This document discusses explosive forming, a metal forming process that uses explosives. There are two main types - confined and unconfined. Unconfined uses a standoff distance between the explosive and workpiece, while confined places the explosive in direct contact with the workpiece. The process works by placing the metal workpiece on a die, then igniting the nearby explosive. The explosive's shockwave deforms the metal into the die's shape. Research showed deformation of an aluminum plate reached 39mm after 400 microseconds, with peak velocities of 280m/s near the center. Explosive forming can form large, complex parts but requires safety precautions due to using explosives.

1. EXPLOSIVE
FORMING
-Submitted by
N.V.A.S.M.SASTRY
9820010002
1

2. Introduction • It Is a forming process
• It uses a explosive to carry out the
process.
• Two different types of arrangements
available.
• Uses the explosive force to shape the
metals
• Mainly used for sheet metals
2

3. Schematic
of Explosive
forming
3

4. Types of
Arrangements/
Techniques
• Unconfined type or stand off technique
– Explosive is not in contact with the
workpiece
– Vaccum is used
• Confined type or contact technique
– Explosive Is in direct contact with
workpiece
– Workpiece will be usually in tubular shape
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5. Working
5
• Workpiece is placed on die
• Vaccum is created under the
workpiece
• Water is filled into the tank
• Explosive is fitted into the tank
• Explosive is ignited
• Shock waves are produced
• Force will be applied onto the
sheet metal
• Metal will be formed as per the
die shape.
• Metal is then taken out.
Unconfined type or stand off technique

6. Working
6
Confined type or contact technique
• Die are placed at firtst
• Workpiece is placed in the
die.
• Cavity will be created due to
the gap between die and
workpiece
• Explosive is then placed
above on the workpiece
• Explosive is ignited
• Due to the shockwave
workpiece is deformed and
takes the die shape.

7. Experimental
Set up in the
Research paper
7
• Used Standoff technique
• Standoff distance 30 mm.
• Distance between dies 100
mm

8. Deformation
process of
aluminum plate
8
• The deformation of the
plate will develop
immediately when the
explosive is ignited.
• The deformationWill
increase with the time due
to shockwave
transmission.

9. Propagation of
shockwave
9
• Propagation will inititate
immediately after the
explosive ignition
• Pressure decreases with
increase in time
• Wave becomes wider with
respect to time.
• Pressure will be maximum at
the centre of workpiece.
• This is due to the shape of
shockwave.

10. Pro’s and
con’s
• Pro’s
– Extremely large components can be made
easily
– Eliminates costly welds
– Maintains precise tolerances
– Reduces tooling cost
– Controls smoothness of contours
– Less production lead time
– Parts which can’t formed by conventional
methods can also be formed
– Large and thick components can be made
easily 10

11. Pro’s and
con’s
• Con’s
– The metal to be formed must have high
impact resistance and ductility
– The geometries must be simple like
flat,cylindrical,conical
– Requires heavy protection equipment
– High labour cost
– Not suitable for small and thin works
– Dies must be larger and thicker.
– Usage of explosive must is quite risky
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12. Applications • Rocket engine nozzles
• Space shuttle body
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13. Inferences
from the
research
paper
• The amount of deformation of the aluminum plate
from top to bottom surface at 400 μs was shown as 39
mm.
• When the shock wave acting on the central part of the
plate is large, the deformation velocity rises rapidly to
about 280 m/s.
• Peak velocity at center of the aluminum plate
increased up to about 280 m/s.
• Movement of the initial velocity increase is from the
central part of the aluminum plate gradually toward
outer side, with the peak value decreasing as it moves
from the central area to outer side.
• As the distance between the die or the radius value
decreases then velocity will increase very rapidly. 13

14. Reference Research article details
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