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A method and an apparatus or machining a workpiece include the use of a cryogenically cooled oxide containing ceramic cutting tool. The method involves cryogenic cooling of the cutting tool during a cutting operation, which cooling results in enhanced wear resistance and fracture resistance of the

A method and an apparatus or machining a workpiece include the use of a cryogenically cooled oxide containing ceramic cutting tool. The method involves cryogenic cooling of the cutting tool during a cutting operation, which cooling results in enhanced wear resistance and fracture resistance of the cutting tool. A preferred embodiment involves jetting a cryogenic fluid directly at the cutting tool.

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The invention claimed is: 1. An apparatus for machining a workpiece, comprising: an oxide-containing ceramic cutting tool adjacent the workpiece, all or substantially all of the oxide-containing ceramic cutting tool being made of an oxide-containing ceramic material or an other advanced material, s

The invention claimed is: 1. An apparatus for machining a workpiece, comprising: an oxide-containing ceramic cutting tool adjacent the workpiece, all or substantially all of the oxide-containing ceramic cutting tool being made of an oxide-containing ceramic material or an other advanced material, said oxide-containing ceramic or other advanced material having at least about 5% by weight of an oxide ceramic phase throughout all or substantially all of the oxide-containing ceramic cutting tool; and a means for cryogenically cooling the entire oxide-containing ceramic cutting tool, whereby the entire oxide-containing ceramic cutting tool is cooled to a cryogenic temperature prior to and during machining of the workpiece with the oxide-containing ceramic cutting tool. 2. An apparatus as in claim 1, wherein the means for cryogenically cooling the entire oxide-containing ceramic cutting tool comprises a cryogenic fluid. 3. An apparatus as in claim 2, wherein at least a portion of the cryogenic fluid is delivered to the oxide-containing ceramic cutting tool in the form of a cryogenic jet. 4. An apparatus as in claim 3, wherein the oxide-containing ceramic cutting tool has a rake surface and at least a portion of the cryogenic jet impinges on at least a portion of the rake surface. 5. An apparatus as in claim 2, wherein at least a portion of the cryogenic fluid is a two-phase fluid. 6. An apparatus as in claim 2, wherein the cryogenic fluid is selected from a group consisting of liquid nitrogen, gaseous nitrogen, liquid argon, gaseous argon and mixtures thereof. 7. An apparatus as in claim 3, wherein at least a portion of the cryogenic jet has a temperature below about minus 150 degrees Celsius (-150째 C.). 8. An apparatus as in claim 2, wherein the oxide-containing ceramic cutting tool has a cutting edge and the means for cryogenically cooling the entire oxide-containing ceramic cutting tool further comprises a means for delivering at least a portion of the cryogenic fluid to the oxide-containing ceramic cutting tool, said means for delivering having at least one discharge point spaced apart from the cuffing edge by a distance greater than or equal to about 0.150 inches and less than about 3.0 inches. 9. An apparatus as in claim 1, wherein at least a portion of the oxide-containing ceramic cutting tool is frosted when the workpiece contacts the oxide-containing ceramic cuffing tool. 10. A method for machining a workpiece, comprising the steps of: providing an oxide-containing ceramic cutting tool adjacent the workpiece, all or substantially all of the oxide-containing ceramic cutting tool being made of an oxide-containing ceramic material or an other advanced material, said oxide-containing ceramic or other advanced material having at least about 5% weight of an oxide ceramic phase throughout all or substantially all of the oxide-containing ceramic cuffing tool; and cryogenically cooling the entire oxide-containing ceramic cutting tool, whereby the entire oxide-containing ceramic cuffing tool is cooled to a cryogenic temperature prior to and during machining of the workpiece with the oxide-containing ceramic cuffing tool. 11. A method as in claim 10, wherein the entire oxide-containing ceramic cutting tool is cryogenically cooled by a cryogenic fluid. 12. A method as in claim 11, wherein at least a portion of the cryogenic fluid is delivered to the oxide-containing ceramic cuffing tool in the form of a cryogenic jet. 13. A method as in claim 12 wherein the oxide-containing ceramic cutting tool has a rake surface and at least a portion of the cryogenic jet impinges on at least a portion of the rake surface. 14. A method as in claim 11, wherein at least a portion of the cryogenic fluid delivered to the cutting tool is a two-phase fluid. 15. A method as in claim 11, wherein the cryogenic fluid is selected from a group consisting of liquid nitrogen, gaseous nitrogen, liquid argon, gaseous argon and mixtures thereof. 16. A method as in claim 12, wherein at least a portion of the cryogenic jet has a temperature below about minus 150 degrees Celsius (-150째 C.). 17. A method as in claim 11, wherein the oxide-containing ceramic cutting tool has a cuffing edge and wherein a means for delivering a portion of the cryogenic fluid to the oxide-containing ceramic cuffing tool has at least one discharge point spaced apart from the cuffing edge by a distance greater than or equal to about 0.150 inches and less than about 3.0 inches. 18. A method as in claim 10, wherein at least a portion of the oxide-containing ceramic cutting tool is frosted when the workpiece contacts the oxide-containing ceramic cutting tool.