| 摘要 |
A CNC machine tool has a turret (10), a reservoir of coolant, a pump supplying coolant under pressure from the reservoir (not shown) to the turret (10), a tool holder (13) mounted on the turret at a tool station (8) opposite a rotatable spindle (not shown) upon which a workpiece is mounted for a cutting operation. A coolant bored tool bar (18) is clamped in the tool holder. It has an insert (9) with a rake face (38) for gouging out metal chips. The insert rake face and chips have an an edge boundary temperature gradient decreasing away from the rake face. A sleeve (24) removeably attaches to the coolant bored tool bar and an O-ring (25) seals around the end of the bar defining a chamber (30) supplied with coolant under pressure. The only outlet from this chamber is the bore (32) of the tool bar. It has a blind end (35) from which a passageway restriction (34) extends toward the surface of the bar for directing a jet of high pressure coolant on the insert behind the boundary layer of plastic deformation of chip formation. The temperature gradient away from the friction face of the tool is reduced to prolong tool life and promote consistent chip breaking.
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