• Title/Summary/Keyword: bending

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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
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    • v.18 no.2
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    • pp.349-355
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    • 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.

Study on the Prediction of the Work-Energy to the Maximum Load and Impact Bending Energy from the Bending Properties (국산 소경재의 휨 성질을 이용한 충격에너지와 최대하중까지 일-에너지 예측연구)

  • Cha, Jae-Kyung
    • Journal of the Korea Furniture Society
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    • v.19 no.5
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    • pp.350-357
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    • 2008
  • This research investigates the bending properties to predict the work-energy to maximum load and impact bending energy from static bending and impact bending test. Specimens were prepared from lumber made of thinning crop-trees. Matched specimens were used for MC 12% and green moisture specimens to measure the effect of moisture content on the absorbed energy from static and impact bending tests. The bending properties such as MOE, MOR, etc. is a good predictor to investigate the work-energy and work-energy per unit volume from static bending and impact bending test. The impact bending energy is increased with increasing moisture content. However, the work to maximum load from static bending test is increasing with increasing the MC only for higher density species.

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A Study of Bending Process for Development of Subframe by Hydroforming (일체화 성형 서브프레임 개발을 위한 벤딩 공정의 영향성 연구)

  • 서창희;이우식;김헌영;임희택
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.262-265
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    • 2003
  • In the present study, subframe was developed using hydroforming technology. The manufacturing process for subframe consists of tube bending, pre-forming and hydroforming. The effects of bending process for manufacturing hydroformed subframe were researched. And the variables of bending process were studied by FEM simulation. The bending method is rotary draw bending that is the most popular, cost-effective bending method for thin walled tubes.

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A study on the unfolding length of Z-bending machining using thin plate (박판을 이용한 Z-굽힘 가공의 전개 길이에 관한 연구)

  • Park, Yong-Sun;Choi, Kye-Kwang
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.15 no.3
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    • pp.19-25
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    • 2021
  • The bending process of a press die is to bend a flat blank to the required angle. There are V-bending, U-bending, Z-bending, O-bending etc. for bending processing, and the basic principle of calculating the unfolding length of die processing is used as the neutral plane length. Since the constant of the length value of the neutral surface is different depending on the type of bending, it is impossible to accurately calculate it. In particular, Z-bending processing is performed twice, and it is set on the upper and lower surfaces of the blank, and bending processing occurs at the same time as the upward and downward bending, and the elongation of the material occurs and the material increases. It is not possible to check with the calculated value, and it occurs in many cases where the mold is modified after start-up. This study aims to minimize die modification by developing a formula to calculate the development length of Z-bend.

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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
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    • v.6 no.4
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    • pp.373-378
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    • 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.

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The Ic degradation behavior in Bi-2223 superconducting tapes during hard bending (Hard bending시 Bi-2223 초전도테이프의 임계전류 열화 거동)

  • 신형섭;최수용;고동균;하홍수;하동우;오상수
    • Progress in Superconductivity and Cryogenics
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    • v.4 no.1
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    • pp.40-44
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    • 2002
  • Influences of bending strain on the critical current (Ic) were investigated in Bi-2223 superconducting tapes at 77K. The effect of bending mode on the Ic degradation behavior was discussed in viewpoints of test procedure, n-value and damage morphology Especially, in this paper, we reported the Ic behavior in Ag alloy/Bi-2223 multifilamentary superconducting tapes under bending occurred within a width plane of the tape which was called as a hard bending. The Ic degradation under hard bending appeared significantly as compared with that under easy bending. The n-value decreased slightly with the increase in bending strain under the hard bending.

A Study on Improvement of Bending Quality of Hemmed Plates in Sheet Metal Forming (헤밍 (Hemming) 구조를 가진 박판의 굽힘품질 개선에 관한 연구)

  • Kim, Pan Gun;Park, Sang Hu
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.12
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    • pp.1360-1367
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    • 2012
  • A bending process is considered as one of fundamental sheet metal forming processes, and it is widely used for fabrication of simple or complicated sheet metal products in industrial fields. Most of automobiles and electronics have many parts made by the bending process inside or outside of them. However, till now, there is few research reports on the bending process of hemmed plates. A hemmed plate has a locally different bending strength, so a waving shape occurs after bending. A poor outlook due to local uneven shape influences greatly on product competitiveness. To settle this problem, we studied the bending parameters of a hemmed plate and showed the major sensitive design-parameters on the bending quality.

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
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    • v.10 no.4
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    • pp.329-337
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    • 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.

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The Relation of Bending Buckling Strength in Vehicle and Three Point Bending Maximum Strength of Door Impact Beam (도어 임팩트 빔의 3점 굽힘 최대강도와 차량 장착 시 굽힘 좌굴강도와의 관계)

  • Kang, Sungjong;Lee, Sangmin
    • Journal of Auto-vehicle Safety Association
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    • v.11 no.1
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    • pp.40-47
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    • 2019
  • First, three point bending analysis for the inclined press door impact beam was carried out to investigate inclination angle effect on the maximum strength with varying support distance. Next, for the system model with spring elements representing body stiffness at door mounting area, the bending structural behavior of impact beam mounted on vehicle was estimated. The mounting distance and inclination angle were changed and the beam bending buckling strength was presumed at the head displacement below which spring stiffness change has little effect on the load. Finally strength ratio to predict the bending buckling strength of impact beam mounted on vehicle from three point bending maximum strength of fixed support distance was suggested.

A study about shape processing for the bend of the Copper-Tube that use Hair Pin Bending Machine (Hair Pin Bending Machine을 이용한 동 튜브 굽힘 성형가공에 관한 연구)

  • Kang, Heung-Sik;Kim, Dong-Sung;Heo, Sin;Hong, Sung-In
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1705-1708
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    • 2003
  • The purpose of this study is to investigate the manufacturing technique on the U type Draw-Bending of inner grooved tube. This bending process make the U shape tube by Hair Pin Bending machine. The U type tube requires the quality of product that satisfy sufficient conditions for a heat exchanger. The mandrel components act the important roles that prevent wrinkles and keep the shape of cross section of bended tube at bending process. We performed the FEM simulation using LS-DYNA software and the bending test of inner groove tube and then, compared bending simulation with bending test results about mandrel ball diameter, mandrel position and optimal clearance between mandrel and tube.

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