Forces Acting on Saw Teeth during Timber Processing - A Practical Approach

Abstract

Two oak cant timbers were sawn up to a total of 58 boards. As a dependent variable, the energy consumption while manufacturing a board was measured. As influencing variables, timber and saw blade characteristics were assessed, including density, moisture content, log feed speed, blade profile, and sawing sequence. Four types of forces acting in a saw-tooth were derived, namely, the dust particle shaving force, the particle accelerating force, the dust compressing force, and the frictional force as a consequence of blade wear. The experiment showed that the most prominent factor is the shaving force if the blade was newly sharpened, and that the dust accelerating and compressing forces were negligibly small. The frictional force grew from insignificant at the first board to more than one fourth of the force total at the 58th board. With each board, the saw tooth tips receded by more than 2 μm. With these data, the course of blades’ deterioration from wear was characterised.

Keywords

• Shaving force
• Frictional force
• Saw blade wear
• Saw dust compaction