As a developer of a very successful line of speed and feed calculators I sometimes get questions like : "I calculated speeds and feeds for a conventional toolpath. Got 5.5 cubic inches MRR(Material Removal Rate). And then I calculated S&F for the same endmill with HSM parameters turned on and got almost the same amount of  MRR! What is even the point in using HSM parameters?" -they ask.

I would like to clear some things up for my friends.
In this article I will explain exactly WHY HSM machining is better and HOW to achieve better productivity and tool life.

For starters here are the main features of a HSM-capable cutter:

As usual there are several components of HSM that need to be present in order for it to work to its fullest. These are:

a) Machine
b) Tool
c) Workpiece geometry
d) Workpiece material

I intentionally did not number these as each one of those is equally important.