MW 5x5 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• Their strength is durable, and after approximately 10 years, it drops only by ~1% (according to research),
• They protect against demagnetization induced by ambient magnetic influence very well,
• Because of the lustrous layer of silver, the component looks high-end,
• Magnetic induction on the surface of these magnets is notably high,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• With the option for customized forming and precise design, these magnets can be produced in various shapes and sizes, greatly improving design adaptation,
• Wide application in modern technologies – they find application in HDDs, electric drives, healthcare devices as well as high-tech tools,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They can break when subjected to a strong impact. If the magnets are exposed to external force, it is advisable to use in a metal holder. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time enhances its overall strength,
• They lose field intensity at elevated temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• They rust in a humid environment. For outdoor use, we recommend using encapsulated magnets, such as those made of non-metallic materials,
• Limited ability to create precision features in the magnet – the use of a external casing is recommended,
• Safety concern related to magnet particles may arise, if ingested accidentally, which is significant in the protection of children. Furthermore, minuscule fragments from these devices may disrupt scanning if inside the body,
• Due to the price of neodymium, their cost is considerably higher,

Highest magnetic holding force – what affects it?

The given lifting capacity of the magnet represents the maximum lifting force, determined in the best circumstances, that is:

• with mild steel, used as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a polished side
• with no separation
• under perpendicular detachment force
• under standard ambient temperature

What influences lifting capacity in practice

Practical lifting force is dependent on elements, by priority:

• Air gap between the magnet and the plate, as even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity was determined using a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate lowers the holding force.