01-04-2015, 01:26 PM
Jack,
The VP15TF is the grade, and it's an Aluminum Titanium Nitride (AlTiN) coating that's meant for very high cutting speeds in steels, stainless steels and even superalloys. It's one of the most "universal" grades that Mitusbishi had ever made and is still current. Note I didn't say it's a terrific grade, just that it's current. ;)
That said, it needs HEAT to work well. Are you cutting dry and at higher speeds? What materials have you tried cutting and at what cutting speeds?
The lack of a stated chipbreaker in the nomenclature is Mitsubishi's "standard" chipbreaker, according to their published info. What that means to me is that it's a fairly "open" geometry for medium-high feed rates and depth of cut. To me that means depth of cuts from .030" (per side, or .060" on diameter) and feed rates of .006" to .014" per rev. The problem I see with this is that the VNMG is designed to be a "finishing" insert by nature of its acute included angles, and is inherently too weak for pushing at those rates to get chips to break.
A big DUH to Mitsubishi for that, and perhaps part of the reason someone gifted the inserts to you. They probably weren't working well for the original buyer either. Almost all the VNMG inserts I have are in finishing chipbreaker designs to be used at .004" to .060" depth of cut and feed rates of .002 to .010 per rev.
The VP15TF is the grade, and it's an Aluminum Titanium Nitride (AlTiN) coating that's meant for very high cutting speeds in steels, stainless steels and even superalloys. It's one of the most "universal" grades that Mitusbishi had ever made and is still current. Note I didn't say it's a terrific grade, just that it's current. ;)
That said, it needs HEAT to work well. Are you cutting dry and at higher speeds? What materials have you tried cutting and at what cutting speeds?
The lack of a stated chipbreaker in the nomenclature is Mitsubishi's "standard" chipbreaker, according to their published info. What that means to me is that it's a fairly "open" geometry for medium-high feed rates and depth of cut. To me that means depth of cuts from .030" (per side, or .060" on diameter) and feed rates of .006" to .014" per rev. The problem I see with this is that the VNMG is designed to be a "finishing" insert by nature of its acute included angles, and is inherently too weak for pushing at those rates to get chips to break.
A big DUH to Mitsubishi for that, and perhaps part of the reason someone gifted the inserts to you. They probably weren't working well for the original buyer either. Almost all the VNMG inserts I have are in finishing chipbreaker designs to be used at .004" to .060" depth of cut and feed rates of .002 to .010 per rev.