Over the Top (OTT) Market Size & Growth Outlook 2024-2030
High velocity forming
1. HIGH VELOCITY FORMINGHIGH VELOCITY FORMING
COMPARISON WITHCOMPARISON WITH
CONVENTIONAL FORMINGCONVENTIONAL FORMING
N. PRAKASAN
ME METALLURGY
2. HIGH VELOCITY FORMING :
High velocity metal forming was studied fairly
extensively between about 1955 to 1970.
HVF or High velocity forming involves imparting a high
kinetic energy to the work piece by accelerating it to a
highly velocity, before it is made to hit the appropriate
die
These techniques include methods such as
Explosive forming,
Electro hydraulic and
Electromagnetic forming.
High velocity metal forming techniques have
advantages in
INTRODUCTIONINTRODUCTION
3. HIGH VELOCITY FORMING :
In these forming processes large amount of
energy is applied for a very short interval of
time.
Many metals tend to deform more readily
under extra – fast application of load which
make these processes useful to form large size
parts out of most metals including those which
are otherwise difficult to form.
INTRODUCTIONINTRODUCTION
4. HVF Advantages:
• Forming complex parts with close tolerances,
form alloys that might not be formable by
conventional (stampings).,
• Material does not show spring-back effect
(differential elastic strains through the
thickness of a sheet while forming).
• Die costs are low,
• The production cost of components by such
processes is low.
The limitation of these processes is the need
for skilled personnel.
INTRODUCTIONINTRODUCTION
5. CONVENTIONAL FORMING :
In conventional metal forming operations, usually
force is applied to the metal to be worked upon using
simple hammer blow or a power press.
Deform metal by using heavy tools moving at
relatively low velocity.
These techniques include methods such as,
Forging
Extrusion
Drawing
Punching
Joining etc.,
INTRODUCTIONINTRODUCTION
6. The comparison of conventional and high
velocity forming conditions is essential
because, design and manufacturing engineers
utilize the correct forming process based on,
• Applicability of part shape,
• Part size,
• Number of parts to be formed
• Material required
• Tooling etc.,
COMPARISONCOMPARISON
7. Deformation velocity range:
• The velocities of conventional machines are
generally lower by the order of 103
compared
to the high velocity forming systems.
• Velocity Ranges:
• Conventional : 0.1 ~ 30 ft / sec
• HVF systems : 10 ~ 1000 ft / sec
COMPARISONCOMPARISON
8. STRAIN :
The strain distribution is much more uniform in
a single operation of HVF as compared to
conventional forming techniques.
This results in making it easy to produce
complex shapes without inducing unnecessary
strains in the material.
In HVF, strains required to failure are much
higher and thus ductility obtained is more what
is typically observed at conventional strain
rates
COMPARISONCOMPARISON
9. FORMABILTY:
Aluminum in Automotive body components,
In conventional method, the obstacles are,
• 1) The forming limits of aluminum are significantly
lower than those for steel (Al has zero strain rate
sensitivity at RT). Aluminum is particularly prone to
tearing at bends.
• 2) As the elastic modulus of aluminum is lower than
that of steel, springback (differential elastic strains
through the thickness of a sheet while forming) is
more severe and it is difficult to keep dimensional
tolerances.
• 3) Conventional die tryout with mating male and
female dies is always slow and expensive.
COMPARISONCOMPARISON
10. FORMABILTY:
Aluminum in Automotive body components,
Super plastic and high velocity super plastic
forming can be used to form auto body
components.
These techniques have the advantages of
delivering exceptional formability (10-50%
increases), potentially giving good
dimensional tolerance.
COMPARISONCOMPARISON
11. PART SIZE:PART SIZE:
There are no fundamental limitations to the
size of the parts in High velocity forming, larger
parts means more energy required which
translates into larger capacitor banks and
higher initial capital expenditure.
Whereas in conventional forming, there are
limitations in size, eg. Relatively heavy
components.
COMPARISONCOMPARISON
12. In comparing the HVF and conventional forming
methods,
Applicable for HVF
Deep recessing (cup, Cones),
Shallow recessing (Beaded panels, irregular shapes),
Bulged parts (Tubes, Nozzles, ducts),
Plane contoured parts (singly curved, compound
curvature, reversely curved
Applicable for Conventional method,
Bending (Straight flanges, sections),
Flanged parts (Stretch, shrink),
Linear contoured parts (Angles, channels),
Plane contoured parts.
COMPARISONCOMPARISON
13. Plane contoured, flanged parts and deep recessing
parts:
COMPARISONCOMPARISON
15. High Velocity forming of Metals_ Frank W Wilson,
American society of Tool and manufacturing engineers
High Velocity Sheet Metal Forming: State of the Art
for Advanced Commercialization
Prepared by: Glenn S. Daehn
Department of Materials Science and Engineering
The Ohio State University
Columbus, OH
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