HSMAG Magnets FAQ
Q: How do I clean a hard magnet?
A: You want to make sure that you properly store your magnets at all times. Make sure you store your magnets in a cool dry place, in a closed container or box, and in attracting position to preserve magnetization. Ideally it would be best if you can store your magnets with spacers between them. In the event that that the magnets attract metal particles, you can wipe them off with a dry cloth.
Q: What is the maximum operating temperature of my magnet?
A: The maximum operating temp for each magnet material varies.
Q: What are the different types of magnets?
A:There are two types of magnets, permanent magnets and electro magnets. Permanent magnets produce their own magnetic field while electro magnets require an external source of power i.e. a battery.
*This chart represents the approximate maximum operating temp of each material.
Material Maximum operating temperature
NdFeB 140 284
SmCo 300 572
Ferrite 300 572
Alnico 540 1,004
Flexible 100 212
Q: What is the difference between isotropic material and anisotropic material?
A: Isotropic material is non-oriented material which can be magnetized in any direction. During the manufacturing process, the magnet is not exposed to a magnetic field.
Anisotropic material is oriented material which can be magnetized in one direction. During the manufacturing process, the magnet is exposed to a magnetic field to orient the material in the preferred direction of magnetization to heighten the magnets performance.
Q: What materials can I use to block magnetic field or redirect poles?
A: Materials that are attracted to magnets can be used to block magnetic field or redirect poles. Cold rolled steel plates are commonly used to accomplish this. To ensure that you have blocked the magnetic field completely, you can do a simple paper clip test. Simply place a paper clip against the material that you are using to block the magnetic field while the magnet is attracted to the opposite side. If the paper clip is attracted to the metal, you have leakage and you might want to use a thicker piece of metal to completely block the magnetic field and retest.
Q: Can I machine the magnets if I need to?
A:Hard magnets can be machined but you have to be familiar with the special machining techniques to avoid damaging the magnet. Depending on the magnet, you might require special diamond tools and grinding wheels. Do not machine magnetized material.
Q: Differences between permanent magnets and electromagnets?
A: The permanent magnet has magnetism itself. As the nature of permanent magnets, the magnetism will not be eliminated by outside effect. While, electromagnets are made of coil and core. When the core is energized, the electromagnet has magnetism and it does not have magnetism when out of energy. Another difference is that the magnetism of permanent magnets does not change, but the magnetism of the electromagnet with change according to the coil turns, current and the material of the core.
Q: Which appliances that used in neodymium magnets production?
A: Appliances that used in neodymium magnets production: melting furnace, cracker, ball mill, jet mill, press molding machine, vacuum packaging machine, isocratic presses, sintering furnace, heat treatment, vacuum furnace, magnetic properties tester gauss meter.
Appliances that used in neodymium magnet processing: dedicated slicker, WEDM, flat mill sided machine, punching machine, chamfering machine, electroplating equipment.
Q: What are the basic coatings for neodymium magnets?
A: For neodymium magnets, they often need to be coated with Zn, Ni, NiCuNi, epoxy, and other coatings to protect their surfaces from corrosion and oxidization. But for AlNiCo, SmCo or ferrite magnets, they commonly do no need to be coated due to their own remarkable resistance against corrosion and oxidization.
Q: Which are the strongest magnets nowadays?
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 150C and above), the Samarium Cobalt types can be stronger that the Neodymium-Iron-Boron types (depending on the magnetic circuit).
Q: What are Rare Earth Magnets?
A: 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: 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 (Alnicos), Strontium-Iron (Ferrites, also known as Ceramics), 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: What is the Grade of a magnet?
A: The grade of a magnet directly refers to the Maximum Energy Product of the material that composes the magnet. It in no way refers to the physical properties of the magnet. Grade is generally used to describe how “powerful” a permanent magnet material is. The energy product is specified in the units Gauss Oersted. One MGOe is 1,000,000 Gauss Oersted. Grade N40 would have a Maximum Energy Product of 40 MGOe. The higher the grade the stronger the magnet.
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, as example, this has been shown to be less that 1% over a period of ten years.
Q: What are the characteristics of magnets?
A: Magnets are characterized by three main characteristics. These are known as the:
1.) Residual Induction (given the symbol Br, and measured in Gauss). This is an indication of how strong the magnet is capable of being.
2.) Coercive Force (given the symbol Hc, and measured in Oersteds). This is an indication of how difficult it is to demagnetize the magnet.
3.) Maximum Energy Product (given the symbol BHmax, and measured in Gauss-Oersteds). This is an indication of what volume of magnet material is required to project a given level of magnetic flux.
Q: How to measure the strength of the magnets?
A: Gauss meters are used to measure the magnetic field density at the surface of the magnet. This is referred to as the surface field and is measured in Gauss (or Tesla). Pull Force Testers are used to test the holding force of a magnet that is in contact with a flat steel plate. Pull forces are measured in pounds (or kilograms).
Q: How to identify the poles of the magnets?
A: Three methods are listed as below can be used to distinguish the North and South poles of magnets.
1) Use a compass, the end of the needle that normally points North will be attracted to the South pole of the neodymium magnet.
2) 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.
3) Use a Gauss Meter.
Q: Are there any industry standards for magnets?
A: Yes. Two industry associations produce standards. The Magnetic Materials Producers Association (MMPA) publishes standards for the production of magnetic materials, and the Magnet Distributors and Fabrications Association (MDFA) produces standards on various ways of testing magnets and magnetic devices.
Q:What is the machining process of sintered neodymium magnets ?
A: Basically the main machining process includes burdening, smelting, pulverization, molding, sintering, testing, machining, electroplating, magnetizing, final examining and packing.
Q: What factors determine the cost of machine magnets?
· Quantity – the larger the quantity, the lower the cost since set-up charges must be amortized over the quantity, and special tooling can be created to machine larger quantities;
· Material – SmCo materials are more costly to machine since they are very brittle, flexible materials are very inexpensive to machine because of their physical characteristics;
· Shape – complex shapes are more expensive than simple shapes; and,
· Tolerances – the closer the required tolerances, the more expensive it will be to machine the magnets.
Q: What might affect a magnet’s strength?
A: The factors below can affect a magnet’s strength:
· 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 physically damage to the materials.
Q: Tips on handling and storing magnets
· Always handle permanent magnets with care! Magnets can snap together, take off like a projectile, injure personnel/bystanders or cause damage to the handler. We do not accept any liability whatsoever for mishandling of magnets once we ship from our facility
· Keep magnets away from magnetic media – such as floppy discs, credit cards and computer monitors.
· Store magnets in closed containers, so that they don’t attract metal debris.
· If several magnets are being stored, they should be stored in attracting positions.
· Alnico magnets should be stored with “keepers” (iron or magnetic steel plates that connect the poles of the magnet) since they can easily become demagnetized.
· Magnets should be kept away from pacemakers!
Q: If a magnet which has lost its magnetism can be re-magnetized?
A: The magnet can be re-magnetized back to its original strength, provided that the material has not been damaged by extreme heat.
Q: How to separate the magnets?
A: Small magnets can be parted by hand, sliding bit by bit off other magnets. If they are of big size, you can separate them by using edge of desk or corner. Place magnets on the desk with a magnet hanging over ,then use your whole body to press the magnet down, but you should be careful at the same time, do not get off your balance. There are two easy ways below, the magnets are colored in grey.
1.Use two nailed sticks, put the magnets between the sticks, please refer to the sketch as below;
2.Use one object to press one magnet, then use another heavy object to push down the other magnet, please refer to the sketch as follows;
Q: How to assemble magnets to a device?
A: If a magnet needs to be fastened to a device, you can use either mechanical means, or adhesives to secure the magnet in place. Adhesives are often used to secure magnets in place. If magnets are being adhered to uneven surfaces, you will need an adhesive with plenty of ‘body’ so that it will conform to the uneven surface. Hot glues have been found to work well for adhering magnets to ceramics, wood, cloth, and other materials. For magnets being adhered to metal, ‘super-glues’ can be used very effectively.
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Q: Refund / Return Policy?
A: We will review returns on a case by case basis within 30 days of shipment. No returns past 30 days of shipment. No returns on custom orders; however, stock items may be returned with authorization. Please call us for an authorization number. Returned items must be unused and unopened in its original packing and may be subject to a 15%-25% restocking fee. Before applying credits, Magnet Products International must inspect and approve returned material. We will replace any material that is deemed defective by our quality department to be replaced only. No refunds will be offered after your order has been entered into our system and processed for production. We will consider replacement material only if we can verify and determine a Manufacturer workmanship error or defect has occurred based on our material and work. We cannot be held responsible for any shipping delays after product has been shipped according to order details or possible delays in proof approval process.
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