THEORETICAL RESEARCH OF THE VIBROACOUSTIC DYNAMICS OF THE CUTTING TOOLS FOR MILLING RECESSING AND CHAIN MORTISE WOODWORKING MACHINES

Abstract

Milling recessing machines are designed to select mortises with end mills of the rectangular-shaped sockets. To the characteristic features of these machines, distinguishing them from the machines of the milling group is the additional oscillatory movement of the milling cutter on the chain ridged machines. The sockets are selected with the rectangular shape of the milling chain. These machines are operated at constant spindle speeds. Therefore, in these machines there are no multistage gear boxes with a large number of the spindles. These features lead to the fact that the vibrations of the cases of the speed boxes of woodworking machines (unlike metal-cutting machines) are much less and, accordingly, the intensity of their sound radiation is also less. The frequency of the rotation of the cutting tool is significantly higher. Therefore, it can be assumed that the main source of the noise that exceeds sanitary standards is the workpiece cutting tool system. The purpose of theoretical studies with obtained results show the analytical dependencies of the active sound pressure levels created by the cutting tool of the milling recessing and chain mortise machines providing for geometrical, physic-mechanical parameters of the tool and technological cutting conditions. The used acoustic source models are monocle for the tool of the milling recessing machines and a linear source for the milling chain and the noise levels obtained on their basis showed that for engineering calculation it is necessary to determine the oscillation velocities of the sources on their own oscillation modes. The speeds of the oscillations are determined from the differential oscillation equations; the solutions are obtained taking into account the cleat boundary conditions. The calculation of the noise spectra makes it possible at the design stage of both similar equipment and technological processes of the wood processing to determine the magnitudes over the maximum allowable values and in fact at the same stage to design noise protection systems.