• Title/Summary/Keyword: conventional forming

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New Process Design of Open Backward Extrusion to reduce the Forming Load (성형 하중 저감을 위한 개방형 후방 압출의 신공정 설계)

  • 정덕진
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.125-130
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    • 1999
  • In order to reduce the forming load of backward extrusion to a feasible level a new backward extrusion processes are proposed. In these process the shape of punch and die for conventional backward extrusion are change to open backward extrusion. To analyse the process numerical simulations by the finite element method has been performed, This simulation gave good results concerning the prediction of the forming load material flow and the corresponding shape of forged products, . These predictions set the limits of the preform shape and forming load depending on the punch and die geometry. The results show that the forming load is reduced significantly when the conventional backward extrusion change to open backward extrusion.

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Comparison of Forming Limit Diagram to Prove Improved Formability of High-speed Forming Acquired Experimentally and Theoretically (고속 성형의 성형성 향상 입증을 위한 실험 및 이론적 성형한계선도 획득 및 비교)

  • M. S. Kim;Y. H. Jang;J. Kim
    • Transactions of Materials Processing
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    • v.33 no.2
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    • pp.87-95
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    • 2024
  • The current study aims to prove that high-speed forming has better formability than conventional low-speed forming. Experimentally, the quasi-static forming limit diagram was obtained by Nakajima test, and the dynamic forming limit diagram was measured by electrohydraulic forming. For the experiments, the LS-DYNA was used to create the optimal specimen for electrohydraulic forming. The strain measurement was performed using the ARGUS, and comparison of the forming limit diagrams confirmed that EHF showed better formability than quasi-static forming. Theoretically, the Marciniak-Kuczynski model was used to calculate the theoretical forming limit. Swift hardening function and Cowper Symonds model were applied to predict the forming limits in quasi-static and dynamic status numerically.

Fundamental Study on the Development of a New Incremental Roll Forming Process for Structural Pipe Manufacturing (구조용 파이프 생산을 위한 새로운 점진적 롤 성형 공정 개발에 관한 기초 연구)

  • Son, Jong Youn;Yoon, Hee Seok;Park, Won Kyun;Shim, Do Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.34 no.3
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    • pp.217-224
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    • 2017
  • Structural pipe frames are usually manufactured by complex processes, in which a straight pipe with an arbitrary cross-section is prepared via a roll-forming process and then fabricated into three-dimensional shapes by a secondary process. These conventional processes have low productivity. Recently, the inefficiency of the conventional processes has created the need to develop new forming technologies. In this study, a new incremental roll-forming process is proposed. The study is aimed at verifying the feasibility of the proposed process and investigating the fundamental process parameters using finite-element simulations. The result of the simulation demonstrates that the proposed process can be used effectively for cold fabrication of various shapes of structural pipes. In addition, the result of the investigation of parameters shows that the forming amount, number of roll sets, and distance between roll sets are significant factors to be considered in resolving dimensional errors of the product and improving its quality.

A Study on the Uniform Thickness Distribution in Superplastic Blow Forming Process (초소성 블로우 성형품의 두께분포 균일화 연구)

  • Lee, Jeong-Hwan;Kim, Hyeon-Cheol;Lee, Yeong-Seon;Lee, Sang-Yong;Sin, Pyeong-U
    • Transactions of Materials Processing
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    • v.7 no.6
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    • pp.610-619
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    • 1998
  • The superplastic blow forming technology has advantages of cost reduction and low material consumption. compared to the conventional sheet metal forming technology due to the capability of precisely forming with high elongation and low flow stress. however it has a disadvantage that its partial thickness distribution is non-uniform. A processing technology like diaphragm forming has been developed even though it is difficult to prepare materials for superplastic blow forming. in this study a hemisphere forming of sheet before superplastic forming. It was found that the rotary forming material was less in quantity of cavitation at pole than that of hemisphere part that was superplastic formed without rotary forming treatment. Also discussed are the critical strain which is closely related to cavity shape and size.

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New Barrier Rib Forming Method for PDP Fabrication

  • Kim, I.T.;Cho, C.R.;Koo, B.J.;Lee, S.H.;Kong, S.S.;Kim, W.B.;Mun, J.D.;Hwang, K.T.;Kim, J.D.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.351-355
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    • 2003
  • In this paper, a new barrier rib forming method of embossed barrier rib (EBR) formation process for the PDP rear panel was introduced. The process is mainly composed of green sheet fabrication, lamination of the green sheet on the rear glass panel having data electrodes, and roll embossing followed by firing. The EBR process has two advantages over the conventional barrier rib forming methods. One is the process requires less equipment investment than the conventional methods by about 20% of the current rear panel fabrication equipment investment owing to the simplified fabrication process. The other advantage is its reduced rear panel manufacturing cost by eliminating the time consuming and complicated processes and waste of materials in the conventional methods. In this study, general procedure of EBR fabrication process is described and the characteristics of prototype PDP using EBR panel are discussed.

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Effect of Forming Temperature on Spring-back in Hot Forming Quenching of AA6061 Sheet (AA6061 판재의 핫 포밍 퀜칭 공정에서 성형온도가 스프링백에 미치는 영향)

  • Shim, I.B.;Kim, J.H.;Kim, B.M.
    • Transactions of Materials Processing
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    • v.26 no.2
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    • pp.101-107
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    • 2017
  • Aluminum alloys are widely used in automotive industry because of their high strength-to-density ratio and excellent corrosion resistance. However, conventional cold stamping of aluminum alloys leads to low formability and excessive spring-back. To overcome these problems, Hot Forming Quenching (HFQ) is applied to manufacture automotive part using aluminum alloy. The purpose of this study is to investigate effect of forming temperature on spring-back in HFQ of T6 heat treated AA6061 sheet. In this study, hat shape forming test was adopted to evaluate spring-back characteristics according to various forming temperatures. In additions, the test was also performed with warm forming conditions in comparison with dimensional accuracy of HFQed part. The experimental results showed that dimensional accuracy of HFQed part was superior to warm formed part and amount of spring-back was decreased as forming temperature rise.

Multi-Point Sheet Forming Using Elastomer (탄소중합체를 이용한 다점 박판 성형)

  • 박종우
    • Transactions of Materials Processing
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    • v.13 no.2
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    • pp.129-136
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    • 2004
  • Recently, instead of a matched die forming method requiring a high cost and long delivery term, a multi-point dieless forming method using a pair of matrix type punch array as flexible dies has been developed. Since the conventional multi-point dieless forming method has some disadvantages of difficulty in precise punch control and high-cost of equipment, a new concept of multi-point dieless forming method combined with an elasto-forming method has been suggested in this study. For optimal selection of elastomers, compression tests of rubbers, polyethylene and foams were carried out together with FEM analysis of the deformation behavior during sheet forming process using a rigid punch and elastomers. Compressive strain was concentrated on the upper central area of the elastomer under the punch, and the rubber exhibited higher concentration of the compressive strain than foams. Two-dimensional curved surface was formed successfully by the multi-point elasto-dieless forming method using an optimal combination of rubber and foam materials.

Finite Element Analysis for Precision Roll Forming Process of Stainless Slide Rail (스테인러스 슬라이드 레일의 정밀 롤 포밍을 위한 유한요소해석)

  • Lee, Taek-Sung;Kim, Gun-Wan
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.8
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    • pp.96-103
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    • 2009
  • The roll forming process is commonly used for the conventional 'Fe' metal products such as a furniture drawer guide or an up-down slide guide. Recently its applications are variously expanded to the sanitary facilities or electronic devices. It is essentially required the cleanness for the high technology application and any corrosion or rust are not allowed. Therefore, in those applications the stainless steel materials are strongly demanded as the substitution of 'Fe' steel. However the mechanical properties of stainless steel are not suitable for forming process compared with those of 'Fe' steel. Up to now, the conventional F.E.M.(Finite Element Method) has been used to analyze and design the roll forming process. The purpose of this research is to obtain the proper production process and the shape of rolls to manufacture the high precision slide rails made of stainless steel material. The commercial program, SHARPE-RF, is used to analyze the entire roll forming process. The results show that the rolling process and the roll design by F.E.M. are useful from the good agreement between the shapes of products estimated by F.E.M. and those of the actual products.

Finite Element Analysis of Micro Forming Process by Crystal Plasticity (결정소성학에 의한 미세 성형공정의 유한요소해석)

  • Kim H. K.;Oh S. I.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.05a
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    • pp.209-212
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    • 2001
  • It is known that the mim forming processes show somewhat different phenomena compared with the conventional metal forming processes, namely, the size effect, enhanced friction effect and etc. Such typical phenomena, however, are not predicted by the conventional finite element analysis, which has been an efficient numerical tool to predict the metal forming processes. It is due to the fact that the constitutive relations used does not describe the microstructural characteristics of the materials. In the present investigation, the finite element formulation using the rate-dependent rigid plastic crystal plasticity model of the face-centered cubic materials is conducted to predict the micro mechanical behaviors during the mim forming processes. The finite element analysis, however, provides mesh-dependent solutions for the intragranular deformations. Therefore, the couple stress energy is additionally introduced into the variational principle and formulated within the framework of the rigid plastic finite element method to obtain mesh-independent solutions. Micro deformations of single crystal and bicrystal with various orientations are calculated to show the potential of the developed formulation.

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Development of CAD/CAM system for dieless CNC forming (Dieless CNC Forming 을 위한 CAD/CAM 시스템 개발)

  • 최동우;진영길;강재관;왕덕현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.405-408
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    • 2004
  • The sheet parts are formed with dies conventionally. But this conventional forming process is not suited to small volume and varied production for the reason of high cost. For the solution of this problem, a new forming process, which is called CNC incremental sheet forming, is being introduced. This process can form sheet parts without die, and is very well suited to small volume and varied production in space flight and automobile. In this paper, dieless CNC forming system based on a machining center is developed. A special device to grasp and pull the blank sheet built in the machining center and tool path generation S/W from STL file of 3-D model are developed. Several sheet parts are incrementally formed to verify the effectiveness of the developed system.

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