RM R4 - 5000 Gs / N52 - magnetic distributor

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their superior magnetism, neodymium magnets have these key benefits:

• They virtually do not lose strength, because even after 10 years, the decline in efficiency is only ~1% (according to literature),
• They are very resistant to demagnetization caused by external field interference,
• Because of the reflective layer of gold, the component looks high-end,
• They possess significant magnetic force measurable at the magnet’s surface,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to build),
• With the option for customized forming and precise design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Significant impact in cutting-edge sectors – they serve a purpose in HDDs, electric motors, diagnostic apparatus and high-tech tools,
• Thanks to their power density, small magnets offer high magnetic performance, with minimal size,

Disadvantages of NdFeB magnets:

• They can break when subjected to a strong impact. If the magnets are exposed to shocks, they should be placed in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage while also increases its overall strength,
• They lose power at increased temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the dimensions and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Due to corrosion risk in humid conditions, it is recommended to use sealed magnets made of plastic for outdoor use,
• Limited ability to create threads in the magnet – the use of a magnetic holder is recommended,
• Potential hazard related to magnet particles may arise, especially if swallowed, which is important in the context of child safety. Furthermore, tiny components from these magnets have the potential to disrupt scanning after being swallowed,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Maximum magnetic pulling force – what contributes to it?

The given strength of the magnet represents the optimal strength, measured in ideal conditions, namely:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a smooth surface
• with no separation
• in a perpendicular direction of force
• in normal thermal conditions

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is affected by these factors, in descending order of importance:

• Air gap between the magnet and the plate, since 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.

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet and the plate reduces the holding force.