Cylindrical lapping

Patent metadata

Field	Value
Publication number	US-9561576-B2
Application number	US-201414185074-A
Country	US
Kind code	B2
Filing date	Feb 20, 2014
Priority date	Jun 7, 2013
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

The described embodiments relate generally to lapping operations and related systems and apparatuses. Various embodiments of lapping tables are described for applying a lapping operation to a non-planar surface of a workpiece. For example, methods and apparatus are described which allow a lapping operation to be applied to a curved outer surface portion of a cylindrical workpiece. Lapping of non-planar outer surfaces of workpieces is conducted by rotating the workpieces during the lapping operations.

First claim

What is claimed is:

1. A method for performing a lapping operation, the method comprising:
providing a lapping table comprising an abrasive disc defining a substantially planar abrasive surface;
during a first rotation, rotating the abrasive disc about a first axis, wherein the first axis extends substantially perpendicular to the substantially planar abrasive surface;
during a second rotation, rotating a workpiece about a second axis, the second axis being non-parallel to the first axis; and
during a third rotation, rotating the workpiece about a third axis offset from and substantially parallel to the first axis, such that a three-dimensional outer surface of the workpiece is in contact with and lapped by the substantially planar abrasive surface of the rotating abrasive disc, wherein the first, second and third rotations are driven independent of each other.

2. The method of claim 1 , wherein the workpiece is a cylindrical workpiece and the second axis extends between a first and second end surface of the cylindrical workpiece.

3. The method of claim 2 , wherein rotating the cylindrical workpiece about the second axis comprises engaging the first and second end surfaces of the cylindrical workpiece.

4. The method of claim 3 , wherein the pressure applicator includes an actuator that is configured to apply a variable amount of pressure between the cylindrical workpiece and the substantially planar abrasive surface of the abrasive disc.

5. The method of claim 3 , wherein a controller is in communication with the pressure applicator to adjust an amount of pressure that is applied to the cylindrical workpiece.

6. The method of claim 2 , wherein the lapping table further comprises a pressure applicator, and the pressure applicator engages the first and second end surfaces of the cylindrical workpiece.

7. The method of claim 1 , wherein the first rotation, the second rotation, and the third rotation are concurrently driven.

8. The method of claim 1 , further comprising pressing the workpiece against the substantially planar abrasive surface of the abrasive disc.

9. The method of claim 1 , wherein the lapping table further comprises at least one conditioning ring that is coupled to the workpiece such that the at least one conditioning ring presses the workpiece against the substantially planar abrasive surface of the abrasive disc during the lapping operation.

10. The method of claim 9 , wherein the lapping table further comprises at least one support member that is coupled to the at least one conditioning ring.

11. The method of claim 10 , wherein the at least one support member comprises an inner engagement mechanism having a roller that is configured to rotate the at least one conditioning ring.

12. The method of claim 1 , wherein the first, second and third rotations are driven independent of each other by a controller.

13. The method of claim 12 , wherein the controller is configured to control at least one finishing parameter during the lapping operation to produce a pre-determined surface finish on the workpiece.

14. The method of claim 13 , wherein the at least one finishing parameter comprises rotational speed, direction, or pressure.

15. The method of claim 1 , wherein a second rotational mechanism causes the second rotation and a third rotational mechanism causes the third rotation.

16. The method of claim 1 , wherein the third axis is offset by a non-zero distance from the first axis.

17. The method of claim 1 , wherein the method is configured to be executed by a non- transitory computer readable medium of a computing device.

18. The method of claim 1 , wherein the abrasive disc is coupled to a first rotational mechanism.

19. The method of claim 1 , wherein the rotation of the workpiece along the third axis is in a direction that is opposite the first axis.

20. The method of claim 1 , wherein the workpiece is characterized as having a substantially even surface finish subsequent to the lapping operation.

Assignees

• Apple Inc

Inventors

• Lancaster-Larocque Simon Regis Louis
• Chan Collin D

Classifications

• B24B5/042

  for grinding several workpieces at once using one grinding wheel · CPC title

• B24B37/005

  Control means for lapping machines or devices · CPC title

• B24B5/047

  of workpieces turning about a vertical axis · CPC title

• B24B37/02 Primary

  designed for working surfaces of revolution · CPC title

• B24B5/045

  with the grinding wheel axis perpendicular to the workpiece axis · CPC title