MP 5x2.7/1.2x5 C / N38 - ring magnet

Strengths as well as weaknesses of rare earth magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• Their magnetic field remains stable, and after approximately 10 years it drops only by ~1% (according to research),
• Magnets perfectly protect themselves against loss of magnetization caused by ambient magnetic noise,
• The use of an refined layer of noble metals (nickel, gold, silver) causes the element to present itself better,
• Neodymium magnets create maximum magnetic induction on a small area, which ensures high operational effectiveness,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling operation at temperatures approaching 230°C and above...
• In view of the possibility of precise molding and customization to custom needs, neodymium magnets can be manufactured in a broad palette of geometric configurations, which makes them more universal,
• Huge importance in advanced technology sectors – they are commonly used in HDD drives, electric motors, medical devices, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which makes them useful in miniature devices

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Limited possibility of creating nuts in the magnet and complicated forms - preferred is casing - magnet mounting.
• Health risk to health – tiny shards of magnets are risky, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these products can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

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

Information about lifting capacity was defined for the most favorable conditions, taking into account:

• using a plate made of low-carbon steel, acting as a circuit closing element
• whose transverse dimension reaches at least 10 mm
• characterized by even structure
• with total lack of distance (no paint)
• for force applied at a right angle (in the magnet axis)
• in stable room temperature

Lifting capacity in real conditions – factors

It is worth knowing that the magnet holding may be lower subject to elements below, in order of importance:

• Clearance – existence of foreign body (paint, dirt, gap) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Load vector – maximum parameter is obtained only during perpendicular pulling. The force required to slide of the magnet along the surface is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick steel does not close the flux, causing part of the power to be wasted to the other side.
• Steel grade – the best choice is high-permeability steel. Cast iron may have worse magnetic properties.
• Surface quality – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was conducted on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the holding force.