engleski

Variation of Natural Frequencies by Circular Saw Blade Rotation

During technological processes wooden materials are exposed to various mechanical effects. The behavior of wood materials deviates essentially from the generally known elastic materials. Wood is an anisotropic material with viscoelastic properties which have highly aggravated derivation of generally valid relationships. Machining usually alters the shape, size and surface quality of wood. Machining occurs by cutting in most cases and chips are the by product. In this paper the influence of circular saw blade rotational speed on its natural frequencies is investigated. First the results were obtained analytically for freely spinning circular saw blade and they are compared to those obtained using Finite Element Method. In addition to a circular saw blade without the slots the models with 4 slots are also investigated. In the majority of cases, wood is cut at high feed rate and high rotational speed by circular saw blades with tungsten carbide tips brazed on the periphery of metal circular plates. Slots are made at several places from the periphery towards the center of a saw blade to prevent lateral vibration, both in idling and cutting, and to prevent a drop in critical rotational speed caused by heat expansion on the blade periphery during the cutting operation. Each model had different slot lengths from 0 to 30 mm. Finally the analysis are conducted to prove the influence of slots on natural frequencies for a spinning circular saw blade.

Numerical Simulation ; Natural Frequencies ; Circular Saw Blade ; Rotational Speed Influence

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