MACHINING APPARATUS AND PROCESS

• US 20110048183A1
• Filed: 02/19/2010
• Published: 03/03/2011
• Est. Priority Date: 02/19/2009
• Status: Active Grant

• Current Assignee: Purdue Research Foundation (Purdue University)
• Original Assignee: Purdue Research Foundation (Purdue University)
• Inventors: Shin, Yung C.
• Granted Patent: US 8,839,497 B2
• Time in Patent Office: Days
• US Class Current: 82/1.11
• CPC Class Codes: B23B 2222/88 Titanium
• CPC Class Codes: B23B 2260/092 Lasers
• CPC Class Codes: B23B 27/10 Cutting tools with special provision for cooling drills with lubricating or cooling equipment B23B51/06; features relating to lubricating or cooling of milling cutters B23C5/28; arrangements or devices for cooling or lubricating tools or work B23Q11/10
• CPC Class Codes: B23P 25/006 Heating the workpiece by laser during machining
• CPC Class Codes: B23Q 11/1053 using the cutting liquid at specially selected temperatures controlling the temperature of the cutting liquid for maintaining machine parts at a constant temperature B23Q11/146
• CPC Class Codes: Y10T 29/5114 Lathe and tool
• CPC Class Codes: Y10T 407/14 with means to apply fluid to cutting tool
• CPC Class Codes: Y10T 407/27 comprising tool of specific chemical composition
• CPC Class Codes: Y10T 82/10 Process of turning
• CPC Class Codes: Y10T 82/16065 Combined with means to apply fluid
• CPC Class Codes: Y10T 82/16081 Combined with means to heat tool and/or work

Abstract

A machining process and apparatus capable of increasing removal rates achievable when machining titanium and its alloys. The process includes heating a portion of a workpiece with a laser beam, cryogenically cooling a cutting tool with a cryogenic fluid without flowing the cryogenic fluid onto the workpiece, and machining the heated portion of the workpiece with the cutting tool. The apparatus includes a cutting tool, a device for heating a portion of a workpiece with a laser beam prior to being machined with the cutting tool, and a device for cryogenically cooling the cutting tool with a cryogenic fluid without flowing the cryogenic fluid onto the workpiece. The cryogenic fluid is circulated around the cutting tool to achieve a temperature differential between the workpiece and the cutting tool that is capable of improving removal rates and extending tool life at cutting speeds of, for example, above 100 m/min.

Claims

1. A machining process comprising:

heating a portion of a workpiece with a laser beam;

cryogenically cooling a cutting tool with a cryogenic fluid without flowing the cryogenic fluid onto the workpiece; and

machining the heated portion of the workpiece with the cutting tool.

2. The machining process according to claim 1, wherein the portion of the workpiece is heated by the laser beam so as to be at a temperature of less than 300°

C. when machined by the cutting tool.

3. The machining process according to claim 1, wherein the portion of the workpiece is heated by the laser beam so as to be at a temperature of greater than 100°

C. to about 275°

C. when machined by the cutting tool.

4. The machining process according to claim 1, wherein the portion of the workpiece is heated by the laser beam so as to be at a temperature of about 250°

C. when machined by the cutting tool.

5. The machining process according to claim 1, wherein the cutting tool is cryogenically cooled by flowing the cryogenic fluid through a reservoir on a tool holder in which the cutting tool is mounted.

6. The machining process according to claim 1, wherein the cryogenic fluid is liquid nitrogen.

7. The machining process according to claim 1, wherein the cryogenic fluid evaporates after flowing onto the cutting tool and prior to any contact with the workpiece.

8. The machining process according to claim 1, wherein the cutting tool is a carbide cutting tool.

9. The machining process according to claim 1, wherein the cutting tool is a WC/Co carbide cutting tool.

10. The machining process according to claim 9, wherein the WC/Co carbide cutting tool has a coating of TiAlN or TiC/TiN.

11. The machining process according to claim 9, wherein the WC/Co carbide cutting tool has a coating of TiAlN.

12. The machining process according to claim 1, wherein the workpiece is machined at a cutting speed of greater than 60 m/min.

13. The machining process according to claim 1, wherein the workpiece is machined at a cutting speed of greater than 100 m/min.

14. The machining process according to claim 1, wherein the workpiece is machined at a cutting speed of about 150 m/min or more.

15. The machining process according to claim 1, wherein the workpiece is machined at a cutting speed of about 100 to about 200 m/min.

16. The machining process according to claim 1, wherein the workpiece is formed of titanium or an alloy thereof.

17. The machining process according to claim 1, wherein the workpiece has a nominal composition of, by weight, about 6% aluminum, about 4% vanadium, the balance titanium and incidental impurities.

18. A machining apparatus comprising:

a cutting tool;

means for heating a portion of a workpiece with a laser beam prior to being machined with the cutting tool; and

means for cryogenically cooling the cutting tool with a cryogenic fluid without flowing the cryogenic fluid onto the workpiece.

19. The machining apparatus according to claim 18, wherein the cutting tool is mounted in a tool holder, and the cryogenic cooling means comprises a reservoir on the cutting tool and from which the cryogenic fluid flows onto the cutting tool.

20. The machining apparatus according to claim 18, wherein the cryogenic fluid is liquid nitrogen.

21. The machining apparatus according to claim 18, wherein the cryogenic cooling means is adapted to cause the cryogenic fluid to evaporate after flowing onto the cutting tool and prior to any contact with the workpiece.

22. The machining apparatus according to claim 18, wherein the cutting tool is a carbide cutting tool.

23. The machining apparatus according to claim 18, wherein the cutting tool is a WC/Co carbide cutting tool.

24. The machining apparatus according to claim 23, wherein the WC/Co carbide cutting tool has a coating of TiAlN or TiC/TiN.

25. The machining apparatus according to claim 23, wherein the WC/Co carbide cutting tool has a coating of TiAlN.

26. The machining apparatus according to claim 18, further comprising the workpiece mounted to the apparatus, wherein the workpiece is formed of titanium or an alloy thereof.

27. The machining apparatus according to claim 26, wherein the workpiece has a nominal composition of, by weight, about 6% aluminum, about 4% vanadium, the balance titanium and incidental impurities.

28. The machining apparatus according to claim 18, wherein the machining apparatus is mounted to a lathe.