culture. So this research was carried out for making packing cases of kinds of Korean dried confectionery using Hanji by traditional manufacturing method, Hanji textile, charcoal Hanji and jade Hanji, and for developing environmental-friendly Korean dried confectionery package as more luxurious packaging papers by putting an exterior design on the surface. The results measured physical properties, air permeability and anti-mold activity of Hanji, and designing Korean dried confectionery are as follows. The physical properties and air permeability used to manufacture Korean dried confectionery package, turned out to be no affection to the food packaging Hanji. In order to avoid the monotonousness of Korean dried confectionery package, it was designed with Hanji textile together with elegant traditional pattern. It is estimated to increase the value of Korean dried food and to make the anti-mold activity of Hanji added charcoal and jade effective. In conclusion, by developing individual properties of traditional food and proper packaging paper as well as packaging design according to circulating situation, it is considered that the taste and the fancy can be maximized. After all, by applying excellent traits contained in our race's culture, it is possible to develop the package cases into competitive ones. And it would be able to increase utilization of Hanji. Namely, production of high quality traditional food package with Hanji is expected for new valuable industry of Hanji.

• Polymer(Korea)
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• v.28 no.4
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• pp.305-313
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• 2004

A vacuum pressure-difference technique for making a nano-precision replica is investigated for various applications. Master patterns for replication were fabricated using a nano-replication printing (nRP) process. In the nRP process, any picture and pattern can be replicated from a bitmap figure file in the range of several micrometers with resolution of 200nm. A liquid-state monomer is solidified by two-photon absorption (TPA) induced by a femto-second laser according to a voxel matrix scanning. After polymerization, the remaining monomers were removed simply by using ethanol droplets. And then, a gold metal layer of about 30nm thickness was deposited on the fabricated master patterns prior to polydimethylsiloxane molding for preventing bonding between the master and the polydimethylsiloxane mold. A few gold particles attached on the polydimethylsiloxane stamp during detaching process were removed by a gold selecting etchant. After fabricating the polydimethylsiloxane mold, a nano-precision polydimethylsiloxane replica was reproduced. More precise replica was produced by the vacuum pressure-difference technique that is proposed in this paper. Through this study, direct patterning on a glass plate, replicating a polydimethylsiloxane mold, and reproducing polydimethylsiloxane replica are demonstrated with a vacuum pressure-difference technique for various micro/nano-applications.