Electromagnetic Forming Systems and Simulations
Vanessa Castaneda, Louis Steinmetz, Dr.David Wetz
Department of Electrical Engineering, The University of Texas at Arlington, Arlington, Texas 76019
Results
Abstract
Electromagnetic forming is a process that uses
pulsed power technology to achieve the magnetic
forming of electrically conductive metal into desired
shapes without physical contact. Some devices use
its concept to remove dents from airplane fuselages,
unite metal parts, and for aluminum sheet forming.
An electromagnetic forming unit was designed,
constructed and tested in order to gain a better
understanding of the formability process and find
ways to improve coil efficiency, make the apparatus
easy to use and improve overall design through a
combination of experiments and analysis. Computer
simulation was used and data collected was
imported to the simulation for validation.
Introduction
Summary and Conclusions
.
ump
Dump
resistor
resistor
Ross
relays
Charge
Resistor
Ignitron driver
Coil
Ignitron
Capacitor
Figure 3: Constructed electromagnetic forming unit.
Figure 6: Circuit simulation used to compare simulation data to data
collected when using 2kv of power.
Current Through Coil #1
Day
Day 51
Constructing a unit that can deform an aluminum
object through electromagnetic induction is a useful
way of learning about the electromagnetic
forming process. Our apparatus uses the change in
the capacitors voltage to produce a high amount of
current through a multi-turn primary inductor. Our
aluminum can acts as a single turn
secondary coil which leads to Eddy currents
induced in the aluminum can. This
produces a magnetic field which in turn
creates a force that is perpendicular to the Figure 1: Forces
and Fields
magnetic field. A high repulsive force
produced on the
can
causes the can to deform inwards.
Materials and Methods
-10kV power supply
-2 Ross Relays used for charging a capacitor
-Diode (for safety purposes)
-500 Ω Charging Resistor
-Maxwell Capacitor: 206 uF 22kV
-350 mΩ Resistor
Current Through Coil #2
Figure 4:Aluminum metal can formed with a 10kv shot using
improved coil design #2. Simulation data indicated that, with a
10kV power supply , the current through coil design #1 was
18.29 kV and through coil design #2 was 19.07kA
Testing and Data collection from improved coil design:
Ross relay and 100 Ω Dump Resistor (for safety purposes)
Originally a laser pointer was used to send a trigger signal
to our ignitron driver, but to make the unit more efficient and
easier to use we designed and constructed a fiber optic
transmitter circuit which we placed inside our trigger box
(figure 8). For further work it would be beneficial to increase
the number of samples and gain more knowledge about the
EMF process. This will allow for the unit to be capable of more
complex operations.
Figure 7: On left is the current through our primary inductor from
simulation(red) compared to data collected from oscilloscope (blue)
and isolated current monitors (green). On the right is capacitor
voltage discharge from simulation(green) and data from voltage
probes (blue)
-Ignitron
-Ignitron Driver
- 200 µ fiber optic cable.
-Laser pointer
Measuring devices:
-Oscilloscope
-voltage measuring probes
B
-Isolated current monitors
Our apparatus was constructed and was tested. Efficient
transfer of energy was required to get the best results from the
forming process. For this reason we analyzed and tested
different coils. The first coil produced a very slight forming
affect which led us to change the coil design to increase the
strength of the coil’s crushing force. We found that by reducing
the air space between the coil and the can we could
significantly increase the forming produced by our coil. Other
aspects affecting the “crushing” force were the number of turns
and the length of the coil. After improving our coil design we
began data collecting with our improved coil. We used FEMM
to simulate the magnetic fields produced around our can. Also
from the FEMM simulation we found that the mutual
inductance of our coil and can was 263nH with a DC current.
A new circuit simulation was created based on the found
inductance of the can and on the behavior of a transformer
(figure 6). Using this design we compared our simulation data
to our collected data. We found that the current in our primary
coil from our simulator closely matched the current collected
with our measuring devices. We also compared the current of
the can from our data collected to the current from the can
based on our simulation. From this we could conclude that our
circuit simulation was reliable and we can use it to predict the
current that will go through our can when we increase or lower
the power supply.
Literature cited
All About Circuits.(2012). Calculating Inductance . Retrieved July 10th, 2014 from
http://www.allaboutcircuits.com/vol_1/chpt_15/3.html
Anter El-Azab,Mark Garnich,Ashish Kapoor (2003). Modeling of The Electromagnetic
Forming of Sheet Metals: state-of-the-art and future needs. Journal of Materials
Processing Technology Vol 142(3), pp.744-754.
EPRI(1999). Pulsed Power Technology and Applications-Scandinavia, Palo Alto,CA:TR112566.pg.1-1:1-3 Retrieved from http://www.energy.ca.gov/process/pubs
/pulsed_power_tech_tr112566.pdf
UCI Physics and Astronomy(2010).Forces and Fields produced on the can [Illustration].
Retrieved from: http://www.physics.uci.edu/~demos/pdf/el-mag/5k20.65electromagnetic_can_crusher.pdf
V.Psyk, D. Risch, et al (2011). Electromagnetic Forming--A review. Journal of materials
processing technology Vol.211,No.5, pp.787-829.Retrieved July 15th,2014 from
http://www.sciencedirect.com/science/article/pii/S0924013610003821
Acknowledgments
100
B
Figure 2:Schematic used to construct our unit
Figure 5: FEMM model simulation displaying the magnetic fields
surrounding the coil.
D
Figure: 8: Schematic for our Fiber Optic
Transmitter circuit
F
I will like to thank Dr. David Wetz for allowing me to work in his lab, and for all the
technical support he provided and my lab partner Louis Steinmetz for his help. I
also give thanks to Dr. Kambiz Alavi and Mohammadreza Jahangir Moghadam
for coordinating the REU Program. Finally, I thank NSF and UTA for funding and
hosting the REU program.
NSF grant # EEC-1156801: Research Experiences for undergraduates in Sensors
and Applications at University of Texas at Arlington
Further Information
Contact: Vanessa Castaneda (vycastaneda@miners.utep.edu).