• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.246-249
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• 2007

This study is concerned with deep drawability of magnesium sheets(AZ31B) at the warm conditions. Especially the dependency on forming speed has been investigated at the temperature of $200^{\circ}C$ and $300^{\circ}C$. Deep drawing test has been carried out at the temperature of $200^{\circ}C$ and $300^{\circ}C$. The die and blank holder are kept at test temperature by local heating and the punch is kept at room temperature by cooling technique. The magnesium sheets called AZ31B with the thickness of 0.5mm have been applied to deep drawing of circular cup. The drawability has been estimated at the conditions of forming speed (0.1, 1, 10 mm/sec). The results of deep drawing experiments show that the drawability is better at $300^{\circ}C$. Also the deep drawability is improved at the low speed(1mm/sec).

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.87-90
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• 2004

In this paper, net-shape forming of an automobile gear is investigated. Barrel, a component of automobile start motor, is adopted as a net-shape forming. In order to accomplish the goal of net-shape forming without cutting of tooth and cam after forming, forming ability is raised through billet treatment and die design. As a technique of billet treatment spheroidizing annealing of billet to get low hardness and molybdenum disulphide coating to get low contact friction between billet and die is carried out. One of critical points of die design, fillet radii variation of tooth of die is applied to get smooth surface of barrel after cold forging. As a measurement of tooth accuracy, distance between two pins and lead-tooth alignments are investigated. Cam profile accuracy is checked with a 3D measuring instrument. Results obtained from the tests revealed reasonable result with respect to design goal. By these results, the paper shows that reasonable results can be obtained by billet treatment and die design for net-shape forming.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.4 no.4
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• pp.7-15
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• 1995

• Transactions of Materials Processing
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• v.1 no.1
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• pp.5-10
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• 1992

• Journal of Power System Engineering
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• v.17 no.3
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• pp.65-71
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• 2013

The under rail slide is the latest device to make accurate rectilinear reciprocating motion. In these day, 3-point type is used mostly for the products requiring high strength and performance such as refrigerator door guide or furniture drawer guide. However, It is all imported from foreign countries due to lack of the roll forming technique to make 3-point type under rail slide in domestic. Therefore, design and manufacturing technology for the 3-point type under rail slide are need to development through systematic study. In this paper, to make center member of 3-point ball-type under rail slide for the refrigerator doors, the roll forming modeling and simulation are performed using Shape-RF software. Tensile test is performed about SCP-1 1/2H for determine the mechanical properties of materials. Interference between the roll and the final shape are predicted from the results of the simulation ; this result show that the desirable performance and usefulness of the designed roll forming process.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.113-118
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• 2007

The flow forming has been used to produce long thin walled tube parts, with the reduced fanning force and the enhanced mechanical and surface quality for a good finished part, compared with the fanned parts using other method. Therefore, flow fanning technique is used widely in industrial production. Spinning and flow fanning techniques are used frequently in automotive, aerial and defense industries. The main factors for the flow fanning machine design are motor power, bed rigidity, mandrel stiffness, spindle power, roller profile, etc. Especially, mandrel, spindle power and roller are important factors for flow fanning machine capacity. In this paper, three dimensional finite element method for analysis of one-roller backward flow fanning of a workpiece has been carried out to study effects of roller profile on fanning force. Applied roller profile have roller lead geometries of angle $20^{\circ},\;30^{\circ},\;40^{\circ}$, concave and convex. Axial and radial fanning forces on various roller profiles are obtained and compared with each analysis cases.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.04a
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• pp.63-66
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• 2003

Thermoforming of fiber reinforced thermoplastic (FRTP) braided tubes was studied as a new forming technique. FRTP braided tubes with four plies are fabricated by the pressure bonding method are used in thermoforming. Bulge forming, bending process, pipe fittings and FE analysis are carried out in this study. In bulge forming the composite tube can be expanded up to about two times initial diameter. The suggested bending process can be obtained bent products with various bending radii. In pipe fitting it is possible to fabricate T-shape fitting, cross fitting and two-branch fitting. These results exhibit developed forming processes become useful processes for textile composite tubes.

• Transactions of Materials Processing
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• v.9 no.3
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• pp.257-264
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• 2000

In this study, optimization for press forming condition of low arm was performed with explicit dynamic FEM code, Pam-Stamp. FEM simulation was coupled with the Taguchi's experiment technique having three design variables - friction coefficient, plastic anisotropy parameter, and blank shape - which are chosen to be optimized. The simulation results were compared with those of experiment. We found out the change of blank shape among these three design variables is very effective in optimizing press forming condition of low arm. In addition, the modified blank shape shows high yield of slitting coil.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.111-115
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• 2017

This forged piston is proposed with a lighter weight and higher durability than a gravity casting piston for gasoline engines. However, a forged piston is very difficult to develop and mass-produce due to lack of basic technologies such as design, material and forging technique. First, we benchmarked existing forged pistons according to database design parameters. Second, we evaluated two solidification processes, continuous casting and spray forming, to produce heat-resistant alloy billets for forging. The spray forming process gives better mechanical properties at all temperatures, particularly at elevated temperatures except when poor formability is present. We used DEFORM simulation to determine the optimum process condition with billet from spray forming and successfully commercialized it with LF Sonata HEV.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.125-136
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• 2012

Wrinkle and fracture are two major defects frequently found in the sheet metal forming process. In this process there are more than one design attributes to optimize and several uncontrollable factors which cannot be ignored in determining the optimal values of design variables. Therefore, attempts to reduce defects through a traditional optimization technique are often led to failures. In this research, a new design method for reducing the wrinkle and fracture under uncontrollable factors is presented by using decision-making theory. To avoid the psychological difficulties in determining the scaling constants of the multi-attribute utility function by using the ordinary lottery questions, a pair-wise comparison procedure is adapted to avoid this problem. The effectiveness of the proposed method is illustrated through a robust design of sheet metal forming process of a side member of an automotive body.