An innovative approach to the forecasting of energetic effects while wood sawing

Abstract

In the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specifi c cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, the cutting forces (power) problem may be tackled with an innovative, up-to-date fundamental analysis of the mechanics of sawing based on modern fracture mechanics. This line of attack is an improvement on traditional approaches for cutting forces and power, many of which are empirical and based upon limited information. Such formulae do not permit generalisation to new conditions of operation of sawmills, such as e.g. the use of narrow-kerf blades. The presented algebraic model, for cutting power determination while sawing, in addition to timber ‘strength’ and friction between tool and workpiece, takes into account the property called ‘fracture toughness’ (resistance to cracking), which is a vital ingredient. Furthermore, forecasting of the shear plane angle with this model is achievable even for small values of uncut chips. Moreover, the mentioned model is a universal one, and useful for determination of energetic effects of sawing of every kinematics such as: frame sawing machines, bandsawing machines and circular sawing machines.