• Title/Summary/Keyword: Surface drawing

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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 $MoS_2$ 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.

The Effects of Draw Ratio of Worsted Yarn on the Mechanical Properties of Knitted Fabrics (소모연신사의 연신비가 니트의 역학적 성질에 미치는 영향)

  • Han, Won-Hee;Kim, Seung-Jin
    • Textile Coloration and Finishing
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    • v.22 no.3
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    • pp.272-281
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    • 2010
  • This paper surveys the effects of drawing conditions of the worsted staple yarns on the mechanical properties of the knitted fabrics for highly aesthetical fabrics. The drawn worsted yarns were made on the yarn drawing system with various draw ratios under the fixed conditions of setting time, reduction and oxidation. The knitted fabric specimens were prepared on the 16 gauge circular knitting machine using these drawn worsted staple yarns. The tensile, shear, bending, compression and surface properties of these knitted fabrics were measured by KES-FB-AUTO-A system and also discussed with the drawing conditions. The tensile linearity, shear stiffness and bending rigidity decreased with increasing draw ratio. Any changes were not shown on the compressional properties with drawing conditions. But the friction coefficient of the knitted fabric on the course direction increased with increasing draw ratio, while there was no change according to the draw ratio on the wale direction.

A Study of the Springback Reduction in Aluminium Sheet Forming Using Response Surface Method (반응표면분석법을 이용한 알루미늄 판재 성형공정의 스프링백 저감에 관한 연구)

  • 양재봉;전병희;오수익
    • Transactions of Materials Processing
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    • v.9 no.5
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    • pp.526-532
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    • 2000
  • Springback simulation is receiving increasing attention throughout the automotive industry and the academic world. The knowledge of the real springback of stamped parts can help the stamping technicians to modify the process parameters or die geometry in order to reduce the shape defect. This paper presents the results of springback simulation after aluminium square cup deep drawing and trimming simulation, and results of springback optimization using response surface method.

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A General Tool Surface Contact Search and its Application to 3-D Sheet Forming (일반적인 금형면에서의 접촉탐색과 3차원 박판성형에의 응용)

  • 서의권;심현보
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.121-124
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    • 1997
  • In the present study, a general tool surface contac search ad check algorithm is proposed. A general tool surface is described by triangular FE mesh. To check a proposed algorithm, clover cup and L-shape cup deep drawing processes are calculated. The elastic-plastic FEM using SEAM (Shear Energy Augmented Membrane) element is adapted for numerical stability.

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Effects of Cryogenic Temperature on Wear Behavior of 22MnB5 Under Cold Stamping (극저온이 22MnB5강의 냉간 스탬핑 마모에 미치는 영향)

  • Ji, Min-Ki;Noh, Yeonju;Kang, Hyun-Hak;Jun, Tea-Sung
    • Tribology and Lubricants
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    • v.38 no.6
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    • pp.241-246
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    • 2022
  • This paper presents the effects of cryogenic temperature on the wear behavior of 22MnB5 blank under cold stamping. After immersing the blank in liquid nitrogen (LN2) for 10 min, a strip drawing test was performed within 10 s. The hardness was measured using the Rockwell hardness test, which increased from 165 HV at 20℃ to 192 HV at cryogenic temperature. The strip drawing test with 22MnB5 blank and SKD61 tool steel shows that for the different wear mechanisms on the tool surface with respect to temperature; adhesive wear is dominant at 20℃, but abrasive wear is the main mechanism at cryogenic temperature. As the friction test is repeated, sticking gradually increases on the tool surface at 20℃, whereas the scratch increases at cryogenic temperature. For the friction behavior, the friction coefficient rapidly increases when adhesive wear occurs, and it occurs more frequently at 20℃. The results for nanoindentation near the worn blank surface indicate a difference of 1.3 GPa at 20℃ and 0.8 GPa at cryogenic temperature compared to the existing hardness, indicating increased deformation by friction at 20℃. This occurs because thermally activated energy available to move the dislocation decreases with decreasing temperature.

A Study on the Sweep Surface Modeling for Reverse Engineering (역공학을 위한 Sweep 곡면 모델링에 관한 연구)

  • 임금주;이희관;양균의
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.426-429
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    • 2001
  • Many various products are manufactured which have sculptured surfaces recently. Constructing surface of these models is required technique called reverse engineering. In reverse engineering, a product which has sculptured surfaces is measured and we create surface model to acquire complete model data of object. Measured point data needs preprocess and sampling. Next a set of point data in a plane fit section curve. At last, surface is generated by fitting to section curves. Here we uses sweep surface. Sweep surface is compatible fitting CAD model to drawing. This paper discusses converting approximation of NURBS surface as a standard surface.

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A Study on The Construction of 3-Dimensional Edge Blend Surface Modeling (곡면 모델링에서 3차원 경계 곡면 블렌드 구성에 관한 연구)

  • 이창억
    • Journal of the Korean Professional Engineers Association
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    • v.27 no.3
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    • pp.121-131
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    • 1994
  • It is very difficult to partially describe the hull shape made up of 3-dimensional free form surface. With computerizing skill in ship design, the geometric modeling technique has been developed. In hull shape modeling, the blending technique has not yet been adapted to the hull shape surface has a variable curvature. By adapting the blend surface, small surface on drawing plane is to be softly blended with given hull surface and a projecting part. This study has adapted to the ship design one of the blending methods by which offsets data of the blend surface can be obtained by the input of blend radius on two base surfaces.

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A Study on the Surface Roughness in the A 5032 Sheet Metal Forming (A 5032 판재성형에서 발생하는 표면거칙기에 관한 연구)

  • 박서운;김진무
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.546-551
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    • 1997
  • In sheet metal forming, since the surface area of workpiece is apparently larger than the volume of it, the surface condition of the sheet metal is much varied. The formability of sheet metal is decided by the forming limit and the macroscopic suface defect as like fracture and wrinkle, and microscopic asponent, The factors affected in forming limit are stain herdening exponent, strain-rate scnsitivity exponent, anisotropic coefficient. The increasing of surface roughness is decresed the forming limit curve. It is known that the greater plastic deformation the more surface roughness by Kienzle, Osadaka. The purpose of this study is to investigate the influences of surface roughness in a uniaxial tension and the traperzoidal-shaped box drawing.

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Prediction of Surface Residual Stress of Multi-pass Drawn Steel Wire Using Numerical Analysis (수치해석을 이용한 탄소강 다단 신선 와이어 표면 잔류응력 예측)

  • Lee, S.B.;Lee, I.K.;Jeong, M.S.;Kim, B.M.;Lee, S.K.
    • Transactions of Materials Processing
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    • v.26 no.3
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    • pp.162-167
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    • 2017
  • The tensile surface residual stress in the multi-pass drawn wire deteriorates the mechanical properties of the wire. Therefore, the evaluation of the residual stress is very important. Especially, the axial residual stress on the wire surface is the highest. Therefore, the objective of this study was to propose an axial surface residual stress prediction model of the multi-pass drawn steel wire. In order to achieve this objective, an elastoplastic finite element (FE) analysis was carried out to investigate the effect of semi-die angle and reduction ratio of the axial surface residual stress. By using the results of the FE analysis, a surface residual stress prediction model was proposed. In order to verify the effectiveness of the prediction model, the predicted residual stress was compared to that of a wire drawing experiment.

Characteristics of Heat Treatment on Different Materials during Laser Surface Hardening of Cast Iron for Die (금형재료용 주철의 레이저 표면경화처리시 재료에 따른 열처리 특성)

  • Kim, Jong-Do;Song, Moo-Keun;Hwang, Hyun-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.12
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    • pp.1663-1668
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    • 2011
  • Surface hardening treatment is required to improve the wear-resistance of press die because severe abrasion of die occurs during the drawing process in which the forming of the automotive body is completed and during the trimming process in which the unnecessary parts are cut. In this study, experiments on the laser surface treatment of press die are performed. Specimens are heat-treated separately at certain plate and edge position by using a diode laser to carry out suitable surface hardening treatment to reduce the wear during the drawing and the trimming processes, and the proper conditions for heat treatment are found. Spheroidal and flake graphite cast iron specimens are used, and the heat treatment characteristics of the two materials are compared. From the results of the study, it is confirmed that the heat treatment characteristics differed depending on the materials.