FLEXIBLE MAGNET STRIPS AND SHEETS
Flexible magnet material is a form of Ferrite magnets produced by mixing ferrite powder with carrier made of plastic material. Standard shapes are typically strips or sheets roll formed to a variety of thicknesses, sizes, lengths, and grades. Custom Flexible magnets can be manufactured by methods of: extrusion, injection molding (for high volumes), die cut, slit, or scored to customer specifications. Other attributes with the flexible magnet material is it can be bent, twisted, coiled, printable surface, silk screened, painted and adheres to most surfaces.
Flexible magnet materials offer product designers valued properties at a lower cost compared to the other magnet materials.
There are two methods by which flexible magnets can be acquired one is Calendaring the second is an Extrusion.
Calendaring- Is the process of shaping the flexible magnet material into wide sheets. This process involves squeezing a wet powder compound between rollers to flatten and compress the material in form of a sheet. The sheet then continues to be processed repeatedly through a set of rollers until it reaches a specified thickness.
Extrusion- Is the process of shaping the flexible magnet material into strips. This process involves the squeezing of heated wet powder compound through a pre-shaped hard die, cooling the material as it exits the die to the fabricated profile.
The challenges designing into flexible magnet materials are:
- Magnetic on one side only
- Low magnetic strength
- Usage above 120ºC has limits due to the binder material stability
- Environmental conditions can degrade the binder causing brittleness and cracking
The adhesive on the back of the material must be stored in a cool and dark environment to prevent the adhesive from deteriorating.
It is recommended (prior to ordering production quantities) to test adhesives on the actual surface type to ensure proper bonding.
Proper attention must be taken adhering flexible magnets to painted surfaces, especially under outdoor conditions to prevent any damage to vehicle paint.
|Material Grade||Type||Br (kGauss)||Hc (kOersteds)||Hci (kOersteds)||BHmax (MGOe)||Temperature||Coefficients (%/°C)|
|Coefficient of||Thermal Expansion1||Curie||Temperature|
|(kg/m3 )||(lbs/in3)||(kg/m2)||(lbs/in2)||(kg/m2)||(lbs/in2)||// M||”´M||(°C)||(°F)|
|3.8 x 103||0.140||450||840|