Tutorial: Engineering technology
Topic: Flat forming - punching, bending
Prepared by: Ing. Elena Nová
Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002
je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.
Flat forming-punching, bending
3.Punching – stamping sheets are pierced by
shearing (die) cutter.
Its main parts are blanking punch and
punching / blanking die.
Blanking punch- moving
part of tool
Punching die- stationary part
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Cutting clearance – between blanking punch
and punching die is axial clearance. If too big
cut is rough with tear edges.
Clearance should be 0,5% of sheet thickness.
Schema of cutting using cutting tool (SKcutting punch, SC- cutting die)
ms=cutting clearance
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Simple cutting tool
First tool is simple cutter designed for one
operation.
Strip position is secured by solid stop, shift
by one step (size of product plus allowance)
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With big and series production are used
progressive tools.
Shift of strip is usually from right to left.
Right (small) circular blank
falls to waste, from the left
part of tool falls finished
product – washers.
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4. Bending is a forming process where usually
is material permanently deformed at different
bend angles with smaller or bigger edge
radius.
For bending are use tools named – bending
dies (roll and die).
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Bending principles
At bending, inner part has ‘compression and
outer side traction stresses generating plastic
deformations. If the worked material is not
sufficiently ductile cracks can develop on the
outer surface!
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Seaming is edge bending either manually or
using flanging rolls.
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Roll-bending is bending between rolls.
It is used at production of cylindrical or conical
tubes, casing jackets and even plates 30mm thick.
Thicker plates are usually ‘hot bended’.
Machines used for this process are called ‘bending
rollers’.
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Production of thin-walled tubes.
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