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Sawing Accuracy
Dimensional tolerances of sawn boards, cutting straightness
etc. depend very much on the stability of the bandsaw blade. Under normal
conditions the distribution of a specific lumber thickness in a sawmill can be
illustrated as in figure 1.
Distribution
of lumber thickness in a mill for an average lumber thickness of 25mm (~1").
If everything is kept constant and the feed speed increased,
the thickness tolerance of the sawn lumber will be wider.
The situation is illustrated in figure 2, where the target
sizes differ at the two different feed speeds to reach the same minimum
allowable lumber thickness of 24-mm (.94in.)
Change of target size at increased feed
speed
The result is a waste of raw material and the cost is of
course related to the cost of the raw material and the demand for accuracy to
size from the market.
One explanation for the wider deviation at increased feed
speed is to be found in the design of the tooth geometry.
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