• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.842-845
• /
• 2000

The purpose of this paper is to investigate the influences on mechanical properties of motor pistons manufactured by casting, conventional forging and powder forging, using the comparison of characteristics like microstructure, hardness, tensile strength, and elongation. To form conventional forging piston, the experiment of visioplasticity was performed. As the model material, plasticine was used. To form powder forging piston, the shape of piston was simplified as simple cup shape. Material properties like workability, density variation before and after forging, and strain loci of material during forging were investigated. Powder forging and conventional forging technologies were effective to gain dense microstructure. In powder forging, distribution of such dense microstructuer was uniform. For hardness, pistons from powder forging and conventional forging technologies were much better than that from casting. For tensile strength and elongation, powder forging and conventional forging technologies were also advantageous.

• Design & Manufacturing
• /
• 제6권2호
• /
• pp.24-30
• /
• 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.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 춘계학술대회 논문집
• /
• pp.837-841
• /
• 1997

An upper bound elemental technique(UBET) program has been developed to analyze forging load, die-cavity filling and optimum kinematically admissible velocity fields for flashless forging. The simulation for flashless forgings are applied plane and axisymmetric closed-die forging with rib-web type cavity. The kinematically admissible velocity fields for inverse triangular and inverse trapezoidal elements, are used to analyze flashless forging. Experiments have been carried out with pure plasticine billets at room temperature. Theoretical predictions of the forging load in plane-strain and axisymmetric forging are in good agreement with experimental results.

• International Journal of Precision Engineering and Manufacturing
• /
• 제2권4호
• /
• pp.69-74
• /
• 2001

Powder forging technology has been introduced to manufacture the parts for vehicles. This paper describes the process conditions for the powder forging of aluminium also piston for vehicles including the determination of composition of aluminum alloy by experiment, preform design by FEM simulation, coed compaction of aluminum alloy powder, sintering of preform, and the experiment of powder forging. The mechanical properties such as hardness, tensile strength, and elongation of the farmed piston were invested and compared with casted piston and forged piston. The tensile strength and hardness of the piston formed by powder forging technology were much more excellent than other pistons.

• 한국정밀공학회지
• /
• 제14권12호
• /
• pp.105-113
• /
• 1997

In this study, the forging process of spur gears has been investigated. The forging process of spur gears has been classified into two type of operations, guiding one and clamping one in this investigation. Two type forgings of spur gears have been analysed by using upper bound method. The predicted values of the forging load were compared with those obtained from the forging experiments. The forging experiments were carried out with a commercial aluminium alloy. The forged parts obtained through the guiding type forging were campared with those obtained through the clamping type forging.

• 한국정밀공학회지
• /
• 제21권1호
• /
• pp.32-39
• /
• 2004

Traditional forging of a hollow T-shaped part has been applied to forge a solid T-shaped product from a solid billet and then to machine the hollow in that. In a case, a hollow T-shaped part can be forged by backward-extruding from a solid billet. In this study, four types of forging were suggested for manufacture of hollow T-shaped parts. Forging simulations for each of these forging methods were carried out to investigate folding defect, metal flow pattern, effective strain, and forging loads. Experimental works were carried out to be compared with the simulation results. Here, the ratio of the thickness of the hollow tube to that of the flange was selected to investigate a forging defect like folding.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1993년도 추계학술대회 논문집
• /
• pp.218-223
• /
• 1993

An UBET(Upper Bound Elemental Technique) program has been developed to analyze forging load, die-cavity filling and effective strain distribution for flashless forging. To analyze the process easily, it is suggested that the deformation is divided into two different parts. Those are axisymmetric part in corner and plane-strain part in lateral. The total power consumption is minimized through combination of two deformation parts by building block method, from which the upper-bound forging load, the flow pattern, the grid pattern, the veocity distribution and the effective strain are determined. To show the merit of flashless forging, the result of flashless and flash forging processes are compared through theory and experiment. Experiments have been carried out with plasticine billets at room temperature. The theoretical predictions of the forging load and the flow pattern are in good agreement with the experimental results.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2001년도 추계학술대회 논문집
• /
• pp.321-325
• /
• 2001

This paper describes the basic structure of high-precision warm forging process for ball joint socket. If this research is successfully finished, We expect that productivity improvement, reduction of material cost and machining process, and cost down than conventional warm forging process.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 춘계학술대회 논문집
• /
• pp.1015-1019
• /
• 1997

In this study, the forging process of spur gears has been investigated. The forging peocess of spur gears has been classified into two type of operations, guiding one and clamping one in this investigation. Two type forgings of spur gears have been analysed by using upper bound method. The predicted values of the forging load were compared with those obtained from the forging experiments. The forging experiments were carried out with a commerial aluminium alloy. The forged parts obtained through the guiding type forging were campared with those obtained through the clamping type forging.

• 한국기계가공학회지
• /
• 제17권4호
• /
• pp.83-90
• /
• 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.