Machining method and apparatus for thread formation on workpiece

• US 20080194348A1
• Filed: 04/10/2007
• Published: 08/14/2008
• Est. Priority Date: 10/28/2005
• Status: Active Grant

• Current Assignee: Orchid MPS Holdings, LLC (Orchid Orthopedic Solutions LLC)
• Original Assignee: Sandvik Medical Solutions Oregon, Inc.
• Inventors: Ferrell, Adam
• Granted Patent: US 7,559,846 B2
• Time in Patent Office: Days
• US Class Current: 470/72
• CPC Class Codes: B21H 3/02 external screw-threads ; Making dies for thread rolling
• CPC Class Codes: B21H 3/042 Thread-rolling heads
• CPC Class Codes: Y10T 409/30028 to regulate cutting depth [e.g., relief, taper, etc.]
• CPC Class Codes: Y10T 409/300504 Plural cutters or work holders

Abstract

Machining techniques and machining apparatus are provided for treating workpieces in an efficient and reliable manner. The machining techniques and machining apparatus employ multiple thread whirling heads associated with a single machining assembly, such that each of the thread whirling heads is able to act on a workpiece during a single, uninterrupted machining process. Screw threads may be formed that include first and second thread profiles and an intermediate transition region. The machining apparatus generally includes a processor that is programmed to control operation of the multiple thread whirling heads in a sequential manner.

Claims

1. A machining apparatus, comprising:

(a) at least two thread whirling heads; and

(b) a processor programmed so as to energize the at least two thread whirling heads to contact a workpiece in a sequential manner;

wherein the at least two thread whirling heads are mounted so as to contact the workpiece and form a first thread profile and a second thread profile on said workpiece in a single, uninterrupted machining process.

2. A machining apparatus according to claim 1, wherein the at least two thread whirling heads are positioned within a machining chamber.

3. A machining apparatus according to claim 1, wherein the at least two thread whirling heads are mounted in a side-by-side orientation.

4. A machining apparatus according to claim 1, wherein the processor implements computer numerical control (CNC) with respect to the at least two whirling heads.

5. A machining apparatus according to claim 1, further comprising at least one additional tool selected from the group consisting of a turning tool, a milling tool, a drilling tool, and a deburring tool.

6. A machining apparatus according to claim 1, wherein each of said at least two thread whirling heads includes a plurality of cutting heads.

7. A method for machining a workpiece, comprising:

(a) providing a workpiece of metal stock;

(b) feeding the workpiece into a machining apparatus that includes (i) at least two thread whirling heads and a processor programmed so as to energize the at least two thread whirling heads to contact the workpiece in a sequential manner;

(c) machining the workpiece with each of the at least two thread whirling heads in a single, uninterrupted machining process.

8. A method according to claim 7, wherein the machining apparatus is a computer numerical control (CNC) unit.

9. A method according to claim 7, wherein the workpiece is machined so as to define a first thread profile and a second thread profile on the workpiece.

10. A method according to claim 9, wherein the first thread profile is formed by a first thread whirling head and the second thread profile is formed by a second thread whirling head.

11. A method according to claim 9, further comprising forming a transition region between the first thread profile and the second thread profile.

12. A method according to claim 11, wherein the first thread profile is formed by a first thread whirling head and wherein the second thread profile and a majority of the transition region are formed by a second thread whirling head.

13. A method according to claim 7, wherein the workpiece is machined to define a screw thread transition selected from the group consisting of:

(i) a transition from a first single lead form to a second single lead form;

(ii) a transition from a first double lead form to a second double lead form;

(iii) a transition from a single lead form to a triple lead form, and combinations thereof.

14. A method according to claim 7, further comprising performing at least one additional processing step with respect to the workpiece.

15. A method according to claim 14, wherein the at least one additional processing step is selected from the group consisting of turning, milling, drilling and deburring.

16. A method according to claim 7, wherein the at least two thread whirling heads are mounted in a side-by-side orientation within the machining apparatus.

17. An orthopedic screw fabricated according to the method of claim 7.

18. An orthopedic screw according to claim 17, said orthopedic screw including a first thread profile, a second profile and a transition region between the first and second thread profiles.