METHOD AND APPARATUS FOR EMBEDDING ABRASIVE PARTICLES INTO SUBSTRATES

1 . A dressing bar assembly for embedding abrasive particles into a surface of a substrate, the dressing bar assembly comprising:

a support structure;

a gimbal assembly connecting a dressing bar to the support structure, the gimbal assembly permitting displacement of the dressing bar in at least pitch and roll;

a preload mechanism for biasing an active surface on the dressing bar toward the substrate; and

at least one fluid bearings for generating a lift between the active surface of the dressing bar and the substrate while the active surface applies a downward force sufficient to embed the abrasive particles into the surface.

2 . The dressing bar assembly of claim 1 wherein the fluid bearing is a hydrodynamic bearing.

3 . The dressing bar assembly of claim 1 wherein the fluid bearing is a hydrostatic bearing.

4 . The dressing bar assembly of claim 3 wherein the dressing bar has at least one port therein, the port for delivering a fluid to the active surface of the dressing bar, the fluid used in forming a hydrostatic fluid bearing.

5 . The dressing bar assembly of claim 4 further comprising a fluid conduit in fluid communication with the port, the fluid conduit delivering a fluid to the at least one port on the dressing bar.

6 . The dressing bar assembly of claim 5 further comprising a plurality of actuators located at an interface between a hydrostatic bearing mechanism that includes the fluid conduit and the dressing bar.

7 . The dressing bar assembly of claim 1 further comprising at least one actuator positioned between the dressing bar and the support structure.

8 . A dressing bar comprising:

at least one active surface on the dressing bar;

at least one pressure generating surface located generally along a leading edge of the dressing bar; and

at least one pressure generating surface located generally along a trailing edge of the dressing bar.

9 . A dressing bar of claim 8 comprising:

a plurality of discrete active surfaces on the pressure generating surface on the dressing bar;

a plurality of pressure ports located generally along a leading edge of the dressing bar; and

a plurality of pressure ports located generally along a trailing edge of the dressing bar.

10 . The dressing bar of claim 8 comprising:

a plurality of discrete active surfaces on the dressing bar; and

a plurality of pressure ports substantially surrounding at least one of the plurality of active surfaces.

11 . The dressing bar of claim 8 wherein the active surface comprises a surface area greater than a cross-sectional area of the dressing bar measured parallel to the surface of a substrate over which the dressing bar is adapted to pass.

12 . The dressing bar of claim 6 wherein the at least one active surface comprises a taper at a leading edge configured to progressively embed the abrasive particles into the substrate.

13 . The dressing bar of claim 6 wherein the at least one active surface further comprises a substantially circular structure having a plurality of grooves therein: and

a taper located around a perimeter of the substantially circular structure.

14 . The dressing bar of claim 6 further comprising a plurality of spacer pads, the spacer pads attached to the active surface and having a height generally corresponding to a selected height of an embedded abrasive particle above a surface of a substrate.

15 . An abrasive article comprising:

a substantially flat substrate;

particles embedded into at the substantially flat substrate at a substantially uniform distance above the substrate, the substantially uniform distance varying in a range of 1 to 5 percent of nominal protruding height of the particles.

16 . The abrasive article of claim 15 contains concentrically and circumferentially spaced rings of embedded particles.

17 . The abrasive article of claim 15 wherein the substrate further comprises a soft layer of plastically deformable material for accepting the abrasive particles.

18 . A dressing bar assembly for embedding abrasive particles into a substrate to make an abrasive article, the dressing bar assembly comprising:

a support structure; and

a dressing bar supported by the support structure, the dressing bar including a taper at a leading edge.

19 . The dressing bar assembly of claim 18 has a taper angle of less than 10 milli radians.

20 . The dressing bar assembly of claim 18 wherein the dressing bar comprises a generally circular structure and the taper is located around a perimeter edge thereof.

21 . The dressing bar assembly of claim 18 wherein the dressing bar comprises a flat region adjacent to the taper, the flat region including a plurality of grooves therein.

22 . The dressing bar assembly of claim 18 wherein the dressing bar is adapted to force abrasive particles into a substrate as the dressing bar passes over the substrate, the dressing bar assembly further comprising a plurality of spacer pads located on a flat region of the dressing bar, the spacer pads having a selected height corresponding to a selected distance that the abrasive particles extend above the substrate after being embedded into the substrate.

23 . The dressing bar assembly of claim 18 further comprising a plurality of spacer pads located on a flat region of the dressing bar, the spacer pads having a selected height.

24 . The dressing bar assembly of claim 18 comprising a gimbal assembly connecting a dressing bar to the support structure, the gimbal assembly applying a preload to the dressing bar.

25 . The dressing bar assembly of claim 18 comprising a hydrostatic bearing assembly including a plurality of ports fluidly coupled to a source of compress air, the ports oriented toward the substrate to maintain a hydrostatic fluid bearing between the dressing bar assembly and the substrate.