• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.267-272
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• 2021

In this study, the output results of 3D printed exterior materials for application to buildings of various shapes are output tests using test specimens, in which 3D printing concrete is cast in a mold and accelerating agents are used to ensure stackability. The unit weight and strength characteristics of the body were analyzed. Compared to the unit weight of concrete placed in the mold, the unit weight of 3D printing concrete using accelerating agents tends to decrease by approximately 3.5% to 5.0%, and the compressive strength is the compressive strength of the concrete placed in the mold. In comparison, the compression strength of the output by 3D printing tended to decrease by approximately 36% to 46%. In the flexural strength, the compressive strength of the output through 3D printing decreased by approximately 36% to 46% compared to the compressive strength of concrete placed in the mold. The impact on the strength characteristics of 3D printed concrete using accelerating agents tended to decrease by approximately 2.0 to 5.8%. Therefore, 3D printing output accelerating agents can be used.

• Journal of Korea Foundry Society
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• v.43 no.3
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• pp.107-136
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• 2023

Natural silica sand was commonly used for sand casting of cast steel products, and chromites sand was used to suppress seizure defects due to the lack of thermal properties of silica sand. However there are disadvantages such as deterioration by repeated use, system sand mixing problem, difficulty separating and removing, increased during mold according to high density and to being waste containing chrome. Recently, industrial waste reduction and atmospheric environment improvement have been highlighted as important tasks in the casting industry. In order to solve the problems that occur when using foundry Sand and to improve the environment of casting factories, various artificial sands that can be applied instead of natural silica sand have been developed and introduced. Artificial sands can be classified into artificial sand manufactured by the electric arc atomization or gas flame atomization, artificial sand manufactured by the spray drying & sintering process, artificial sand manufactured by the sintering & crushing process and exhibit different physical properties depending on the type of raw-minerals and manufacturing method. In this study, comparative evaluation tests were conducted on the physical properties of various foundry sands, mold strength, physical durability, thermal durability, and casting test pieces. When comprehensively considering the actual amount of molding sand used according to density, the mold strength according to the shape of sand, the physical and thermal durability of foundry sand, and the heat resistance characteristics of foundry sand, 'Molten artificial sand A1' or 'Molten artificial sand B' is judged to be the most suitable spherical artificial sand for casting of heavy steel castings.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.4
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• pp.301-308
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• 2006

Today's automobiles are changing into miniaturization and light weight for saving natural resources and energies. In order to raise the sufficiency of fuel consumption, new mechanism and components are required. Therefore, the expectations on the new materials are very high. Especially, Al materials are widely used to reduce the motors weight. Al using in automobiles is mostly casting material, and the material is developing rapidly in step with technical innovation. Al die casting has become an important field, as we are turning today's motor into light weight. One of the parts in steering system, valve housing, plays a role to reduce the operating effort of drivers. If valve housing being a part of steering system is produced by gravity casting, the space that manufacturing equipments are installed will be increased, and more energies and workers will be needed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.108-113
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• 2013

Industrialization and modernization of the beginning of the IT industry is growing very fast. Since telecommunications industry was developed rapidly, technologies about miniaturization and high-precision of parts have been actively developed to lead information revolution. generally, the entire shear surface of the product applying fine blanking technology must be very precise. Fine blanking is used to save cost by avoiding post-processing of the product. When using press blanking, it spends a lot of money on the production by using many post-processing. Fine blanking typically used in 0.5~18 mm thick steel plate. Because a lot of post-processing cost can be used to process, except for fine blanking. In order to develop components "CHANCE CONTENTS" in the fine blanking process, the purpose of this study is to minimize the edge of the bridge, secured 95% of the material thickness of the shear surface using the 1.6 mm thickness of the material SPCC. Blanking process by introducing after changing thickness through forging process, due to change in vee-rring force and counter force, the experimental amount of depressions and flatness and the shear surface were analyzed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.3
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• pp.26-33
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• 2003

The term 'High Speed Machining' has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000-100,000rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminum. In recent year, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. With increasing cutting speed used in modern machining operation, the thermal aspects of cutting become more and mole Important. It not only directly influences in rate of tool weal, but also affects machining precision recognized as thermal expansion and the roughness of the surface finish. Hence, one needs to accurately evaluate the rate of cutting heat generation and temperature distributions on the machining surface. To overcome the heat generation, we used to cutting fluid. Cutting fluid plays a roles in metal cutting process. Mechanically coupled effectiveness of cutting fluids affect to friction coefficient at tool-workpiece interface and cutting temperature and chip control, surface finish, tool wear and form accuracy. Through this study, we examined the behavior of heat generation in high-speed machining and the cooling performance of various cooling methods.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.422-428
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• 2001

The term High Speed Machining has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent year, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. With increasing cutting speed used in modern machining operation, the thermal aspects of cutting become more and more important. It not only directly influences in rate of tool wear, but also will affect machining precision recognized as thermal expansion and the roughness of the surface finish. Hence, one needs to accurately evaluate the rate of cutting heat generation and temperature distributions on the machining surface. To overcome the heat generation, we used to cutting fluid. Cutting fluid play a roles in metal cutting process. Mechanically coupled effectiveness of cutting fluids affect to friction coefficient at tool-work-piece interface and cutting temperature and chip control, surface finish, tool wear and form accuracy. Through this study, we examined the behavior of heat generation in high-speed machining and the cooling performance of various cooling methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.912-916
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• 2000

The term ‘High Speed Machining’has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry fur the machining of light alloys, notably aluminium. In recent you, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. And the end mill is an important tool in the milling process. A typical examples for the end mill is the milling of pocket and slot in which a lot of material is removed from the workpiece. Therefore the proper selection of cutting parameter fur end milling is one of the important factors affecting the cutting cost. The one of the advantages of HSM is cutting thin-walled part of light alloy like Al(thinkness about 0.1mm). In this paper, firstly, we study characteristics of HSM, and then, we choose the optimal parameters(cutting forces) to cut thin-walled Al part by experiment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.343-348
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• 2000

The term‘High Speed Machining’has been used for many years to describe end milling with small diameter tools at high rotational speeds. typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent years, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. And the end-mill is an important tool in the milling process. A typical examples for the end mill is the milling of pocket and slot in which a lot of material is removed from the workpiece. Therefore the proper selection of cutting parameters for end milling is one of the important factors affecting the cutting cost. The one of the advantages of HSM is cutting thin-wall part of light alloy like Al (thinkness about 0.3mm). In this paper, firstly, we study characteristics of HSM, and then, we choose the optimal parameters(cutting forces) and investigate various machining strategies to cut thin-wall part by experiment.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_1
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• pp.541-547
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• 2020

This paper relates a rheo die casting using electromagnetic force, which is one of the representative semi-solid methods for aluminum. The most important factors in electromagnetic stirring would be the melt temperature, sleeve temperature, electromagnetic force, and input time. The effect of the temperature of molten alloy on the direct rheo-casting is assessed in this study. The temperature of the molten alloy is set to 590 ℃ with a solidification of 40%, 600 ℃ with 30%, and 610℃ with less than 20%. Under the condition of 590 ℃ with a solidification of 40%, the whole molten alloy is solidified, causing non-forming during forming process. Meanwhile, under the condition of 600 ℃, where the solidification was 30%, appropriate amount of molten alloy is solidified, filled well into the mold, resulting in good forming, while at 610 ℃ with the solidification of 20%, the molten alloy is not sufficiently solidified and scattered away. The investigation of the defects inside the product with the help of the X-ray equipment shows that the electromagnetic stirring at 590 ℃ with a solidification of 30% produces many air-pores inside the product.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.113-120
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• 2020

The objective of the study was to assess the survival of microencapsulated Lactobacillus plantarum ATCC8014 produced using the emulsion technique in alginate gel combined with pectin and maltodextrin components. The microcapsules were then added to cupcake dough that was further baked at 200℃ for 12 min. The viability of L. plantarum was assessed during baking and the 10 days of storage at 4℃ as well as in simulated gastrointestinal conditions. In addition, yeast-mold and water activity were investigated. After baking, the samples with microencapsulated L. plantarum contained more than 5 log CFU/g, which was higher compared to the bacterial concentration of the control samples. The concentration of L. plantarum was more than 6 logs CFU/g after the end of the storage; therefore, the probiotic functioned as a biopreservative in the cake. The prebiotic component strengthened the microcapsules network and helped protect the viability of L. plantarum in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) media. The results show that the addition of L. plantarum microencapsules did not affect the sensory scores of the cupcake while ensuring the viability of the probiotic during baking and storing.