Why does the same magnet from your competitor have double the adhesive force?
The adhesive force indicated in our shop has been empirically defined and can be reached under ideal conditions.
Measuring with wrong devices can lead to the establishment and promotion of much too high adhesive forces.
Customers often ask us why a particular neodymium magnet from a competitor has an adhesive force of 400 kg, for instance, while our magnet of the same size is much "weaker". Well, certain competitors simply measure the adhesive force incorrectly (see below). We are more than happy to lay out our procedure.
Customers often ask us why a particular neodymium magnet from a competitor has an adhesive force of 400 kg, for instance, while our magnet of the same size is much "weaker". Well, certain competitors simply measure the adhesive force incorrectly (see below). We are more than happy to lay out our procedure.
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Procedure for measuring the adhesive force at supermagnete
The procedure for determining the adhesive force depends on the magnet. For rotationally symmetrical magnets, we use a computer program to calculate the adhesive force. This program is also the basis for our Adhesive Force Tool. It automatically calculates the value based on the entered data. For cube magnets, block magnets and magnet systems, we determine the adhesive force with an adhesive force measuring instrument, and we have had a professional adhesive force measuring device since 2020. Before, we measured the adhesive force with a device developed in-house. You can read more about that below.With the adhesive force measuring device, we measure the adhesive force four to five times. We then calculate the average value which we state for the respective product in the online shop. Therefore, you can rest assured that our indicated adhesive force can actually be achieved under ideal conditions. Read our FAQ "How strong is this magnets?" to find out what constitutes ideal conditions.
Measurements with our professional equipment
Preparation
We add suitable hooks to magnets that have a screw socket or internal thread and use them to suspend the magnet with the help of a tearproof cord (shown green in the photo). For other magnets to be measured, we glue a small wooden block to the magnet and screw a hook into it. Instead of wood, we could also use aluminium or other non-magnetic material. The important thing is that the glue doesn’t fail at the slightest resistance or force.
We add suitable hooks to magnets that have a screw socket or internal thread and use them to suspend the magnet with the help of a tearproof cord (shown green in the photo). For other magnets to be measured, we glue a small wooden block to the magnet and screw a hook into it. Instead of wood, we could also use aluminium or other non-magnetic material. The important thing is that the glue doesn’t fail at the slightest resistance or force.
The measuring process
1. We attach the magnet to the 2 cm thick steel plate in the lower section of the adhesive force measuring device in such a way that the small wooden block or hook on the magnet points upwards.
1. We attach the magnet to the 2 cm thick steel plate in the lower section of the adhesive force measuring device in such a way that the small wooden block or hook on the magnet points upwards.
2. The hook in the wooden block or on the magnet is then connected via a cord to the mechanism on the device.
3. On the machine, we set the speed at which the magnet is to be pulled off the steel plate. During the measuring process, the steel plate moves downward, which causes an increase in tension.
4.Once we have made the desired calibrations, the instrument takes over at the push of a button.
5. We repeat the measuring process a few times with the same speed but position the magnet a little differently each time to account for different possibilities.
6. Once the process has been repeated four to five times, we calculate the average value of the results. It is this value that we can, in good conscience, guarantee for the respective magnet.
Measurements with our adhesive force measuring device developed in-house
Before we decided on the equipment described above, we determined the adhesive force with an adhesive force measuring device we developed ourselves. The measuring process was similar to today.To determine the adhesive force of our neodymium magnets, we first calculated the adhesive force using a computer program. Then we prepared the magnets for the device, using wooden blocks and hooks as well. With this machine, however, the pull on the magnets was not performed automatically but manually, using a vehicle jack mounted on the side.
Preparation
We glued a small wooden block onto each magnet to be measured and then screwed a hook into the wood. Instead of wood, we could have also used aluminium or another non-magnetic material.
We glued a small wooden block onto each magnet to be measured and then screwed a hook into the wood. Instead of wood, we could have also used aluminium or another non-magnetic material.
The measuring process
1. We attached the magnet to the 2 cm thick steel plate in the lower section of the adhesive force measuring device with the small wooden block pointing upwards.
2.
We used a carabiner to connect the hook of the machine with the hook in the wooden block.
3.
Then we used the vehicle jack mounted on the side to pull until the magnet separated from the plate.
The integrated digital scale stopped when the maximum adhesive force was reached.
Video of a measurement
We captured the adhesive force measurement of a hook magnet on video. The sequence here is easier to describe than above, because the hook on the machine is directly attached to the hook of the pot magnet. This eliminates the need to glue on a block of wood. In the video you can hear a snapping sound when the hook magnet detaches from the metal. You can see the separation happen at 0:33/34. Even after it has been detached, the magnet is still so close to the steel plate that you have to look very closely.
Wrong measurements with steel
Other vendors often attach a piece of metal to the top of the magnet. However, metal on the opposite side increases the adhesive force of a magnet dramatically. This approach measures the adhesive force of a magnet system (i.e. a magnet between two steel plates). Such technically incorrectly executed measuring efforts lead, for example, to an alleged adhesive force of 400 kg for a 50 x 50 x 25 mm neodymium magnet (comparable with our DEATH MAGNET), which is simply impossible. A magnet of this size cannot reach such a high adhesive force, not even with the strongest possible N52 magnetisation.Such measurements do not correspond to the standardised and precisely defined method of measuring the adhesive force.
The recommended measurement method was developed by the Magnet Distributors and Fabricators Association (MDFA for short) and is explained in detail here: Test method to determine the breakaway force of a magnet.
In the end, it can be said that these vendors deceive their customers.
Our adhesive forces may not sound as spectacular as those of our competitors - but they can actually be achieved.