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)
“Yes, that’s what I needed. Living flesh from humans for my experiments. What difference did it make if a few people had to die? Their flesh taught me how to manufacture arms, legs, faces that are human. I’ll make a crippled world whole again.”
—Robert Tusker, and Michael Curtiz. Wells (Preston Foster)
“Culture is an instrument wielded by teachers to manufacture teachers, who, in their turn, will manufacture still more teachers.”
—Simone Weil (1909–1943)