SM 32x425 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• Their magnetic field remains stable, and after approximately 10 years it drops only by ~1% (according to research),
• They feature excellent resistance to magnetism drop when exposed to external magnetic sources,
• Thanks to the metallic finish, the coating of nickel, gold-plated, or silver gives an visually attractive appearance,
• Neodymium magnets create maximum magnetic induction on a their surface, which allows for strong attraction,
• 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 the ability of precise shaping and adaptation to specialized requirements, neodymium magnets can be produced in a variety of geometric configurations, which makes them more universal,
• Versatile presence in electronics industry – they are utilized in HDD drives, electric drive systems, diagnostic systems, also other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a strong case, which not only secures them against impacts but also increases their durability
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• We suggest a housing - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complex forms.
• Possible danger resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. Furthermore, tiny parts of these devices are able to disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what it depends on?

Breakaway force was defined for optimal configuration, taking into account:

• using a plate made of mild steel, functioning as a circuit closing element
• possessing a thickness of at least 10 mm to ensure full flux closure
• with an ideally smooth touching surface
• with total lack of distance (without impurities)
• for force acting at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Practical aspects of lifting capacity – factors

During everyday use, the actual holding force results from a number of factors, listed from the most important:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by veneer or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Load vector – highest force is reached only during perpendicular pulling. The shear force of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Metal type – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
• Surface finish – full contact is possible only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Temperature – heating the magnet results in weakening of force. Check the thermal limit for a given model.

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under perpendicular forces, whereas under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Moreover, even a small distance {between} the magnet and the plate decreases the lifting capacity.