MW 38x12 / N38 - cylindrical magnet

Strengths as well as weaknesses of rare earth magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have unchanged lifting capacity, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
• They maintain their magnetic properties even under close interference source,
• By covering with a lustrous layer of silver, the element presents an aesthetic look,
• Neodymium magnets deliver maximum magnetic induction on a contact point, which allows for strong attraction,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Considering the ability of free forming and adaptation to specialized requirements, magnetic components can be modeled in a variety of shapes and sizes, which expands the range of possible applications,
• Universal use in innovative solutions – they are commonly used in mass storage devices, electromotive mechanisms, medical devices, and industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• They are fragile upon heavy 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
• NdFeB magnets lose power 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 very resistant to heat
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Due to limitations in creating threads and complex shapes in magnets, we recommend using a housing - magnetic holder.
• Possible danger resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child health protection. Furthermore, small elements of these magnets can be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what it depends on?

Information about lifting capacity is the result of a measurement for the most favorable conditions, taking into account:

• on a plate made of mild steel, optimally conducting the magnetic field
• with a cross-section no less than 10 mm
• with a plane perfectly flat
• without the slightest air gap between the magnet and steel
• during pulling in a direction perpendicular to the mounting surface
• at room temperature

What influences lifting capacity in practice

Holding efficiency is influenced by specific conditions, such as (from priority):

• Clearance – existence of foreign body (paint, tape, gap) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Direction of force – highest force is reached only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – low-carbon steel gives the best results. Higher carbon content decrease magnetic properties and lifting capacity.
• Smoothness – ideal contact is obtained only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.