• Title/Summary/Keyword: ?드로잉 가공

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Evaluation of Warm Deep Drawability of Magnesium Alloy AZ31 Sheet Using Solid-Type Lubricants (고체 윤활제를 사용한 마그네슘 합금 AZ31 판재 온간 디프 드로잉의 성형성 평가)

  • Kim, H.K.;Kim, J.D.
    • Transactions of Materials Processing
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    • v.15 no.6 s.87
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    • pp.453-458
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    • 2006
  • While the die casting has been mainly used to manufacture the magnesium alloy parts, the press forming is considered as an alternative to the die casting for saving the manufacturing cost and improving the structural strength of the magnesium alloy parts. Because the magnesium alloy has low formability at room temperature, forming at elevated temperatures is a necessary condition to obtain the required material flow for press forming. However, the elevated temperature forming does not always guarantee the sufficient formability under the dry friction condition because the surface damage such as scratch or wear may accelerate the material failure. In the present study, the solid-type lubricants such as PTFE, graphite and MoS2 were tested for the square cup warm deep drawing using the magnesium alloy AZ31 sheet. The formability improvement by using the lubricant was examined by comparing the maximum deep drawing depth using the PTFE against no lubricant. The formability difference for the different lubricant was also examined based on the maximum deep drawing depth.

Numerical Simulation for a Multi-Stage Deep Drawing of Anisotropic SUS409L Sheet into a Rectangular Cup (초기 이방성 SUS409L 박판재의 직사각 컵 성형을 위한 다단 디프드로잉 공정 적용에 관한 수치적 연구)

  • Park, J.W.;Ku, T.W.;Kang, B.S.
    • Transactions of Materials Processing
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    • v.22 no.3
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    • pp.133-142
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    • 2013
  • Recently, electric vehicles and hybrid cars are being promoted as alternatives to reduce automobile emissions. Generally, thin sheet materials such as aluminum alloy AA300X and cold-rolled steel sheet such as JIS-G-3141 are used for the container for the lithium-ion secondary batteries. In this study, a multi-stage deep drawing process is used to produce a rectangular cup from thin stainless steel sheet material, SUS409L, with an initial blank thickness of 0.4mm for the battery container application. Numerical simulations of the first through the fifth stages for the multi-stage deep drawing with thin SUS409L sheet were conducted using LS-Dyna3D Implicit/Explicit. Special consideration was given to the deformation characteristics due to the normal anisotropy of the sheet material. The numerical simulations were conducted with both isotropic properties and the anisotropic properties of the initial blank material. An unexpected forming failure, barreling in the bottom region of the deep drawn rectangular cup, was observed. This failure mode can be avoided by additional ironing thickness control during the process.

A Experimental Study of Cup forming by Stretch-Drawing Process (인장드로잉법에 의한 원통성형에 관한 실험적 연구)

  • 김영수
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.04a
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    • pp.123-128
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    • 2000
  • Fundamental and informative data of axi-symmetric stretch-drawing of several sheetmetals with thicknesses of 0.7-1.0mm are presented both for single and double operations. Very small radius is applied to the die profile (or-shoulder) ion all operations. to induce wall-thinning by the effect of bending-under-tension from which the name 'stretch-drawing' comes. It is clearly demonstrated that deeper cups could be formed by single and double stretch-drawings from smaller circular blanks due to such wall-thinning action than in the usual deep-drawing of larger blanks, From this fact it is emphasized that the deep-drawability of a sheet metal is not evaluated simply by the conventional L.D.R (limiting drawing ratio) but the depth of the drawn cup should also be taken into account./ Many experimental data about various metals and thicknesses given in this paper offer a valuable information in this process for more general use which recommends to replace the conventional deep-drawing process by the stretch-drawing process both for single and double operations. In the single stretch-drawing it is also confirmed that a deeper cup can be produced by raising the blank-holding force at later stage of operation.

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A Study on the Drawability of Clad Sheet Metal (STS304-A1050-STS304) by Warm Draw Die (온간금형에 의한 클래드판재(STS304-A1050-STS304)의 드로잉성 연구)

  • Ryu H. Y.;Kim J. H.;Ryu J. G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.136-143
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    • 2002
  • Warm draw die technique which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical and square cup drawing of stainless-aluminum clad sheets. In experiments the temperature of die and blank holder is varied from room temperature to 180C, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch comer area. Test materials chosen for experiments are STS304-A1050-STS304 clad sheets. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio and relative drawing depth as well as quality of drawn cups(distribution of thickness)are investigated and validity of warm drawing process is also discussed. No separation between each laminated material after drawing occurred through inspection by microscope as well as application of penetrant remover and bond strength test. Therefore, warm forming technique was confirmed to give better results in deep drawing of stainless clad sheet metal.

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Finite Element Analysis of Multi-Stage Deep Drawing Process for High Precision Rectangular Case with Extreme Aspect Ratio (세장비가 큰 사각컵 디프 드로잉의 유한요소 해석)

  • Ku T.W.;Ha B.K.;Song W.J.;Kang B.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.274-284
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    • 2002
  • Deep drawing process for rectangular drawn section is different with that for axisymmetric circular one. Therefore deep drawing process for rectangular drawn section requires several intermediate steps to generate the final configuration without any significant defect. In this study, finite element analysis for multi-stage deep drawing process for high precision rectangular cases is carried out especially for an extreme aspect ratio. The analysis is performed using rigid-plastic finite element method with an explicit time integration scheme of the commercial program, LS-DYNA3D. The sheet blank is modeled using eight-node continuum brick elements. The results of analysis show that the irregular contact condition between blank and die affects the occurrence of failure, and the difference of aspect ratio in the drawn section leads to non-uniform metal flow, which may cause failure. A series of experiments for multi-stage deep drawing process for the rectangular cases are conducted, and the deformation configuration and the thickness distribution of the drawn rectangular cases are investigated by comparing with the results of the numerical analysis. The numerical analysis with an explicit time integration scheme shows good agreement with the experimental observation.

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Finite-Element Analysis of Warm Square Cup Deep Drawing Process of Magnesium Alloy AZ31 Sheet (마그네슘 합금 AZ31 판재의 온간 사각컵 디프드로잉 공정의 유한요소 해석)

  • Kim H.K.;Lee W.R.;Hong S.K.;Kim J.D.;Han B.K.
    • Transactions of Materials Processing
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    • v.15 no.3 s.84
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    • pp.232-240
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    • 2006
  • Magnesium alloys are expected to be widely used fur the parts of structural and electronic appliances due to their lightweight and EMI shielding characteristics. While the die casting has been mainly used to manufacture the parts from the magnesium alloys, the press forming is considered as an alternative to the die casting for saving the manufacturing cost and improving the structural strength of the magnesium alloy parts. However, the magnesium alloy has low formability at room temperature and therefore, in many cases, forming at elevated temperatures is necessary to obtain the required material flow without failure. In the present study, square cup deep drawing tests using the magnesium alloy AZ31 sheet were experimentally conducted at various elevated temperatures as well as room temperature, and the corresponding finite-element simulations, which calculated the damage evolution based on the Oyane's criterion, were conducted using the stress-strain relations from the tensile tests at various temperatures. The formability predictability by the finite-element analysis was investigated by comparing the predicted damage distributions over the deformed AZ31 sheet at elevated temperatures with the corresponding experimental deformations with failures.

Finite Element Inverse Analysis of the Deep Drawing Process Considering Bending History (굽힘이력을 고려한 딥드로잉공정의 유한요소역해석)

  • Huh, J.;Yoon, J.H.;Bao, Y.D.;Huh, H.
    • Transactions of Materials Processing
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    • v.16 no.8
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    • pp.590-595
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    • 2007
  • This paper introduces a new approach to take account of bending history in finite element inverse analysis during sheet metal forming process. A modified membrane element was adopted for finite element inverse analysis so that bending-unbending energy was additionally imposed in the total plastic energy, predicting bending-unbending regions using the geometry of the final shape and tools. An algorithm was applied to a cylindrical cup deep drawing process. The blank shape and the distribution of the thickness strain were compared with those obtained from the incremental finite element analysis in order to evaluate the effect of the bending history. The algorithm reduced the difference between the results of the inverse analysis from those of the incremental analysis due to bending history. The analysis was also carried out with the variation of the thickness of the initial blank to investigate the effect of bending deformation. The results showed that the difference was remarkably reduced as the thickness of the initial blank increased. This indicates that the finite element inverse analysis cooperated with the suggested scheme is useful to obtain more accurate results, especially when bending effects are significant.

Improvement of Formability of AZ31 Magnesium Alloy Sheet during Warm Deep Drawing (AZ3l 마그네슘합금의 온간디프드로잉시 판재성형성 향상)

  • Rhee, Myeong-Sup;Kang, Dae-Min
    • Transactions of Materials Processing
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    • v.15 no.2 s.83
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    • pp.148-152
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    • 2006
  • In this study, the experiments of warm deep drawing were done with heated die, and with heated die, and blankholder, and cooled punch in order to investigate the formability of AZ31 magnesium alloy sheet in warm deep drawing. For this, warm deep drawing experiments were executed under various temperatures and punch velocities. The results of warm deep drawing with heated die showed that fracture occurred around the punch part at punch velocity of 75mm/min and punch stroke of 10mm under temperature range of 373-523K, but did not occur under temperature range of 548-673K even punch stroke of 25mm. And fracture at the punch stroke of 25mm and the temperature of 523K did not occur under the punch velocity of 30mm/min, but occurred under punch velocity of 75 and 125mm/min. Also warm deep drawing with heated die and blankholder, and cooled punch showed that the temperature range happening maximum height under punch velocity of 10-100mm/min was around 498-523K. Finally, with heating and cooling technique necking of AZ31 magnesium alloy occurred at punch shoulder part under the temperature range of 293-423K, but at die wall part under the temperature range of 473-573K.

Finite-Element Analysis of Formability in Warm Square Cup Deep Drawing of Magnesium Alloy AZ31 Sheet (마그네슘 합금 AZ31 판재의 온간 사각컵 딥드로잉 성형성의 유한요소 해석)

  • Kim Heung-Kyu;Lee Wi Ro;Hong Seok Kwan;Han Byoung Kee;Kim Jong Deok
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.122-125
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    • 2005
  • Magnesium alloys are expected to be widely used for the parts of structural and electronic applications due to their lightweight and EMI shielding characteristics. While the die casting has been mainly used to manufacture the parts from the magnesium alloys, the press forming is considered as an alternative to the die casting for saving the manufacturing cost and improving the structural strength of the magnesium alloy parts. However, the magnesium alloy has low formability at room temperature and therefore, in many cases, forming at elevated temperatures is necessary to obtain the required material flow without failure. In the present study, square cup deep drawing tests using the magnesium alloy AZ31 sheet were experimentally conducted at various elevated temperatures as well as room temperature, and the corresponding finite-element simulations, which calculated the damage evolution based on the Oyane's criterion, were conducted using the stress-strain relations from the tensile tests at various temperatures. The formability predictability by the finite-element analysis was investigated by comparing the predicted damage distributions over the deformed AZ31 sheet at elevated temperatures with the corresponding experimental deformations with failures.

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Experimental Study on Non-Axisymmetric Rectangular Cup using Multi-Stage Deep Drawing Process (직사각 컵 성형을 위한 다단 디프드로잉 공정의 실험적 연구)

  • Ku, T.W.;Park, J.W.;Heo, S.C.;Kang, B.S.
    • Transactions of Materials Processing
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    • v.19 no.4
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    • pp.253-262
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    • 2010
  • For multi-stage deep drawing process including ironing operation and biaxial forming in this study, tool developments are achieved, and the developed tool sets are applied to experimental investigations. In process and tool designs, a contact condition between intermediate blank and lower die is considered as the sequential one. In this study, the material used is cold-rolled thin sheet (SPCE) with the initial thickness of 0.4mm. From the experimental approaches, several failures such as tearing, localized thickening and thinning, are observed. To solve these failures, the contact surface on the lower die is modified. As the experimental results by applying the modified lower die, it is investigated that the failures are not occurred, and the excessive deformation behavior due to the thinning and thickening effects are decreased. Furthermore, the thickness distributions on the major axis and the minor axis of each intermediate blank are investigated to be already satisfied the target (ironing) thickness, respectively. By this systematic approach, it is confirmed that the experimental results show good agreements with the designed and required configuration of each deformed and final products.