SM 25x175 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

Apart from their superior magnetic energy, neodymium magnets have these key benefits:

• They virtually do not lose strength, because even after 10 years the decline in efficiency is only ~1% (in laboratory conditions),
• They do not lose their magnetic properties even under external field action,
• The use of an refined layer of noble metals (nickel, gold, silver) causes the element to look better,
• Neodymium magnets ensure maximum magnetic induction on a contact point, which increases force concentration,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for action at temperatures reaching 230°C and above...
• In view of the option of accurate forming and customization to specialized projects, NdFeB magnets can be manufactured in a variety of shapes and sizes, which increases their versatility,
• Fundamental importance in electronics industry – they are used in mass storage devices, drive modules, medical equipment, also industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Drawbacks and weaknesses of neodymium magnets and ways of using them

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of creating threads in the magnet and complex forms - recommended is casing - magnet mounting.
• Possible danger 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 devices can disrupt the diagnostic process medical after entering the body.
• With large orders the cost of neodymium magnets is a challenge,

Detachment force of the magnet in optimal conditions – what contributes to it?

The load parameter shown concerns the limit force, recorded under laboratory conditions, namely:

• with the application of a sheet made of low-carbon steel, guaranteeing full magnetic saturation
• possessing a thickness of minimum 10 mm to avoid saturation
• characterized by even structure
• without any clearance between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Lifting capacity in real conditions – factors

Please note that the magnet holding may be lower subject to the following factors, starting with the most relevant:

• Clearance – existence of foreign body (paint, dirt, gap) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When slipping, the magnet holds significantly lower power (often approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick steel does not close the flux, causing part of the flux to be wasted to the other side.
• Material composition – not every steel reacts the same. Alloy additives weaken the interaction with the magnet.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases field saturation. Rough surfaces weaken the grip.
• Temperature – temperature increase causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet and the plate lowers the load capacity.