Cutting insert with cooling channels, a nozzle, a base plate, and a tool holder therefor

A cutting insert, comprising:

• a body having a pair of upper and lower parallel horizontal surfaces and at least three sidewalls extending therebetween, the body further including at least one cutting corner region defined between two, first and second, adjacent sidewalls and the upper horizontal surface, and a cooling portion associated with said cutting corner region, said cutting corner region having a rake surface at the corresponding horizontal surface, a first relief surface at the first side sidewall, a second relief surface at the second sidewall, and having respective first and second cutting edge portions and a curved cutting edge portion therebetween, each cooling portion including:
• a cooling channel formed in the corresponding horizontal surface, open to an exterior of the insert along a depth thereof, the cooling channel extending between a coolant inlet and a coolant outlet and comprising an upstream section associated with the coolant inlet, extending towards the curved cutting edge portion along and spaced from the first cutting edge portion, a downstream section associated with the coolant outlet, extending away from the curved cutting edge portion and extending along and spaced from the second cutting edge portion, and a curved section interconnecting the upstream and downstream sections and extending along the curved cutting corner and spaced therefrom;
• and
• a through-aperture extending from the lower horizontal surface towards the upper horizontal surface, such that the coolant inlet merges with the through-aperture, so as to allow coolant to flow therein from at least the lower horizontal surface into the cooling channel via the coolant inlet in order to facilitate heat removal from the cutting corner region.