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    Drawing Process: Bulk Deformation Processes in Metalworking

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    marah nimer

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    © All Rights Reserved
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    Drawing Process: Bulk Deformation Processes in Metalworking

    Uploaded by

    marah nimer
    75 views42 pages

    Original Title

    Drawing Process

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    © © All Rights Reserved

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    Copyright:

    © All Rights Reserved
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    75 views42 pages

    Drawing Process: Bulk Deformation Processes in Metalworking

    Uploaded by

    marah nimer

    Copyright:

    © All Rights Reserved
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
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    BULK DEFORMATION

    PROCESSES
    IN METALWORKING

    Drawing Process

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Wire and Bar Drawing

    Cross section of a bar, rod, or wire is reduced by pulling


    it through a die opening
     Similar to extrusion except work is pulled
    through die in drawing
     It is pushed through in extrusion
     Although drawing applies tensile stress, compression
    also plays a significant role since metal is squeezed
    as it passes through die opening

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Wire and Bar Drawing

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Area Reduction in Drawing

     Change in size of work is usually given by area


    reduction:
    Ao  Af
    r 
    Ao

    where r = area reduction in drawing; Ao = original


    area of work; and Ar = final work

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Wire Drawing vs. Bar Drawing

     Difference between bar drawing and wire drawing is


    stock size
     Bar drawing - large diameter bar and rod stock
     Wire drawing - small diameter stock - wire sizes
    down to 0.03 mm (0.001 in.) are possible
     Although the mechanics are the same, the methods,
    equipment, and even terminology are different

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Drawing Practice and Products

     Drawing practice:
     Usually performed as cold working
     Most frequently used for round cross sections
     Products:
     Wire: electrical wire; wire stock for fences, coat
    hangers, and shopping carts
     Rod stock for nails, screws, rivets, and springs
     Bar stock: metal bars for machining, forging, and
    other processes

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Bar Drawing

     Accomplished as a single‑draft operation ‑ the stock


    is pulled through one die opening
     Beginning stock has large diameter and is a straight
    cylinder
     Requires a batch type operation

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Bar Drawing Bench

     Hydraulically operated draw bench for drawing metal


    bars

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Wire Drawing

     Continuous drawing machines consisting of multiple


    draw dies (typically 4 to 12) separated by
    accumulating drums
     Each drum (capstan) provides proper force to
    draw wire stock through upstream die
     Each die provides a small reduction, so desired
    total reduction is achieved by the series of dies
     Annealing sometimes required between dies to
    relieve work hardening

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Continuous Wire Drawing

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Features of a Draw Die

     Entry region - funnels lubricant into the die to prevent


    scoring of work and die
     Approach - cone‑shaped region where drawing
    occurs
     Bearing surface - determines final stock size
     Back relief - exit zone - provided with a back relief
    angle (half‑angle) of about 30
     Die materials: tool steels or cemented carbides

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version
    Other Pictures for the
    Drawing types

    ©2010 John Wiley & Sons, Inc. M P Groover, Principals of Modern Manufacturing 4/e SI Version

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