How to enhance magnetism if permanent magnet size is the same?

Some customers might ask how to strengthen magnetism of permanent magnets in the same size. They prefer not to enlarge size. China Rare Earth Magnet Limited would like to talk about this.

For customer who has no specific requirement for size of magnet, we could just enlarge the size, thicken the magnet, which is the most effective way. However some might have strict demands of specification and do not want to change the size. In such case, we could try magnet in a higher grade to strengthen the magnetism and give customer what they want. Another solution is that add an iron sheet to one side of the magnet. Thus, its magnetism would be enhanced. That is also how single-side magnet works.

Before arranging mass production, customer could purchase samples to make sure if the requirement for magnetism is met. If not, customer should keep trying permanent magnet in a higher grade until customer is satisfied with the magnetism.

Above are some tips on magnetism strengthening for magnet in the same size. Feel free to contact us if there if any question about above content.

Tags: permanent magnet

How can permanent magnets be brought on board and meet air transport standards?

We often see the question in the major forums and Tieba how strong magnets can bring on the plane, what measures need to be done. What are the packaging requirements? Today, we strong permanent magnet manufacturer- China Rare Earth Magnet Limited would like to talk to you in detail.

The International Air Transport Association (IATA) lists magnetic cargo as a category 9 hazard, which must be restricted at the time of shipment, because a weak stray magnetic field has the interference of the aircraft's navigation system and control signals. So now some of the cargo with magnetic substances in the air needs to be magnetically tested in order to ensure the normal flight of the aircraft. Magnetic testing is carried out on magnetic materials, acoustic materials and other instruments containing magnetic accessories.

Magnet Air Transport Standard. According to the relevant provisions of IATA902, if the maximum magnetic field strength measured at 2.1m from the measured object does not exceed 0.159A/m (200nT, that is equal to 2mGs =0.002Gs), the item is not restricted as a magnetic substance and can be treated as a general cargo.
If the maximum magnetic field strength measured at 2.1m from the measured object exceeds 0.159A/m, but the strength of any magnetic field at 4.6m from the surface of the measured item is less than 0.418A/m, the goods can be transported as dangerous goods.If the strength of any magnetic field at 4.6m above the surface of the measured item is greater than 0.418A/m, the item is strictly prohibited for air transport.

How can the cargo meet the air transport standard?
In order to meet the above air transport requirements, degaussing treatment is needed. Although called demagnetization, it is not to demagnetize the magnet. Instead, it is through special shielding packaging, so that the external display of the magnetic package to meet the required aviation safety transport requirements. Shielded packaging will generally use high magnetic materials, such as cold-rolled plate, galvanized plate, if the size of permanent magnetic material is big, it will need multi-layers package. The conductivity of high magnetic conducting material is very high. According to the Faraday electric cage principle, magnetic field will circulate mainly in the box after package, so there is little magnetism leaking out. Cartons or wooden box packaging will be used after shielding package.

Packaging matters for magnets transported by air should be concerned.
1, Magnetron, illuminometer and other instruments, devices, the opposite magnetic pole must be relatively placed.
2, Permanent magnets must do the shielding package, in order to prevent the magnetic field from causing the deviation of the compass instrument.

3, Ensure that before the shipment, the field strength measured from the surface of the package 4.6 meters (15 feet) is not more than 0.418A/m (0. 00525 Gauss).
4, It is recommended a large cargo should use wooden box packaging.

Magnetic detection. Airlines or logistics companies that carry magnetic materials require customers to do magnetic testing to ensure the normal flight of the aircraft. On-site testing by qualified professional identification company professionals, and then issued a appraisal report. Magnetic testing needs customers to pack goods according to air transport requirements. Detection will not destroy the packaging of goods. In principle, the test is not open to the goods, but the six sides of each piece of goods for stray magnetic field detection. If the goods magnetic test is not qualified, they will be returned to repacking, and then re-do magnetic testing. Magnetic inspection fees also need to be re-charged.

If you have any other questions about magnets, please feel free to contact us.

Tags: permanent magnets

Permanent Magnet Used in Motor of Windscreen wiper 20191031

Windscreen wiper is mainly used to clean the rain or snow on windshield and make sure range of vision of driver is clear in rainy or snowy days.

Driven by electric motor, windscreen wiper is consisted of retarder, wiper switch, linkage and blade.
The left and right blades of the windscreen wiper are pressed on the windscreen by wiper’s arms. Electric motor turns the retarder and drives the linkage to reciprocate which would put the arms of wiper and blade in motion. Thus, the windshield is cleaned.

Electric motor (electric motor of wiper) can be classified according to their magnetic field. There are permanent magnet motor and electromagnetic motor.
Structure of permanent magnet motor used in windscreen wiper

Permanent magnet motor has long been in common usage as its magnetic pole is permanent magnet, normally is ferrite magnet. Small, light and simple and cheap, those are advantages of permanent magnet motor. So this kind of motor is widely used in cars.

Tags: permanent magnet, motor magnet

What kinds of rotor permanent magnets are inside servo motors?

What are the internal rotors of servo motors?
The internal rotors of servo motors are permanent magnets. The so called permanent magnets refer to those magnets that have unchanged magnetic poles and magnetic field strength. Servo motors mainly used arc magnets, just as below pictures:

Here is some information of servo motors magnets.
1、Do the rotor magnets of servo motors need adhesive?
The rotor magnets must need adhesive. There are many types of adhesive, such as KR series of high temperature resistant adhesive, AB adhesive and so on.
2、Why can't we use electromagnets to replace permanent magnets as the rotors?
Some netizens might reply that the electricity needs money, and in a finite electricity and space, the magnetic fields that can be generated are not necessarily stronger than the permanent magnets.
3、What magnets are the hard disc head servo motors use?
The hard disc head servo motors are voice coli motors, which are the same as general permanent magnet synchronous motors; the magnetic material is rare earth permanent magnets NdFeB.

The servo driver controls the U/V/W three-phase electricity forming an electromagnetic field, and the rotor rotates under the action of this magnetic field. At the same time, motor built-in encoder feedback signal to the driver, the driver will compare the target value according to the feedback value, so as to adjust the angle of the rotor rotation. The precision of servo motor depends on the precision of encoder (line number).
PS: When the servo motor is working, it should avoid the entering of oil and water. Because the servo motor is not the fully waterproof equipment, it is not suitable to put it in the water or oil environment. While connecting to the reduction gear, users should pay attention to prevent the oil of reduction gear from entering the motor, as well as preventing cables from oil and water.

Professionalism makes the future, success accompanies you and us. Our company is specialized in manufacturing hall sensor magnets, motor permanent magnets, irregularity magnets, multi-poles injection magnet rings, etc. If you have any demand for magnets, welcome to contact our company—China Rare Earth Magnet Limited.

Tags: permanent magnet, motor magnets

what are one-side permanent magnets?

Are you wondering what one-side magnet is? Here to introduce the one-side magnets.

The Introduction of One-side Magnets
Permanent Magnets have two poles, but in some specific working positions a single-pole magnet is needed. So we need to encase one side of magnet by metal plates, in order to shield the magnetism of that side. And strengthen the magnetism of the other side through the refraction of metal plates. These magnets are collectively known as one-sided magnets. But actually, the real one-sided magnets don’t exist.

The Material of One-side Magnets
The material used for one-side magnets is neodymium rare earth magnets. Most of the one side magnets are disc shapes.

The Application of One-side Permanent Magnet
1、One-side magnets are widely used in presswork industry. There exist one-side magnets in gift boxes, phone boxes, tobacco and wine boxes, MP3 boxes and moon cake boxes, etc.
2、They are also widely used in leather industry, such as bags, suitcases, briefcases, traveling bags, cell-phone cases, wallets and so on.
3、In Stationery industries, one side magnets are used in notebooks, white boards, folders, and magnetic name badges.

The Purchasing Considerations of One-side Magnets.
The manufacture of one-side magnets is to artificially put the neodymium magnets into the metal plates. So it will take a pretty long time to produce. Customers who want to purchase should place the order in advance.

There are many specifications of one-side magnets. China Rare Earth Magnet limited can customize the magnets according to your requirements. Please send e-mail to us if you have any demand for magnets.

Tags: permanent magnet

What kind of permanent magnet needs a mould in production?

Someone might wonder what magnet needs a mould while others do not. China Rare Earth Magnet Limited would like to discuss about this.

Permanent magnets that our company mainly manufacture: NdFeB magnet, ferrite magnet, SmCo magnet, bonded NdFeB magnet and injection molding magnet.

Sintered NdFeB magnet, also called strong magnet, has the strongest magnetism which is also one of its advantage. NdFeB magnet can be customized as per customer’s requirement without molding.

Apart from sintered NdFeB magnet, bonded NdFeB magnet is also a kind of neodymium. Its advantage is that it can be shaped in one shot without further processing. Bonded NdFeB magnet can be made into various complex shapes while sintered NdFeB magnet can not. The application of bonded NdFeB magnet can significantly decrease the volume and weight of motor. A mould of bonded NdFeB magnet ranges in price from $450 to $900.

Ferrite permanent magnet, also called normal magnet. Its magnetism is weaker than NdFeB magnet’s and thereof its price is lower than NdFeB’s. So ferrite magnet is wildly used. Ferrite magnet is divided into two classes: molding ferrite magnet and cutting ferrite magnet. Obviously the former needs a mould during production while the later do not.


SmCo magnet is mainly used in product which works at a temperature higher than 300℃. SmCo magnet is seldom applied as its high price. Mould is not a necessary for the production of SmCo magnet.

Mould is a must for the production of injection molding permanent magnet. We have available moulds in various size and we welcome your inquiry with detailed information.


To sum up, magnets need moulds during production include injection molding magnet, bonded NdFeB magnet, irregular ferrite magnet, multi-pole magnetized ferrite magnet and large-sized NdFeB magnet.

Do you know magnets that need mould during production better after reading above content? Feel free to contact us if there is any question.

Tags: permanent magnet

What are the advantages of electromagnets? What are their main applications?

Electromagnets are not our products of permanent magnets. There are many differences between them. We have encountered with customers that need electromagnets many times.  Unfortunately, China Rare Earth Magnet Limited does not produce this kind of electromagnet. Today we are talking about the advantages and applications of electromagnets.

What are the advantages of electromagnets? 
Electromagnets have many advantages: such as its magnetism can be controlled by electricity and power outage; its magnetic strength can be controlled by the strength of the current; its north and south poles can be controlled by the direction of the transformation current.

What are the main uses of electromagnets?
Electromagnetic switch, traction electromagnet, electromagnetic crane, grinder suction cup, solenoid valve, electromagnetic brake, water level automatic alarm, automatic electrical electromagnetic system and so on.

To give you a few examples, such as the electromagnetic crane has a large electromagnet. Through the current, a few tons of heavy steel material can be sucked up to move to a designated location. There is no fixture on the Grinder Workbench in the machinery factory, but the machined work piece is sucked on top for processing. Workbench is also a large electromagnet. It can attract steel or work pieces with power. When there is no power, it can release steel or work pieces. Electromagnetic dressing machine by the role of electromagnets can separate iron and non-ferrous matter.

If there is any other question about permanent magnet, please feel free to contact us.

Tags: permanent magnet, electromagnets