The main problems during cutting with circular saw blade are inaccurate cut, low quality of surface, high level of noise. These adverse eff ects are related to oscillation of circular saw blade. This oscillation cause adverse eff ects not only on workpiece but also on tool. In some case the circular saw blade reaches the value of critical rotational speed which leads to its instability and cause the oscillation of blade which may leads to destruction of tool. So the reduction of the amplitude of oscillation is essential for removing the adverse eff ects. This paper deals about infl uence of shapes of teeth as a type of modifi cation that has positive eff ect oncritical rotational speed of circular saw blade. The parameters of studied models of circular saw blade were 42 number of teeth and the height of teeth with slice from sintered carbide was 14 mm. The variable parameter was the ratio between surface of teeth and surface of teeth gap. In this study was used computer so ware Creo Parametric 1.0 for obtaining natural frequencies of studied models. This so ware uses in analysis fi nite element method (FEM). There were done some steps to idealize the models. For calculating static and dynamics natural frequencies of modelswere used modal analysis. The critical rotational speed was calculated from obtained results by Creo Parametric 1.0 and compared on 5 models of tool.

• In most cases high cutting speed is used when cutting wood by circular saw. This results in oscillat-

No abstract