MW 8x1.5 / N38 - cylindrical magnet

Pros and cons of NdFeB magnets.

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

• They retain attractive force for almost 10 years – the drop is just ~1% (based on simulations),
• They are extremely resistant to demagnetization induced by presence of other magnetic fields,
• Thanks to the smooth finish, the plating of Ni-Cu-Ni, gold, or silver gives an clean appearance,
• Magnets are characterized by impressive magnetic induction on the outer side,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, enabling action at temperatures approaching 230°C and above...
• Thanks to versatility in constructing and the ability to modify to unusual requirements,
• Key role in high-tech industry – they are utilized in magnetic memories, motor assemblies, precision medical tools, and industrial machines.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets experience a drop in power. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• We recommend cover - magnetic mount, due to difficulties in realizing nuts inside the magnet and complicated forms.
• Potential hazard related to microscopic parts of magnets are risky, in case of ingestion, which gains importance in the aspect of protecting the youngest. Additionally, small components of these products are able to disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

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

The load parameter shown concerns the peak performance, measured under optimal environment, meaning:

• using a base made of low-carbon steel, functioning as a ideal flux conductor
• possessing a massiveness of minimum 10 mm to avoid saturation
• characterized by lack of roughness
• without any clearance between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

Effective lifting capacity impacted by specific conditions, mainly (from priority):

• Clearance – the presence of foreign body (rust, tape, gap) interrupts the magnetic circuit, which lowers power steeply (even by 50% at 0.5 mm).
• Direction of force – highest force is obtained only during perpendicular pulling. The shear force of the magnet along the plate is usually many times lower (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel attracts best. Alloy admixtures reduce magnetic permeability and lifting capacity.
• Plate texture – ground elements guarantee perfect abutment, which improves field saturation. Rough surfaces reduce efficiency.
• Thermal factor – high temperature weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under a perpendicular pulling force, in contrast under parallel forces the load capacity is reduced by as much as 5 times. In addition, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.