• Design & Manufacturing
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• v.15 no.1
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• pp.14-20
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• 2021

The objective of this study is to introduce the new possibility of sensing technology based on inductive displacement sensors to monitor the status of wheel position in the hot forging process. In order to validate effectiveness of proposed sensing technology, the indirect forging force measurement with displacement sensor was applied into a typical closed hot forging die-set used for the manufacturing of flange bolts. The locations to implement the displacement sensor were selected carefully by simulating forming process and static structural. From the measurement results of the forging force change during one hot forging cycle, it was found that the proposed monitoring system can provide useful information to understand the detailed behaviors of die-set in the closed hot forging process.

• Transactions of Materials Processing
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• v.9 no.2
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• pp.159-164
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• 2000

In this paper, a computer simulation technique for the forging process having a floating die is presented. The penalty rigid-plastic finite element method is employed together with an iteratively force-balancing method, in which the convergence is achieved when the floating die part is in force equilibrium within the user-specified tolerance. The force balance is controled by adjusting the velocity of the floating die in an automatic manner. An application example of a three-stage cold forging process is given.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.391-394
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• 2006

In this paper, a criterion on enclosed die forging with a double action link type hydraulic die set is presented. Operational principle of the die set in enclosed die forging is introduced with emphasis on force transfer from the press and the hydraulic system to the material through links, die components and punches. Force transfer mechanism is examined and three different modes are introduced. Requirements on force equilibrium are applied to the three force transfer modes and a criterion on enclosed die forging with a double action link type hydraulic die set is drawn. The criterion is discussed to minimize forming load.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.109-117
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• 1993

Force balance method is employed to predict forging information such as forging load, tool pressure and normal stress at the surface of tangential velocity discontinuity. The incipient stages of deformation for the plane strain forging of rectangular billets in V-shaped dies of different semi-angles are analysed. To construct an approximate model for the analysis of deformation by the force balance method in the incipient deformation stages, slip-line field is used. When the deformation mode by slip-line method is the same as that by force balance method, the slip-line method and the force balance method give identical solutions. The effects of die angle, coefficient of friction, billet geometries and deforma- tion characteristics are also investigated. In order to verify the validity of force balance analysis, the rigid-plastic finite element simulation for the various forgig parameters are performed and performed and find to be in good agreement.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.77-81
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• 1999

The predictions of metal flow forging load optimal die angle and preform size are not so easy in turbine blade forging. First of all the quality of final product is influenced by side force which is one of the significant factors. in this study slab method is applied to determine optimal die angle minimizing side force and the position of preform Finally drawing of die design is obtained in optimal die angle with developing tool that is composed of Visual Basic.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.103-107
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• 1999

In this paper, a computer simulation technique for the forging process having a floating die is presented. The penalty rigid-plastic finite element method is employed together with an iteratively force-balancing method, in which the convergence is achieved when the floating die part is in force equilibrium within the user-specified tolerance. The force balance is controled by adjusting the velocity of the floating die in an automatic manner. An application example of a three-stage cold forging process is given.

• Transactions of Materials Processing
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• v.8 no.6
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• pp.569-575
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• 1999

Computer programs have been developed to design the forging dies of turbine and compressor blades. The design of forging dies is based the side force and the filling of die cavity. In this study, slab method has been applied to simulate forging processes numerically. the program composed of Visual Basic also provides the informations of mean stress, total forging load, distribution of temperature, position of neutral line, total volume and volume of flash in the final stage to users. The preform position is predicted by the reverse slab method. The program has been successfully applied to various types of turbine blades.

• Transactions of Materials Processing
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• v.12 no.6
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• pp.536-541
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• 2003

In this paper, the rigid-viscoplastic finite element method is employed together with an iteratively force-balancing method to analyze a piercing and trimming process with a spring-attached die in hot former forging. An actual piercing and trimming process with a spring-attached die is investigated in detail and a generalized analysis model is proposed. A multi-stage hot former forging process is simulated under various spring constants. The analyzed results are discussed in order to investigate the effects of spring constants on the metal flow lines and the formed shapes. Then an optimal piercing and trimming process in hot former forging is devised.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.31-40
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• 1995

Powder metallurgy process has many advantages such as hight efficientyof material, mass productivity and complex shape production with good mechanical properties. Among the powder forming processes, incremental forging allows the consolidation to be achieved with amaller force then those required by conventional forging. In particular the proces known as rotary forging is an unique and prodominant process known as rotary forging is an unique and prodominant process in which the working constraints approximate to those in normal closed die forging. This study is concerned with the powder compaction by rotary forging process. An experimental rotary forging press with 500kN load capacity has been developed, which is equippe dwith the rotational conicla die inclined to the central axis of the press at arbitrary angle. It is found that the highly densified P/M parts can be obtained by rotary forging process and the material properties are superior to those of the conventrional sintered parts. The detailedcomparision of the mechanical properties by rotary forging process with those by conventional process are given.

• Journal of Drive and Control
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• v.19 no.4
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• pp.10-18
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• 2022

Air-drop hammer press and counterblow hammer press are widely used power-drop forging hammersemploying different forging blow mechanisms. It is important and necessary to analyze mechanical vibrations of these two different hammers in their forging processes in order to develop high performance forging hammers. In this study, these two forging hammers were mathematically modelled as mass-spring-damper systems. For these two different types of forging hammers, the forging efficiency and mechanical vibrations due to hammer forging blow were theoretically analyzed and compared. The force transmitted to the ground was also determined and compared. Especially, effects of mass ratio and restitution coefficient on forging efficiency were investigated.