inserts etc
Inserts are made of various hard materials to be used as replaceable cutting edges in different kinds of machining applications. Milling inserts are used in cutting wheels for milling machines. Negative and negative rake inserts are for use in cutting tools with the seat for them cut at such an angle that the cutting edge and nose are tipped down at a slight angle, so that the cutting forces are actualy pushing the edge slightly into the insert for more strength and support at the cutting edge that a negative rake tool, which cuts cleaner, but pulls the cutting edge slightly away from the insert, making it easier to break the edge off the tool. Ceramic inserts are made of one of several grades of ceramic, which is harder and will stand more cutting speed than the carbide grades. CBN inserts are harder yet, with diamond even harder.
Harmonic vibrations occure when a part of the machine or of the work have a natural frequency that is the same or close to the frequency of a vibration scource that can "exite" it, or transfer the frequency to it. The worst case of this I've seen was a persistant vibration in a roll grinding machine that was ruining the finish grind on some large chilled iron rolls. Using vibrometers, it was eventualy traced to a pedestal grinder with a badly out of balance wheel that was over 60 feet away, but the frequency was traveling through a 10" slab cement floor to exite a part of the rollgrinder at the same frequency.
I've never run a 5 axis machine, but I have been known to have some rigidity issues occasionaly, but I don't want to talk about it.
lwbates