FM Ruszt magnetyczny do leja fi 200 jednopoziomowy / N52 - magnetic filter

Strengths and weaknesses of NdFeB magnets.

Besides their remarkable pulling force, neodymium magnets offer the following advantages:

• They do not lose power, even after around 10 years – the drop in lifting capacity is only ~1% (theoretically),
• They are extremely resistant to demagnetization induced by external magnetic fields,
• In other words, due to the aesthetic surface of silver, the element gains visual value,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of exact forming as well as adjusting to atypical requirements,
• Fundamental importance in innovative solutions – they are used in computer drives, brushless drives, diagnostic systems, as well as technologically advanced constructions.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Problematic aspects of neodymium magnets: weaknesses and usage proposals

• At very strong impacts they can break, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape as well as 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 immune to moisture, in case of application outdoors
• Due to limitations in creating nuts and complex forms in magnets, we propose using casing - magnetic mechanism.
• Health risk to health – tiny shards of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small components of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what it depends on?

Holding force of 0 kg is a measurement result performed under the following configuration:

• using a base made of high-permeability steel, serving as a ideal flux conductor
• whose transverse dimension is min. 10 mm
• characterized by smoothness
• without the slightest clearance between the magnet and steel
• during detachment in a direction perpendicular to the plane
• at ambient temperature approx. 20 degrees Celsius

Key elements affecting lifting force

Effective lifting capacity is influenced by specific conditions, such as (from most important):

• Distance – existence of foreign body (paint, dirt, air) acts as an insulator, which reduces power steeply (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits much less (typically approx. 20-30% of maximum force).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Cast iron may generate lower lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Uneven metal weaken the grip.
• Thermal factor – hot environment weakens pulling force. Too high temperature can permanently damage the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.