Research of the effect of saw blade set dullness on the dimensions of longitudinally cut fir and spruce slats

This paper analyzes the problem of choosing the best way of operating and maintaining a set of circular saws intended for longitudinal processing. The study objective was the analysis of current procedures of tools usage and recommendations for their improvement, in order to achieve better quality and longer operating life of tools. The tested set (24+5 blades) was mounted on multisaw blade machine which produces slats from fir or spruce planks for three-layer parquet. Changes in thickness of sawed slats, operation time between two sharpenings and blade size changes after removing saw blades from machine and aftesharpening, were monitored. Control x-charts were used for stability evaluation. Work quality of saw blade set for longitudinal cut of fir and spruce planks was presented by cost-effectiveness ratio, ratio of total costs (for purchase of set and its servicing) and volume of sawed timber. The saw blade set did not reach the targeted coefficient based on the previous tests. After each sharpening, the set had a different persistence presented in time, and we could not determine the work dynamics. The persistence of saw blade set was affected by wood resin that accumulates on the saw blade surface, the method and angles of sharpening, work dynamics and the continuity of cutting.