METHOD AND APPARATUS FOR RECIPROCAL POLISHING

1 . A polishing apparatus for polishing work pieces, the polishing apparatus comprising:

a reciprocal motion generator;

a polishing pad located on the reciprocal motion generator, the polishing pad having a plurality of discrete fluid channels;

an abrasive article located on the polishing pad; and

a controller fluidly coupled to the discrete fluid channels and programmed to selectively alter a fluid pressure in one or more of the discrete fluid channels to selectively deform the abrasive article to preferentially remove material from the work piece.

2 . The polishing apparatus of claim 1 wherein the fluid channels are configured in one of linear, curvilinear, or concentric pattern.

3 . The polishing apparatus of claim 1 further comprising sensors adapted to monitor material removal from the work piece.

4 . The polishing apparatus of claim 3 further comprising a closed-loop control system for polishing the work piece.

5 . The polishing apparatus of claim 1 further comprising a gimbal assembly connecting the work piece bar to a support structure, the gimbal assembly applying a preload that biases the work piece toward the abrasive article.

6 . The polishing assembly of claim 5 further comprising one or more actuators configured to alter the pitch and roll of the work piece relative to the abrasive article.

7 . The polishing apparatus of claim 1 further comprising a hydrostatic bearing assembly including a plurality of ports fluidly coupled to a source of compress air, the ports oriented toward the abrasive article to maintain a hydrostatic air bearing between the work piece and the abrasive article.

8 . The polishing apparatus of claim 1 wherein the abrasive article is one of flexible, rigid or semi-rigid.

9 . The polishing apparatus of claim 1 wherein the fluid channels are configured to create a crown or camber on the work piece.

10 . A method of polishing a work piece comprising the steps of:

locating a polishing pad on a reciprocal motion generator, the polishing pad including a plurality of discrete fluid channels;

locating an abrasive article on the polishing pad;

reciprocally energizing the abrasive article relative to the work piece; and

selectively altering a fluid pressure in one or more of the discrete fluid channels to selectively deform the abrasive article to preferentially remove material from the work piece.

11 . The method of claim 10 further comprising configuring the fluid channels in one of a linear, a curvilinear, or a concentric pattern.

12 . The method of claim 10 further comprising:

monitoring sensors adapted to measure material removal from the work piece; and

altering the fluid pressure in one or more of the discrete fluid channels in response to a signal from the sensors.

13 . The method of claim 12 further comprising controlling fluid pressure in the fluid channels in accordance with a closed-loop control system.

14 . The method of claim 10 further comprising:

supporting the work piece with a gimbal assembly; and

applying a preload to bias the work piece toward the abrasive article.

15 . The method of claim 10 further comprising actuating one or more actuators to alter the pitch and roll of the work piece relative to the abrasive article.

16 . The method of claim 10 further comprising creating a hydrostatic bearing between the work piece and the abrasive article.

17 . The method of claim 10 further comprising the steps of delivering a compressed gas to a plurality of ports on a work piece holder to maintain a hydrostatic air bearing between the work piece and the abrasive article.

18 . The method of claim 10 further comprising altering the pressure in one or more of the fluid channels to create a crown or camber on the work piece.

19 . The method of claim 10 wherein the work piece comprises one of machined metal parts, silicon wafers, slider bars for hard disk drives, lenses, or optical fibers.