• Design & Manufacturing
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• v.6 no.2
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• pp.24-30
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• 2012

In this study, the hot forging technology for precision forming of spline teeth of the inner race in the auto-transmission was developed in order to minimize its finishing allowance. Several blocker and finisher shapes for the precision hot forging process of the inner race were proposed and the forging processes were analyzed using the three-dimensional finite element method. The optimum hot forging process was obtained considering some parameters such as metal flow patterns, forging defects and forming load. Blocker and finisher dies for the hot forging process were designed by selecting the most suitable shapes obtained from the finite element analysis. Experimental works were also performed in order to verify the optimum design of hot forging process.

• Transactions of Materials Processing
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• v.11 no.2
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• pp.165-170
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• 2002

The preform design of forging processes plays a key role in improving product qualities, such as defect prevention, dimensional accuracy and mechanical strengths. In the industry, preforms are generally designed by the iterative trial-and-error approach, but it results in significant tooling cost and time. It is thus necessary to minimize lead-time and human intervention through an effective preform design method. In this paper, the equi-potential lines designed in the electric field are introduced to find the preform shape, and then the optimization process is used to choose the equi-potential lines that will keep the die wear to a minimum Because, in the forging process, the die wear is a function of various important factors, such as forming stress and strain, microstructure and mechanical properties of a Product.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.10a
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• pp.93-98
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• 1996

Process design is one of the most important fields in metal forming, where the finite element method has appeared a useful method for industrial applications. In this study. A finite element method has been applied for iso-thermal forging design in turbine disk. This kind of approach is good for minimize actual redesign of die. which can reduce die production cost. - vital importance in current industrial environment.

• Transactions of Materials Processing
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• v.13 no.7
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• pp.635-641
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• 2004

Today the specific outputs of modern supercharger DI diesel engine for passenger cars reach values exceeding 50kw/1. By development of the articulated piston, specific output of up to 70kw/1 are sought. In doing so, peak cylinder pressure increases from the current 14-16MPa to 18-20MPa. The Articulated piston was composed Al cast skirt part and steel forged crown part. We have the target fer the design of forging process and die of the steel forged crown part. The design parameters of the forging process of the piston were obtained by the forging industry experiences and our experimental data and analysis result of finite element simulation. Especially, the design parameter of preform in blocker die was decided by finite element simulation using numerical package DEFROM3D. And also we can verify the design parameter by conducting visio-plasticity test using plasticine material. When we compared the results of analysis and experiment, a metal flow and load curve showed good agreement. Through this research, we could design optimal preform shape of articulated piston for this supercharged DI diesel engine.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.2
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• pp.295-303
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• 2009

Forging of square spline was investigated by using finite element methods in this study. Spline is widely used by torque transmitter in the fields of automobile, aircraft, and shipping etc. Friction on the surface of die is regarded as the most important factor to improve the dimensional accuracy for complete forming of spline teeth. Finite element simulation was carried out to improve the formability of the spline, especially remove unnecessary burrs which were extruded in gap between the die and the punch. To remove the burrs, various friction factors are considered on the surfaces of the die in the simulations and punch flat surface was designed. The simulated results were compared with experimental ones. As a results, it is possible to control the growth of burrs and improve formability of spline teeth by applying various friction factors and design of punch flat surface.

• Transactions of Materials Processing
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• v.8 no.5
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• pp.498-506
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• 1999

The metal forming processes of aluminum alloy wheel forging at elevated temperature are analyzed by the finite element method. A coupled thermo-mechanical model for analysis of plastic deformation and geat transfer is adapted in the finite element formulation. In order to consider the strain-rate effects on material properties and the flow stress dependence on temperatures, rigid-viscoplasticity is introduced in this formation. In this paper, several process conditions were applied to the dimulation such as die speed, rib thickness, and depth of die cavity. Simulation results are compared, and discussed with each case. Metal flow, die pressure distributions, temperature distributions, velocity fields and forging loads are summarized as basic data for process design and selection of a proper press equipment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.249-250
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• 2010

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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• pp.106-113
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• 1996

Using stainless steel as the cold forged parts especially the outer parts of automobile is gradually increasing because it can bear up against the erosion and the wear. During cold forging of the stainless steel the working pressure acting on die surface are very high therefore the wear on die surface can be greatly increased. In cold forging processes, die failure must be considered before die design. One of the main reasons of die failure in industrial application of metal forming technologies is wear. The die wear affects the tolerances of forged parts, metal flow and costs of processes etc. The only way to to control these failures is to develop methods which allow prediction of the die wear and which are suited to be used in the desing stage in order to optimize the process. In this paper, the rigid-plastic finite element method was combined with the wear prediction routine and then the forward extrusion process using stainless steel was analysed simultaneously. To minimize the die wear the FPS algorithm was applied and the optimal conditions of die configuration are suggested.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.83-90
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• 2018

In this research, we developed a process design hot-forging technology that precisely forms an inner race. The inner race transmits power to a one-way clutch of an automatic transmission and minimizes the CNC machining allowance. For a multi-stage hollow shape (inner race), we proposed several shapes of blocker and finisher for the precision hot-forging process and analyzed the forging process using DEFORM. The hot-forging process was optimized for several parameters, such as metal flow pattern, forging defect, and forming load. Blockers and finisher dies in the hot-forging process were designed to select optimal shapes from finite element analysis, and experiments were conducted to optimize the hot-forging process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.144-148
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• 2007

In this paper, we present a systematical procedure to develop a precision enclosed die forging process for a bevel gear of a passengers' car. The detailed procedure involves bear gear CAD modeling, process design and CAE simulation, CAM and die making, material preparation, and prototype manufacturing using both the technologies and machines accumulated and equipped in the technology innovation center(TIC) of Gyeongsang National University. It is demonstrated that the presented approach guarantees bevel gears with the second KS grade quality, which can be used for the differential gear of the passengers' car.