INTRODUCTION
Magnetic abrasive finishing (MAF) is one of the advanced finishing processes, which produces a high level of surface quality and is primarily controlled by a magnetic field. In MAF, the work piece is kept between the two poles of a magnet. The working gap between the work piece and the magnet is filled with magnetic abrasive particles.
A magnetic abrasive flexible brush (MAFB) is formed, acting as a multipoint cutting tool, due to the effect of the magnetic field in the working gap. When inserting a cylindrical work piece in such a processing field giving revolution, feed and vibration in axial direction, surface and edge finishing are carried out by magnetic brush. In the application of ferromagnetic substance of work, for instance,
…show more content…
There are several options for achieving the necessary motion. A common setup is the rotation of the magnetic pole tip. This is done by either rotating the entire permanent magnet setup or by rotating only the steel pole. Another method which is commonly utilized in internal finishing is the rotation of the workpiece, this is unfortunately limited to axial symmetric workpieces. In additional to rotational motion there is oscillatory and vibrational configurations that are applicable
Magnetic Force on a Particle
Start with the common expression for force on a magnetic dipole moment in a magnetic field, From here, make the assumption that the moment of the magnetic particle is co-linear with the applied field. This is a reasonable assumption given the small size and high susceptibility of the magnetic particles. So the equation becomes, Using the following identities to obtain a more usable equation to describe the force experienced by a single magnetic particle,
Substituting the above definitions into the magnetic force equation yields, where,
• is the maximum applied field for saturation of the magnetic particle
• is the applied magnetic field intensity
• is the magnetic flux density
• is the magnetization of the particle, assumed to be saturated
• is the magnetic dipole moment
• is the magnetic field gradient
• is the volume of the particle (assuming sphere
In a DC motor, the armature consists of any number of windings, each one an electromagnet. The armature is immersed in a directional external magnetic field. This external field does not move, and can come from permanent magnets or electromagnets.
The force F acting upon a charge that is moving with a velocity v perpendicular to the magnetic field B is
The force in the previous equation can be calculated using Newton’s Second Law of Motion, F=ma (University of Tennessee, 2014).
Milling offers the advantages of being highly precise and having much smoother surface finish (surface roughness of easily around 1 µm ) compared to powder bed fusion additive manufacturing (layer thickness in the range of 20 µm and above; surface roughness of 15 µm and above ). Flat surfaces and sharp corners can be obtained with CNC milling. Similarly, features such as threads and holes are more accurately created through
Electric discharge machine developed in late 1940’s has been accepted worldwide as a standard process in manufacturing and is capable of machining geometrically complex or hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, nitrated alloy, carbides, heat resistant steels etc. EDM has become an important and cost-effective method of machining extremely tough and brittle electrically conductive materials. It is widely used in the process of making moulds and dies and sections of complex geometry and intricate shapes. The work piece material selected in this experiment is EN-41 alloy steel taking into account its wide usage in industrial applications. In today’s world EN-41 alloy steel contributes to almost half of the world’s production and consumption for industrial purposes. The input variable parameters are current, pulse on time and duty cycle. Taguchi method is applied to create an orthogonal array of input variables using the design of experiment (DOE). The effect of the variable parameters mentioned above upon machining characteristics such as material removal rate (MRR), tool wear rate (TWR) is
Since we are working in a three dimensional space we will give our formula vectors. We will now assume there are no other forces applied to the system we find;
We all know certain situations where magnets are used, hanging things on a refrigerator for example. But other applications are much more useful in our society. They are used in all kinds of speakers, and in many computer parts including hard drives and floppy drives ( for recording and reading purposes). Perhaps a more common use that goes unnoticed is the magnetic strip on credit and debit cards. These have a certain magnetic makeup, that is why you are to keep them away from other magnets. Magnets are also used in many motors, in such items like a dishwasher, DVD and VHS players, and a pager or cell phone vibrator.
Using the d-orbital electron configuration for cobalt in high and low states, the number of unpaired in electrons can be used to calculate the magnet moment for each spin state using the equation, µso¬ = √(4S(S+1)), where S = ½ the number of unpaired electrons. The magnetic moment for the high spin state was calculated to be 8.944 and 0 for the low spin state.
Metal stamping is the procedure of cutting and molding metal compounds into particular structures, particularly to be utilized as segments for expansive hardware or structures. Metal sheets can be formed into various pre-decided shapes for use as standard items like container and jars. The most well-known combinations that are utilized as a part of metal stamping are steel, zinc, nickel, aluminum and titanium. Metal stamping is an exceptionally financially savvy and gainful method for creating numerous sorts of metal items on an extensive scale.
As the name of this group of abrasive operations suggests, their objective is to achieve superior surface finish up to mirror-like finishing and very close dimensional precision. The finishing operations are assigned as the last operations in the single part production cycle usually after the conventional or abrasive machining operations, but also after net shape processes such as powder metallurgy, cold flashless forging, etc. The finishing processes discussed in this section include honing, lapping, superfinishing, polishing, and buffing. Honing is a finishing process performed by a honing tool, which contains a set of three to a dozen and more bonded abrasive sticks. The sticks are equally spaced about the periphery of the honing tool. They
Maxwell’s Equations are a set of four equations that govern all of electromagnetism. The equations show a unification of the electric and magnetic fields and are often considered one of the greatest unifications in physics, describing one of the four fundamental interactions, the electromagnetic force. The unification of the electric and magnetic forces in the 19th century by Maxwell’s Equations led to several scientific advancements – including an entire new branch of physics, electromagnetism – and inventions that transformed the world, consequently providing the world with wide-ranging improvements in quality of life, communications and navigation.
Electric currents produce magnetic fields, they can be as small as macroscopic currents in wires, or microscopic currents in atomic orbits caused by electrons. The magnetic field B is described in terms of force on a moving charge in the Lorentz force law. The relationship of magnetic field and charges leads to many practical applications. Magnetic field sources are dipolar in nature, with a north and south magnetic pole. The magnetic field SI unit is the Tesla, it can be seen in the magnetic part of the Lorentz force law F magnetic = qvB composed of (Newton x second)/(Coulomb x meter). The smaller magnetic field unit is the
Abrasive Jet Machining (AJM) is the removal of material from a work piece by the application of a high speed stream of abrasive particles carried in gas medium from a nozzle. The AJM process is different from conventional sand blasting by the way that the abrasive is much finer and the process parameters and cutting action are both carefully regulated. The process is used chiefly to cut intricate shapes in hard and brittle materials which are sensitive to heat and have a tendency to chip easily. The process is also used for drilling, de-burring and cleaning operations. AJM is fundamentally free from chatter and vibration problems due to absence of physical tool. The cutting action is cool because the carrier gas itself serves as a coolant and takes away the heat.
The first time we know about magnets was in 1269, when a soldier named Peter Peregrinus, wrote a letter about everything that was known at that time about a stone called magnetite. It is reported that he was writing this when he was guarding the walls of Lucera, a small town in Italy. It is also reported that, “While people insi...
Magnetism was not studied or utilized before 1821 as it is today. A few hundred years ago people understood how magnets worked, but didn’t have many applications of the magnet because they were limited by the technology of their time. The applications of magnets today have opened a new door as to how we can harness the power of a magnet. I had a basic working knowledge of how magnets worked, such as polarity, but with researching different aspects of the magnet I have learned that we need to advance the potential capabilities of the magnet and fully understand how we can harness the magnet. In my research I looked at how a magnet works, the physics behind a magnet, the magnetic fields of Earth, why can’t magnets be used as energy, and magnets for pain relief benefits.