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General
Information
Flexible
materials offer the product designer a uniquely desirable combination
of properties at lower cost than other magnet materials. The flexibility
and machinability of these materials permit design innovations and automated
manufacturing techniques not possible with rigid or brittle materials.
Flexible
materials can be bent, twisted, coiled, punched, and otherwise machined
into almost any shape without loss of magnetic energy.
Higher energy
flexible materials may sometimes replace Ceramic 1 materials, if close
tolerances are not required, and if operating temperatures are below about
250 F. Standard
grades of flexible materials have energy products from 0.6 MGOe to 1.6
MGOe.
Manufacturing
Methods
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Extrusion:
to produce materials in strip form (from about 1/4" to 10"
wide)
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Calendering:
to produce materials in sheet form (up to about 24" wide) |
For both
methods, the first step is to form a "compound", which is a
wet slurry of powder in the binder material.
Extrusion
involves squeezing heated compound through a shaped die, cooling the shaped
material as it exits the die, and magnetizing the material. The standard
grade materials are only magnetic on one side.
Calendering
involves squeezing the compound between rollers to compress and flatten
it to form a sheet. The sheet is fed through sets of rollers several times
until it reaches the desired thickness. It is then slit to the desired
width and magnetized. The standard grade materials are only magnetic on
one side.
Shapes,
Sizes, and Grades Available
Standard
stocked shapes include strip and sheet in the lower energy grades, strip
and a variety of punched parts in ring, disc, and bar shapes in the higher
energy grades. Non-standard shapes and sizes can be fabricated to blueprint
specifications from raw stock. Non-standard profiles of the 0.6 MGOe material
can be extruded by fabricating special dies.
Assemblies
Assemblies
using metal or other components and magnets can be fabricated by adhering
magnets with adhesives to suit a range of environments, by mechanically
fastening magnets, or by a combination of these methods. We are able to
laminate a variety of standard pressure sensitive adhesives to magnetic
strip. Standard adhesives are type "A", for general purpose
indoor use, and type "T", for general purpose outdoor use. Type
"T" adhesives are formulated for greater resistance to UV effects.
Surface
Treatments
No surface
treatments are required to protect against corrosion. We are able to laminate
a variety of decorative facings to magnetic strip.
Machining
Flexible
materials are relatively easy to fabricate: they may be cut, scored, punched,
slit, or die cut to shape. We are equipped to fabricate these materials
to specification.
Magnetizing
and Handling
Low energy
flexible magnets are magnetized with multiple poles on one surface to
give greater holding force. Higher energy flexible magnets are magnetized
either multiple pole, or single pole on one surface. No special handling
precautions have to be taken with flexible magnets since they are relatively
weak magnetically, and are not brittle.
Temperature
Effects
Magnetic
properties of flexible magnets degrade linearly with temperature in the
same way as Ceramic magnets. However, the limiting factor for flexible
magnets are the binder materials used to render them flexible: these begin
to flow at temperatures of about 250F.
Common
Applications for Flexible Magnets
Flexible
magnets are used in a variety of applications from labeling, holding,
door gaskets, and signs, to micromotors and CRT focusing. Typical applications:
crafts, toys, games, magnetic signs, displays, production control (or
visual aid) systems, warehouse shelf labeling, door gaskets, door and
cabinet closures, small tool and instrument holders, movable markers,
advertising premiums, magnetic business cards, architectural planning
layouts, etc.
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