• Transactions of Materials Processing
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• v.9 no.4
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• pp.413-420
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• 2000

In the die casting process, the flow of liquid metal has significant influence on the quality of casting products and die life. For the optimal process design of front housing part of aircon compressor, various analyses were performed in this study by using computer simulation code, MAGMAsoft. The simulation has been focused on the molten metal behaviors during the filling and solidification stages for the sound casting products. Two cases of casting design that have different types of gating system are considered in the analysis. The potential sites where the casting defects may occur is examined by computer simulation and an improved design process is proposed. Also the effect of partial squeeze on the quality of casting products is considered and the optimal time lag after filling process is determined. For the die-stability, the effect of operational parameters such as die temperature, heat cycle and spot cooling on the die life has also been analyzed.

• Design & Manufacturing
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• v.2 no.1
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• pp.39-43
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• 2008

There occur not only many problems in the injection process but also low quality productivity due to the injection conditions of various injection factors. Injection molding process factors such as molding temperature, injection pressure, flow rate and flow velocity, must be controlled properly in filling and packing phases in the injection molding process. In this study, effects of these factors on the injection molding were investigated through the flow analysis for the holding pressure affecting cooling time. Results of this study would be helpful to setting of holding pressure for optimization of forming condition in order to reduce cooling time in injection molding.

• Transactions of Materials Processing
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• v.20 no.6
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• pp.427-431
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• 2011

In general, hot stamped component is trimmed by costly and time consuming laser cutting when the material strength is over 1,500MPa. The aim of this work was to demonstrate that the trimming die life is improved and the trimming load is decreased by lowering the strength of the region to be trimmed. The model employed in this study was a hat shape, similar to the cross section of many hot stamped products. FE-analysis of hot stamping process was performed to evaluate the effect of tool shape on cooling rate at the area to be trimmed. The best tool shape was thus identified, which created slower cooling and lower hardness at the region to be trimmed. The wear at the cutting tool edge was also reduced.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.127-130
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• 2007

Effect of the forging process parameters on the void crushing is the cogging process has been studied in order to find the most effective factor. The Process parameters used for this study are die width ratio, reduction ratio and pre-cooling time before cogging process. Void crushing analysis about the selected process parameters was carried out using FE analysis. The results of FE analysis were evaluated by Taguchi method. It was found that the efficiency of void crushing increases with an increase in the values of all selected process parameters and the principal factor controlling the void crushing was identified as the reduction ratio.

• Transactions of Materials Processing
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• v.16 no.7
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• pp.502-508
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• 2007

Effect of the process parameters of the cogging process on the void crushing has been studied in order to identify the most effective factor. The process parameters considered in this study are die width ratio, reduction ratio and pre-cooling time before cogging process. Void crushing analysis with the selected process parameters was carried out using FE analysis. The results of FE analysis were evaluated by Taguchi method. It was found that the efficiency of void crushing increases with an increase in the values of all selected process parameters and the principal factor controlling the void crushing was identified as the reduction ratio.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.11
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• pp.44-51
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• 2007

Condenser tubes are mainly produced by precision extrusion with a porthole die and are used in the flow pass of refrigerant cooling systems in automobiles. The recent technical trend of condenser tube requires the tube to be of more multi cellizing, high strength and small size, and to increase the heat transfer area and heat efficiency. Hence, this paper is shown that the results of FE-simulation are in good agreement with the experimental ones. Finally, the extrusion die shape is proposed through analysis of FE-simulation and performance of trial extrusion. Chamber shape dimension and initial temperatures of die is adjusted analysis results. And the possibility of extrusion is estimated that forming load, welding pressure and stress analysis of die in this paper. The validity of simulated results was verified into extrusion experiments on the condenser tubes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.110-113
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• 2008

This study was performed to predict the shape of polymer extrusion product and to find the cause of defective products Experiments was performed to extrude the complex profile shape using PC/ABS composite resin with new profile die and cooling die. A finite element analysis for the Polymer Extrusion process considering the heat transfer and thermal deformation was also performed, and the result was compared with the experimental data. It is found that the predicted profile shape in F. E. M was similar to the experimental result and the thickness of extruded product was thin when the velocity of profile die outlet was slow than the velocity of production (2m/min).

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.93-98
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• 2005

The purpose of this study is to confirm the improvement of formability of AZ31 magnesium alloy sheet by using local heating and cooling technique. For this, the experiments of warm deep drawing were done under the temperatures of $100^{\circ}C\~400^{\circ}C$, and the punch velocity of 10, 100mm/min. Also FE analysis under the temperatures of blankholder and die of $150^{\circ}C,\;225^{\circ}C\;and\;300^{\circ}C$ for tools(holder and die) was executed with considering heat teansfer. From the results, the formability of AZ31 magnesium alloy, espicially the temperatures of $225^{\circ}C\~250^{\circ}C$ for tools(holder and die)improved remarkably. And the experiments and simulations showed that necking under room temperature for tools occured under the part of punch shoulder while at $300^{\circ}C$ for tools, at the part of die shoulder.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.1030-1033
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• 2002

In this study, it is important that we have an understanding of the metal flow for manufacturing condenser tube in porthole die extrusion, because this need to provide for household appliances market that is expected to grow into the major market of the cooling system hereafter. Condenser tube is mainly manufactured by conform exclusion. However, this method was not satisfied a series of the needs for manufacturing condenser tube as compared with porthole die extrusion. The deforming skill recently is required high-productivity, high-accuracy and reducing lead-time, thus it is essential to substitute conform exclusion by porthole die exclusion. Porthole die extrusion has many advantages such as improvement of productivity, reduction of production cost etc. In general, the porthole die extrusion process consists of three stages(dividing, welding and forming stages). In order to obtain the detailed mechanics, to assist in the design of proper die shapes and sizes, and to improve the quality of products, porthole die extrusion should be analyzed in as non-steady state as possible during the entire process to evaluate detailed metal flow, temperature distribution, welding pressure and extrusion lead, and therm stress analysis was practiced to obtain effective stress and elastic deformation value. A analytical results provide useful information the optimal design of the porthole die for condenser tube.

• Journal of Korea Foundry Society
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• v.13 no.3
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• pp.268-275
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• 1993

In gravity die casting, die cooling systems are frequently employed with water cooling to remove the heat of the solidifying metal. Thermal modeling is an important technique in mold design for improving the productivity of the process. Computer simulation system which consists of pre-processor, main solidification simulator and post-processor has been developed for three dimensional solidification analysis of cyclic gravity die casting. The pre-processor is used for mesh generation in a PC system. The modified finite difference method is adopted for the main solidification simulation algorithm during all the casting cycles. The post-processor graphically presents the simulation results. Several experiments in automotive cast piston were carried out. The temperature variations in casting and mold with time are measured experimentally, and the results are compared with calculation results. The effects of cycle number on solidification pattern are also studied. Several experimental results for the prediction of shrinkage defects are compared with calculated results.