• Title/Summary/Keyword: Radius of die and punch

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Statistical Study on Correlation Between Design Variable and Shape Error in Flexible Stretch Forming (가변스트레치성형 설계변수와 성형오차의 상관관계에 대한 통계적 연구)

  • Seo, Y.H.;Heo, S.C.;Kang, B.S.;Kim, J.
    • Transactions of Materials Processing
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    • v.20 no.2
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    • pp.124-131
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    • 2011
  • A flexible stretch forming process is useful for small quantity batch production because various shape changes of the flexible die can be achieved conveniently. In this study, the design variables, namely, the punch size, curvature radius and elastic pad thickness, were quantitatively evaluated to understand their influence on sheet formability using statistical methods such as the correlation and regression analyses. Forming simulations were designed and conducted by a three-way factorial design to obtain numerical values of a shape error. Linear relationships between the design variables and the shape error resulted from the Pearson correlation analysis. Subsequently, a regression analysis was also conducted between the design variables and the shape error. A regression equation was derived and used in the flexible die design stage to estimate the shape error.

Springback for the Warm 2D Draw-bending of Steel Sheets (박판의 온간 2차원 드로오 벤딩에서의 스프링백)

  • Lee S. M.;Chang S. H.;Choi Y. C.;Heo Y. M.;Seo D. G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.10a
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    • pp.75-80
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    • 2001
  • The purpose of this study is to investigate the characteristics of springback for various process conditions of the 2D draw-bending operation. The process variables are the forming temperature, the geometry of tools such as punch profile radius(Rp) and die profile radius(Rd). Especially, in order to control the springback, the use of the warm forming method is applied. For the warm draw-bending, five steps of temperature ranges, from room temperature to $200^{\circ}C$, were adopted. And two kinds of steel sheets, namely SCP1 and TRIP(transformation-induced plasticity), the newly developed high strength Steel, were adopted. As a result, the springback was affected by the elevated temperature and the geometry of tools in two kinds of steel sheets.

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Blanking Process of Aluminum Thin Sheet for Lithium Ion Battery (리튬 이온전지용 알루미늄 박판의 블랭킹 공정에 관한 연구)

  • Kim, M.G.;Kim, J.H.;Shin, H.J.;Moon, J.H.;Ko, D.C.
    • Transactions of Materials Processing
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    • v.30 no.4
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    • pp.179-185
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    • 2021
  • Lithium ion batteries are generally manufactured by laser and etching using aluminum thin sheet. These processes are relatively expensive and have low productivity. In this study, blanking process of aluminum thin sheet for lithium ion battery was employed to replace laser cutting and etching process, all to reduce the production cost and improve productivity. Mechanical properties for aluminum and coating were determined by experimental results and rule of mixture for FE analysis of blanking process. Normalized Cockcroft-Latham criteria was also applied to describe shear behavior and critical damage values were determined by comparison of analytical and experimental result. We performed FE analysis to investigate the effects of clearance and punch-die radius on sheared surface of aluminum thin sheet and to determine optimal process condition. We manufactured the die set using the determined optimal process and conducted an experiment to confirm the feasibility of blanking process. The sheared surface of manufactured product was observed by optical microscope. As a results, the proposed process conditions successfully achieved the dimensional requirement in production of lithium ion battery parts.

Process Design and Forming Analysis of Permalloy Shielding Can for Instrument Cluster (자동차 계기판용 퍼멀로이 실딩 캔의 성형해석 및 공정설계)

  • Kim, Dong-Hwan;Lee, Seon-Bong;Kim, Byung-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.2
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    • pp.177-185
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    • 2001
  • This study shows the process design and forming analysis of permalloy shielding can that support the automobile multi-display parts to indicate the accurate information of car. This study is particularly important, since the strain and thickness of permalloy shielding can is known to affect the magnetic properties such as coercivity and permeability quite thickness of permalloy shielding can is known to affect the magnetic properties such as coercivity and permeability quite sensitively. The objective functions are strain and thickness deviation. The punch radius, die radius and blank holding force are considered as design parameters. Orthogonal array (OA) table and characteristics are applied to neural network (NN) as train data. After training, the optimal and robust condition of design parameters is selected. This study shows the correlation between the design methodology of NN and the statistical design of experiments (DOE) approach.

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Forming of Circular Protrusion by Half-Piercing and its Application to Marking of Sheet Metal (하프피어싱에 의한 원형돌기의 성형 및 마킹공정에의 응용)

  • Jung, H.K.;Kim, J.H.
    • Transactions of Materials Processing
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    • v.21 no.3
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    • pp.202-206
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    • 2012
  • Marking is a process that engraves letters or a pattern onto the surface of sheet metal. During marking, it is important to set the proper working conditions for clarity of the letters. In this study a simple case for forming circular protrusions by half-piercing and embossing was initially attempted to determine the working conditions which gave good results with respect to shape accuracy. Corner-radius and flatness of circular protrusions made under several experimental conditions were measured and compared. It is shown that the precision of protrusions by half-piercing is superior to that of embossing, and the clearance between punch and die exerts a strong influence on the shape accuracy rather than the penetration percentage into the thickness of the sheet metal. The marking dies for "SNUT" letters, as an example, by applying the above results were manufactured with four different clearances. The working variables for the experiment were clearance and marking depth. For the very shallow depth of 0.1mm the letters were not clearly read. Letters marked under other conditions were easily distinguished with increasing marking depth. It was confirmed that the half-piercing technique with proper values of the working variables gives good quality for the marking of sheet metal.

A Study on the Characteristics for the Blanking of Lead Frame with the nickel alloy Alloy42 (니켈합금 Alloy42를 사용하는 리드프레임의 블랭킹 특성에 관한 기초연구)

  • Bahn Gab-su;Suh Eui-kwon;Lee Gwang-ho;Mo Chang-ki
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.6
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    • pp.87-93
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    • 2004
  • An experimental is carried out to investigate the characteristics of blanking for nickel alloy Alloy42 (t=0.203mm), a kind of IC lead frame material. By varying clearance between die and punch the shapes of shear profile are examined. Finite element analysis with element deletion algorithm for ductile fracture mode is also carried out to study the effect of clearance theoretically and to compare with experimental results. The rectangular shape specimen with four different comer radius is used to study the characteristics of blanking for straight side and comer region simultaneously. As the result the ratios measured k(m experiment of roll over, burnish and fracture zone based on initial blank thickness are compared with those of FE analysis. Both experiment and FE analysis show that the amount of mil over and fracture is increased as the clearance increases. When the radius of comer is less than thickness of blank it has been found that larger clearance is required than that of straight region in order to maintain same quality of shear profile at the comer region.

A Study on the process planning of Deep drawing using personal computer (퍼스널 컴퓨터에 의한 디이프드로잉 공정설계의 전산화에 관한 연구 (I))

  • Choi, Jae-Chan;Jin, In-Tai
    • Journal of the Korean Society for Precision Engineering
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    • v.5 no.3
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    • pp.31-42
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    • 1988
  • This paper describes a computer aided process planning system called "Deep-Drawing", "Deep-Drawing" is designed for the drawing sequence of cylindrical and rectangular cups with or without taper and flange. The computer program has written in BASIC language with personal computer. Design Rules for process planning are formulated from process limitation, plasticity theory and experimental results including the know-how of many manufacturing factories. "Deep-Drawing" Capabilities include the analysis of drawing sequence by the determination of optimal drawing ratio, the determination of intermediate shape, dimensions, punch and die radius etc., the calculation of drawing loads and blank holder force to perform each drawing step, and the graphic outputs for the operation sheet.tputs for the operation sheet.

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Material Flow and Surface Expansion in Radial-Backward Extrusion (레이디얼 압출과 연계된 후방압출의 소재유동과 표면확장)

  • 고병두;최호준;장동환;황병복
    • Transactions of Materials Processing
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    • v.12 no.3
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    • pp.251-258
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    • 2003
  • The paper deals with an analysis of an extrusion process with a divided material flow in a combined radial - backward extrusion. The paper discusses the influences of tool geometry such as punch nose angle, relative gap height, die comer radius on material flow and surface expansion into can and flange region. To analyze the process, numerical simulations by the FEM and experiment, an Al alloy as a model material have been performed. Based on the results, the influence of design parameters on the distribution of divided material flow and surface expansion are obtained.

Analysis on Roll Over in the Tube Hydro-Piercing Process (튜브 하이드로 피어싱시 롤 오버의 실험적 분석)

  • Choi, Sung-Ki;Ahn, Ick-Tae;Moon, Young-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.7
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    • pp.992-998
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    • 2004
  • During the tube hydropiercing, the region adjacent to the pierced hole will be deformed and will be drawn away from the die block as the punch advances through the wall of the tube. The deformation in the region may range from a substantially flat form to a countersunk form, so called rollover. In this study, the effects of material properties, shape of piercing punches, roundness of tube surface and internal pressure within the tube during piercing on the rollover have been investigated experimentally. The results provide the quantitative variation of rollover at given hydropiercing parameters, and a relationship between the deformed radius and the rollover caused by the deformation has been established.

A Study on Spring Back in Sheet Forming of Amorphous Alloys (아몰퍼스 판재 성형의 스프링 백에 관한 연구)

  • Yoon S.H.;Lee Y.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1757-1760
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    • 2005
  • This paper is concerned with spring back after sheet forming of bulk amorphous alloys in the super cooled liquid state. The temperature-dependence and strain-rate dependence of Newtonian/non-Newtonian viscosities as well as the stress overshoot/undershoot behavior of amorphous alloys are reflected in the thermo-mechanical Finite Element simulations. Hemispherical deep drawing operations are simulated for various forming conditions such as punch velocity, die corner radius, friction, blank holder force, clearance and initial forming temperature. Here, spring back by an instantaneous elastic unloading was followed by thermal deformation during cooling and two modes of spring backs are examined in detail. It could be concluded that the superior sheet formability of an amorphous alloy can be obtained by taking the proper forming conditions for loading/unloading.

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