Belt sander
.jpg)
The belt sander is a power tool for large-area sanding of workpieces.
construction
Belt sanders use an endless sanding belt that is guided around two rollers (drive roller and deflection roller). Depending on the machine, the required grinding belts have different dimensions (width and circumference, each specified in millimeters, e.g. 40 x 303, 75 x 457, 100 x 610). As a rule, these are strips of sandpaper glued together at an angle with a textile base. There is no abrasive in the area of the 1–2 cm wide bond. The specification of the grit corresponds to that of sandpaper, but not all grits are available for all dimensions. The usual market grain size is between 40 and 240.
commitment
Belt sanders are primarily used for sanding large surfaces, such as B. for grinding work on wood , metal or plastic . Belt grinders are particularly suitable for processing non-ferrous metals, such as B. aluminum , the chips of which tend to clump on the sandpaper, since the relatively small diameter of the rollers leading the sanding belt promotes chipping of the chips from the sandpaper. Belt sanders lead to rapid material removal, especially when working with wood, and to a relatively coarse sanding, measured by the grain size, so that they are or should only be used for preliminary work or for material removal, including color removal. In accordance with the procedure for sanding with sandpaper, you must start with the largest grain and continue with the finer grain. As with all grinding work, materials with a preferred direction should only be worked in this direction and not across it. While with many eccentric and orbital sanders the sandpaper lies on a soft surface, with the belt sander it glides over a flat metal plate. The belt sander therefore adapts to unevenness in the material less well, elevations are removed more and thus straightened (greater material loss). With round materials, the contact area with the belt sander is reduced, which is why z. B. thin sheets are sometimes sanded through.
New belt sanders must be equipped with a dust extraction system that protects the user from the resulting grinding dust . Modern devices have an electronic speed control with which the belt speed can be adjusted. Speed control is particularly important for heat-sensitive materials such as plastic, but also some woods, as the preset speed of a belt sander tends to generate a lot of heat, even with coarse-grained sandpaper, which can melt plastics and discolor wood.
variants
While the belt sander is guided to the fixed workpiece on the handheld devices, the workpiece must be held above the belt sander on the stationary models. Stationary models are often combined with a side grinding wheel. Some hand-held devices can be mounted on a work surface using special screw clamps and thus converted into a stationary model.
