The Research Of The Theory Of String Vibration Applied In The Woodworking Band Saw Blade

Woodworking band saw is the most widely equipment used in wood processing industry. The force of Saw Blade is extremely complex when it's working, there will be resonance and sway (quiver) on band Saw Blade, which will affect the sawed quality When the saw is in operations, so the study of vibration characteristics of its tension is particularly important. In this paper both domestic and foreign literature was unscrambled and the vibration of band Saw Blade was study on the basis of string vibration theory, The band saw was simplified into a string, with the vibration of saw Blade to be simplified to the string vibration for the first time, vibration of the tensile and bending coupling effect of plate girder structure and reverses vibration of staff. Analyze its static mechanical computing model and dynamic mechanical computing model, main including the string vibration theory, finite element approximate solution, random excitation spectroscopy experiments mutual authentication and supplement, also applied traveling wave theory of the spanking and quiver phenomenon of the band Saw Blade was studied at the same time, namely, this paper considered three things which were the changes of the band Saw Blade's Preload(T₀) (pre-pull) force when the band saw was static, the changes of tension difference (â–³T)between its tight-edge and the loose-edge was brought about Its torque when the band saw was running, and the inertia forces(Q_n) was caused when the band saw was running, in order to establish its relationships between first frequency, travelling frequency, strain , tension and its stress.According to studies, (1) In terms of the analysis of static and dynamic computing model, and the mutual validation of random excitation spectrum analysis and dynamic spectrum analysis, the string vibration theory is applicable to the study of saw blade vibration system. (2) Statically, the tight-edge and the loose-edge of saw blade had the same natural frequency; non-loadedly, saw blade's tight-edge natural frequency was higher than its static value, while saw blade's loose-edge natural frequency was less than its static value; (3) The horizontal swing of band saw blade related to rotation speed of band saw wheels, which results from the spanking and quiver. (4) Measured first frequency of band saw blade vibration can be used to determine its tension and stress; (5) Actual Saw Blade is a long band with fixed width and length, there is not only horizontal vibration but also torsion vibration. At the same time, the vertical vibration of the band saw should also be considered when studying the vibration of the band saw, and these issues need further study. In conclusion, this innovative method of studying the vibration of band saw blade via string vibration theory simplified the complex band saw blade system into the string vibration, considered again its actual complex factors and applied classic vibration theory to the studies of wood working band saw machine, which will provide theoretical evidence for the further design of tension timely detection apparatus and a new generation of China-made high-quality wood working band saw machine.