SMZR 32x175 / N52 - magnetic separator with handle

Strengths and weaknesses of neodymium magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They have unchanged lifting capacity, and over around ten years their attraction force decreases symbolically – ~1% (according to theory),
• They maintain their magnetic properties even under close interference source,
• In other words, due to the shiny layer of gold, the element gains visual value,
• Magnetic induction on the working part of the magnet is strong,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of accurate machining as well as adapting to complex needs,
• Wide application in high-tech industry – they serve a role in data components, motor assemblies, medical equipment, and technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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 very resistant to heat
• They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing threads and complicated shapes in magnets, we propose using casing - magnetic mechanism.
• Health risk resulting from small fragments of magnets pose a threat, if swallowed, which gains importance in the aspect of protecting the youngest. Additionally, tiny parts of these devices are able to be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets is a challenge,

Maximum magnetic pulling force – what it depends on?

The force parameter is a theoretical maximum value performed under standard conditions:

• using a base made of mild steel, functioning as a ideal flux conductor
• with a cross-section of at least 10 mm
• with a plane cleaned and smooth
• with zero gap (no coatings)
• for force applied at a right angle (in the magnet axis)
• at temperature room level

Determinants of lifting force in real conditions

Bear in mind that the working load will differ influenced by the following factors, in order of importance:

• Space between surfaces – every millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel grade – ideal substrate is high-permeability steel. Stainless steels may attract less.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Temperature – temperature increase results in weakening of force. Check the thermal limit for a given model.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, in contrast under attempts to slide the magnet the holding force is lower. Additionally, even a minimal clearance {between} the magnet and the plate decreases the load capacity.