MPL 40x10x4 / N38 - lamellar magnet

Pros as well as cons of NdFeB magnets.

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

• They do not lose power, even after around ten years – the reduction in power is only ~1% (according to tests),
• Neodymium magnets prove to be highly resistant to loss of magnetic properties caused by magnetic disturbances,
• A magnet with a shiny gold surface has an effective appearance,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Thanks to modularity in shaping and the ability to modify to specific needs,
• Fundamental importance in innovative solutions – they serve a role in computer drives, drive modules, medical equipment, as well as complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Problematic aspects of neodymium magnets and ways of using them

• Brittleness is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a special holder, which not only secures them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 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 producing nuts and complicated forms in magnets, we recommend using cover - magnetic mechanism.
• Potential hazard to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small elements of these devices can disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The lifting capacity listed is a measurement result conducted under the following configuration:

• using a base made of mild steel, acting as a ideal flux conductor
• with a cross-section minimum 10 mm
• characterized by even structure
• without the slightest air gap between the magnet and steel
• under perpendicular application of breakaway force (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

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

• Gap between surfaces – every millimeter of distance (caused e.g. by veneer or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Steel grade – the best choice is high-permeability steel. Hardened steels may have worse magnetic properties.
• Surface finish – ideal contact is possible only on polished steel. Rough texture create air cushions, reducing force.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was assessed by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under attempts to slide the magnet the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.