UMGB 67x28 [M8+M10] GW F 120+ Lina GOBLIN / N38 - goblin magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They have unchanged lifting capacity, and over around ten years their attraction force decreases symbolically – ~1% (according to theory),
• They are very resistant to demagnetization caused by external field interference,
• The use of a polished gold surface provides a eye-catching finish,
• They have very high magnetic induction on the surface of the magnet,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to form),
• Thanks to the flexibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in diverse shapes and sizes, which broadens their usage potential,
• Significant impact in new technology industries – they are utilized in hard drives, electric drives, clinical machines along with high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in compact dimensions, which allows for use in compact constructions

Disadvantages of rare earth magnets:

• They may fracture when subjected to a strong impact. If the magnets are exposed to physical collisions, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture and strengthens its overall resistance,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a wet environment, especially when used outside, we recommend using encapsulated magnets, such as those made of non-metallic materials,
• Limited ability to create threads in the magnet – the use of a external casing is recommended,
• Potential hazard linked to microscopic shards may arise, in case of ingestion, which is crucial in the family environments. It should also be noted that minuscule fragments from these devices may hinder health screening when ingested,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which may limit large-scale applications

Maximum lifting force for a neodymium magnet – what it depends on?

The given pulling force of the magnet means the maximum force, measured under optimal conditions, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Key elements affecting lifting force

In practice, the holding capacity of a magnet is conditioned by these factors, in descending order of importance:

• Air gap between the magnet and the plate, as even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity was measured using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, however under attempts to slide the magnet the load capacity is reduced by as much as 5 times. In addition, even a minimal clearance {between} the magnet and the plate lowers the load capacity.