Dynamic characterization of the tool holder material : An Experimental Thesis

Abstract: The major factors putting limitation to high productivity and good product surface quality is machining vibration. A lot of scientific research has been concentrated controlling the vibration while machining. There is a good sum of research going in department of production engineering at KTH to find out ways to reduce the machining vibration and enhancing the productivity but so far, they have been concentrated only on use of conventional steel as there of cutting tool. This they have tried by introducing damping in the conventional steel tooling system or by coating the tool with different composition of materials to improve the tool resistances to vibration.In this paper, the research has been concentrated to finding out an alternative material to conventional steel, which is more resistance to machining vibration. The theory in the paper is mainly concentrated to give the basic understanding about frequency response function, forced vibration, and stability lobe diagram (SLD) and their applications. Through experimental modal analysis (EMA), machining tests and surface roughness of the machined surface (toolox 33 plates), SSAB toolox 44 steel cutting tool is compared against its counterpart the conventional steel (H13). The natural frequencies and damping factor are obtained for both free hanging and attached to machine condition. Afterwards, a stability lobe diagram is being plotted using the EMA data. Machining tests are being conducted according to SLD to their limits to determine and verify the material capability until tools starts showing vibrations.In the end, the results is being compared by analyzing the sound emitted during the machining process and determining the surface roughness of the machined surface both visually and by white light interferometry. Then comparing the toolox 44 with conventional steel (H13), to find out which one is more resistance to vibrations.