• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.127-133
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• 2006

Rapid prototyping technologies have been widely used to reduce the development cost of new products. Manufacturing industries are nowadays characterized by the flexibility and complexity of products. This to due to the rapid development of manufacturing technology and diverse needs of customers. In this paper, the best homing out and casting condition for getting casting product of resin pattern(photopolymer) have been examined experimentally. In generally, the burning out and casting conditions have effect on the casting products. Using the direct casting. we directly Producted the Jewelry. And in this paper, we used only gypsum. Many study of casting for resin have been used to dental investment. A dental investment is good for resin casting. but dental investment is too hard and not useful on the jewelry casting. Therefore we need to find the way of resin casting by gypsum.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.169-176
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• 2017

Casting process includes wax pattern, investment, dewaxing, curing, casting, etc., and each single process is important to achieve a good result. Since 2000, 3D printers have been developed and widely used; as more prefer UV Curavle resin method over wax method, resultant casting defects have become worse. To resolve such problem, preceding research revealed casting defects of existing wax method. In particular, defects of UV Curavle resin method showed difference in investment, dewaxing, deresinating and curing compared to the existing one. Accordingly, results were presented through casting tests; especially, a temperature rising curve only for UV Curavle resin was shown rather than one for the existing method. Lastly, this research classified those not available with direct casting and suggested mold manufacturing. This research is expected to be useful for 3D printer users or those who would conduct direct casting with UV Curavle resin.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.1-6
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• 2000

As dies and molds have become more and more complicated in the recent years, the demand for lower cost and shorter production time is also growing stronger. Rapid prototyping and Tooling technologies are expected to be used for more rapid and lower cost tool fabrication. However the rapid tooling methods have not yet reached the level of application to the manufacturing of metallic dies and molds which require high dimensional accuracy. As the rapid tooling technology, there are the slurry casting, the powder casting, the direct laser sintering, and so on. Generally, in the slurry casting, the alumina powder and the water soluble phenol were mainly used. However, the mechanical properties of the phenol were not good enough to apply to molds directly. In this study, pure epoxy and two types of aluminium powder reinforced resin are applied to the slurry casting. The mechanical and thermal properties are better than phenol because the epoxy is the thermosetting resin. And mechanical characteristics such as shrinkage rate, hardness, surface roughness are measured for the sake of comparison. Metal powder reinforced resin molds are better than the resin tool form the viewpoint of shrinkage rate and hardness. Finally, it has been shown that the application possibility of this process is high, because the manufacturing time and cost savings are significant.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.39-45
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• 1998

In the previous study. the powder casting was attempted as the rapid tooling. The powder casting was the process to cast dry powder into the casting mold transferred from R/P model and infiltrate the liquid binder to solidify the powder. And then, the melted copper was infiltrated to control the shrinkage rate of the final mold Conseqently, the shrinkage rate was under 0.1% through that process. The mechanical characteristic was also excellent. Generally, in the slurry casting, the alumina powder and the water soluble phenol were mainly used. However, the mechanical property of the phenol was not good enough to apply to molds directly. In this study, aluminium powder filled with epoxy is applicated to the slurry casting to solve these problems. The mechanical and thermal properties are better than phenol because the epoxy is the thermosetting resin. We achieved a successful result that the shrinkage rate is shortened about 0.047%. Futhermore, the manufacturing time and cost savings are significant. Finally, we assume that the developing possibility of this process is very optimistic.

• Journal of Powder Materials
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• v.26 no.6
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• pp.502-507
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• 2019

Macro-porous carbon foams are fabricated using cured spherical phenolic resin particles as a matrix and furfuryl alcohol as a binder through a simple casting molding. Different sizes of the phenolic resin particles from 100-450 ㎛ are used to control the pore size and structure. Ethylene glycol is additionally added as a pore-forming agent and oxalic acid is used as an initiator for polymerization of furfuryl alcohol. The polymerization is performed in two steps; at 80℃ and 200℃ in an ambient atmosphere. The carbonization of the cured body is performed under Nitrogen gas flow (0.8 L/min) at 800℃ for 1 h. Shrinkage rate and residual carbon content are measured by size and weight change after carbonization. The pore structures are observed by both electron and optical microscope and compared with the porosity results achieved by the Archimedes method. The porosity is similar regardless of the size of the phenolic resin particles. On the other hand, the pore size increases in proportion to the phenol resin size, which indicates that the pore structure can be controlled by changing the raw material particle size.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.406-410
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• 2004

Rapid prototyping technologies have been widely used to reduce the development cost of new products. Manufacturing industries are nowadays characterized by the flexibility and complexity of products. This to due to the rapid development of manufacturing technology and diverse needs of customers. In this paper, the burning condition for getting casting product of resin pattern have been examined experimentally. In generally, the burning conditions have effect on the casting products. Using the direct casting. we directly producted the jewelry.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.36-44
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• 1999

The rapid Tooling technique is classified into two methods: one to directly utilize the model which was made by rapid prototyping technologies for dies, and the other to make a transferred type using the model as a master model and create dies and molds using it. In this study, the Al powder filled resin was made several mixed ratios and meshes sizes, and applied to slurry casting. And, variation of mechanical characteristics such as the shrinkage rate, the tensile strength, the elongation, the hardness, and surface roughness, are measured to compare. Consequently, as higher is the powder mixed ration and as smaller is the grain size of the power, the mechanical characteristics of the final mold are improved. Finally, the metal short fiber which can be fabricated easily and cheaply, if the self-excited vibration of an elastic tool, was also applied to slurry casting. It has been found tat the hardness gets higher, while the shrinkage rate lower, if mixed with short fiber.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.1
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• pp.27-35
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• 2006

The aim of this study was to identify the sources of benzene detected in airborne of casting workplace where benzene was not used as raw material. We have identified benzene by GC/FID and GC/MSD. In this pilot test, small size iron chamber(diameter 30 cm, height 20 cm) was used. As the raw materials, new sand, recovered sand, and mixed casting sand(new sand + solidifying agent + organic resin + coating material) was tested, respectively. In the new sand benzene was not detected, but in the recovered sand and the mixed casting sand was detected. Xylenesulfonic acid(solidifying agent), one of the mixed casting sand ingredients was thought to product benzene by thermal decomposition above $400^{\circ}$..., but the other raw materials(organic resin and coating material) were thought not to product benzene. In this experiment, the most of benzene by thermal decomposition was produced within 1 hour after pouring the iron solution($1560^{\circ}$...) in small size iron chamber. When the mixed casting sand with coating material was used, the concentration of the produced benzene was average 2.91 ppm(range 1.98~3.72 ppm), and without coating material, benzene concentration was average 0.11 ppm(range 0.08~0.14 ppm).

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.124-131
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• 2000

Rapid Prototyping(RP) models are no longer used only for design verification. Currently, parts built utilizing layer manufacturing technology can be employed as functional prototypes and as patterns or tools for different manufacturing processes such as vacuum casting, investment casting, injection molding, precise casting and sand casting. This trend of Rapid Prototyping application meets the requirement of concurrent engineering and its range covers a more spreaded area. The aim of this paper is saving the manufacturing lead time and cost of plastic parts having hollow space shapes used by prototype-car. Using rapid prototype patterns, made by the Selective Laser Sintering(SLS) technique, a new approach of manufacturing resin-based blow mold is discussed. It has a great potential fur making prototype-car parts with the batch size of under 200 parts, in case of rapid modification due to a subsequent design changes in developing stage. So, the process proposed in this research shows reduction of process time and manufacturing cost when compared with the conventional process such as a Zinc Alloy fur Stamping(ZAS) mold.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.228-228
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• 2008

본 논문에서는 epoxy bonding film의 phenoxy resin의 함량변화에 따른 특성 변화에 대하여 연구하였다. epoxy bonding film은 미세패턴 구현을 위해서 사용되는 기판재료로써 epoxy, hardener, silica, phenoxy resin 등이 첨가되어진다. phenoxy resin 함량을 변화를 주면서 tape casting 방법을 통해서 flim 형성을 한 후, 제작된 film의 phenoxy resin 함량변화에 따른 조도 특성의 연구를 위해서 sweller, desmear 공정을 후 RA(Roughness Average)를 측정하고, SEM으로 표면을 관찰하였다. 또한 제작된 bonding film을 가열 가압 후 구리 도금공정을 거쳐 peel strength를 측정하였다. phenoxy resin 함량이 증가 할수록 RA가 증가되어지는 것이 관찰되어졌고, 또 한 peel strength 증가하였다.