Development of a new technology for bandsawing using a tip-inserted saw. 1. Consideration of cutting tool hardness, tool wear, and accuracy of kerf width

Saw teeth of high wear resistance and high sawing accuracy are being sought by the wood industry with the objective of increasing productivity and product yield. A new technique for bandsawing using a tip-inserted saw was developed to meet these objectives. The materials used for the tipped edge were high speed steels (HSS) of designations SUS420J2 and SKH 51 according to the Japan Industrial Standards (JIS). Materials for the tip edge also include titanium nitride- (TiN) coated SKH 51 manufactured by the physical vapor deposition (PVD) method. The saw blade was manufactured from carbon steel of designation SKS 51 according to JIS. The cutting performances of the tip-inserted bandsaw and Stellite-tipped saws were investigated, and comparisons were made between the hardness of the tipped materials, cutting edge recessions, and accuracy of the kerf widths. It was observed that the Vickers hardness of the Stellite-tipped teeth decreases drastically toward the tooth base whereas the tip-inserted teeth manufactured by the metal injection molding (MIM) process from HSS of designations SUS420J2 and SKH 51 did not show significant reduction in hardness toward the tooth base. It was also observed that the cutting edge recession of TiN-coated SKH 51 was the smallest, followed by SKH 51, SUS420J2, and Stellite. The edge recessions of TiN-coated SKH 51 was about one-third the edge recession of Stellite, and the edge recession of SKH 51 was almost 50 percent of the edge recession of Stellite. The F-test for equality of variance at a 5 percent level of significance showed that there was no significant difference between the accuracy of kerf width of tip-inserted saws and Stellite-tipped saws.