Forming - Bulk Forming - RWTH Aachen of Forming Technology: Bulk Forming – Sheet Metal Forming Bulk forming: ... Warm forming Advantages and Disadvantages of Warm Forming Warm

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    WZL/Fraunhofer IPT

    Forming - Bulk Forming

    Manufacturing Technology II

    Lecture 4

    Laboratory for Machine Tools and Production Engineering

    Chair of Manufacturing Technologies

    Prof. Dr.-Ing. Dr.-Ing. E. h. F. Klocke

    Seite 1 WZL/Fraunhofer IPT

    Outline

    Introduction

    Cold forming

    Warm forming

    Forging

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    Casting Forming Cutting Joining Coating Changing of Material properties

    Compressive Forming

    Tension Com-pressive Forming

    TensilForming Bending

    Shear Forming Severing

    TranslateTwistIntersperse

    Manufacturing Processes

    Open die forgingClosed die forgingCold extrusionRod extrusionRollingUpsettingHobbingThread rolling

    Stretch formingExtending ExpendingEmbossing

    Deep drawingIroningSpinningHydroformingWire drawingPipe drawingCollar forming

    With linear tool movementWith rotational tool movement

    ShearingFine BlankingCutting with a single bladeCutting with twoapproaching bladesSplittingTearing

    IntroductionMethods of Forming Classification DIN 8580 ff

    Seite 3 WZL/Fraunhofer IPT

    Sheet metal forming

    no or low unwanted changing of the original wall thickness

    smaller deformations

    smaller material strain hardening

    lower forces

    than by bulk forming procedures

    IntroductionProcess of Forming Technology: Bulk Forming Sheet Metal FormingBulk forming:

    large changing of cross section and dimension

    large form modification

    large material strain hardening

    high forces

    high tool stresses

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    Bulk forming

    massivesemi-finished material

    component

    IntroductionWhat is Bulk Forming?

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    semi-finished part component

    Cutting

    1,3 kg

    Forming

    0,4 kg

    IntroductionAdvantages of Bulk Forming

    componentbasic workpiece

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    bulk forming allows function integration e.g. stability and leak tightness

    Joiningof singel-piece

    joined by welding

    flange

    can

    fitting

    Function integrationby bulk forming

    formed by extrusion

    Introduction Advantages of Bulk Forming

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    Outline

    Introduction

    Cold forming

    Introduction

    Upsetting

    Extrusion

    Warm forming

    Forging

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    fcc

    bcc

    recrystallizing

    Cold formingIron-Carbon Diagramm

    Carbon content in weight percent

    Cermentite content in weight percent

    Seite 9 WZL/Fraunhofer IPT

    workpiece temperatur / C

    Stra

    in j

    Flow

    stre

    ss k

    f/ M

    Pa

    Laye

    r of s

    cale

    / m

    Cold forming Material Properties

    high flow stresses and low achievable strain by classic steel materials

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    Cold forming Advantages and Disadvantages of Cold Forming

    Cold FormingAdvantages:

    low tool material costslow influence of forming velocityno energy costs for heatingno dimension faults caused by dwindlinghigh surface qualityincreasing strength of the component

    Disadvantages:high forceslimited plastic strain

    Seite 11 WZL/Fraunhofer IPT

    forming cold warm hotworkpiece weight 0,001 30 kg 0,001 50 kg 0,05 1.5plasticity < 1,6 r

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    Forming process IT-statement like DIN ISO quality

    5 6 7 8 9 10 11 12 13 14 15 16

    Cold extrusion

    Warm extrusion

    Hot extrusion

    centerline average Ra / m

    0,5 1 2 3 4 6 8 10 12 15 20 25 30

    achievable with special proceedings achievable without special proceedings

    Cold forming Efficiency

    small shape, dimension and position tolerances as well as good surface qualities are possible

    Seite 13 WZL/Fraunhofer IPT

    extrusion full extrusion hollow extrusion cup extrusion

    forwardextrusion

    backwardextrusion

    radialextrusion

    before after

    Cold forming Forming Processes

    a: punch, b: die, c: workpiece, d: ejector, e: counter punch, f: spike

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    workpieceinsertion

    compression extrusion ejection

    punch

    workpiece

    cavity

    ejector

    die

    Cold forming Full Forward Extrusion

    production of a pin

    Seite 15 WZL/Fraunhofer IPT

    workpiece insertion

    compression extrusion ejection

    punch

    workpiece

    die

    ejector

    Cold forming Cup Backward Extrusion

    production of a cup

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    workpieceinsertion

    closing ofthe die

    extrusion ejection

    upper punch

    workpiece

    lower dielower punch

    upper die

    production of a cardan joint

    Cold forming Radial Extrusion of a Cardan Joint

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    Cold forming Typical Cold Formed Components

    gear shafts

    tubes

    denticulations

    screws

    Hirschvogel Hirschvogel

    FuchsSchraubenwerk

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    Prozesskette

    Cold forming Process Chain of a Screw Production

    almost all screw geometries are produced by extrusion processes.

    ejector

    upper die

    die

    finished part

    Seite 19 WZL/Fraunhofer IPT

    blank full forwardextrusion

    full backwardextrusion

    radialextrusion

    Cold forming Process Chain of a Gear Shaft Production

    the production of components is usually charactarized by a combination of different extrusion processes

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    Cold forming Film: Cold Extrusion of a Gear Shaft

    Seite 21 WZL/Fraunhofer IPT

    Cold forming Cracks by Radial Extrusion Processes

    during upsetting or radial extrusion processes surface cracks can appear on the collar surface

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    Cold forming Crack Reduction by Superposition of Compressive Stresses

    punchgasketdieworkpiecepressure mediumrelief pressure valve

    tearing could effectively be shift to higher strains by superposition of compressive stresses

    Seite 23 WZL/Fraunhofer IPT

    without axialpressure superposition

    with axialpressure superposition

    max. availabledeformation

    fixed fixed

    Cold forming Crack Prevention by Superposition of Compressive Stresses

    superposition of compressive stresses can be realized by modifying the tool concept

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    Cold forming Chevron Cracks by Full Forward Extrusion

    Seite 25 WZL/Fraunhofer IPT

    3. forming step real workpiece

    Cold forming Chevron Cracks by Full Forward Extrusion

    a unfavourable dispersion of the interior material generates cracks

    Chevrons

    FEM-Simulation

    DEFORM

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    bucking upsetting indirect cup extrusion

    cutting radial extrusion burr cutting calibration

    recrystallization recrystallization recrystallization

    Cold forming Phases of Production of a Bevel Gear

    achievable deformation can be increased by recrystallization

    Seite 27 WZL/Fraunhofer IPT

    Outline

    Introduction

    Cold forming

    Warm forming

    Forging

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    Warm formingIron-Carbon Diagram

    fcc

    bcc

    recrystallization

    Carbon content in weight percent

    Cermentite content in weight percent

    Seite 29 WZL/Fraunhofer IPT

    Warm forming Material properties

    workpiece temperatur / C

    reduction of flow stress and increase of the avchievable strain

    Stra

    in j

    Flow

    stre

    ss k

    f/ M

    Pa

    Laye

    r of s

    cale

    / m

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    Warm forming Advantages and Disadvantages of Warm Forming

    Warm formingAdvantages:

    strengthening of the workpiecesmall range of tolerance caused by dwindlinggood surface quality

    Disadvantages:energy input for heatinghigh flow stresses

    Hirschvogel

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    forming cold warm hotworkpiece weight 0,001 30 kg 0,001 50 kg 0,05 1.500 kgplasticity

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    Forming process IT-statement like DIN ISO quality

    5 6 7 8 9 10 11 12 13 14 15 16

    Cold extrusion

    Warm extrusion

    Hot extrusion

    centerline average Ra / m

    0,5 1 2 3 4 6 8 10 12 15 20 25 30

    achievable with special proceedings achievable without special proceedings

    Warm forming Efficiency

    mean shape, dimension and position tolerances as well as mean surface quality are possible

    Seite 33 WZL/Fraunhofer IPT

    Warm forming Typical Warm Formed Components

    hinge flange cylinder injector

    Hirschvogel Hirschvogel

    Audi

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    Outline

    Introduction

    Cold forming

    Warm forming

    Forging

    Introduction

    Open die forging

    Closed die forging

    Ring rolling

    Seite 35 WZL/Fraunhofer IPT

    ForgingIron-Carbon Diagram

    fcc

    bcc

    recrystallization

    Carbon content in weight percent

    Cermentite content in weight percent

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    Seite 36 WZL/Fraunhofer IPT

    Forging Material Properties

    Workpiece temperatur / C

    low flow stress and high achievable strain

    Stra

    in j

    Flow

    stre

    ss k

    f/ M

    Pa

    Laye

    r of s

    cale

    / m

    Seite 37 WZL/Fraunhofer IPT

    Forging Advantages

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