SM 18x100 [2xM5] / N42 - magnetic separator

Strengths and weaknesses of neodymium magnets.

Besides their exceptional field intensity, neodymium magnets offer the following advantages:

• Their power is maintained, and after approximately ten years it decreases only by ~1% (according to research),
• Magnets perfectly protect themselves against demagnetization caused by ambient magnetic noise,
• In other words, due to the glossy surface of gold, the element becomes visually attractive,
• Magnetic induction on the top side of the magnet remains extremely intense,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to modularity in designing and the capacity to modify to unusual requirements,
• Key role in innovative solutions – they serve a role in hard drives, electric drive systems, diagnostic systems, as well as multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Characteristics of disadvantages of neodymium magnets and ways of using them

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• Neodymium magnets decrease their power 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 waterproof magnets made of rubber, plastic or other material resistant to moisture
• Limited ability of making nuts in the magnet and complicated forms - recommended is cover - magnetic holder.
• Potential hazard resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small elements of these devices are able to be problematic in diagnostics medical in case of swallowing.
• Due to neodymium price, their price is relatively high,

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

The load parameter shown concerns the peak performance, measured under ideal test conditions, namely:

• with the contact of a sheet made of special test steel, ensuring maximum field concentration
• whose transverse dimension reaches at least 10 mm
• characterized by even structure
• without the slightest clearance between the magnet and steel
• during detachment in a direction vertical to the mounting surface
• in neutral thermal conditions

Determinants of practical lifting force of a magnet

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

• Clearance – existence of foreign body (paint, tape, gap) acts as an insulator, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Load vector – maximum parameter is reached only during pulling at a 90° angle. The shear force of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Steel thickness – too thin steel does not close the flux, causing part of the flux to be lost into the air.
• Material composition – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Surface quality – the more even the surface, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Temperature – temperature increase causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, however under shearing force the holding force is lower. Additionally, even a minimal clearance {between} the magnet and the plate lowers the lifting capacity.