Method of orthopaedic implant finishing

Patent metadata

Field	Value
Publication number	US-9561578-B2
Application number	US-201314404756-A
Country	US
Kind code	B2
Filing date	May 31, 2013
Priority date	Jun 1, 2012
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A process to effectively remove machine lines blending the surface to a high luster uniform visual standard while reducing the surface roughness to below 8 Micro inches. The process does not remove or move the affected material greater than 0.02 mm, and the process is designed to produce a visually acceptable part that reduces surface roughness below 8 micro inches and holds tightly toleranced complex geometries.

First claim

What is claimed is:

1. A method of surface finishing an orthopaedic implant comprising:
a. fixturing a machined orthopaedic implant having a targeted surface with machine lines on a platform in a wet blasting cabinet, the wet blasting cabinet having at least one nozzle;
b. rotating the platform at a speed of about 5 to about 360 revolutions per minute;
c. moving the at least one nozzle and the platform relative to one another in a linear motion at a speed of 10 to 60 inches per minute; and
d. applying a slurry mixture at an impaction angle to the targeted surface through the at least one nozzle at pressure of 15 to 60 pounds per square inch to effectively remove the machine lines blending the targeted surface, wherein the pressure is a combination pressure of both air pressure and slurry pressure, and wherein the at least one nozzle is located from about 0.25 inches to about 18 inches away from the targeted surface, and the at least one nozzle has a bore from about 0.25 inches to about 0.50 inches in diameter.

2. The method of claim 1 wherein the pressure is about 35 to about 50 pounds per square inch.

3. The method of claim 1 wherein the pressure is 50 pounds per square inch.

4. The method of claim 1 wherein the slurry pressure is created by a motor driven impeller.

5. The method of claim 1 wherein the slurry pressure is 30 psi.

6. The method of claim 1 wherein the at least one nozzle is located at 11.25 inches from the targeted surface.

7. The method of claim 1 wherein the at least one nozzle provides a solid stream or full cone spray pattern.

8. The method of claim 1 wherein the at least one nozzle has a bore of about 0.375 inches.

9. The method of claim 1 wherein the at least one nozzle has a length from about 0.5 inches to about 3 inches.

10. The method of claim 1 wherein the at least one nozzle has a length of about 1.5 inches.

11. The method of claim 1 wherein the platform rotates at about 5 to about 20 revolutions per minute.

12. The method of claim 1 wherein the impaction angle is selected from the group consisting 45, 60, and 90 degrees.

13. The method of claim 1 wherein the media is between about 0.001 and about 0.125 mm in size.

14. The method of claim 1 wherein the media is about 85 percent spherical.

15. The method of claim 1 wherein the slurry mixture is heated from about 40 to about 100 degrees Fahrenheit.

16. The method of claim 1 wherein the slurry mixture is heated from about 70 to about 80 degrees Fahrenheit.

17. The method of claim 1 wherein there are three nozzles.

18. The method of claim 17 wherein the three nozzle do not interfere with one another.

19. The method of claim 1 wherein the slurry mixture is made from water and media and has a media concentration of about 5 to about 35 percent.

20. The method of claim 19 wherein the slurry mixture has a media concentration of 23 percent.

21. A method of surface finishing an orthopaedic implant comprising:
a. fixturing a machined orthopaedic implant having a targeted surface with machine lines on a platform in a wet blasting cabinet, the wet blasting cabinet having at least one nozzle, the at least one nozzle has a bore from about 0.25 inches to about 0.50 inches in diameter, and the at least one nozzle has a length from about 0.5 inches to about 3 inches;
b. rotating the platform at a speed of about 5 to about 20 revolutions per minute;
c. moving the at least one nozzle and the platform relative to one another in a linear motion at a speed of 10 to 60 inches per minute;
d. heating a slurry mixture in a range from about 70 to about 80 degrees Fahrenheit, the slurry mixture is made from water and media, the media has a media concentration of about 5 to about 35 percent, and the media is between about 0.001 and about 0.125 mm in size; and
e. applying the slurry mixture at an impaction angle to the targeted surface through the at least one nozzle at pressure of 30 to 50 pounds per square inch to effectively remove the machine lines blending the targeted surface, wherein the pressure is a combination pressure of both air pressure and slurry pressure, and the impaction angle is selected from the group consisting 45, 60, and 90 degrees.

22. A method of surface finishing an orthopaedic implant comprising:
a. fixturing a machined orthopaedic implant having a targeted surface with machine lines on a platform in a wet blasting cabinet, the wet blasting cabinet having at least three nozzles, the at least three nozzles are each located from about 0.25 inches to about 18 inches away from the targeted surface, and the at least three nozzles each has a bore from about 0.25 inches to about 0.50 inches in diameter, and the at least three nozzles each has a length from about 0.5 inches to about 3 inches;
b. rotating the platform at a speed of about 5 to about 20 revolutions per minute;
c. moving the at least three nozzles and the platform relative to one another in a linear motion at a speed of 10 to 60 inches per minute;
d. heating a slurry mixture in a range from about 70 to about 80 degrees Fahrenheit, the slurry mixture is made from water and media, the media has a media concentration of about 5 to about 35 percent, and the media is between about 0.001 and about 0.125 mm in size; and
e. applying the slurry mixture at an impaction angle to the targeted surface through the at least three nozzles at pressure of 30 to 50 pounds per square inch to effectively remove the machine lines blending the targeted surface, wherein the pressure is a combination pressure of both air pressure and slurry pressure, and the impaction angle is selected from the group consisting 45, 60, and 90 degrees.

Assignees

• Smith & Nephew Inc

Inventors

• Geyer Christopher D
• Babb Terry N

Classifications

• B24C1/10

  for compacting surfaces, e.g. shot-peening (for deforming sheet metal, tubes or profiles B21D31/06; as a metallurgical treatment C21D7/00, C22F1/00) · CPC title

• B24C1/08 Primary

  for polishing surfaces, e.g. {smoothing a surface} by making use of liquid-borne abrasives · CPC title

• A61F2002/30906

  shot- sand- or grit-blasted · CPC title

• B24C7/0023

  of feed pressure · CPC title

• A61F2/30767 Primary

  Special external or bone-contacting surface, e.g. coating for improving bone ingrowth · CPC title