• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.357-364
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• 2017

Metal casting is a process in which molten metal or liquid metal is poured into a mold made of sand, metal, or ceramic. The mold contains a cavity of the desired shape to form geometrically complex parts. The casting process is used to create complex shapes that are difficult to make using conventional manufacturing practices. For the optimal casting process design of sleeve parts, various analyses were performed in this study using commercial finite element analysis software. The simulation was focused on the behaviors of molten metal during the mold filling and solidification stages for the precision and sand casting products. This study developed high-life sleeve parts for the sink roll of continuous hot-dip galvanizing equipment by applying a wear-resistant alloy casting process.

• Journal of Korea Foundry Society
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• v.18 no.3
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• pp.246-253
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• 1998

Precision metal mold casting process is a casting method manufacturing mechanical elements with high precision, having heavy/light alloys as casting materials and using permanent mold. To improve dimensional accuracy and the final mechanical properties of the castings, the solidification speed and the cooling rate of the casting should be controlled with the optimum mold cooling system, and moreover, to obtain more accurate control of the whole process interfacial heat transfer characteristic at the mold/casting interface must be studied in advance. In the present study, aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling system was designed and the temperature histories at points inside the metal mold were measured during the casting process. The heat transfer phenomena at the mold/casting interface was characterized by the heat flux between solidifying casting metal and metal mold, and the heat flux history was obtained using inverse heat conduction method. The effect of mold cooling condition upon the heat flux profile was examined, and the analysis shows that the heat flux value has its maximum at the beginning of the process.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.3
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• pp.244-248
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• 2013

In this paper, we describe the smart metal casting processing management system, in which we applied case-based reasoning on the window environment. Metal casting is one of the most common casting processes. The metal casting processing is complex and variable depends on a kind of metal casting products. Especially, the metal casting industry has a feature which produces small quantities but produces a lot of different types of metal casting products. And we developed the smart metal casting processing management system which could show the processing route according to the product cases intelligently using the result of case-based reasoning. The experimental result shows that our metal casting processing management system schemes achieves more productivity than manual management schemes.

• Journal of the Korean Society of Visualization
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• v.16 no.1
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• pp.54-60
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• 2018

It is important to develop more efficient and productive casting processes for an automated high precision molten-metal casting system. Detailed analysis of molten-metal flow in the casting process by the numerical approach will help to optimize the control of a ladle. In this study, the smoothed particle hydrodynamics method was applied to analyze casting flow characteristics with different tilting angular speed and initial molten-metal level. The smoothed particle hydrodynamics technique has advantages to easily handle non-linear free surface behavior with the absence of a computational mesh. We found that tilting angular speed has relatively greater effect on the casting flowrate and that the effect of the initial molten-metal level is only minor. Further extensive study will be necessary to find an optimal condition for high efficient casting system.

• Journal of Korea Foundry Society
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• v.24 no.1
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• pp.3-9
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• 2004

Die casting is "a process in which molten metal is injected at high velocity and pressure into a mold(die) cavity". Casting with smooth surfaces, high dimensional precision, complicated shapes, and reduced weight can be obtained using this process. But this process is susceptible to casting defects such as porosities, scattered chilled layers, hard spots, etc. For preventing casting defects, we developed "low-velocity high pressure die casting technology", "squeeze die casting technology", "heat insulating sleeve lubricant technology", and "direct pouring technology". The "direct pouring technology" is useful for producing molten metal without oxide contamination. It consists of a pumping system which supplies pure molten metal to the die casting machine. By using this technology, we have successfully reduced oxide contamination in castings to 1/20 of that of our previous castings.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.180-186
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• 2002

The simulated die-casting process in which the traditional plaster casting process is combined with Rapid Prototyping technology is being used to produce Al, Mg, and Zn die-casting prototypes. Unlike in the die-casting process, molten metal in the conventional plaster casting process is fed via a gravity pour into a mold and the mold does not cool as quickly as a die-casting mold. The plaster castings have much larger and grosser grain structure as compared as the die-castings and the thin walls of the plaster mold cavity may not be completely fillet Because of lower mechanical properties induced by the large grain structure and incomplete Idling, the conventional plaster casting process is not suitable for the trial die-casting Process. In this work, an enhanced trial die-casting process has been developed in which molten metal in the plaster mold cavity is vibrated and pressurized simultaneously. Patterns for the casting are made by Rapid Prototyping technologies and then plaster molds, which have runner system, are made using these patterns. Imparted pressurized vibration to molten metal has made grain structure of castings much finer and improved fluidity of the molten metal enough to obtain complete filling at thin walls which can not be filled in the conventional plaster casting process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.102-106
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• 1999

One of the main causes of unwanted dimensional changes in precision metal mold casting parts is excessive and irregular residual stresses induced by temperature gradients and plastic deformation in the solidifying shell. Residual stresses can also cause stress cracking and lower the fatigue life and fracture strength of the casting parts,. In the present study aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling units was designed and the casting specimens were produced to quantify the effects of different cooling conditions on the development of residual stresses. the layer removal method was used to measure the biaxial residual stresses in casting specimens produced from the experiments. The experimental results agreed with Tien-Richmond's theoretical model for thermal stress development for the solidifying metal plate

• Journal of Korea Foundry Society
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• v.20 no.5
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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.

• Design & Manufacturing
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• v.15 no.2
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• pp.30-35
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• 2021

The casting method uses a mold to solidify a liquid metal to make a solid metal. Since it uses a liquid metal with the least deformation resistance, it has the characteristic that it can easily manufacture even a complex shape. However, the process of solidifying a liquid metal into a solid metal inevitably involves a volume change and contains internal defects such as shrinkage holes. Therefore, in the design of the casting plan, an excess volume called a pressurization compensates for the volume shrinkage. in the product, and it induces the shrinkage hole defects to occur in parts other than the product1). In this study, casting analysis was performed using casting analysis software (anycasting) in order to optimize the design of the tilting gravity casting method for automobile brackets. In particular, the filling and solidification analysis according to the shape and volume of the pressurized metal was conducted, and applied to the actual product to study the effect of the pressurized metal on the shrinkage defect. Through this study, it is possible to understand the effect of the pressure metal on shrinkage defects in the actual product and propose a design of the pressure metal that improves reliability and productivity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.2087-2095
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• 1999

One of the main causes of unwanted dimensional changes in precision metal mold casting parts is excessive and irregular residual stresses induced by temperature gradients and plastic deformation in the solidifying shell. Residual stresses can also cause stress cracking, and lower the fatigue life and fracture strength of the casting parts. In the present study, aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling units was designed and the casting specimens were produced to quantify the effects of different cooling conditions on the development of residual stresses. The layer removal method was used to measure the biaxial residual stresses in casting specimens produced from the experiments. The experimental results agreed with Tien-Richmond's theoretical model for thermal stress development for the solidifying metal plate.