MW 5x15 / N38 - cylindrical magnet

Pros and cons of rare earth magnets.

Apart from their superior magnetic energy, neodymium magnets have these key benefits:

• They retain full power for almost 10 years – the drop is just ~1% (according to analyses),
• They are noted for resistance to demagnetization induced by external magnetic fields,
• Thanks to the metallic finish, the plating of nickel, gold-plated, or silver gives an clean appearance,
• Magnets have impressive magnetic induction on the outer layer,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Considering the possibility of flexible shaping and customization to unique solutions, magnetic components can be manufactured in a variety of forms and dimensions, which increases their versatility,
• Significant place in modern industrial fields – they are utilized in mass storage devices, electromotive mechanisms, advanced medical instruments, as well as industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of creating threads in the magnet and complex forms - recommended is casing - mounting mechanism.
• Potential hazard related to microscopic parts of magnets are risky, in case of ingestion, which is particularly important in the context of child safety. Furthermore, tiny parts of these products can disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

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

The lifting capacity listed is a measurement result performed under specific, ideal conditions:

• using a sheet made of high-permeability steel, functioning as a ideal flux conductor
• possessing a massiveness of minimum 10 mm to avoid saturation
• with a plane cleaned and smooth
• under conditions of no distance (surface-to-surface)
• during detachment in a direction perpendicular to the mounting surface
• at temperature approx. 20 degrees Celsius

Lifting capacity in practice – influencing factors

In practice, the actual lifting capacity is determined by a number of factors, presented from crucial:

• Gap between surfaces – every millimeter of separation (caused e.g. by varnish or dirt) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is obtained only during perpendicular pulling. The force required to slide of the magnet along the surface is typically many times lower (approx. 1/5 of the lifting capacity).
• Steel thickness – insufficiently thick plate causes magnetic saturation, causing part of the flux to be lost to the other side.
• Metal type – different alloys attracts identically. Alloy additives weaken the interaction with the magnet.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Uneven metal weaken the grip.
• Temperature influence – high temperature reduces magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity was determined using a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the lifting capacity.