UMGB 107x40 [M8+M10] GW F400 +Lina GOBLIN / N38 - goblin magnetic holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose power, because even after ten years, the decline in efficiency is only ~1% (according to literature),
• They show strong resistance to demagnetization from external field exposure,
• Thanks to the glossy finish and nickel coating, they have an visually attractive appearance,
• They possess intense magnetic force measurable at the magnet’s surface,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• The ability for custom shaping or adaptation to custom needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Important function in cutting-edge sectors – they serve a purpose in computer drives, electric motors, medical equipment as well as technologically developed systems,
• Thanks to their power density, small magnets offer high magnetic performance, in miniature format,

Disadvantages of NdFeB magnets:

• They may fracture when subjected to a sudden impact. If the magnets are exposed to shocks, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from damage and enhances its overall resistance,
• They lose strength at increased temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to damp air can oxidize. Therefore, for outdoor applications, it's best to use waterproof types made of non-metallic composites,
• Limited ability to create precision features in the magnet – the use of a external casing is recommended,
• Health risk from tiny pieces may arise, in case of ingestion, which is notable in the context of child safety. Furthermore, tiny components from these devices might interfere with diagnostics once in the system,
• In cases of tight budgets, neodymium magnet cost may be a barrier,

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

The given strength of the magnet means the optimal strength, calculated under optimal conditions, specifically:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a refined outer layer
• with no separation
• with vertical force applied
• in normal thermal conditions

Practical lifting capacity: influencing factors

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

• Air gap between the magnet and the plate, because even a very small distance (e.g. 0.5 mm) can cause 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.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Additionally, even a slight gap {between} the magnet and the plate lowers the load capacity.