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a machine designed for polishing the surfaces of various articles. Three types of polishing machines are distinguished in machine building and instrumentation: machines with laps, wet-blasting machines, and centrifugal machines. The last two are used for polishing articles of complex shape.
In a polishing machine with laps, the workpiece is secured to a workbench and the polishing is done with a rotating lap mounted on a spindle; the lap moves with the spindle over the surface being polished. Laps are made from soft metals, such as copper, and wood, felt, or leather. Polishing and lapping materials may be in coatings bonded to the laps, or they may be added during the finishing process. Finely dispersed diamond powders, up to 1 micron in size, and pastes having such powders as a base make it possible to use lapping machines with a lower lap rotation rate for polishing.
With wet-blasting machines the article is placed in a chamber and the polishing is done by means of a jet of liquid saturated with an abrasive. The flow rate of the liquid suspension from the nozzle reaches 50 m/sec, and the nozzle automatically travels along the length of the article during the polishing process.
Centrifugal polishing machines have a container that is filled with an abrasive powder or suspension. As the container rotates, the abrasive mixture is set in motion and polishes the article, which remains fixed.
Two types of polishing machines are used in furniture manufacture and carpentry. One is used for polishing wood, and one for polishing paint and varnish coatings. The first type imitates the process of manual polishing. One or more pads mounted on a working head are rotated by an electric motor; a reciprocating motion is produced as the head and pads move over the surface being polished. Only broad surfaces can be finished with these machines. Polishing machines with soft rotating drums made up of cloth disks are used for polishing paint and varnish coatings. Broad surfaces, edges, cylindrical articles, and workpieces of other shapes are also polished on this type of machine.
R. F. KOKHAN and E. V. ZHUKOV