Belt sanding machines

LEV - dust capture at fixed belt sanding machines... 

Belt sanding machines used for woodworking must be provided with guards at each nip point where the sanding belt runs onto a pulley, and the unused run of the sanding belt must be shielded to prevent accidental contact. 

Draglines are equipped with a 71-m bucket at the end of a 111-m boom and can be employed to dig both a portion of the overburden, which is free-cast into the mining pit, and the tar sand, which is piled in windrows behind the machine. Bucket-wheel reclaimers, similar to bucket-wheel excavators, load the tar sand from the windrows onto conveyor belts which transfer it to the plant. 

One distinction between test types is that some use a loose abradant and others use a solid abradant. A loose abrasive powder can be used rather in the manner of a shotblasting machine as a logical way to simulate the action of sand or similar abradants impinging on the plastic in service. Conveyor belts or tank linings are examples of products subject to abrasion by loose materials. A loose abradant can also be used between two sliding surfaces to simulate a contaminant or wear debris. The majority of wear situations involve the plastic moving in contact with another solid material and solid abradants can consist of almost anything. 

Properly graded sanding with appropriate sandpapers is a prerequisite for a satisfactory wood surface. Industrially, sanding is performed on cylindrical abrasive-belt machines or automatic grinders, followed by brushing and suction to remove abrasive dust. 

Low-stress abrasion (scratching) is defined as wear that occurs clue to relatively light rubbing contact of abrasive particles with the metal. The criteria established for low-stress abrasion is that the forces must be low enough to prevent crushing of the abradant. Wear scars usually show scratches, and the amount of subsurface deformation is minimal. Consequently, the surface does not work harden appreciably. Parts such as screens, chute liners, blades, and belts that are exposed to sand slurries or abrasive atmospheres could experience low-stress abrasion. Many machine components such as bushings, seals, and chains that operate in dust will wear by low-stress abrasion. Figure 6(a) shows a siuface that was subjected to low-stress abrasion. 

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