Guide to wide belt sanders | 3
After calibrating, the fine sanding follows. The aim is to achieve a surface that is as uniform as possible, in which the structure of the wood is shown to its best advantage, free from traces of processing. Veneered surfaces are demanding here, as are surfaces to which high-gloss lacquers are to be applied. Sanding pad aggregates are used in those cases. These offer the desired adaptability with exchangeable inserts in different hardnesses and numerous additional functions.
Rigid sanding pads
Rigid sanding pads are "floating" on pneumatic elements. As the workpiece passes through, they adapt to differences in height in the longitudinal direction.
When sanding soft solid wood and veneered workpieces, unwanted rounding occurs on the workpiece edges when the sanding pad hits the workpiece. This is prevented by the jump-in control. It causes the sanding pad to be lowered to the workpiece surface when the front edge of the workpiece is already under the pad. The pad raises as soon as the rear edge of the workpiece is under the pad.
Air cushion pad
More flexible is an inflatable sanding pad, also called "air cushion sanding pad" or just "air cushion pad". In this case, a hose is placed between the sanding pad insert and the sanding pad, which is inflated with adjustable pressure. This enables unevenness transverse to the throughput direction to be compensated in the range of a few tenths of a millimetre. The manufacturer SCM offers a special form of the air cushion pad, the so-called "elastic sanding pad". In this case the sanding pad is divided into individual segments. These compensate for unevenness on the surface and differences in thickness between small workpieces up to 0.8 mm.