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Effect of saw tooth side clearance on stability and cutting accuracy of guided circular saws

University of British Columbia

This research considers the effect of saw tooth side clearance on stability and cutting accuracy of guided circular saws. The objective of the study is to achieve a better understanding of variables controlling the saw-workpiece interactions and their influence on the cutting accuracy of guided circular saws. This study intended to facilitate the optimum design of guided circular saws. The research work includes investigation of saw-workpiece interaction, identification of controlling variables, development of hypotheses, formulation of a theoretical model and experimental studies. The investigations identified saw tooth side clearance as a primary variable controlling the saw-workpiece interactions and the behavior of guided circular saws. The hypotheses explaining the significance of tooth side clearance were developed based on earlier sawbody-workpiece interaction models. Based on the hypotheses a 'circular beam model' was developed to represent the effect of tooth side clearance on the cutting characteristics of a guided circular saw. Results of the theoretical model indicated increased sawbody-workpiece interactions and reduced cutting accuracy at very small saw tooth side clearances. An extensive series of experiments was performed to verify the theoretical observations. The experimental studies analyzed the variation of cutting accuracy and saw-workpiece interactions as a function of saw tooth side clearance, tensioning states and sawing configurations. Experiments were also carried out to simulate the possible errors in the workpiece feed system of sawmills and to study their effect on the cutting accuracy of guided circular saws. In general, the experimental results supported the theoretical expectations. Experimental results showed a clear relationship between the saw tooth side clearance and the cutting accuracy of guided circular saws. Reduction of saw tooth side clearance increases the saw-workpiece interactions close to the guides and results in inferior sawing performance. Observations also revealed the ability of climb cutting saws to perform even at very small tooth side clearances. Experiments with simulated feed error showed higher sawcut standard deviations for feed errors greater than tooth side clearances.

Thesis/Dissertation

application/pdf

2009-08-06

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http://hdl.handle.net/2429/11948

Mechanical Engineering

University of British Columbia

UBCV

DSpace