MW 14x10 / N38 - cylindrical magnet

Strengths as well as weaknesses of NdFeB magnets.

Apart from their consistent holding force, neodymium magnets have these key benefits:

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (according to literature),
• Neodymium magnets remain highly resistant to demagnetization caused by external interference,
• Thanks to the metallic finish, the surface of nickel, gold-plated, or silver-plated gives an modern appearance,
• Neodymium magnets create maximum magnetic induction on a small surface, which ensures high operational effectiveness,
• 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 ability to customize to complex applications,
• Fundamental importance in electronics industry – they serve a role in data components, electromotive mechanisms, diagnostic systems, and multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in producing nuts and complicated shapes in magnets, we propose using a housing - magnetic mechanism.
• Potential hazard resulting from small fragments of magnets pose a threat, in case of ingestion, which gains importance in the context of child health protection. Additionally, tiny parts of these products can complicate diagnosis medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what affects it?

Information about lifting capacity was defined for optimal configuration, including:

• using a plate made of mild steel, acting as a ideal flux conductor
• with a thickness of at least 10 mm
• characterized by even structure
• with direct contact (no impurities)
• for force applied at a right angle (in the magnet axis)
• in neutral thermal conditions

Lifting capacity in practice – influencing factors

Bear in mind that the application force may be lower influenced by the following factors, in order of importance:

• Space between magnet and steel – every millimeter of separation (caused e.g. by varnish or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Force direction – note that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Plate thickness – insufficiently thick steel does not accept the full field, causing part of the flux to be lost to the other side.
• Material type – the best choice is high-permeability steel. Cast iron may have worse magnetic properties.
• Base smoothness – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Thermal factor – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the holding force is lower. In addition, even a slight gap {between} the magnet and the plate reduces the load capacity.