MW 70x50 / N38 - cylindrical magnet

Pros and cons of neodymium magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• Their magnetic field is maintained, and after around ten years it drops only by ~1% (theoretically),
• They are noted for resistance to demagnetization induced by presence of other magnetic fields,
• Thanks to the glossy finish, the plating of Ni-Cu-Ni, gold-plated, or silver-plated gives an elegant appearance,
• Neodymium magnets ensure maximum magnetic induction on a small surface, which ensures high operational effectiveness,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• In view of the option of free shaping and adaptation to individualized solutions, neodymium magnets can be modeled in a variety of shapes and sizes, which amplifies use scope,
• Significant place in modern technologies – they are utilized in HDD drives, motor assemblies, advanced medical instruments, also modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Problematic aspects of neodymium magnets: weaknesses and usage proposals

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• We recommend cover - magnetic mechanism, due to difficulties in producing threads inside the magnet and complicated forms.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child health protection. Additionally, tiny parts of these products are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what it depends on?

The declared magnet strength represents the limit force, recorded under laboratory conditions, namely:

• with the application of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• whose thickness reaches at least 10 mm
• with a plane perfectly flat
• without the slightest insulating layer between the magnet and steel
• during pulling in a direction perpendicular to the plane
• at room temperature

Determinants of lifting force in real conditions

During everyday use, the actual lifting capacity is determined by many variables, presented from most significant:

• Distance (between the magnet and the plate), since even a microscopic distance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Force direction – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Steel thickness – insufficiently thick sheet does not close the flux, causing part of the power to be wasted into the air.
• Plate material – mild steel attracts best. Higher carbon content lower magnetic permeability and lifting capacity.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Temperature – heating the magnet results in weakening of force. Check the thermal limit for a given model.

* Lifting capacity was determined using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet and the plate decreases the load capacity.