• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.4
• /
• pp.29-35
• /
• 2007

The main objective of this paper is to propose the optimal design method of forging process using genetic algorithm. Design optimization of forging process was doing about one stage and multi stage. The objective function is considered the filling of die. The chosen design variables are die geometry in multi stage and initial billet shape in one stage. We performed FE analysis to simulated forging process. The optimized preform and initial billet shape was obtained by genetic algorithm and FE analysis. To show the efficiency of GA method in forging problem are solved and compared with published results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1997.10a
• /
• pp.11-16
• /
• 1997

In this study, the finite element analysis of AA6061 wheel forging processes over hot working range is performed and a thermo-viscoplasticity theory applicable to hot forging is applied for simulation. Aluminum alloy has frequently been utilized to manufacture automobile and aircraft parts due to its various advantages such as lightness, good forgeability, and wear resistance. Several forging conditions are applied to the simulation, such as die speeds, rib thicknesses, and depth of die cavity. The effectiveness of the simulation results is summarized in terms of metal flow, strain distributions, temperature distributions, forging load, which are essential to over all process design.

• Journal of Powder Materials
• /
• v.2 no.1
• /
• pp.19-28
• /
• 1995

Powder forging is a combined technology of powder metallurgy and precision hot forging. Recently, the technology is developing rapidly because of its economic merits, especially in automotive part manufacturing. In the present study, the finite element technique was developed to predict density variation during P/M forging and the technique was applied to analysis of forging of a P/M connecting rod. Although deformation mode of the connecting rod was quite complex, several sections were selected and analyzed under an assumption of asymmetric or plane strain deformation. It was found that some modifications were necessary on the cross section of the beam portion. Therefore, the cross section was modified repeatedly until a satisfactory result of the analysis was obtained. On the other hand, no modifications were necessary in the ring and the pin portions. It is anticipated that the developed technique can be used to optimize preform design and manufacturing processes in P/M forging, which are highly critical to produce successful products in practice.

• Transactions of Materials Processing
• /
• v.3 no.3
• /
• pp.271-281
• /
• 1994

Titanium-6242 $({\alpha}+{\beta})$ alloy has been used for aircraft engine components such as disks and blades, because it has an excellent strength/weight ratio at high temperatures. When this material is forged to manufacture disks, process parameters should be carefully designed to control strain and temperature distributions within the process windows by which desirable mechanical properties can be produced. In the present investigation, it was intended to design the process parameters for a conventional hot forging of this material by using a rigid-thermoviscoplastic finite element analysis technique. It was assumed that the process was performed by a screw press which is capable of maintaining a constant ram speed during loading. From the analysis results, it was found out that the initial temperature of the workpiece and the die shape were important parameters to control the forging process. In result, these parameters were properly designed for hot forging of a disk with specific dimensions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.25 no.9
• /
• pp.1438-1443
• /
• 2001

The significance of the casting/forging process for reducing the production cost of large components is being noted in these days. This casting/forging process is a method of forging a workpiece preformed by casting into the final shape. In this study, the casting/forging process has been applied in manufacturing a large aluminum flange in order to reduce press capacity and material cost. Firstly, a hot compression test was performed with cast cylindrical billets in order to determine the optimum forging condition of the aluminum flange. The optimum range of forging temperature of Al 5083 was from 420$\^{C}$ to 450$\^{C}$. The suitable strain rate was 1.5 sec(sup)-1. The deformation amount of a preform of a preform in a forging process is a key role in the mechanical properties of casting/forging products. In order to find the change of mechanical properties according to effective stain of cast aluminum billets, a hot upsetting test were performed with rectangular blocks and then a uniaxial tensile test was performed with specimens cut from the upsetted billets. The tensile strength and the elongation of cast/upsetted aluminum billets were increased largely until the effective strain was 0.7. FE analysis was performed to determine the configurations of case preform and die for an aluminum flange. In the FE analysis, the forging load-limit was fixed 1500ton for low equipment cost. The cast preform was designed so that the effective stain around the neck of a flange exceeded 0.7. From the result of FE analysis, optimal configurations of the cast preform and the die were designed for a large flange. The filling and solidification analysis for a sound cast-preform was carried out with MAGMA soft. In the forging experiment for an aluminum flange, it was confirmed that the optimal configuration of the cast preform predicted by FE analysis was very useful. The cast/forged products using designed preform were made perfectly without any defects.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.905-909
• /
• 2002

Commutators of a starting motor for automobiles has been produced through various processes such as forging, segmenting, and assembling. And the conventional method producing an automotive motor commutator is not appropriate for saving material and cost, because it makes each segment separated one by one. Therefore a new process design is required in oder to avoid the assembling process. In this study, a new process design of the commutator of an automotive starting motor has been carried out to save material and manufacturing time by FE analysis. In the FE analysis, three forging processes are proposed for producing the copper(ASTM Cl1000) commutators of a starting motor. And forging experiments are performed to make an unsegmented commutator in order to verify the theoretically proposed process. And then, in order to get the final product, the forged commutator is passed through various postprocessing such as resin terming, and machining. From the experimental result, the forging process proposed from the FE analysis is verified to be an economical method for producing the commutator of an automotive starting motor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2002.05a
• /
• pp.149-153
• /
• 2002

The commutator of an automotive fuel pump motorhas been produced through various processes such as forging, segmenting, and assembling. And the conventional method producing the commutator of an automotive fuel pump motor is not appropriate for saving material and cost, because it makes each segment separated one by one. Therefore a new process design is required in order to avoid the assembling process. In this study, a new process design of the commutator has been carried out to save material and manufacturing time by FE analysis. In the FE analysis, three forging processes are proposed for producing copper(ASTM C11000) commutator of an automotive fuel pump motor. And forging experiments are performed to make an unsegmented commutator in order to verify the theoretically proposed process. And then, in order to get the final product the forged commutator is passed through various postprocessing such as machining, bending, resin forming, and shearing process. From the experimental result the forging process proposed from the FE analysis is verified to be an economical method for producing the commutator for an automotive fuel pump motor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.10a
• /
• pp.34-38
• /
• 2003

In metal working, cold forging that has profit to satisfy dimension accuracy is using in various manufacturing products. Recently, most of the interest thing is precision forging of gear. Gear forging product is more strength than broaching gear, and it has many advantages with reduction of factory expenses. The reason of difficulty to improve accuracy of gear dimension compare to another products is the dimension accuracy is very high, approximately 10$\mu\textrm{m}$, and because die of involute teeth and elastic strain of forged tool differ from standard curve. This paper represent quantitative analysis of die and teeth of forged tool, namely difference of curves, with experiments and analyze the factor of dimension gap, finally, will design compensated involute curve.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.05a
• /
• pp.386-390
• /
• 2006

In this paper, kinematic analysis of a double-action link-type die set for the enclosed die forging is carried out. Operational principle of the die set in the enclosed die forging is introduced in detail. A closed form solution of the relative velocity of the middle plate with respect to the upper plate is given. The effect of link lengths on both strokes and velocities is investigated.

• Transactions of Materials Processing
• /
• v.16 no.6
• /
• pp.479-487
• /
• 2007

Die life is generally estimated taking failure life and wear amount into consideration. In this study, the forging die life was investigated considering both of these two factors. The fatigue life prediction for the die was performed using the stress-life method, i.e. Goodman's and Gerber's equations. The Archard's wear model was used in the wear life simulation. These die life prediction techniques were applied to the die used in the forging process of the socket ball joint of a transportation system. A rigid-plastic finite element analysis for the die forging process of the socket ball was carried out and also the elastic stress analysis for the die set was performed in order to get basic data for the die fatigue life prediction. The wear volume of the die was measured using a 3-dimensional measurement apparatus. The simulation results were relatively in good agreement with the experimental measurements.