Preliminary examination of high-velocity metal-shaping with electrical wire explosion
-
Upload
emmanuel-meyers -
Category
Documents
-
view
50 -
download
2
description
Transcript of Preliminary examination of high-velocity metal-shaping with electrical wire explosion
Preliminary examination ofPreliminary examination ofhigh-velocity metal-shaping withhigh-velocity metal-shaping with
electrical wire explosionelectrical wire explosion
EAPPC 2006 – Speaker: Mirko WoetzelEAPPC 2006 – Speaker: Mirko Woetzel
Overview• Some remarks about explosive shaping
• Replacement of explosives by “Electro-explosives”
• Direct experimental comparison of “electro-explosives” and explosives
• Discussion of the results
Shaping with Explosives
Workpiece hits the matrix with
>100 m/s
ADVANTAGES
• Very easy to use under special conditions
• Used for prototype production
• Low tool cost
DISADVANTAGES• Use of explosives strongly
regulated by laws• Extensive safety measures• Special skilled staff • In-house production very
critical too expensive for series
production!
Shaping with Explosives
• How the advantages of explosive shaping can be used without its disadvantages?
• Approach: – Replacement of explosives by “inert” materials– Suggestion: high power arc, wire explosion
• Very well known processes• But, with respect to sheet metal shaping:
– No direct comparison of “electro-explosives” available– No direct comparison with explosives available
Shaping with Explosives
Parameters:
Different “electro-explosive” media
aluminum wire, copper wire and electrical arc
Different environments
water, oil or air
Constant electrical energy inputConstant electrical energy input
1000 Joule
Electro-explosive Shaping
Test box
20 mm(1) Aluminium – Master-Frame
(2) Teflon – Isolator of electrodes
(3) Smooth Copper – Seal
(4) Aluminium – Shaping Matrix(1)
(2)
(3)
(4)
Volume: 65 ml water, oil or air wires: 0.7 mm
C = 20 µF
VC0 = 10 kV
WC0 = 1 kJ
Energy-Supply
Energy supply
Mounting plate
Rogowski coil
Capacitor
Conductor
Test realization “electro-explosive”
Open test box
Dismantled test box Evaluation
Capacitor discharge:
Closed test box filled with water, oil or air
Metal-sheet inside
î = 30 kAf=50 kHz
primary explosive 100 mg (lead azide detonator)
explosive 185 mg
285 mg explosive with <1,3 kJ energy
Test realization “explosive”
Evaluation “electro-explosion”Evaluation “electro-explosion”
““Electro-explosive”mediumElectro-explosive”medium
Arc Copper Aluminum
Air
Oil
Water
En
viro
nm
ent
En
viro
nm
ent mmh 0
mmh 5.10
mmh 5.10
mmh 1.0
mmh 5.5
mmh 0.4
mmh 0.1
mmh 8.9
mmh 19
3
Comparison “electro-explosive” vs. explosiveComparison “electro-explosive” vs. explosiveEnvironment:Environment:WaterMaterial:Material:Explosive
mmh 20
Environment:Environment:WaterMaterial:Material:Aluminum
mmh 19
Advantages of
• no reaction with outside effects no reaction with outside effects
• no special skilled staff no special skilled staff
• easy storage and transportation easy storage and transportation
• not usable for the crime scenenot usable for the crime scene
• no toxic gasesno toxic gases
• Conclusion– An electro-explosive metal-shaping process was
investigated: Reactive Al-wire/water explosion yields the best shaping result
– At comparable energies comparable results obtained for both electro-explosive and explosive shaping procedures
– Safety aspects• Electro-explosive system=water+aluminum+voltage=
“very safe”• Explosive system=explosives+water+laws+laws+…=
“not too safe”
• Future work – Minimization of electrical energy requirements
(investment and operation cost!)– Proof of principle for large sheet metals– Automation– Introduction to industry