| Popis: |
Published work concerning the performance of coated and uncoated carbide tipped circular saw blades has been searched and reviewed. The search has shown that little similar experiments on the carbide tipped circular saw blades have been conducted. Furthermore the evidence shows that no work has been published on the application of coatings to the carbide tipped circular saw blades. Finite element analysis has been widely applied to the cutting process, but the application of finite element methods to the carbide tipped circular saw blade is still a new area of research. In this investigation the performance and life of the carbide tool both uncoated and coated were quantified by rigorous measurement. The proposed carbide properties ( composition, cobalt distribution, specific gravity, micro-structure and red hardness of carbide) have been experimentally tested. The failure modes for the carbide circular saw blades and carbide tipped saw segments have been established. In this work a novel experimental approach was used, in which TiN and TiAlN coatings were applied to the carbide tipped circular saw. A feature of this approach is that a lower coating temperature is used and yet still retains the good bonding strength between the substrate and the coating. The parameters obtained in this investigation were used as a basis in the development of a finite element model. This model was used to optimise tooth geometry and predict the failure mode with respect to temperatures and stresses. Investigation has shown that TiN and TiAlN coatings have largely enhanced the tool life in the case of cutting proposed workpiece materials. The crater wear, flank wear and large chipping have been arrested or reduced. Computer model and transverse rupture strength figure have been established. The results shows that the model used for qualitative analysis of a problem is possible and the examples conducted in the case of cutting mild steel is completely consistent with the failure modes obtained in the cutting tests. |
