• Title/Summary/Keyword: Bending Radius

Search Result 291, Processing Time 0.022 seconds

A Research on the Processing Method to Minimize the Outer Radius(Sharp edge) in Sheet Metal Z-bending Work (박판의 Z-굽힘가공에서 외측 굽힘반지름 치수의 최소화(샤프에지) 가공법에 관한 연구)

  • Yun, Jae-Woong
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.18 no.2
    • /
    • pp.349-355
    • /
    • 2017
  • Bending work using press dies involves bending a flat blank to a desired angle. The bending produces a flange (the bent part) and a web (the unbent part). The bending line will have a bending angle, and there is an inner and outer bending radius. The minimum inner radius size is determined by the material used. When the inner radius size is too small, there will be excess metal welding, which will cause a crack in the outer radius part. The outer bending radius size cannot be controlled by a bending punch and die block. Types of bending include V-bending, U-bending, O-bending, edge bending, twist bending, and crimping. Z-bending involves two bending lines, which are set on the upper side and under surface of the blank, respectively, and upward or downward bending is used. Z-bending is also called crank bending. Z-bending using this type of die structure will produce a standard inner bending radius. The standard size is the minimum bending radius that represents the angle radius of the bending punch. In industry, there is a need for a sharp edge shape with a very small size (R=0.2mm), but that is not possible when using bending punch and die block. The purpose of this research is to meet the need by development.

Analysis and Process Design of Hot Pipe Bending Process With Small Bending Radius (작은 곡률반경 파이프 벤딩을 위한 열간 파이프 벤딩공정 해석 및 설계)

  • 류경희;김동진;김병민;이동주
    • Transactions of Materials Processing
    • /
    • v.10 no.4
    • /
    • pp.329-337
    • /
    • 2001
  • The finite element simulation model and the program to calculate the reverse moment have been developed to analyse the stress state and deformation of pipe bending using local induction heating with small bending radius in this study. The reverse moment that is to be applied on the bending arm to control the wall thinning ratio of the bending outside to within a particular value. Even though the demand of pipes with small bending radius is increasing in power plants and ship buildings, the welded elbows are still widely used. The bending process with or without a reverse moment acting on the bending arm has been simulated. The reverse moments calculated from the developed program are in good agreement with the finite element simulations and the experiments.

  • PDF

The Development of Inner Structure of Metallic Sandwich Plates for Bending (굽힘성형을 위한 금속 샌드위치판재의 내부구조재 개발)

  • Seong, D.Y.;Jung, C.G.;Yoon, S.J.;Shim, D.S.;Lee, S.H.;Ahn, D.G.;Yang, D.Y.
    • Transactions of Materials Processing
    • /
    • v.15 no.2 s.83
    • /
    • pp.126-131
    • /
    • 2006
  • Metallic sandwich plates are ultra-light materials not only with high strength and stiffness but also with other multifunctional physical properties. Inner dimpled shell structure can be fabricated by a piecewise sectional forming process, and then bonded with face sheets of the same material by resistance welding. Possible region for bending and limit radius of curvature are defined to compare the formability of sandwich plates. Tests have shown that sandwich plates with inner dimpled shell structure subject to bending have longer possible region for bending and smaller limit radius of curvature than other types of sandwich plates. The proposed inner dimpled shell structure is shown to have better formability of sandwich plates for bending than other types inner structures.

Characteristic of Critical Current after Repetitive Bending for High Superconducting Tapes (고온초전도 선재의 Bending횟수에 따른 임계전류의 특성)

  • Kim, Hae-Joon;Joo, J.H.;Kim, S.W.;Kim, H.J.;Bae, J.H.;Cho, J.W.;Seong, K.C.
    • Proceedings of the KIEE Conference
    • /
    • 2003.07b
    • /
    • pp.900-902
    • /
    • 2003
  • Critical current($I_c$) degradation of HTS tapes after bending is one of the holiest issues in HTS development and application studies. Many people are measuring $I_c$ degradations for effect of tending radius. However even if the bending radius is larger than the breaking radius a HTS tapes can be damaged by repetitive bending, which is unavoidable in the winding processes. Therefore, We studied the $I_c$ degradation after repetitive bending, at 77K with self-field, of Bi-2223 tapes processed by "Powder-in-Tube" technique, which was made by America Superconductor Corporation(AMSC), Innova Superconductor Technology(InnoST) and Korea Electro-technology Research Institute(KERI). For each specimen $I_c$ degradation was measured various bending radius as function of repetitive bending number.

  • PDF

Critical Current Degradation Characteristics by Temperature Difference of L$N_2$-Normal in Repetitive Bending Strain of High Temperature Superconducting Tape (고온 초전도 선재의 굽힘횟수와 온도차에 의한 임계전류저하특성)

  • 김해준;김석환;송규정;김해종;배준한;조전욱;성기철
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
    • /
    • 2003.10a
    • /
    • pp.274-277
    • /
    • 2003
  • Critical current(Ic) degradation of HTS tapes after bending is one of the hottest issues in HTS development and application studies. Many people are measuring Ic degradations for effect of bending radius. However even if the bending radius is larger than the breaking radius a HTS tapes can be damaged by repetitive bending, which is unavoidable in the winding processes. Therefore, We studied the Ic degradation after repetitive bending. at 77K with self-field, of Bi-2223 tapes processed by "Powder-in-Tube" technique, which was made by America Superconductor Corporation(AMSC) and superconductiing tapes that strain is imposed measured critical current by temperature difference of L$N_2$ and normal temperature. Like this, critical current could measure that degradation about 1~3% by temperature difference. These results will amount the most important basis data in power electric machine of superconductivity cable, magnet, etc that winding work is require.

  • PDF

A Study on the Mechanical Properties and Bending Formability Evaluation of the Spring Strip Materials (박판 스프링용 재료의 기계적특성과 굽힘가공성 평가 연구)

  • Won, S.T.;Lim, K.H.
    • Transactions of Materials Processing
    • /
    • v.15 no.9 s.90
    • /
    • pp.660-666
    • /
    • 2006
  • This study examined the mechanical properties and bending formability evaluation of spring strip materials(SK5 CSPH, STS 301 CSP-EH, C7701-H). The hardness test and tensile test were performed at room temperature($20^{\circ}C$) for mechanical properties. The U-bending test were carried out at various conditions of punch corner radius(Rp), ratio of punch comer radius/thickness(Rp/t) and ratio of clearance/thickness(Rp/t) and ratio of clearance/thickness(C/t) for bending formability evaluation.

A Trench Structure for Low Bending Loss of Bent Optical Waveguides (원형으로 굽은 광도파로의 low bending loss를 위한 trench 구조설계: 원통좌표계 FD-BPM)

  • 한영진;김창민
    • Korean Journal of Optics and Photonics
    • /
    • v.6 no.4
    • /
    • pp.373-378
    • /
    • 1995
  • Bending losses of bent optical waveguides are calculated by virtue of the finite difference-beam p propagation method in the cylindrical coordinate system. In order to minimize the radiating losses of bent optical waveguides, we apply the trench structure to the bent waveguides and perform the a analysis to keep track of: 1) the influence of curvature radius on the bending loss without the trench, 2) the influence of curvature radius and refractive index difference on the bending loss with the trench, 3) the influence of the trench width on the bending loss.

  • PDF

Analysis on the Mechanism of Fluting in the Bending of Low Carbon Steels (저탄소강판을 이용한 굽힘 가공에서 발생하는 꺾임 현상에 대한 발생기구 해석)

  • Park, K.C.;Yoon, J.B.
    • Transactions of Materials Processing
    • /
    • v.16 no.4 s.94
    • /
    • pp.317-322
    • /
    • 2007
  • In order to investigate the cause and condition of fluting in tangential bending of low carbon steel sheet, an analytic analysis, an experiment and a series of finite element analysis for bending process were done. The fluting in bended sheet was related with the yield point elongation of material. Due to the yield point elongation, unstable plastic hinge was occurred in course of bending of elastic perfectly plastic sheet. According to the analysis and computational results, lower yield point elongation than 5% was required to prevent fluting in 0.5-0.6t sheet in $15{\sim}25mm$ radius bending. The tendency of fluting occurrence was reduced as decreasing the radius of bending, increasing thickness of bended sheet, and removing irregularity in sheet and bending processes.

A Study on the Bendability of Stainless Steel Tubes (스테인리스 강관의 굽힘 특성 연구)

  • Lee, G.Y.;Lee, H.J.;Yi, H.K.;Kim, Y.K.;Moon, Y.H.
    • Transactions of Materials Processing
    • /
    • v.18 no.4
    • /
    • pp.336-341
    • /
    • 2009
  • Hydroformed parts have higher dimensional accuracy, structural strength, and dimensional repeatability. Particularly in the automotive industry, manufacturing of parts with complex shapes from tubular materials sometimes requires one or more pre-forming operations such as bending before the hydroforming process. The pre-bending process is an important process for the successful hydroforming in the case where the perimeter of the blank is nearly the same as that of final product. The bendability of a tube depends on the parameters such as the bending radius, welding methods, mechanical properties and hardness. Through the stainless steel tubes bent by rotary draw bending machine, this study shows the following : (1) The influence on spring back ratio variation with stress level in the welded bent tube. (2) The Cross-section ovality variation with weld seam position and bending radius. (3) The relation between elongation and thickness reduction of tension zone with weld seam position and bending radius. (4) Workability evaluation of bent stainless steel tubes through the hardness of materials and hardness increment. The results of this study may help to understanding of characteristics on bendability of stainless steel tubes.

Experimental Analysis of the Damper of a Loudspeaker (스피커 댐퍼의 실험적 분석)

  • 최도성;이성수
    • The Journal of the Acoustical Society of Korea
    • /
    • v.23 no.3
    • /
    • pp.192-196
    • /
    • 2004
  • A decision of the modulus of elasticity is made by using the degree of bending strength of materials for loudspeaker damper and the radius of corrugation lines and the radius of curvature of each corrugation as a geometrical element. And it is compared with experimental measurements. As a result. the elasticity of damper is proportional to the degree of bending strength and inversely proportional to the radius of corrugation lines and inversely proportional to the square of the radius of curvature. We made a small loudspeaker using a modified damper which take the form of inner small curvature and outer large curvature of each corrugation. This loudspeaker have the increased sensitivity in high frequency and also in low frequency region.