The freshly glued boards have a relatively uneven surface. Reasons for this can be misalignment during gluing, unclean planed surfaces, curvature of the lamellas or glue leakage. The top and bottom surfaces are therefore smoothed before further processing and the boards are brought to a uniform thickness. This processing step is called calibrating.
A planer can be used for calibration. However, this requires a relatively large working width in order to be able to process wide panels. Not every planing machine is equipped for this. Due to the machining process, a planer can achieve a large amount of material removal in a single pass.
More common, however, are wide-belt sanding machines which, in addition to sanding units, are equipped with one or even several calibrating rollers. These special wide belt sanding machines are also called calibration sanding machines. They produce a high surface quality due to the sanding process itself. The maximum possible material removal depends on the number of aggregates; the workpieces may have to pass the machine several times.
For high demands on performance and surface quality, calibration sanding machines are offered which are additionally equipped with a planing unit.
