Prediction of Cutting Time When Crosscutting Rounds, Pipe, and Rectangular Bar With a Gravity Fed Portable Bandsaw

Abstract

Portable bandsaws are gaining in popularity for their use on remote jobsites to efficiently cut structural materials such as bar, pipe, and channel. Some of their increased popularity is due to the recent introduction of high watthour lithium ion batteries, which has further improved the portability of bandsaws by making them cordless. However, with cordless bandsaws, knowledge of cutting rates becomes more important as battery runtime limits productivity. Unlike industrial cutoff bandsaws that typically have feed rate control, the cutting rate of portable bandsaws is determined by operator applied pressure and gravity. While some research has highlighted the cutting mechanics of bandsaws and related wear processes, there is a lack of progress in the area of predicting cutoff time as a function of sawing parameters, such as applied thrust force, blade speed, workpiece material properties, and geometry of the cross section. Research was conducted to develop and experimentally verify a mechanistic model to predict cutting rates of various cross sectional geometries with a gravity fed portable bandsaw. The analytical model relies upon experimental determination of a cutting constant equation, which was developed for a low carbon steel workpiece cut with an 18 teeth per inch (TPI) blade. The model was employed to predict crosscutting times for steel rounds, squares, and tubes for several conditions of thrust force and blade speed. Model predictions of cutting time were in close agreement with experimental results.