P. Bach, Czech Technical University in Prague, Prague 2, Czech Republic
The paper is focused on milling of Titanium alloy Ti6Al4V using HSS cutters. This kind of material is obviously machined by carbide tools. But, it is possible to use also HSS tools and low cutting velocity. Under this condition performance of the HSS tools can be higher than the performance of the carbide tools. Performance of any machining operation is limited by chattering. When milling, stability diagram can be calculated to find stable depth of cut (DOC) and stable ranges of spindle speed. DOC level depends on dynamic stiffness of the tool – spindle mechanical system. Titanium milling needs a stiff tool-spindle structure powered by a strong motor. Stable DOC at low cutting speeds is significantly higher comparing to stable DOC available within high speed range. The paper shows stable diagrams as well as couple of curves referring the tool life under this condition. The results for tool materials obtained by the technology of Powder Metallurgy are promising.
Summary: The Titanium alloys are machined using carbide tools. Cutting conditions are obviously vc=40-120 m/min, fz=0,05-0,1mm/z, ap= 2-8 mm, ae=0,1- 0,5mm. But, there is a possibility to use also HSS tools. In this case, the cutting conditions are vc=15 – 35 m/min, fz=0,1mm/z, ap=10 – 80 mm, ae=0,3 – 1 mm. Under this conditions performance of the HSS tools is much better than the performance of the carbide tools. The research results performed at RCMT, which is the research institute of the Czech Technical University in Prague, give the evidence.
