• Title/Summary/Keyword: Initial blank

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Initial Blank Optimization Design of Square Can Multistage Drawing considering Formability and Product Shape (사각형 캔 드로잉 다단 공정에서 성형성과 제품형상을 동시에 고려한 초기 블랭크 형상 최적 설계)

  • Park, Sang-Min;Kim, Dong Kyu;Hong, Seokmoo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.320-326
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    • 2017
  • Multistage deep-drawing technology is used widely in the production of mobile phone battery cases to improve productivity and economy. To ensure adequate capacity and rigidity, such cases are fabricated as a rectangular cup with a high slender ratio. The multistage deep-drawing of a rectangular cup entails a high slender ratio, and the heights of the product sides may be non-uniform because of the complicated deformation mechanisms. This causes problems in product assembly that affects the surface quality of the case. This study examined a blank shape that minimizes the height variations of the product to resolve the aforementioned problems. Optimization design and analysis were performed to identify the shape that yields the least variation. The long and short sides of an oval blank were set as the design variables. The objective function was set to yield the lowest height difference, and the thickness reduction rate of the product was set to the target range. In addition, the height of the final shape was set as a constraint. The height difference was minimized successfully using the optimized design. The design process of the initial blank for all rectangular shapes can be automated in the future.

Stamping process design to develop a urea tank cover for excavators based on sheet metal forming analysis (굴삭기 요소수 탱크 커버의 신규 모델 개발을 위한 CAE 기반 프레스 성형 공정 설계)

  • Jeon, Yong-Jun;Heo, Young-Moo;Yun, Seok-Hyun;Kim, Dong-Earn
    • Design & Manufacturing
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    • v.14 no.2
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    • pp.49-55
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    • 2020
  • Recently, when a new component of construction equipment is designed, a stamping process capable of producing parts having high appearance quality and precision has been gaining attention. However, in general, as it is developed based on existing parts made by welding metal sheets and tubes, frequent to die modification occurs, which increases the time and cost of developing new parts. Thus, it is necessary to reduce the cost by shortening the die development period. In this study, a stamping process was designed for the urea tank cover, which is a part for excavators, to reduce the die development period through sheet metal forming analysis. The stamping process was designed by determining the blank holding force after selecting the initial blank shape and size. The round value at the corner was modified such that formability is ensured. After selecting process parameters, the thickness reduction rate and spring-back effect were reviewed.

A study on measuring friction vibration in flange area during deep drawing process (프레스 딥 드로잉 가공 시 플랜지부의 마찰진동 측정에 관한 기초연구)

  • Jae-Woong Yun
    • Design & Manufacturing
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    • v.17 no.4
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    • pp.8-13
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    • 2023
  • In this study, it was studied whether a new measurement factor "frictional vibration" that occurs due to the material flow of the die and sheet metal in the flange area during deep drawing process, could be measured using an vibration sensor. The blank holder force acting on the flange area during drawing processing acts as a friction force in the opposite direction into which the sheet material flows and causes friction vibration. As the blank holder force increases, the friction force increases, and as the blank holder force decreases, the friction force also decreases. Because of this, friction vibration also increases and decreases in proportion to the size of the blank holder force. According to this theory, whether frictional vibration occurs was measured using a flange simulator and a vibration sensor. The initial pressure was created using a torque wrench, and it was confirmed that the amplitude increased by about 4 times when torque 6 Nm was increased. When the forming velocity was rapidly changed to 300 mm/min, the amplitude increased approximately 4 times. It was confirmed that the amplitude of frictional vibration according to the measurement location was greater the further away from the specimen. It was verified that a new measurement factor "friction vibration" in the flange area can be measured and used for online monitoring.

Optimization of Initial Blank Shape of Multi-stage Deep Drawing for Improvement of Formability (타원형 다단 딥 드로잉 제품의 성형성 향상을 위한 초기 소재 형상 최적 설계)

  • Lee, Sa-Rang;Park, Sang-Min;Hong, Seokmoo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.10
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    • pp.696-701
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    • 2016
  • Multi-stage deep drawing is a widely used industrial manufacturing process, and its applications are gradually expanding to both small products and large metallic products. The USB C-type socket used in smart phones, for example, is manufactured using oval multi-stage deep drawing. The socket is very small and slender and it requires precise manufacturing. The thickness distribution of the final product is guaranteed only if it is uniform throughout the overall process. Therefore, minimizing the height difference between long and short sidewalls after the first operation is important for this goal. An initial blank optimization was performed for an oval-type drawing process based on finite element simulations. The goal was to determine an initial blank geometry that can maintain uniform height and thickness after the first draw operation. The initial blank shape of the sheet metal was optimized, and the results show that it satisfied the conditions of minimal thickness reduction and even thickness distribution. The geometry from the optimized simulation was compared with experimental results, which showed good agreement.

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.

Development of form rolling technology for high precision worm using the rack dies of counter flow type (Counter Flow 방식의 랙 다이를 이용한 고정밀도 Worm 전조기술 개발)

  • 고대철;박준모;김병민
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1861-1864
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    • 2003
  • The objective of this study is to suggest the form rolling technology to produce high precision worm. Rack dies and roll dies are usually used to roll parts with worm teeth. The form roiling processes of worm shaft used as automotive part using the rack dies of counter flow type and the roll dies are considered and simulated by the commercial finite element code, DEFORM-3D. It is also important to determine the initial blank diameter in form rolling because it affects the quality of thread. The calculation method of the initial blank diameter in form rolling is suggested and it is verified by FE-simulation. The experiments using rack dies and roll dies are performed under the same conditions as those of simulation. The results of simulation and experiment in this study show that the from rolling process of worm shaft using the rack dies is decidedly superior to that using rolling dies from the aspect of the surface roughness and the profile of worm.

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Optimum Design of Trimming Line by One-Step Analysis for Auto Body Parts (역해석을 이용한 차체 부재의 트리밍라인 최적설계)

  • Bao, Y.D.;Huh, H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.06a
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    • pp.49-54
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    • 2006
  • During most of manufacturing processes of auto-body panels, the trimming line should be designed in advance prior to flanging. It is an important task to find a feasible trimming line to obtain a precise final part shape after flanging. This paper proposes a new fast method to find feasible trimming line based on one-step analysis. The basic idea of the one-step analysis is to seek for the nodal positions in the initial blank from the final part, and then the distribution of strain, stress and thickness in the final configuration can be calculated by comparing the nodal position in the initial blank sheet with the one of the final part. The one-step analysis method is able to predict the trimming line before flanging since the desired product shape after flanging can be defined from the final configuration and most of strain paths are simple during the flanging process. Finally, designers can obtain a discrete trimming line from the boundary of the developed meshes after one-step analysis and import it into CAD system in the early design stage. The proposed method has been successfully applied to two basic curve flanging processes demonstrating many advantages.

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Automatic Tool Compensation for an UHSS Automotive Component Using a Compensation Module (금형보정 모듈을 이용한 초고강도강 자동차부품용 프레스금형의 자동보정)

  • Lee, J.H.;Kim, S.H.
    • Transactions of Materials Processing
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    • v.25 no.2
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    • pp.109-115
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    • 2016
  • In the current study, automatic tool compensation is accomplished by using a finite element stamping analysis for a center roof rail made of UHSS in order to satisfy the specifications for shape accuracy. The initial blank shape is calculated from a finite element inverse analysis and potential forming defects such as tearing and wrinkling are determined by the finite element stamping analysis based on the initial tool shape. The blank shape is optimized to meet the shape requirements of the final product with the stamping analysis, and die compensation is determined with the information about springback. The specifications for shape accuracy were successfully achieved by the proposed die compensation scheme using the finite element stamping analysis. The current study demonstrates that the compensation tendency is similar when the proposed scheme is used or when the compensation is performed by trial and error in the press-shop. This similarity verifies that the automatic compensation scheme can be used effectively in the first stage of tool design especially for components made from UHSS.

Effect of Local Softening for Spring-back Reduction of Ultra High Strength Steel on Microstructure and Mechanical Properties (스프링백 저감을 위한 초고강도강의 국부적 연화 열처리에 따른 미세조직과 기계적 특성 변화에 관한 연구)

  • Park, S.E.;Park, B.H.;Oh, M.H.;Kang, B.S.;Ku, T.W.
    • Transactions of Materials Processing
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    • v.30 no.3
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    • pp.134-141
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    • 2021
  • In order to improve excessive spring-back behavior as a result of the roll forming process using ultra high strength steel (UHSS) sheet, local softening in region of a partial area expected to be deformed on an initial blank is considered in this study. With SPFC1470 UHSS sheet with initial blank thickness of 1.20mm, the local softening is performed with the following conditions: temperatures of 500℃, 550℃, 600℃ and 650℃, and holding time of 20s, 40s, 80s and 160s. Mechanical properties, such as yield stress and tensile strength, as well as elongation, are evaluated through uniaxial tensile tests, while the microstructural characteristics as a result of local softening are also investigated using the heat-treated specimens. As a result, it is shown that the spring-back behavior of the roll-formed prototype was reduced about by 78.9%, when the local softening at about 500℃ was performed for 160s considering the practical manufacturing condition.

Analysis of the Bottom Groove in L-shaped Profile Ring Rolling (L형상 프로파일 링롤링 공정의 하부면 그루브 결함 분석)

  • Oh, I.Y.;Hwang, T.W.;Kang, P.G.;Moon, Y.H.
    • Transactions of Materials Processing
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    • v.27 no.5
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    • pp.289-295
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    • 2018
  • The profile ring rolling process can realize various ring shapes unlike conventional rectangular cross-sectional ring products. In this paper, the defective groove in the bottom surface of L-shaped ring products was analyzed. Grooves are generated by non-uniform external forces due to profile main roll and initial blank shape. Process parameters such as the motion of dies and working temperature were determined. Mechanism of groove formation was analyzed by FE simulation on the basis of local external forces acting on the blank. Analysis results were similar to the groove actually occurring in the production line. Based on results of the analysis, two solutions were proposed for the groove. The position of the base plate supporting the blank was adjusted and edge length of the main roll was extended to suppress growth of grooves. It has been verified that groove was improved by applying two proposed methods in the shop-floor.