Patent ID: 8220370
Filing Date: 2012-07-17
Classification: B23P,B23Q,Y10S,Y10T

Abstract:
1. A method for reducing a thickness of a thermomechanically-affected layer, including a white layer (WL) and a dark layer (DL), on and under an as-machined surface of a hard metal workpiece, having a surface hardness exceeding 42 Rockwell on Scale C, being machined by a hard cutting tool, having an edge hardness exceeding 1500 Vickers, the hard cutting tool exerting a thermomechanical load on a surface of the hard metal workpiece, comprising: reducing the thermomechanical load being exerted on the surface of the hard metal workpiece by the hard cutting tool, wherein the step of reducing the thermomechanical load comprises one or a combination of at least two of the following: (a) cooling the hard cutting tool with a first precisely aimed jet or spray of an inert, water-free coolant having an initial temperature in a range of about −250° C. to about +25° C.; (b) cooling the as-machined surface of the hard metal workpiece with at least one of the first precisely aimed jet or spray and a second precisely aimed jet or spray of the inert, water-free coolant or an other inert, water-free coolant having an initial temperature in a range of about −250° C. to about +25° C.; and (c) reducing a cutting force component in a direction normal to the as-machined surface of the hard metal workpiece when at least a portion of the thermomechanical load is a component of a cutting force, the component being applied in a direction normal to the surface of the hard metal workpiece.