Electro-Magnetic Pulse Manufacturing Research
Electro-Magnetic Pulse Manufacturing
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Electro-Magnetic Pulse Forming
Electromagnetic (EM) forming is a technique for forming of metals by means of plastic deformation generated by a repulsive force on account of the interaction between the magnetic field of the coil and the current induced in the workpiece. Being a high-strain rate forming method, the EMF process has all the advantages of high-velocity forming process, viz. increased formability, reduced springback and reduced wrinkling of formed parts . It can produce near net shape products by using electromagnetic field.
Electro-Magnetic Pulse Welding
Electromagnetic impact welding is based on Ampere’s observation that the force between two infinitely long parallel conductors carrying currents I1 and I2 and separated from each other. It is repulsive when the currents are in opposite direction, and attractive otherwise. The schematic representation of the electromagnetic equipment used for the experimental work is shown in Pictures above The electromagnetic impact welding setup consists of capacitor bank, high-voltage charging power supply, work coils, discharge circuit, spark gap (high-voltage switch) and current shunt (R).
The photograph of the electromagnetic impact welding facility used for the experimental work is shown in pictures above. The energy stored in the capacitor bank, charged through a DC power supply, is discharged through the work coil by triggering the spark gap. The damped sinusoidal current set up in the work coil produces a transient magnetic field. The work sheets in the vicinity of the work coil cut the transient magnetic field. Hence, the induced electromotive force and the corresponding eddy currents in the work sheets oppose their cause. Slides above shows the transient magnetic flux generated by the coil, which induces the eddy currents within the thickness of the sheets. The induced eddy currents depend upon the material properties (conductivity and permeability). Finally, the work sheets are repelled away from the coil (towards each other) creating an impact.
Electro-Magnetic Pulse Joining by Forming
Manufacturing industries intended to produce spaceframe or lightweight rigid structure constructed in a geometric pattern are looking for joining technique which is best suited and can avoid limitations of existing methods. Joining of dissimilar and similar advanced materials and there alloys like aluminum, titanium and magnesium using conventional methods is challenging. The main challenge related to fusion welding is creation of intermetallic component which have different properties and they are susceptible for failure. Furthermore, thermal distortion associated with high temperature and thermal expansion difference between welded dissimilar part results high stress concentration zone which leads to structural damage. Difficulties to weld similar or dissimilar materials for weight reduction like joining of steel tube to titanium tube forced to seek non-conventional joining technique. Hence researcher developed high speed joining technology known as joining by electromagnetic forming which can deform materials at high strain rate. The main advantage of this processes is that, it does not require any pre-or post-processing since there is no heat or thermal distortion involved. Other advantages are simplicity to join dissimilar materials within few micro seconds, low tooling, and absence of chips, dirt or fumes which provides a safe and hazard-free work environment.
Electro-Magnetic Pulse Shearing
Electromagnetic shearing is high strain rate shearing process. Electromagnetic field generated due to high magnitude electric current. This electromagnetic field acts as punch for shearing operation. The die with suitable shape is placed blow the workpiece. High intensity of Electromagnetic force pushes the metal with very high velocity in the die. This being very high strain rate process the defects like burrs and slivers are comparatively less in electromagnetic shearing operation. It is capable to shear sheets of high strength material which are difficult to shear by conventional shearing process.
Al-SS sheet weld using EM Pulse welding
Al-Al-Li sheet weld using EM Pulse welding
EM Pulse welding of Al to SS sheets
Electromagnetic Welding of Al to AZ 31 sheets
Electromagnetic Welding of Al to SS
Electromagnetic Welding of Cu to Cu
Electromagnetic Welding of Cu to SS
FE Model of EM Welds showing Lorentz Forces
EM Welds of Al to Al
Photograph of EM Welding Setup
Electromagnetic Pulse Welding Schematic Diagram
FE Model of EM Pulse Welding
Al to Al electromagnetically welded sample showing weld and no-weld zones
Al to Al EM welded samples
Magnified view of Al-SS sheet weld using EM Pulse welding
Felicitation of Dr. Sachin Kore by Former President of India Dr. A.P.J. Abdul Kalam, for being expert in Electromagnetic Welding
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