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A method and apparatus for improving the surface finish and/or surface integrity of a workpiece formed or shaped with a tool increase the surface hardness of the workpiece during forming or shaping of the workpiece. A method and apparatus for forming or shaping a workpiece also increase the surface

A method and apparatus for improving the surface finish and/or surface integrity of a workpiece formed or shaped with a tool increase the surface hardness of the workpiece during forming or shaping of the workpiece. A method and apparatus for forming or shaping a workpiece also increase the surface hardness of the workpiece during forming or shaping of the workpiece with a tool, as do a method and apparatus for manufacturing a finished part or product from a workpiece. In some embodiments, an expanding jet of cryogen may be jetted to a surface of a workpiece and a tool from a nozzle, wherein the cryogen is at least partially separated into a condensed phase portion and a vapor portion within a downstream portion of the nozzle.

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The invention claimed is: 1. A method for improving at least one of a surface finish and a surface integrity of a workpiece formed or shaped with a tool, the workpiece having a surface hardness, comprising increasing the surface hardness of the workpiece during forming or shaping of the workpiece w

The invention claimed is: 1. A method for improving at least one of a surface finish and a surface integrity of a workpiece formed or shaped with a tool, the workpiece having a surface hardness, comprising increasing the surface hardness of the workpiece during forming or shaping of the workpiece with the tool by jetting cryogenic fluid from a jet of the cryogenic fluid at at least a portion of the tool at an impingement angle (α) greater than about 30° and less than about 90°, and then said cryogenic fluid impinges the workpiece at a spread angle (β) wherein the spread angle (β) is such that the cryogenic fluid impinges at least the entire length of contact between the tool and the workpiece. 2. A method as in claim 1, wherein said method further comprises the step of impinging at least a portion of said workpiece or at least a portion of said tool with cryogenic fluid from a second jet of cryogenic fluid. 3. A method as in claim 1, wherein the jet of the cryogenic fluid impinges on the surface of the workpiece at a spread angle (β) greater than about 0° and less than about 180°. 4. The method of claim 1 wherein said tool is a cutting tool comprising a rake face, and said at least a portion of the tool is at least a portion of the rake face. 5. A method for improving at least one of a surface finish and a surface integrity of a workpiece formed or shaped with a tool, comprising the steps of: providing a supply of a cryogen; providing a nozzle adjacent the workpiece, the nozzle having at least one inlet adapted to receive a flow of the cryogen, an upstream portion in fluid communication with the at least one inlet, the upstream portion adapted to receive at least a portion of the flow of the cryogen from the at least one inlet, a downstream portion in fluid communication with the upstream portion and adapted to receive at least a portion of the flow of the cryogen from the upstream portion, and at least one outlet in fluid communication with the downstream portion and adapted to receive and transmit from the downstream portion at least a portion of the flow of the cryogen; delivering a portion of the cryogen to the at least one inlet of the nozzle, wherein the cryogen is at least partially separated within the downstream portion of the nozzle into a condensed phase portion and a vapor portion; and jetting at least a portion of an expanding jet of the condensed phase portion and the vapor portion from the at least one outlet of the nozzle to the tool and a surface of the workpiece. 6. A method as in claim 5, wherein the downstream portion of the nozzle has at least one diverging wall and at least one converging wall adapted to converge on the expanding jet. 7. A method as in claim 6, wherein the at least one diverging wall has a diverging angle and the at least one converging wall has a converging angle less than the diverging angle. 8. A method as in claim 6, wherein the diverging wall is open to an ambient atmosphere. 9. The method of claim 5 further wherein the downstream portion of the nozzle has at least one diverging wall open to an ambient atmosphere and at least one converging wall adapted to converge on the expanding jet, and wherein the at least one diverging wall has a diverging angle and the at least one converging wall has a converging angle less than the diverging angle. 10. The method of claim 1 further comprising the step of: providing the tool adjacent the workpiece. 11. A workpiece formed or shaped by a method as in claim 10 and characterized by an improved surface finish, an improved surface integrity, or both an improved surface finish and an improved surface integrity, wherein said workpiece having a work surface roughness (Ra), wherein the work surface roughness (Ra) is eaual to or less than a theoretical low roughness limit (Ra-t), calculated as Ra-t=f2/(32 r), where f is a cutting tool feedrate and r is a cutting tool nose radius. 12. The method of claim 10 wherein the workpiece contains at least one metallic alloy having at least one element selected from a group consisting of cobalt (Co), chromium (Cr), molybdenum (Mo), nickel (Ni), iron (Fe), tungsten (W), aluminum (Al), and titanium (Ti) or contains at least one polymer or at least one polymer-based composite. 13. An apparatus for improving at least one of a surface finish and a surface integrity of a workpiece formed or shaped with a tool, the workpiece having a surface hardness, comprising means for increasing the surface hardness of the workpiece during forming or shaping of the workpiece with the tool, wherein said means for increasing the surface hardness of the workpiece during forming or shaping of the workpiece with the tool comprises a jet of cryogenic fluid impinging at least a portion of the tool at an impingement angle (α) greater than about 30° and less than about 90°, and then said cryogenic fluid impinges the workpiece at a spread angle (β) wherein the spread angle (β) is such that the cryogenic fluid impinges at least the entire length of contact between the tool and the workpiece. 14. An apparatus as in claim 13, further comprising a second jet of the cryogenic fluid that impinges on a portion of the tool or a portion of a surface of the workpiece. 15. An apparatus as in claim 14, wherein the jet of the cryogenic fluid impinges on the surface of the workpiece at a spread angle (β) greater than about 0° and less than about 180°. 16. The apparatus of claim 13, said tool is a cutting tool comprising a rake face and said at least a portion of the tool is a portion of said rake face. 17. An apparatus for improving at least one of a surface finish and a surface integrity of a workpiece formed or shaped with a tool, comprising: a supply of a cryogen; a nozzle adjacent the workpiece, the nozzle having at least one inlet adapted to receive a flow of the cryogen, an upstream portion in fluid communication with the at least one inlet, the upstream portion adapted to receive at least a portion of the flow of the cryogen from the at least one inlet, a downstream portion in fluid communication with the upstream portion and adapted to receive at least a portion of the flow of the cryogen from the upstream portion, and at least one outlet in fluid communication with the downstream portion and adapted to receive and transmit from the downstream portion at least a portion of the flow of the cryogen; means for delivering a portion of the cryogen to the at least one inlet of the nozzle, wherein the cryogen is at least partially separated within the downstream portion of the nozzle into a condensed phase portion and a vapor portion; and means for jetting at least a portion of an expanding jet of the condensed phase portion and the vapor portion from the at least one outlet of the nozzle to the tool and a surface of the workpiece. 18. An apparatus as in claim 17, wherein the downstream portion of the nozzle has at least one diverging wall and at least one converging wall adapted to converge on the expanding jet. 19. An apparatus as in claim 18, wherein the at least one diverging wall has a diverging angle and the at least one converging wall has a converging angle less than the diverging angle. 20. An apparatus as in claim 18, wherein the diverging wail is open to an ambient atmosphere. 21. The apparatus of claim 17 wherein the downstream portion of the nozzle has at least one diverging wall open to an ambient atmosphere and at least one converging wall adapted to converge on the expanding jet, and wherein the at least one diverging wall has a diverging angle and the at least one converging wall has a converging angle less than the diverging angle. 22. The apparatus of claim 17 further comprising: means for forming or shaping the workpiece with the tool. 23. A workpiece formed or shaped by an apparatus as in claim 22 said workpiece having a work surface roughness (Ra), wherein the work surface roughness (Ra) is equal to or less than a theoretical low roughness limit (Ra-t), calculated as Ra-t=f2/(32 r), where f is a cutting tool feedrate and r is a cutting tool nose radius. 24. The workpiece as in claim 23, wherein the workpiece contains at least one metallic alloy having at least one element selected from a group consisting of cobalt (Co), chromium (Cr), molybdenum (Mo), nickel (Ni), iron (Fe), tungsten (W), aluminum (Al), and titanium (Ti) or contains at least one polymer or at least one polymer-based composite. 25. An apparatus for machining a workpiece having a surface hardness, comprising: a cutting tool adjacent the workpiece, the cutting tool adapted to shape the workpiece; means for shaping the workpiece with the cutting tool; and means for increasing the surface hardness of the workpiece during shaping of the workpiece with the cutting tool, wherein the shaped workpiece is characterized by an improved surface finish having a work surface roughness (Ra) equal to or less than a theoretical low roughness limit (Ra-t), calculated as Ra-t=f2/(32 r), where f is a cutting tool feedrate and r is a cutting tool nose radius. 26. A nozzle for jetting an expanding jet of a cryogen to a surface of a workpiece, comprising: at least one inlet adapted to receive a flow of the cryogen; an upstream portion in fluid communication with the at least one inlet, the upstream portion adapted to receive at least a portion of the flow of the cryogen from the at least one inlet; a downstream portion in fluid communication with the upstream portion and adapted to receive at least a portion of the flow of the cryogen from the upstream portion; at least one outlet in fluid communication with the downstream portion and adapted to receive and transmit from the downstream portion at least a portion of the flow of the cryogen; and means for separating the cryogen at least partially into a condensed phase portion and a vapor portion within the downstream portion of the nozzle. 27. A nozzle as in claim 26, further comprising an internal expansion chamber adapted to confine the expanding jet of the cryogen, wherein the nozzle is adapted to clamp a cutting tool having a tool rake surface. 28. A nozzle as in claim 26, wherein the downstream portion of the nozzle has at least one diverging wall and at least one converging wall adapted to converge on the expanding jet of the cryogen. 29. A nozzle as in claim 28, wherein the diverging wall has a diverging angle and the converging wall has a converging angle less than the diverging angle. 30. A nozzle as in claim 19, wherein the diverging wall is open to an ambient atmosphere. 31. The nozzle of claim 26, further comprising an internal expansion chamber adapted to confine the expanding jet of the cryogen, wherein the downstream portion of the nozzle has at least one diverging wall open to an ambient atmosphere and at least one converging wall adapted to converge on the expanding jet of the cryogen, and wherein the diverging wall has a diverging angle and the converging wall has a converging angle less Than the diverging angle, and wherein the nozzle is adapted to clamp a cutting tool having a tool rake surface. 32. The method of claim 1, further comprising the step of: manufacturing the finished part or the finished product from the workpiece shaped or formed with the tool wherein the finished part or the finished product is manufactured tram the workplace without using at least one additional operation needed by at least one other method for manufacturing a comparable finished part or a comparable finished product which the other method forms or shapes from a comparable workpiece having a comparable surface hardness without increasing the comparable surface hardness of the comparable workpiece during forming or shaping of the comparable workpiece, said at least one additional operation being selected from a group consisting of grinding, polishing, honing, deburning, peening, tumbling, burnishing, deep rolling, soft annealing, soft machining, soft shaping, soft forming, and work part cleaning.