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Production Engineering I / Erum Khan

Metal forming includes a group of manufacturing

processes in which plastic deformation is used to changethe shape of metal workpiece.

The tool, usually called a die in metal forming, applies

stresses that exceed the yield strength of the metal.

Stresses applied to plastically deform the metal are

usually compressive. However some forming processes

stretch the metal, while others bend the metal, and some

apply shear stress of the metal.

To be successfully formed, a metal must posses low yield

strength and high ductility.

METALFORMINGDEFORMATIONPROCESSES

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Production Engineering I / Erum Khan

Ductility is increased and yield strength is reduced when

work temperature is raised. Since all processing is done in solid state, there is no

need to handle molten material or deal with the

complexities of solidification.

Material is simply moved or rearranged to produce the

shape, the amount of waste can be substantially reduced.

High forces are required.

Machinery and tooling cost is high.

Use for large production quantities.

METALFORMINGDEFORMATIONPROCESSES

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Production Engineering I / Erum Khan

1. Bulk deformation

Rolling

Forging

Extrusion

Wire and bar drawing

2. Sheet metalworking

Bending

Deep drawing

Cutting

Miscellaneous processes

BASICTYPESOFDEFORMATIONPROCESSES

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Production Engineering I / Erum Khan

Characterized by significant deformations and massive

shape changes.

"Bulk" refers to workparts with relatively low surface

area-to-volume ratios.

Starting work shapes include cylindrical billets andrectangular bars.

BULKDEFORMATIONPROCESSES

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Production Engineering I / Erum Khan

BULKDEFORMATIONPROCESSES

RollingForging

Extrusion

Drawing

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Production Engineering I / Erum Khan

Forming and related operations performed on metal

sheets, strips, and coils.

High surface area-to-volume ratio of starting metal,

which distinguishes these from bulk deformation.

Often called pressworkingbecause presses performthese operations:

Parts are called stampings

Usual tooling: punchand die

SHEETMETALWORKING

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SHEETMETALWORKING

(a) bending

(b) drawing

(c) shearing

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Any deformation operation can be accomplished with

lower forces and power at elevated temperature

Three temperature ranges in metal forming:

Cold working

Warm working

Hot working

TEMPERATUREINMETALFORMING

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ROLLEDPRODUCTSMADEOFSTEEL

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Draft= thickness reduction:

Conservation of Volume:

DIAGRAMOFFLATROLLING

fo ttd

fffooo LwtLwt

fffooo vwtvwt

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ROLLINGMILLS

Various configurations of rolling mills: (a) 2-high, (b) 3-high, (c) 4-high,

(d) cluster mill, (e) tandem rolling mill

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Thread Rolling

OTHERROLLINGOPERATIONS

Ring Rolling

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ROLLING

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ROLLING

Use of front and back tension to

reduce friction in rolling

Strip rolling in four stand continuous millBacking rolls