UBC Theses and Dissertations
Dynamics of guided circular saws Lehmann, Bruce Fredrik
The results of this work will be useful to those interested in predicting or improving the cutting accuracy of guided circular saws. In this thesis an experimentally verified numerical model of the guided fixed collar circular saw is presented. Features of the model include the ability to represent the blade and collar geometry, blade runout, rotational stresses, guide dynamics, guide pad shape, guide lubricant, and guide or blade misalignment. The blade is assumed to be governed by thin plate theory and the guide arms are modelled as a lumped parameter system. The lubricating fluid is modelled as a number of massless spring-dampers. Numerical solutions are given for the natural frequency response, the forced response due to static or harmonic lateral loading, and for the self-excited response caused by the interaction of the blade runout with the guides. The behaviour of the runout as a function of blade rotation speed and the conditions for which a resonant condition is produced in the guides are also determined. Experimental results obtained for the natural response, the deflection caused by a static load, the effect of speed on the blade runout, and the self-excited response correlate well with the numerical results. Numerical results are presented to show the effects of guide position, guide shape and the use of multiple guides on the natural and forced response.
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