Faq

 

FAQ answers about shipping times, store policies and basic technical questions.

Q:Who are we?

A: As a professional magnets manufacturer, magnets supplier and OEM magnet exporter, AOMAG was established in 1996 and specialized in R&D, production and sales of rare earth magnets, permanent magnets, (licensed patent) neodymium magnets, Sintered NdFeB magnets (Neodymium-Ferrite-Boron) , strong magnets, Radial Ring magnets, bonded ndfeb magnets, ferrite magnets, alnico magnets, Smco magnets, rubber magnets, injection magnets, magnetic assemblies etc.

 

Q: What are neodymium magnets?

A: Neodymium magnets are the strongest permanent magnets in the world. They are composed of Neodymium Iron and Boron. Also called NdFeB magnets.

 

Q: How many days does it take to ship my order?

A: Normally your order will be shipped out in 15-30 business days. If we have them in stock, we will ship them in 2-3 days.

 

Q: What is Neodymium Magnet or NdFeB Magnet? Is it same with Rare Earth Magnet?

A: "Neodymium magnets" and "NdFeB magnets" are both used to name the neodymium iron boron magnets. And this kind magnet also belongs to the rare earth magnet category. Even though most people refer to rare earth magnets as just neodymium magnets, the rare earth magnet category also includes Samarium Cobalt magnets (SmCo). To know more about the various magnets, please refer to our knowledge base or BLOG.

 

Q: Can Neodymium Magnets Harm Electronics?

A: Yes. Neodymium magnets can interfere with sensitive electronic equipment. It can mess up the CRT mornitor or TV, turn on/off cell phones. Also please keep neodymium magnets away from media such as credit cards, floppy disks, video tapes, or anything else with a magnetic strip. Those people who wear pace makers or other medical electronic devices should be more cautious when appoaching this strong magnet.

 

Q: Is Temperature a Concern with Neodymium Magnets?

A: Yes. Neodymium magnets are sensitive to heat. There are two temperatures which are critical to the neodymium magnets, i.e. the operating temperature and the curie temperature. For example, the maximum normal operating temperature is 175 F (80 C) for standard N-series grades. If the magnets are heated above this temperature, they will permanently lose a fraction of their magnetic strength. If the N-series are heated above their Curie temperature of 590 F (310 C), they will permanently lose all of their magnetic strength. However, the magnets can be charged again to regain the strength if the magnetic field is weakened in any way.

 

Q: What the Highest Neodymium Operating Temperatures and Curie Temperatures?

A: Different series of neodymium magnets have different temperature ratings. The most common series is N series which are to be used under 80 degree celsius. 90% of our neodymium magnets are N series. If you need high temperature magnets, you need to tell the operating temperature to our sale rep so we can ship you the right ones. We also stock some high temperature neodymium magnets, whose working temperatures are listed in their descriptions. Please refer to the following table for the various series and their temperatures.

 

Temperatures for Different Neodymium Magnet Series

	Working Temperature		Curie Temperature
	Fahrenheit	Celsius	Fahrenheit	Celsius
N Series	176	80	590	310
M Series	212	100	608	320
H Series	248	120	626	330
SH Series	302	150	644	340
UH Series	356	180	662	350
EH Series	392	200	716	380

 

 

Q: Will Magnets Lose Strength Over Time?

A: Very little. If they are not overheated, Neodymium magnets lose about 1% of their strength over 10 years.

 

Q: Are There any Health Concerns to be Aware of?

A: Neodymium magnets should never be handled by anyone with a pacemaker or similar device. They should also be kept away from small children. If swallowed, a Neodymium magnet can be lethal.

 

Q: What Type of Coating do Your Neodymium Magnets Have?

A: The most common neodymium magnets from AOMAG have a triple layer of nickel-copper-nickel coating, which is the best plating available. Nickel is the most common choice for plating neodymium magnets due to its shiny silver finish and corrosion resistance. However the plating will not make the magnet mechanical stronger. We also carry golden and expoxy plated magnets. The epoxy coated magnets are nomally in black color and easy to be glued with.

 

Q: Is the Neodymium Magnet also Fragile?

A: Yes, like other kinds of hard magnets, neodymium magnets are also fragile even though the coated magnets may look like metal. The neodymium magnet contains Boron as one of the major elements which makes it be fragile. The coating will not improve the physical characteristics of the neodymium magnet instead it only prevents it to from rusting.

 

Q: Can I Drill a Hole or Machine the Neodymium Magnets?

A: Yes, if unmagnetized, you can easily to machine the magnets with the right tools, like diamond drill bit or EAD machine. But if the magnets are already magnetized, you need to keep the magnet cool during the machining process. Also since the magnets are fragile, the machine process should be slowly done.

 

Q: How do I Handle Large Neodymium Magnets?

A: Always wear a pair of gloves. When you are going to separate one magnet from the other magnet(s), put the magnets on a durable non-metal surface of a stable table with the magnet to be separated hanging off the edge of the table. Use one hand to firmly hold the other magnets on the table. Use the other hand to hold the magnet you are separating firmly. Push it down and away from the other magnets until you no longer feel any magnetic attraction.

Note that whenever we ship magnets with strong strength, we always include a safety guideline in handling the products in the package. Please read the instruction first. Please contact us, if you have any questions in that regards.

 

 

Q: What does a magnet do?

A: Magnets do the following things:

Attract certain materials, such as iron, nickel, cobalt, certain steels and other alloys;

Exert an attractive or repulsive force on other magnets (opposite poles attract, like poles repel);

Have an effect on electrical conductors when the magnet and conductor are moving in relation to each other;

Have an effect on the path taken by electrically charged particles traveling in free space.

Based on these effects, magnets transform energy from one form to another, without any permanent loss of their own energy. Examples of magnet functions are:

A. Mechanical to mechanical such as attraction and repulsion.
B. Mechanical to electrical such as generators and microphones.
C. Electrical to mechanical such as motors, loudspeakers, charged particle deflection.
D. Mechanical to heat such as eddy current and hysteresis torque devices.
E. Special effects such as magneto-resistance, Hall effect devices, and magnetic resonance.

Q: What are permanent magnets made of?

A: Modern permanent magnets are made of special alloys that have been found through research to create increasingly better magnets. The most common families of magnet materials today are ones made out of aluminum-nickel-cobalt (Alnico), strontium-iron (Ferrites, also known as Ferrites), neodymium-iron-boron (neo magnets, sometimes referred to as "super magnets"), and samarium-cobalt. (The samarium-cobalt and neodymium-iron-boron families are collectively known as the Rare Earths).

Q: How are magnets made?

A: Modern magnet materials are made through casting, pressing and sintering, compression bonding, injection molding, extruding, or calendering processes.

Q: How permanent is a magnet's strength?

A: If a magnet is stored away from power lines, other magnets, high temperatures, and other factors that adversely affect the magnet, it will retain its magnetism essentially forever.

Q: Will magnets lose their power over time?

A: Modern magnet materials do lose a very small fraction of their magnetism over time. For samarium cobalt materials, for example, this has been shown to be less that 1% over a period of ten years.

Q: What might affect a magnet's strength?

A: The factors can affect a magnet's strength:

Heat
Radiation
Strong electrical currents in close proximity to the magnet
Other magnets in close proximity to the magnet

(Neo magnets will corrode in high humidity environments unless they have a protective coating.)
Shock and vibration do not affect modern magnet materials, unless sufficient to physically damage the material.

Q: How does a magnet's strength drop off over distance?

A: The strength of a magnetic field drops off roughly exponentially over distance.
Here is an example of how the field (measured in Gauss) drops off with distance for a Samarium Cobalt Grade 18 disc magnet which is 1 in diameter and 1/2 long.
Distance, x Field at Distance, x

 

Q: What is the governing equation for field strength relative to distance?

A: For a circular magnet with a radius of R and Length L, the field at the centerline of the magnet a distance X from the surface can be calculated by the following formula (where Br is the Residual Induction of the material):

Q: Can a magnet that has lost its magnetism be re-magnetized?

A: Provided that the material has not been damaged by extreme heat, the magnet can be re-magnetized back to its original strength.

Read up on a magnet's Curie temperature.

Q: Can I make a magnet that I already have any stronger?

A: Once a magnet is fully magnetized, it cannot be made any stronger. it is "saturated". In that sense, magnets are like buckets of water: once they are full, they can't get any "fuller."

Q:How do you measure the strength or power of a magnet?

A: Most commonly, Gaussmeters, Magnetometers, or Pull-Testers are used to measure the strength of a magnet. Gaussmeters measure the strength in Gauss, Magnetometers measure in Gauss or arbitrary units (so it's easy to compare one magnet to another), and Pull-Testers can measure pull in pounds, kilograms, or other force units. Special Gaussmeters can cost several thousands of dollars. We only sell the pull-test style magnetic tester, which is our pull-test kit (PTK2000).

Q:If I have a neo magnet with a Br of 12,300 Gauss, should I be able to measure 12,300 Gauss on its surface?

A:

No. The Br value is measured under closed circuit conditions. A closed circuit magnet is not of much use. In practice, you will measure a field that is less than 12,300 Gauss close to the surface of the magnet. The actual measurement will depend on whether the magnet has any steel attached to it, how far away from the surface you make the measurement, and the size of the magnet (assuming that the measurement is being made at room temperature). For example, a 1 diameter Grade 35 Neo magnet that is 1/4"long, will measure approximately 2,500 Gauss 1/16 away from the surface, and 2,200 Gauss 1/8 away from the surface.

Q:What are Magnetic Poles?

A:

Magnetic Poles are the surfaces from which the invisible lines of magnetic flux emanate and connect on return to the magnet.

What are the standard industry definitions of "North" and "South" Pole?

The North Pole is defined as the pole of a magnet that, when free to rotate, seeks the North Pole of the earth. In other words, the North Pole of a magnet seeks the North Pole of the earth. Similarly, the South Pole of a magnet seeks the South Pole of the earth.

Q:Can a particular pole be identified?

A:

Yes, the North or South Pole of a magnet can be marked if specified.

It is relatively simple to identify the poles of a magnet. First, the quickest method is to use another magnet that is already marked. The North pole of the marked magnet will be attracted to the South pole of the unmarked magnet. Second, it is possible to use an even number of magnets and pinch a string in the middle of the stack and dangle the magnets so they can freely rotate on the string.

The North pole of the magnets will settle pointing to the North. This result contradicts the common theory that opposites attract when discussing the rules of magnetism. However, the naming convention of the poles is a historical leftover from the time when the poles were called North-seeking or South-seeking poles. Finally, you can use a compass to identify the poles. The end of the needle that normally points North will be attracted to the South pole of the magnet.

We also stock a magnetic pole indicator device to quickly determine the magnets polarity (PD251). This magnetic pole tester provides an instant zero-delay magnetic pole indication. Just press the push button to activate and the tester will indicate the appropriate magnetic pole via LED's at once.

Q:How can you tell which is the North Pole if it is not marked?

A:

You can't tell by looking. You can tell by placing a compass close to the magnet. The end of the needle that normally points toward the North Pole of the Earth would point to the South Pole of the magnet.

Q:What are the different types of magnets available?

A:

There are 2 types of magnets: permanent magnets and electromagnets.

Permanent magnets emit a magnetic field without the need for any external source of power. Electromagnets require electricity in order to behave as a magnet.

There are various different types of permanent magnet materials, each with their own unique characteristics. Each different material has a family of grades that have properties slightly different from each other, though based on the same composition.

What are rare earth Magnets?

Rare earth magnets are magnets that are made out of the rare earth group of elements. The most common rare earth magnets are the neodymium-iron-boron and samarium cobalt types.

Q:Which are the strongest magnets?

A:

The most powerful magnets available today are the rare earths types. Of the rare earths, neodymium-iron-boron types are the strongest. However, at elevated temperatures (of approximately 150 C and above), the samarium cobalt types can be stronger that the neodymium-iron-boron types (depending on the magnetic circuit).

Q:What does 'orientation direction' mean?

A:

Most modern magnet materials have a "grain" in that they can be magnetized for maximum effect only through one direction. This is the "orientation direction", also known as the "easy axis", or "axis".

Unoriented magnets (also known as "isotropic magnets") are much weaker than oriented magnets, and can be magnetized in any direction. Oriented magnets (also known as "anisotropic magnets") are not the same in every direction. they have a preferred direction in which they should be magnetized.

Q:Can you supply magnets with one pole on the outside and one on the inside?

Ring magnets can be magnetized this way and they are referred to as radially magnetized.

Yes, stacking two or more magnets together will act similar to a single magnet of the combined size. However, due to the air gap between the magnets, the combined holding force is slightly reduced.

Q: What's the strongest type of magnet?

Ferromagnetic materials are strongly attracted by a magnetic force. The elements iron (Fe), nickel (Ni), and cobalt (Co) are the most commonly available elements. Steel is ferromagnetic because it is an alloy of iron and other metals.

Q: Who should I call with questions about these magnets?

You can absolutely reach us using any of the information found here.

Q: Do you sell any cheap magnets?

We offer magnets which are many things, but cheap is not one of them. That doesn't mean our magnets are not affordable, reliable, strong, and tested!

See why our magnets aren't cheap.

Q: Will a magnet with a 10 lb pull force lift a 10 lb object?

Not necessarily. The pull test is a laboratory test under ideal lab conditions. It is the breakaway force required to separate a given magnet from a flat 1018 steel plate. See attached MDFA Pull Test Standard.

When lifting an object with a magnet, many factors can affect the ability of the magnet to lift a given weight. These factors include: surface finish of magnet & object, flatness of magnet & object, coating on either surface & acceleration of lifting motion. Consult our Technical Department for more information on lifting magnets.

Q:Can I cut, drill, or machine magnets?

Yes, but only certain magnets. The only magnets we carry which meet these criteria are our flexible magnets and the bonded neodymium magnets. The flexible magnets can be cut down to size or drilled through. The bonded neodymium magnets can be machined, but we recommend only experienced machinists perform this task. All other stock magnets are brittle making them very difficult to machine.

Q:Which magnets are good for high temperatures?

Of the magnets we carry, three styles are rated for high temperatures. Alnico is rated the highest with an operating temperature up to 1000⁰F. Samarium Cobalt follows Alnico with an operating temperature up to 575⁰F. Ceramic magnets have an operating temperature of up to 480⁰F.

Q:How is neodymium pronounced?

Dictionary: [nē"ōdim'ēum] is pronounced NEE-O-DIM-EE-AM.

Are there any regulations for shipping magnets?

Regulations come into play when trying to ship magnets by air. Due to the strong magnetic field emitting from some magnets they can be considered "hazardous goods", and there are regulations enforced by the International Air Transport Association (IATA). Packages containing magnets must have a reading of .0025 gauss or less when measured from 7 feet away, or less than .00525 gauss at 15 feet from the package. If the gauss rating exceeds .00525 it cannot be shipped by air. Magnets must also be packaged securely to avoid any shifting around during transit. There are methods of packaging that can reduce the magnetic field and can allow shipment by air. Consult our inside sales department for more details.

Q:Why are most neodymium plated or coated?

Neodymium magnets are mainly constructed of Neodymium, Iron and Boron. Iron can oxidize very easily when exposed to moisture and will rust over time. Therefore we have most of our neodymium magnets nickel-plated to protect from oxidation.
 

Q:Will the magnetism be weaker after use years?

Yes, magnets do weaken over time.If you store permanent magnets correct, neodymium magnets will likely lose less than 1% of their flux density over 100 years.The magnetism decline is neglect, that's why we call it Permanent Magnet.

 

Q:Is a sample available ?

Yes, we can offer samples to you If we have in stock. Also we can custom for you.