SM 25x400 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after 10 years the decline in efficiency is only ~1% (in laboratory conditions),
• Neodymium magnets are distinguished by remarkably resistant to demagnetization caused by external field sources,
• By covering with a shiny coating of silver, the element presents an modern look,
• The surface of neodymium magnets generates a powerful magnetic field – this is a key feature,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of exact machining as well as adapting to specific conditions,
• Huge importance in modern industrial fields – they are commonly used in magnetic memories, motor assemblies, advanced medical instruments, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which enables their usage in small systems

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only secures them against impacts but also increases their durability
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in realizing threads and complicated forms in magnets, we recommend using casing - magnetic holder.
• Potential hazard to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Best holding force of the magnet in ideal parameters – what it depends on?

Breakaway force is the result of a measurement for optimal configuration, including:

• with the application of a yoke made of special test steel, guaranteeing maximum field concentration
• with a thickness no less than 10 mm
• with an ideally smooth contact surface
• under conditions of ideal adhesion (metal-to-metal)
• during detachment in a direction perpendicular to the plane
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

Holding efficiency is affected by specific conditions, such as (from priority):

• Gap between magnet and steel – every millimeter of separation (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick plate does not accept the full field, causing part of the power to be escaped into the air.
• Plate material – mild steel attracts best. Alloy admixtures reduce magnetic properties and holding force.
• Plate texture – ground elements guarantee perfect abutment, which increases field saturation. Rough surfaces reduce efficiency.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined by applying a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under attempts to slide the magnet the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the load capacity.