Al2O3 tools towards effective machining of wood-based materials

Tools made of sub-μm-grain Al2O3 ceramics have already been successfully tested in the machining of hardened steels (since they have good technological characteristics), but there is no scientific and technological experience in machining wood-based materials. The aim of the present study was to examine the cutting properties of the edges made of sub-μm-grain Al2O3 ceramic with various structures and properties when used for milling wood-based materials not easily workable.The properties of sub-μm-grain Al2O3 ceramics were correlated with the sharpening ability and wear behavior of the cutting edges made of these ceramics by testing the edges in machining wood-based materials. It has been found that there is strong dependence between the microstructure (which defines the material properties) and the technological properties of the ceramics. The grain size affects both the possibility of shaping appropriately the micro-geometry of the milling knife and its wear behavior: the character of the wear changes from the outbreaking type when the grain size exceeds 500 nm to abrasive with the grain size below 500 nm. Since abrasive wear is not typical of the materials with the mechanical properties predominated by brittle fracture, we can consider 500 nm to be the threshold value above which the material is no longer classified as nano-crystalline for this application.