BM 320x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of NdFeB magnets.

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

• They have unchanged lifting capacity, and over around 10 years their attraction force decreases symbolically – ~1% (in testing),
• They have excellent resistance to weakening of magnetic properties as a result of external fields,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• The surface of neodymium magnets generates a powerful magnetic field – this is one of their assets,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to flexibility in forming and the ability to adapt to individual projects,
• Huge importance in future technologies – they find application in magnetic memories, electric drive systems, advanced medical instruments, as well as modern systems.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a special holder, which not only secures them against impacts but also increases their durability
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• We suggest casing - magnetic holder, due to difficulties in producing nuts inside the magnet and complicated shapes.
• Potential hazard resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small components of these magnets are able to be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Best holding force of the magnet in ideal parameters – what it depends on?

The specified lifting capacity concerns the peak performance, obtained under ideal test conditions, namely:

• with the application of a yoke made of special test steel, guaranteeing maximum field concentration
• whose thickness is min. 10 mm
• with a plane cleaned and smooth
• under conditions of no distance (metal-to-metal)
• for force acting at a right angle (in the magnet axis)
• at ambient temperature room level

Impact of factors on magnetic holding capacity in practice

In real-world applications, the actual holding force is determined by many variables, ranked from most significant:

• Gap (between the magnet and the plate), because even a microscopic clearance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Material type – ideal substrate is high-permeability steel. Cast iron may attract less.
• Plate texture – ground elements guarantee perfect abutment, which increases field saturation. Uneven metal reduce efficiency.
• Temperature – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet and the plate lowers the lifting capacity.