MW 100x10 / N38 - cylindrical magnet

Pros and cons of rare earth magnets.

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

• They have unchanged lifting capacity, and over nearly ten years their performance decreases symbolically – ~1% (according to theory),
• They are extremely resistant to demagnetization induced by external field influence,
• A magnet with a shiny nickel surface is more attractive,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Considering the option of free shaping and adaptation to individualized needs, neodymium magnets can be produced in a broad palette of geometric configurations, which expands the range of possible applications,
• Significant place in innovative solutions – they find application in mass storage devices, electric drive systems, diagnostic systems, as well as complex engineering applications.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a steel housing, which not only protects them against impacts but also increases 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.
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Limited ability of producing nuts in the magnet and complicated shapes - preferred is cover - magnetic holder.
• Health risk related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the context of child safety. Furthermore, tiny parts of these devices can complicate diagnosis medical in case of swallowing.
• Due to complex production process, their price exceeds standard values,

Maximum lifting force for a neodymium magnet – what affects it?

The declared magnet strength concerns the limit force, obtained under laboratory conditions, meaning:

• with the contact of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• with a cross-section no less than 10 mm
• characterized by lack of roughness
• without any clearance between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• at room temperature

Impact of factors on magnetic holding capacity in practice

Bear in mind that the working load may be lower subject to elements below, starting with the most relevant:

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to detachment vertically. When slipping, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of generating force.
• Steel grade – the best choice is pure iron steel. Hardened steels may attract less.
• Surface quality – the smoother and more polished the surface, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
• Temperature – heating the magnet causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet and the plate reduces the holding force.