AM ucho [M12] - magnetic accessories

Pros and cons of rare earth magnets.

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

• They do not lose strength, even after around ten years – the decrease in lifting capacity is only ~1% (theoretically),
• Magnets perfectly defend themselves against loss of magnetization caused by external fields,
• Thanks to the reflective finish, the surface of nickel, gold, or silver gives an elegant appearance,
• Neodymium magnets generate maximum magnetic induction on a small surface, which increases force concentration,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures reaching 230°C and above...
• Thanks to freedom in constructing and the ability to adapt to unusual requirements,
• Significant place in electronics industry – they are used in computer drives, drive modules, diagnostic systems, as well as multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At very strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (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
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Limited possibility of creating threads in the magnet and complicated forms - preferred is cover - magnetic holder.
• Health risk related to microscopic parts of magnets pose a threat, if swallowed, which gains importance in the context of child safety. Additionally, small components of these magnets can disrupt the diagnostic process medical when they are in the body.
• With mass production the cost of neodymium magnets is a challenge,

Magnetic strength at its maximum – what affects it?

The declared magnet strength represents the limit force, measured under laboratory conditions, namely:

• on a block made of structural steel, optimally conducting the magnetic field
• with a thickness of at least 10 mm
• with an ideally smooth touching surface
• under conditions of no distance (metal-to-metal)
• under perpendicular force direction (90-degree angle)
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

It is worth knowing that the application force may be lower subject to elements below, starting with the most relevant:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Plate thickness – insufficiently thick sheet does not close the flux, causing part of the power to be lost to the other side.
• Material composition – different alloys reacts the same. Alloy additives weaken the interaction with the magnet.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Thermal factor – high temperature weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Moreover, even a slight gap {between} the magnet and the plate lowers the load capacity.