Abstrakt

Several properties of wood can be correlated to wood density. It is widely accepted that the cutting power requirements are following this general assumption. Therefore, according to classic literature sources available for determination of the cutting power for both band- and circular- sawing machines, the cutting power requirements (and/or cutting forces) are computed as a function of the wood specific gravity SG. It was shown here that such approach based on specific gravity SG only, might be considered as a rather rough and imperfect estimation of cutting power. Significant differences are obtained between parameters computed on the basis of SG only and results computed on the basis of SG with other parameters (eg. feed per tooth). Samples of Scotch pine (Pinus sylvestris L.) wood of different provenances from Poland and of varying densities were machined on the narrow kerf frame sawing machine PRW-15M. The cutting power data was measured during sawing, stored and then further analysed. The average cutting forces were regressed versus average wood density (estimated on the base of standard gravimetric method). The obtained correlation was significant; however, it was possible to substantially improve the determination coefficient by correlating local values of cutting forces to the local densities. In that case the average values of cutting forces measured at selected points along the sample’s length were regressed to X-ray absorbance (density) estimated by means of X-ray radiography. It seems that analysing maps of density distributions could be a useful tool for estimation of cutting forces in sawing and might substantially improve the reliability of the estimations.

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