Simulation of the intermittent cutting action of a bandsaw blade
Bandsawing is a preferred method used by steel stockholders and steel users in industry for cutting-off to size in the primary and secondary processes. The state-of- the-art features in current industrial bandsaw machines have transformed this method for cutting-off stock to size into a hi-tech operation capable of storage and handling. This method is particularly suitable for use in engineering factories involved in fast, highly automated mass-production techniques, providing the user with continuous batches of cut-to-length materials. Bandsaw machines have now superseded power hacksaws and circular saws in cutting rate and lower kerf loss due to better computer- controlled saw machines and improved blade designs (bi-metal HSS, carbide tipped). Although, there have been some new developments in bandsaw blades (tooth geometry, band material etc.) there are continuous new demands made on the bandsaw blades by materials engineers, challenged with introducing new materials to satisfy the needs of the design engineers, e.g. aerospace industry. There is therefore a need to improve the bandsaw blade. In order to do this we need to have an understanding of the mechanics of the cutting process associated with bandsawing and the various parameters affecting cutting forces, specific cutting energy, metal removal rates etc. One of the primary problems in evaluating metal bandsaws and developing newer variants, including new saw tooth materials, their heat treatment, or special tooth forms and quality, has been the use of costly and time consuming sawing tests. Furthermore, there are no simple ways of quantitatively evaluating the performance and life of these bands during sawing. Traditional method used by machine operators to assess the performance of blades only give global data, which is difficult to apply to individual teeth. Therefore there is a need to develop "time compression" test methods for evaluating the performance of bandsaw blades to replace full bandsaw blade testing. The work presented in this thesis is on the development of a single tooth testing method to simulate the intermittent cutting action of a bandsaw blade. Cutting tests have been performed to assess the testing method by comparing single tooth test results to full bandsaw blade test results. The test method developed is capable of producing scientific data for bandsawing associated with forces, metal removal rate and specific cutting energy when cutting a variety of workpiece materials at different speeds and feeds. Thus, it can be used as a substitute to full bandsaw blade testing. The cutting data for the workpiece materials tested using the single tooth test method was obtained in 25% of the full bandsaw blade evaluation time. This represents a significant saving in time and cost, which should prove useful to design engineers when designing and testing new prototype bandsaw blades for the future needs of the steel and manufacturing industry involved in metal cutting.