MPL 50x20x5 / N38 - lamellar magnet

Pros and cons of rare earth magnets.

Apart from their consistent power, neodymium magnets have these key benefits:

• They do not lose power, even after approximately ten years – the drop in lifting capacity is only ~1% (theoretically),
• They are resistant to demagnetization induced by external magnetic fields,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• The surface of neodymium magnets generates a unique magnetic field – this is one of their assets,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling operation at temperatures approaching 230°C and above...
• Thanks to versatility in designing and the ability to adapt to unusual requirements,
• Fundamental importance in modern industrial fields – they find application in hard drives, brushless drives, medical equipment, also other advanced devices.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• At very strong impacts they can crack, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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 extremely resistant to heat
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in realizing threads and complicated shapes in magnets, we recommend using a housing - magnetic mount.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which is particularly important in the context of child safety. Additionally, small elements of these magnets can be problematic in diagnostics medical in case of swallowing.
• With budget limitations the cost of neodymium magnets can be a barrier,

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

The declared magnet strength refers to the peak performance, measured under optimal environment, specifically:

• with the use of a yoke made of special test steel, guaranteeing full magnetic saturation
• with a thickness of at least 10 mm
• with a plane perfectly flat
• with direct contact (no coatings)
• during detachment in a direction perpendicular to the plane
• in stable room temperature

Determinants of lifting force in real conditions

In real-world applications, the actual holding force depends on many variables, presented from crucial:

• Gap between magnet and steel – every millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Element thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces reduce efficiency.
• Heat – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was assessed using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate decreases the load capacity.