• Journal of Korea Foundry Society
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• v.35 no.4
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• pp.80-87
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• 2015

The Al die casting process has been widely used in the manufacturing of automotive parts when the process requires near-net shape casting and a high productive rate. However, porosity arises in the casting process, and this hampers the wider use of this method for the creation of high-durability automotive components. The porosity can be controlled by the shot condition, but, it is critical to set the shot condition in the sleeve, and it remains difficult to optimize the shot condition to avoid air entrapment efficiently. In this study, the 4.5 mm, 2.0 mm plate die castings were fabricated under various shot conditions, such as plunger velocities of 0.7 m/s ~ 3.0 m/s and fast shot set points of the cavity of -25%, 0%, 25%, and 50%. The mold filling behavior of Al melts in the cavity was analyzed by a numerical method. Also, according to the shot conditions, the results of numerical analyses were compared to those of die-casting experiments. The porosity levels of the plate castings were analyzed by X-ray CT images and by density and microstructural analyses. The effects of the porosity on the mechanical properties were analyzed by tensile tests and hardness tests. The simulation results are in good general agreements with the die-casting experimental results. When plunger velocity and fast shot set point are 1.0 m/s and cavity 25% position, castings had optimum condition for good mechanical properties and a low level of porosity.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.45-50
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• 2005

In this study, the casting/forging process was applied in manufacturing a low control arm, in order to prove that application of casting/forging process to Al6061 is likely to get the effect of light weight compared with existing steel products and to reduce the cost of materials. Firstly, In order to set up the optimum casting condition of the forging material, Al6061, casting experiments were carried out by controlling pouring temperature of the aluminum for casting, mold temperature, and pouring time. $700^{\circ}C$ pouring temperature, $300^{\circ}C$ mold temperature and 10-second pouring time were taken into account as the optimum casting conditions. With respect to a hot forging test, it is practiced on the basis of a temperature of materials, strain rate, and reduction rate so as to observe each microstructure and examine strain-stress curve simultaneously; examine tensile test and hardness test; eventually set up the optimum hot forging condition. A hot forging test, tensile test, hardness experiment, and microstructure observation were carried out on condition of $70\%$ reduction rate, $500^{\circ}C$ temperature of materials, and 1 strain rate. As a result of those experiments, 330MPa tensile strength, $16.4\%$ elongation, and 122.8Hv hardness were recorded. In oder to get a sound preform which has no unfitting cavity and less flash, two preforms were proposed on the basis of volume rate of the final product; the optimum volume rate of preform for the low control arm was $115\%$. In conclusion, it is confirmed that using the forging material rather than casting materials in casting/forging process is likely to get more superior mechanical properties. Compared with Al6061, performed by means of general forging, moreover, cast/forged Al6061 can not only stimulate productivity by reducing production processes, but cut down the cost of materials by reusing forging scraps.

• Journal of Korea Foundry Society
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• v.24 no.1
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• pp.34-39
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• 2004

The effects of casting condition and hot melt glue during Lost Foam Casting were investigated on the fluidity of Al alloy melt. The fluidity increased linearly with increasing pouring temperature in thick castings but non-linearly in thin casting due to the difference in main heat flow direction. The metal flow velocity was in range of $0.5{\sim}2.7$ cm/s in no evacuation condition and the minimum value of it was measured after the melt flow through the hot melt barrier. The mold evacuation improved the metal flow velocity by around $0.5{\sim}1$ cm/s. And the reaction zone layer thickness was about 1 cm in no-evacuation conditions but about 0.6 cm in mold evacuation condition of 710 torr due to the easier removal of pyrolsis product of EPS. And hot melt barrier thickness of 0.6 mm increased the reaction zone layer thickness up to about 2.5 cm. The fluidity decreased remarkably with an enlarged thickness of hot melt due to a lot of pyrolysis products.

• 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 Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.35-40
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• 2017

A most important progress in civilization was the introduction of mass production. One of main methods for mass production is die-casting molds. Due to the high velocity of the liquid metal, aluminum die-casting is so complex where flow momentum is critical matter in the mold filling process. Actually in complex parts, it is almost impossible to calculate the exact mold filling performance with using experimental knowledge. To manufacture the lightweight automobile bodies, aluminum die-castings play a definitive role in the automotive part industry. Due to this condition in the design procedure, the simulation is becoming more important. Simulation can make a casting system optimal and also elevate the casting quality with less experiment. The most advantage of using simulation programs is the time and cost saving of the casting layout design. For a 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 the casting layout design of an automotive Oil Pan_BR2E, Computer Aided Engineering (CAE) simulation was performed with three layout designs by using the simulation software (AnyCasting). The simulation results were analyzed and compared carefully in order to apply them into the production die-casting mold. During the filling process with three models, internal porosities caused by air entrapments were predicted and also compared with the modification of the gate system and overflows. With the solidification analysis, internal porosities occurring during the solidification process were predicted and also compared with the modified gate system.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.60-63
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• 2003

Semi-solid forming is the process of stirring alloy during solidification, making the mixture of liquid and solid, solidifying it, reheating it to the solid-liquid coexistent temperature, and then injecting this semi solid slurry into dies. In the semi-solid die casting process, it is very important to find out the correlation of injection condition, microstructure and mechanical properties. Especially, an improper injection condition is the main cause of liquid segregation and non-homogeneous mechanical properties due to the difference of solid fraction according to the position of the products. To ensure the database requisite to the semi-solid die casting product, it is essential to acquire the mechanical properties considering liquid segregation to the injection condition. In this study, the effect of injection condition on liquid segregation, formability, microstructure and mechanical properties in a thin product was investigated.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.101-109
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• 2001

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. Because of lower mechanical properties induced by the large grain structure and incomplete filling, conventional plaster casting is not suitable for the simulated die casting process. A plaster casting process with pressurized vibration was developed for the simulated die casting process[5]. In this paper, numerical simulation for the filling stage of the process has been performed to show the effect of the pressurized vibration for complete filling. Treatment of boundary condition based on the finite element method has been proposed for imparted pressurized vibration in the plaster casting process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.54-60
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• 2014

In industry, several casting process are widely used to manufacture complex and accurate blank part of hard materials such as aluminum, casting steels, bronze and magnesium alloys which are difficult to manufacture in a blank shape. Even if the casting process does not high accuracy superior surface characteristics other machining process, the casting process is widely used in manufacturing blank part. Furthermore, it is difficult to select appropriate casting process a part among several casting process. for effective selection different process, a careful decision given casting application is necessary. An appropriate casting for a given material and shape condition must be selected for novice engineers in industry. In this paper, an expert system based on an analytic network process(ANP) is suggested for best selection of casting considering a prior interdependency effect among various factors such as material, geometry, process capability, economy and equipment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.1
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• pp.7-12
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• 2001

This study is object to thermal analysis of continuous casting welding-coated mold. A two-dimen-sional transient finite element model was developed to compute the temperature distribution for continuous casting welding-coated mold. For thermal analysis using analysis result from FEM code. This thermal analysis results, many variables such as casting speed, cooling condition, film coefficient, convection and load condition are considered.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.30-34
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• 2000

In this paper we analyzed bulging condition which affect the quality of continuous casting steel by using the numerical analytic method. First solidification analyses are performed for each cooling zones. Solidification analysis are carried out by one-dimensuional finite difference method. The bulging deformation of cast slab has been calculated with a two-dimensional elasto-plastic and creep finite element model. The adequacy of the model has been checked against the experimental results. From this study the effects of the process variables such as casting speed cooling condition roll pitch are examined. The results from these analyses would be able to apply to the design of continuous casting process.