In difficult-to-machine metals, when a pocket or similar deep feature is milled in successively deeper Z-axis levels, oxidation and chemical reaction can affect the tool at the upper surface level of each cut. Early damage to the tool can, therefore, occur at this one spot. The tool might have to be changed because of the wear at this one spot, even though the rest of the tool’s flute length is sharp.
The solution: Change the axial depth of cut for each pass. This will distribute the problem area to different points along the tool, as the drawing above suggests.
This practical advice is one of 10 tips for machining titanium recently provided by cutting tool supplier Stellram.