The Coulumb’s Law for magnetism contains two aspects: one is attractive and repulse force between magnetic pole, and another one is the attractive force between magnetic field and ferromagnetic parts. In reality, this is the initial and general knowledge in most people’s mind regard to the permanent magnet. Influence factors of magnet’s attraction force have been reported in the previous article. The finite element analysis (FEA) results indicate a phenomenon that multi-pole magnetized magnets have stronger attractive force under the small air gap compared to the conventional magnetized magnets, and attractive force will also enhance with increasing pole number. Besides, the attractive force of multi-pole magnetized magnets decrease fast as the air gap increases, and conventional magnetized magnets exhibit strongest force under the large air gap. Meanwhile, unlike multipole magnetized magnets which can limit the flux leakage, conventional magnetized magnets usually generate higher flux leakage and thus produce the negative effect on nearby electronic devices in some applications.
The multi-pole magnets can be realized through two ways. One way is placing several magnets with different magnetizing direction into the specific pattern. Another way is directly magnetizing magnet by multi-pole magnetizing yoke. The above FEA results already showed that optimum design for the attractive force application is different for different air gap range, but regular multi-pole magnetizing yoke cannot provide enough flexibility in the magnetizing process. Therefore, development of programmable magnetizing technology and relevant programmable magnetized magnet becomes very necessary.
What is Programmable Magnetizing?
Programmable magnetizing is software-controlled magnetizing technology which ensures precision control over the magnetic pattern, then provide desirable attractive force under a given gap and limit the flux leakage in the meanwhile.
The “printing head” of creative Magnetic Printer is a pair of small magnetizer and thus magnetize magnet point by point which similar to the process of printing a photograph by needle printer. The minimum magnetized area is around 1mm and printing process is totally controlled by computer programming. Programmable magnetizing is ideally suiting for the new product with the complicated magnetizing patterns due to its excellent flexibility.
Most of the people believe that interactive force between two conventional magnets can be only attractive or repulsive and of independent of the air gap, but the interactive force can be reversed with the air gap in certain magnetizing pattern obtained by programmable magnetizing process.
Demo Kits of Programmable Magnetized Magnet
First, SDM team deeply appreciates the effective technical and sample assistance from FORESEE Group and Hangzhou CMR Polymagnet Co., Ltd.
Latch Type Demo Kit
Two plastic integrated magnets are repelling each other under the certain distance, but repulse force will switch to the attractive force when two magnets are close enough to each other and then latch together.
Spring Type Demo Kit
Two magnets are attracting each other from a specific distance, and attractive force will switch to repulse force as two magnets reach a defined air gap.
Twist Release Type Demo Kit
The attractive force between two magnets is very strong in the latched position, and attractive force will switch to repulse force when rotated 90 degrees in either direction. Actually, the similar application is also can be found in the magnetic perfume cap.
Spring-Latch Combo Type Demo Kit
Two magnets also have strong attractive force in the latched position, and they will transform to spring type when rotated 180 degrees.
