MPL 30x5x5 / N38 - lamellar magnet

Strengths and weaknesses of NdFeB magnets.

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

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (according to literature),
• Neodymium magnets remain extremely resistant to loss of magnetic properties caused by external magnetic fields,
• Thanks to the elegant finish, the plating of Ni-Cu-Ni, gold, or silver gives an clean appearance,
• Magnetic induction on the surface of the magnet remains exceptional,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling functioning at temperatures approaching 230°C and above...
• Possibility of accurate forming as well as optimizing to atypical applications,
• Huge importance in modern technologies – they serve a role in hard drives, brushless drives, advanced medical instruments, as well as complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which enables their usage in small systems

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a special holder, which not only secures them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets experience a drop in power. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of making threads in the magnet and complicated forms - recommended is a housing - mounting mechanism.
• Possible danger resulting from small fragments of magnets can be dangerous, if swallowed, which becomes key in the context of child health protection. Additionally, small elements of these devices are able to disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Detachment force of the magnet in optimal conditions – what it depends on?

The load parameter shown represents the limit force, recorded under laboratory conditions, specifically:

• using a plate made of high-permeability steel, acting as a ideal flux conductor
• whose transverse dimension reaches at least 10 mm
• with an ideally smooth contact surface
• under conditions of no distance (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

Determinants of practical lifting force of a magnet

Real force impacted by specific conditions, such as (from most important):

• Distance (betwixt the magnet and the metal), since even a tiny clearance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Force direction – note that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of converting into lifting capacity.
• Chemical composition of the base – low-carbon steel gives the best results. Higher carbon content lower magnetic permeability and lifting capacity.
• Plate texture – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces weaken the grip.
• Temperature influence – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was measured with the use of a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, in contrast under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the holding force.