Manufacture
The first magnets used were common cylindrical or solid rectangular magnets. Later, a flexible magnet was developed, composed of a high-coercivity ferromagnetic compound (usually ferric oxide) mixed with a plastic binder. This is extruded as a sheet and passes on a conveyor belt over a line of powerful cylindrical permanent magnets. These magnets are arranged in a stack with alternating magnetic poles facing up (N, S, N, S,...) on a freely rotating shaft. This impresses the plastic sheet with the magnetic poles in an alternating line format. No electromagnetism is used to generate the magnets. The pole-pole distance is on the order of 5mm, but varies with manufacturer. A refrigerator magnet will be demagnetised by passing it over a stronger magnet. Decorative elements are then attached to the magnets with adhesive.
Read more about this topic: Refrigerator Magnet
Famous quotes containing the word manufacture:
“I believe that the miseries consequent on the manufacture and sale of intoxicating liquors are so great as imperiously to command the attention of all dedicated lives; and that while the abolition of American slavery was numerically first, the abolition of the liquor traffic is not morally second.”
—Elizabeth Stuart Phelps (1844–1911)
“The profession of magician, is one of the most perilous and arduous specialisations of the imagination. On the one hand there is the hostility of God and the police to be guarded against; on the other it is as difficult as music, as deep as poetry, as ingenious as stage-craft, as nervous as the manufacture of high explosives, and as delicate as the trade in narcotics.”
—William Bolitho (1890–1930)
“Culture is an instrument wielded by teachers to manufacture teachers, who, in their turn, will manufacture still more teachers.”
—Simone Weil (1909–1943)