UMP 94x28 [3xM10] GW F300 GOLD / N38 - search holder

Advantages as well as disadvantages of rare earth magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They do not lose power, even over approximately 10 years – the decrease in lifting capacity is only ~1% (according to tests),
• Magnets very well resist against loss of magnetization caused by external fields,
• The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to present itself better,
• Magnets exhibit very high magnetic induction on the working surface,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of individual shaping and adjusting to individual conditions,
• Key role in advanced technology sectors – they are used in mass storage devices, motor assemblies, advanced medical instruments, and industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in miniature devices

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• We suggest a housing - magnetic mount, due to difficulties in realizing threads inside the magnet and complicated forms.
• Health risk resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these products can complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which can limit application in large quantities

Highest magnetic holding force – what it depends on?

The declared magnet strength concerns the peak performance, recorded under laboratory conditions, specifically:

• using a plate made of mild steel, serving as a magnetic yoke
• whose transverse dimension is min. 10 mm
• with a plane free of scratches
• without any clearance between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at conditions approx. 20°C

What influences lifting capacity in practice

Holding efficiency is influenced by working environment parameters, mainly (from priority):

• Gap between magnet and steel – 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 – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet holds much less (typically approx. 20-30% of maximum force).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – the best choice is high-permeability steel. Stainless steels may attract less.
• Plate texture – smooth surfaces guarantee perfect abutment, which improves field saturation. Uneven metal weaken the grip.
• Thermal factor – high temperature weakens pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.