Influence of the manner of excitation of a machining system on the stability of the process of periodic circular cutting of wood tissue

The article deals with dynamic analysis of the influence of the manner of excitation of a machining system on the stability of the process of periodic circular cutting of wood tissue at an invariable frequency of cutting, taking into account dynamic properties of the machining system. For stability analysis we used a dynamic model developed for this purpose (Bu?ar and Kopa? 1996). The manner of excitation of the machining system has been defined by the radial immersion of the tool and the workpiece, taking into consideration, in modelling the process of cutting, both internal and external modulation of the cutting or exciting force. The internal modulation is the result of the effect of the properties of the machined material which are given by specific cutting pressurek _s, while the external modulation is the consequence of the varying material flux which is affected by relative displacements between the workpiece and the tool. Relative displacements, which are the result of the manner of excitation and dynamic properties of the machining system, are also the cause of self-excitation occurence. The results of analyses point to it that the manner of excitation of a machining system with known dynamic properties is of the essence for the stability of the process of periodic circular cutting of wood tissue.