There are many kinds of motion, so many kinds of bearing designs exist to accommodate them. In the case of a desk or dresser drawer, the metal slide mounted to the desk or dresser allows drawers to be moved in and out.
Ceramic bearings came in a vast variety of shapes and sizes, since they are used in such a variety of products. In the case of rotating axles, a ceramic bearing can be a simple, lubricated cylinder in which the axle turns.
More complicated bearings involve a series of spherical, conic or rod shapes that facilitate the movement of two pieces relative to each other. In each case, the bearing construction material must be strong enough to bear weight, sometimes in uneven distribution, for extended periods of time without breaking.
They must also be abrasion-resistant, as the constant friction caused by movement can wear surfaces down. They must not corrode when exposed to greases and oils necessary for smooth movement, and they must be uniformly shaped so as not to impede movement. Certain ceramics have proven themselves to be perfect bearing construction materials because of their durability, heat and corrosion resistance.
Engineering ceramics, which are all ceramic materials employed in industrial contexts, are non-metal composites characterized by hardness, strength and ease of formation. Because many ceramics are easily shaped, they can be formed into the many shapes that bearings take. Accommodating all of the different kinds of motion involved in moving parts requires the fabrication of a wide range of shapes.
Linear motion, which is the kind of motion involved in opening and closing a drawer, requires long channels to serve as bearings. Ceramics can easily and economically be extruded; extrusion is the best process for creating long, specially-shaped strips and channels. Molding processes are also possibilities in creating ceramic shapes.
In both molding and extrusion, raw ceramic materials like aluminum oxide and silicon carbide are heated to their melting points and forced into a shaping tool. The possibilities for thermoforming processes like these are limited only by manufacturers’ budgets and the imaginations of their design personnel.
Ceramic balls can be created for use as ball bearings; ceramic rods can be extruded for use in axels; ceramic rings can be molded for use as bearing surfaces.