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Flexible
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 250F. Standard
grades of flexible materials have energy products from
0.6 MGOe to 1.6 MGOe.
Manufacturing Methods
Extrusion: to produce materials in strip form (from about
1/4" to 10" wide)
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. Nonstandard 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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