Lapping grain

Because of the vibrations of the shape-generating counterpart during the process, the substrate material of the lapping grain, mostly water, is cyclically compressed and expanded. When the water is expanded. 

The lapping grains remove the material surface, breeldng down in the process and thus adapting as the suteoa bacames progressively finer. 

Metal tools are used in the lapping process (Figure 4.68). These will not slacken and will guide the lapping grain to a precise distance to the work piece surface. 

For the processing of sharp corners, then square, triangular lapping grains, which are moving in an oscillating motion, are better to work with. 

It is important to realize that polishing absolutely cannot be done up to the die wall because the lapping grain cannot roll right up to the wall and thus cannot remove material. 

Sandstone. Sandstone wheels were once quarried extensively for farm and industrial use, and special grades of stone for precision honing, sharpening, and lapping are a small but important portion of today s abrasive industry. Production of honing and sharpening stones from deposits of dense, fine grain sandstone in Arkansas account for 76% of the value (about 2 million in 1987) and 88% of the total quantity of such stones in the United States (4). 

In addition to then use in bonded and coated products, both natural and manufactured abrasive grains are used loose in such operations as polishing, buffing, lapping, pressure blasting, and barrel finishing. AH of these operations are characterized by very low metal removal rates and are used to improve the surface quaUty of the workpiece. 

For, besides illuminating the whole world with its brightness, how admirably does it foster and invigoreate all animals by its heat, and fertilise the earth by its rays, warming the seeds of grain in its lap, and thereby calling forth the verdant blade ... 

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