The optimum log feed speed with bandsaw

摘要

A method is presented to determine the optimum log feed speed of a bandsaw based on its power consumption. Three timber species-oak, beech and pine-were sawn under real sawing conditions in a mill. The target of the experiment was to find the optimum log feed speed with the following characteristics: Minimum energy consumption per unit volume sawdust produced, maximum filling of saw tooth gullets with sufficiently dense sawdust and desired product quality. The experiment revealed that: (1) there is a crucial sawdust expansion rate in the gullet which is hardly varying among the three species. Its magnitude is 1.7-1.9 times the volume of solid wood. At this sawdust expansion the gullet seems to be fully utilized. (2) There is indeed an optimum log feed speed characterized by minimum energy uptake if related to a unit volume wood converted to sawdust. This value is varying with the cutting height, i.e. wide board products will still require a slower log feed speed, narrow boards a faster one. With the help of an equation, the optimum log feed speed can be quickly established for each board to be cut. (3) By comparing the real log feed speeds with the optimum ones, the utilization of the bandsaw can be judged. The results revealed that the real operation times were about 30 % longer than the machine's optimum, and that an energy saving of about 30 % was possible.