Cryogenic Treatment Systems and Processes for Grinding Wheels and Bonded Abrasive Tools

• US 20090260298A1
• Filed: 04/16/2009
• Published: 10/22/2009
• Est. Priority Date: 04/16/2008
• Status: Abandoned Application

• Current Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Original Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Inventors: Ferrell, Robert C., Benoit, Larry L.
• Application Number:
  US12/425,129
• Publication Number:
  US 20090260298A1
• Time in Patent Office: Days
• US Class Current: 51/298
• CPC Class Codes: B22F 2202/03 Treatment under cryogenic or supercritical conditions
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/24 After-treatment of workpieces or articles B22F3/1146 takes precedence
• CPC Class Codes: B24D 18/00 Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
• CPC Class Codes: C21D 1/785 Thermocycling
• CPC Class Codes: C21D 6/04 Hardening by cooling below 0 degrees Celsius
• CPC Class Codes: C21D 9/22 for drills; for milling cutters; for machine cutting tools

Abstract

Embodiments of the invention can provide systems and methods for treating grinding wheels and bonded abrasive tools. A process in accordance with an embodiment of this invention is a cryogenic thermal cycling process for grinding wheels and bonded abrasive tools. Grinding wheels and bonded abrasive tools treated by cryogenic thermal cycling processes in accordance with embodiments of this invention can exhibit improved performance and service life during comparison testing against untreated tools.

Claims

1. A process to treat a bonded abrasive tool using a cycling chamber, the process comprising:

(a) introducing a bonded abrasive tool into a cycling chamber, wherein the tool has a temperature of about ambient temperature;

(b) introducing at least one cryogenic material into the cycling chamber, wherein the internal temperature of the chamber can be controlled by adjusting the flow rate of the at least one cryogenic material;

(c) decreasing the temperature of the cycling chamber or bonded abrasive tool to about −

275 degrees Fahrenheit (F) at a rate of about −

1 degree F. per minute to about −

3 degrees F. per minute;

(d) increasing the temperature of the cycling chamber or bonded abrasive tool to about −

80 degrees F. at a rate of about 1 degree F. per minute to about 3 degrees F. per minute;

(e) repeating elements (c) and (d) at least twice;

(f) further increasing the temperature of the cycling chamber or bonded abrasive tool to about 225 degrees F. at a rate of about 1 degrees F. to about 3 degrees F.; and

(g) maintaining the temperature of the cycling chamber or bonded abrasive tool at about 225 degrees F. for about 240 minutes before reducing the temperature of the cycling chamber or the bonded abrasive tool to about ambient temperature, and resulting in a strengthened and toughened bonded abrasive tool.

2. The process of claim 1 wherein the temperature rate of element (c) is within the range of about −

1 degrees F. per minute to about −

2 degrees F. per minute.

3. The process of claim 2, further comprising (c1) maintaining the temperature of the cycling chamber or bonded abrasive tool at about −

275 degrees F. for about 15 minutes, and (d1) maintaining the temperature of the cycling chamber or bonded abrasive tool at about −

80 degrees F. for about 15 minutes.

4. The process of claim 3, further comprising (e1) maintaining the temperature of the cycling chamber or bonded abrasive tool at about −

275 degrees F. for about 260 minutes.

5. The process of claim 1, wherein introducing a bonded abrasive tool into a cycling chamber, comprises introducing an abrasive tool comprising at least one alumina-based material and one bond material of either resinoid or vitrified.

6. The process of claim 1, wherein introducing a bonded abrasive tool into a cycling chamber, comprises introducing an abrasive tool comprising at least one zirconia-based material and one bond material of either resinoid or vitrified.

7. The process of claim 1, wherein introducing a bonded abrasive tool into a cycling chamber, comprises introducing an abrasive tool comprising at least one alumina-zirconia based material and one bond material of either resinoid or vitrified.

8. A bonded abrasive tool comprising:

at least one abrasive material selected from the group that comprises at least one of alumina, zirconia, or alumina-zirconia;

wherein the bonded abrasive tool is formed by a process comprising;

(a) introducing the bonded abrasive tool into a cycling chamber, wherein the tool has a temperature of about ambient temperature;

(b) introducing at least one cryogenic material into the cycling chamber, wherein the internal temperature of the chamber can be controlled by adjusting the flow rate of the at least one cryogenic material;

(c) decreasing the temperature of the cycling chamber or bonded abrasive tool to about −

275 degrees Fahrenheit (F) at a rate of about −

1 degree F. per minute to about −

3 degrees F. per minute;

(d) increasing the temperature of the cycling chamber or bonded abrasive tool to about −

80 degrees F. at a rate of about 1 degree F. per minute to about 3 degrees F. per minute;

(e) repeating elements (c) and (d) at least twice;

(f) further increasing the temperature of the cycling chamber or bonded abrasive tool to about 225 degrees F. at a rate of about 1 degrees F. to about 3 degrees F.; and

(g) maintaining the temperature of the cycling chamber or bonded abrasive tool at about 225 degrees F. for about 240 minutes, and resulting in a strengthened and toughened bonded abrasive tool.

9. The bonded abrasive tool of claim 8 wherein the temperature rate of element (c) is within the range of about −

1 degrees F. per minute to about −

2 degrees F. per minute.

10. The bonded abrasive tool of claim 9, further comprising (c1) maintaining the temperature of the cycling chamber or bonded abrasive tool at about −

275 degrees F. for about 15 minutes, and (d1) maintaining the temperature of the cycling chamber or bonded abrasive tool at about −

80 degrees F. for about 15 minutes.

11. The bonded abrasive tool of claim 10, further comprising (e1) maintaining the temperature of the cycling chamber or bonded abrasive tool at about −

275 degrees F. for about 260 minutes.

12. The bonded abrasive tool of claim 8, wherein the element introducing a bonded abrasive tool into a cycling chamber comprises introducing a bonded abrasive tool comprising at least one alumina-based material and one bond material of either resinoid or vitrified.

13. The bonded abrasive tool of claim 8, wherein the element introducing a bonded abrasive tool into a cycling chamber, comprises introducing a bonded abrasive tool comprising at least one zirconia-based material and one bond material of either resinoid or vitrified.

14. The bonded abrasive tool of claim 8, wherein the element introducing a bonded abrasive tool into a cycling chamber, comprises introducing a bonded abrasive tool comprising at least one alumina-zirconia based material and one bond material of either resinoid or vitrified.