Analysis of Optimal Roll Tensioning for Circular Saw Stability

When a circular saw is used to cut wood, a substantial and increasingly important fraction of the raw material is wasted because of the excessive width of the sawcut. The process of "roll tensioning" is studied here, whereby sawblade thickness, and hence material loss, can be significantly reduced while still maintaining sawblade stability. A theoretical model is developed that accurately describes the localized plastic deformation that takes place during roll tensioning, the associated residual stresses, and the resulting changes in sawblade natural frequencies. Experimental measurements of the residual stresses and natural frequencies confirm the theoretical predictions. The mathematical model allows reliable prediction of optimal tensioning conditions for any given saw operating state and development of automated control of the tensioning process. An example is presented in which the thickness of an optimally tensioned circular sawblade is 33% smaller than the thickness of an untensioned sawblade of equivalent transverse stability.