Questions and answers on how to make magnets stronger
Is the adhesive force of several stacked magnets just as high as the adhesive force of an individual magnet of the same size?
The coating and unevenness of magnets reduce the adhesive force of the stack compared to an equally high single magnet.
Uncoated and perfectly stacked magnets are comparable though to an equally high single magnet of the same quality.
The reduction due to coating and unevenness, however, is rather small and the bigger the single magnet, the less it is noticeable.
Therefore, if a magnet is not available in the desired size, combining several magnets could be considered as an alternative.
Please note: The force between the top magnet and the rest of the stack might be much smaller than the force between the stack and the steel plate.
Consequently, when subjected to heavy load, the stack could rip apart somewhere in the middle, even if the theoretical adhesive force was not reached.
This is a disadvantage of a magnet stack compared to a single magnet of the same size.
The rule that the adhesive force of magnets increases when they are stacked can be applied to different types of magnets.
These types also include disc magnets or block magnets.
Stacking block magnets with identical side lengths and a height of no more than half the side lengths can increase the adhesive force, similar to disc magnets.
The increase in adhesive force when stacking magnets is based on the principle of magnetic flux density and the interaction between the magnetic fields of the magnets.
When stacking, the magnetic field lines are aligned in such a way that they add up and increase the adhesive force.
If I stack two identical disc magnets on top of each other, is their adhesive force then twice as high?
Yes, the strength of the magnets increases when you place two identical disc magnets on top of each other.
However, this only applies if the disc magnets are sufficiently flat and not diametrically magnetised.
For stacking, the following applies: The magnet stack should only be half as high as the diameter of a single disc magnet.
Up to this height, the adhesive force multiplies with each additional magnet.
After that, the adhesive force gain gradually declines, trending towards a certain value, which will not be exceeded, no matter how high the stack is.
Example:
| Number of magnets | Adhesive force |
| 1 x S-10-01-N | 0,5 kg |
| 2 x S-10-01-N | 1,0 kg |
| 3 x S-10-01-N | 1,5 kg |
| 4 x S-10-01-N | 1,9 kg |
| 5 x S-10-01-N | 2,1 kg |
| 10 x S-10-01-N | 2,9 kg |
| 50 x S-10-01-N | 3,8 kg |
| 1000 x S-10-01-N | 3,9 kg |