<http://schema.org/description>
"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. The solution: Change the axial depth of cut for each pass."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mmsonline.com/blog/post/alter-the-axial-depth>