• 한국주조공학회지
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• 제20권5호
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• pp.330-335
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• 2000

Functional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported. But a system which can build directly 3D parts of high performance functional material as metal park would get long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we translated the wax patterns to numerous metal tool prototypes by new investment casting process combined conventional investment casting with rapid prototyping & rapid tooling process. With this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P pare to metal part.

• 한국정밀공학회지
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• 제16권6호
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• pp.52-57
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• 1999

Funtional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported by song etc. But a system which can build directly 3D parts of high performance functional material as metal part would need long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we tranlsated the wax patterns to numerous metal prototypes by new investment casting process combined conventional investment casting with rapid pototyping & rapid tooling process. with this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P part to metal part.

• 한국공작기계학회논문집
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• 제15권6호
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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.

• 한국정밀공학회지
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• 제16권10호
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• pp.59-67
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• 1999

The lead time for new products is very limited in the current manufacturing processes, therefore the Rapid Prototyping process has been introduced and generally used in the industry. Fused Deposition Manufacturing (FDM) is one of the most common methods in this field. In the FDM process, the patterns are made of Wax of ABS and ABS shows better quality of the patterns. To date, the FDM/ABS patterns are used in investment casting for making silicon moulds to produce was patterns because it is very difficult to dewax FDM/ABS directly. The aim of this paper was to propose a feasibility of using FDM/ABS parts as wax-pattern substitutes in the investment casting process. The effects of casting conditions, such as pre-heat temperature and casting temperature, are provided. Comparisons with the conventional investment casting processes using the wax-patterns under the same prototype are made. Lead-time and saving cost are discussed in using FDM/ABS parts as was-pattern substitutes compared with the products from other rapid prototype systems.

• 대한치과보철학회지
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• 제41권3호
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• pp.342-350
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• 2003

Statement of problem. Titanium-Nickel alloy might be used in various prosthetic restorations since it has a unique property such as super-elasticity and high fatigue resistance. However, little is known about the casting ability of this alloy. Purpose. This in vitro study compared the casting accuracy and the porosity made with different investments and various sprue designs to ascertain what casting condition would be better for the fabrication of Ti-Ni cast restorations. Material and methods. A total of 70 Ti-Ni alloy crowns were made and divided into 7 groups of 10 copings on a metal master die. For measuring the effect of the sprue numbers, two groups with one and two 8-gauge sprues were compared. Moreover, the results of the conventional sprue and the double thickness sprues were compared. Three investments were used; carbon free phosphate bonded investment, titanium investment and gypsum bonded investment. The cast restorations were evaluated at 48 points on the entire circumferential margin with a stereomicroscope measuring in micrometers. Each crown was radiographically examined for casting defects and porosity. Data on casting accuracy were analyzed using two-way and Post hoc Scheffe's comparison to determine whether significant differences existed at the 95% confidence level. Student-Newman-Keuls test were performed to identify significant differences in the number of voids. Results. The double sprueing group and double thickness group had significantly less marginal discrepancy than the single sprueing group (P<.05 and P<.01, respectively). The castings with phosphate bonded investment showed the least marginal discrepancy and the smoothest surface. The castings invested in the gypsum bonded investment had the greatest gaps in margin and the largest failure rate. The double sprueing group and phosphate bonded investment group had significantly smaller void numbers and smaller void size than the other groups. Conclusion. Within the limitations of this in vitro study, the casting accuracy of the groups using thicker, double sprue design and the phosphate bonded investment was significantly superior. Moreover, void number and size were less than other groups.

• 대한치과보철학회지
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• 제16권1호
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• pp.45-47
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• 1978

We use investment to retain the mould of the wax pattern in making dental metal castings. A fin on the metal casting is occasionally formed due to several factors. The factors making the fin are improper burn out time and temperature, improper W/P ratio of investment and lining of asbestos in casting ring. The purpose of this study is to investigate the effect of W/P ratio of investment on the fin formation. Except the W/P ratio of investment which used to invest the wax pattern, the study was done under same condition; burn out time and temperature, W/P ratio of refractory cast(W/P=0.12) and asbestos lining in casting ring. The obtained result is that the fin is more likely to be formed on the casting which invested with higher W/P ratio of investment to that of refractory cast.

• 한국주조공학회지
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• 제22권2호
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• pp.75-81
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• 2002

The main objectives were to investigate the suitability of CaO crucible for melting TiAl alloys and to develop investment mold for investment casting of TiAl alloys. TiAl alloy specimen were prepared by plasma arc furnace under argon atmosphere. After melting of TiAl alloy using CaO crucible, the results showed that there is little contamination of oxygen in the TiAl bulk. Conventional vacuum induction furnaces can be readily adaptable to produce cast parts of TiAl without high skilled techniques. The determination of optical metallography and microhardness profiles in investment cast TiAl alloy rods has allowed the gradation of the relative thermal stability of the oxides examined. The molds used for the present study were $ZrO_2$, $Al_2O_3$, CaO stabilized $ZrO_2$ and $ZrSiO_4$. Even although high temperature of mold preheating, $Al_2O_3$ mold is a promising mold material for investment casting of TiAl alloys in terms of thermal stability, cost and handling strength. It is important to take thermal stability and preheating temperature of mold into consideration for investment casting of TiAl alloys.

• 한국결정성장학회지
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• 제32권1호
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• pp.25-32
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• 2022

인베스트먼트 주조는 정밀기기, 의료분야, 액세서리 등의 제조에 일반적으로 사용되는 생산방식으로 장비의 현대화와 고품질의 재료를 통해 발전을 거듭해 왔으며 그 활용 범위가 확대되고 있다. 본 연구의 목적은 인베스트먼트 주조 공정의 핵심 요소인 금형 온도의 구조적 개선 및 표준화를 도출하여 불량률을 최소화하여 경제성과 생산성을 향상시키는 것이다. 연구의 범위는 소형탕도의 구조와 원리를 이해하기에 적합한 Jewelry 제조 주조 공정에 국한되어 있으며 연구 재료로 soft Wax, 석고 분말 및 14 K Gold를 사용하여 실험적 연구를 수행했다. 그 결과 Alloy 14 k의 주물 패턴에 가장 적합한 주물 표준 온도는 980℃ 플라스크 온도 550℃에서 가장 낮은 난류로 좋은 제품을 생산할 수 있었다. 본 연구의 향후 과제로 소형탕도의 구조 및 표준온도를 데이터를 분석하고, 현장의 생산 불량을 감소시키고 우수한 인베스트먼트 주조 공법의 경쟁력 확보를 위한 데이터를 제공하기 위한 세부 연구가 필요하다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.566-569
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• 2002

Rapid Prototyping is a prototyping technology that produces complicated parts directly form three dimensional CAD data with high efficiency, and has been extensively applied to various manufacturing processes. The aim of this research is to apply a 3D printer part as wax pattern in the investment casting process. The difference between conventional pattern wax and 3D printer wax is compared by experiments. The direct casting method is developed for ceramic-shell investment casting.

• 한국주조공학회지
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• 제21권5호
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• pp.296-303
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• 2001

The effects of the revolution speed on the mechanical properties and microstructure of Cr-Mo steel during vertical centrifugal casting using investment mold were investigated. The casting yield, tensile strength, hardness and absorbed energy during impact test were increased with increasing revolution speed. The effect of mass variation caused by the change in the revolution speed on the grain size was the most significant.