Stacking Magnets  - Custom High Field Magnet Assemblies for Industry

In magnet industries, we use magnet splitting technology, bonding multiple magnets together with a special high temperature insulating adhesive to form laminated magnets. This process improves magnet resistivity and reduces motor magnet eddy currents without changing magnet composition, dimensional parameters or motor performance.

Most of the rotor magnets used in electric motors, especially in electric vehicles can be designed in this way, so the use of laminated magnet is increasing as well. For example, low eddy current loss NdFeB laminated magnets and SmCo laminated magnets are now being used in all types of high speed motors, including axial flux motors.

Magnetic stacking Assembly is made by stacking a bunch of block, disc or ring magnets together with like poles facing one another, repelling each other. Since they repel each other, they need to be held in place with hardware and glue. This structure will generate a strong magnetic field at the surface of the stack.

So if you want to know how to make a magnet more powerful, magnetic stack is a one of good solution.

Do magnets get stronger if stacked with opposite poles facing one another? 

Yes, but the magnetic force does not increase indefinitely. Increasing the magnetic force by simply stacking magnets, the following conditions need to be met: the magnet stack should be half as high as the diameter of an individual disc magnet. Up to this height, the adhesive force multiplies with each additional magnet. After that, the adhesive force gain continuously declines. It strives towards a certain value, which will not be exceeded, no matter how high the stack is. And this is because the magnetic fields are in opposite directions, the magnetic strengths cancel each other out and weaken the magnetic effect.

These components are usually used for magnetic separation to remove magnetic particles, steel parts, nuts and bolts, or other contaminants from other materials; they are also used for traveling wave tubes (TWTs) to amplify microwave signals, and for sensor to detect, identify and locate ferromagnetic and conductive objects, navigation, position tracking and anti-theft systems. Magnetic stacks can also be made into halbach arrays and and magnetic levitation systems for scientific research.

• Sensor
• Linear motor
• Scientific research
• Magnetic separation
• Traveling wave tubes (TWTs)

Our current stacked magnets are mainly made of NdFeB, ferrite and SmCo magnets.

Compared to other permanent magnets, ferrite magnets have weaker magnetic force, but they are inexpensive. Ferrite stack can provide higher potential performance and control the cost as well. Therefore, many customers choose this material. But they can’t used on high precision application because of the machining accuracy of ferrite magnet.

Neodymium magnets are the strongest permanent magnets in the world. The magnets are small, high energy, and have high machining accuracy, so they are usually used in applications where super strong magnetic force and precise size are required.

Samarium cobalt magnets have high-temperature performance and temperature stability that sintered NdFeB magnets can’t compare. They usually used on industrial high temperature devices.

The selection of the correct permanent magnet material and grade is critical in the design of any magnetic product. A number of key parameters should be carefully considered when evaluating the correct material selection for your application. For example, maximum operating temperature, maximum energy product, and inherent coercivity (resistance to demagnetization). Read more or contact us to learn more about material selection.

The magnetic stack is a bit challenging to assemble, since the magnets act to repel each other apart. Our experienced engineers are familiar with the design and assembly of various types of stacked magnet components. We will design and manufacture specific fixtures according to the characteristics of different products, as well as being able to adjust the fixtures in real time based on feedback during the assembly process, and will customize special dispensing machines for regular high volume component orders, making the assembly easier, faster and more accurate.

China Magnets Source is a leading permanent magnet manufacturer, delivering high quality, high precision magnet products for customers in all industries, worldwide. We have competitive advantages in production efficiency, product manufacturing accuracy and cost control. Whether the stacks of permanent magnets or magnetic stacked assemblies, contact us now and we’ll provide you with an immediate price reference.