MW 10x10 / N38 - cylindrical magnet

Strengths and weaknesses of NdFeB magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They do not lose power, even after approximately 10 years – the reduction in lifting capacity is only ~1% (according to tests),
• They maintain their magnetic properties even under external field action,
• A magnet with a metallic silver surface has an effective appearance,
• The surface of neodymium magnets generates a powerful magnetic field – this is a distinguishing feature,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to freedom in shaping and the capacity to modify to specific needs,
• Significant place in advanced technology sectors – they find application in HDD drives, electromotive mechanisms, diagnostic systems, as well as modern systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in miniature devices

What to avoid - cons of neodymium magnets: application proposals

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a steel housing, which not only secures them against impacts but also raises their durability
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Due to limitations in producing nuts and complicated forms in magnets, we recommend using cover - magnetic holder.
• Health risk to health – tiny shards of magnets are risky, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, tiny parts of these products can disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what contributes to it?

Information about lifting capacity was determined for the most favorable conditions, including:

• on a plate made of structural steel, perfectly concentrating the magnetic flux
• whose thickness is min. 10 mm
• characterized by even structure
• under conditions of no distance (metal-to-metal)
• under perpendicular force vector (90-degree angle)
• at conditions approx. 20°C

Lifting capacity in real conditions – factors

In practice, the actual lifting capacity depends on a number of factors, ranked from the most important:

• Distance – existence of any layer (rust, tape, air) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Angle of force application – highest force is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Steel type – mild steel attracts best. Higher carbon content lower magnetic properties and holding force.
• Plate texture – ground elements ensure maximum contact, which increases field saturation. Uneven metal reduce efficiency.
• Heat – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, in contrast under parallel forces the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.