MW 4x8 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have stable power, and over more than 10 years their performance decreases symbolically – ~1% (according to theory),
• They are resistant to demagnetization induced by external field influence,
• Thanks to the metallic finish, the surface of nickel, gold-plated, or silver-plated gives an elegant appearance,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling action at temperatures reaching 230°C and above...
• Possibility of precise modeling and optimizing to individual conditions,
• Key role in electronics industry – they are utilized in hard drives, electric drive systems, diagnostic systems, and complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a special holder, which not only protects them against impacts but also raises their durability
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• Limited ability of creating threads in the magnet and complex shapes - recommended is a housing - mounting mechanism.
• Possible danger to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the context of child safety. Furthermore, small components of these devices are able to complicate diagnosis medical when they are in the body.
• Due to neodymium price, their price exceeds standard values,

Maximum lifting force for a neodymium magnet – what contributes to it?

The load parameter shown concerns the peak performance, measured under ideal test conditions, specifically:

• with the application of a sheet made of special test steel, guaranteeing full magnetic saturation
• possessing a massiveness of minimum 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of ideal adhesion (metal-to-metal)
• during detachment in a direction perpendicular to the mounting surface
• at standard ambient temperature

Impact of factors on magnetic holding capacity in practice

In practice, the actual holding force results from a number of factors, listed from most significant:

• Gap (betwixt the magnet and the plate), because even a tiny distance (e.g. 0.5 mm) can cause a drastic drop in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Loading method – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Chemical composition of the base – low-carbon steel gives the best results. Higher carbon content decrease magnetic properties and lifting capacity.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Temperature – temperature increase results in weakening of induction. Check the thermal limit for a given model.

* Lifting capacity was determined with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular pulling force, 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’s surface and the plate decreases the load capacity.