Sanding is the finishing treatment of the surface using abrasive materials, which results in uniform surface roughness. The degree of roughness depends on the gradation of the sandpaper used. Gradation is determined numerically – the lower the value, the larger the grains, and consequently the deeper the cracks.
The furniture industry uses gradations starting at 40, and in the case of solid wood, up to 2,000 – in the process of preparing for high gloss polishing. In the grinding process, it is important that the jumps between successive gradations are not greater than the value of the currently used gradation. For example, if you apply paper gradation of 120 immediately after using paper gradation of 40, grinding will not bring the expected results, because we are unable to wipe the deep scratches in a reasonable time.
Depending on the material being ground and its dimensions, several tools can be used such as hand grinders, table grinders or an automated grinding line that scans the work pieces at a given moment by adjusting the appropriate pressure force. Electromagnetic shoes used in machines, unlike the popular solution based on pneumatic cylinders, allow for independent pressure from accidental pressure peaks in the compressed air system.