EP2097218A2

EP2097218A2 - Abrasive configuration for fluid dynamic removal of abraded material and the like

Info

Publication number: EP2097218A2
Application number: EP07867765A
Authority: EP
Inventors: Stephen J. Benner
Original assignee: TBW Industries Inc
Current assignee: TBW Industries Inc
Priority date: 2006-12-15
Filing date: 2007-12-14
Publication date: 2009-09-09
Also published as: WO2008076366A2; EP2097218A4; CA2671055A1; WO2008076366A3; US20080160883A1; CN101568406A

Abstract

An abrasive tool utilized to remove material from a workpiece is formed to comprise fluid-dynamically-designed features (apertures, airfoils) configured to efficiently remove abraded material and waste from the surface of the workpiece. An abrasive component (and/or backing plate) is formed to include fluid-dynamically- designed features that create an air flow stream/pressure differential which draws the created debris (variously referred to as 'swarf', meaning in general any material removed by an abrading tool) away from the grinding surface.

Description

ABRASIVE CONFIGURATION FOR FLUID DYNAMIC REMOVAL OF ABRADED MATERIAL AND THE LIKE

Cross-Reference to Related Applications

This application claims the benefit of US Provisional Application No. 60/875,094, filed December 15, 2006.

Technical Field The present invention relates to an abrasive utilized to remove material from a workpiece and, more particularly, to an abrasive including fluid-dynamically-designed features to efficiently use the mechanical energy of the equipment to remove (or direct) abraded material, heat, coolants and waste from the surface of the workpiece.

Background of the Invention

When performing any type of grinding or polishing operation, a large amount of abraded material is generally created and needs to be captured and removed from the work area. Abrasive grinders of the prior art generally comprise a portable body that is adapted to be held by a user, the grinder including a motor that drives a backing plate which in turn carries an abrasive component for grinding the surface of a workpiece. The abrasive component may take the form of a disk, belt, drum, wheel or any other configuration suitable for a given grinding/polishing operation.

In a "vacuum" type grinder, a shroud in the vicinity of the backing plate and abrasive component defines a chamber through which air and entrained particles flow to an outlet leading to an accumulation point. The abrasive and backing plate are provided with holes that, when aligned, form an air passage to allow the flow of air and entrained particles which are drawn by suction applied to the shroud.

One problem with these vacuum-based prior art systems is the large abrasive area in relation to the small, peripheral vacuum area, and indirect path flows, which result in an increase in the temperature of the workpiece and the instability of the process. The generation of heat is particularly problematic in chemical-mechanical planarization (CMP) abrasive disks, where the chemistry at the workpiece surface will be affected by local temperature changes. Abrasive tools having a large abrasive area coupled with a high concentration of fine abrasives also typically become loaded with workpiece debris or swarf, limiting the speed of the abrading process, smearing debris on the workpiece, and creating additional 'workpiece heating'.

Additionally, the vacuum effectiveness cannot be reliably controlled since the vacuum must be sufficient over the surface area of the entire abrasive so as to entrain swarf created at any point on the abrasive (e.g., if grinding on a bevel, only the cross- sectional area being cut is in contact with the abrasive).

Conventional porous abrasive tools, having pores positioned throughout the entirety of the abrasive structure, are well-known in the art. Conventional porous metal composite grinding wheels are commonly formed by sintering a loosely-packed metal composite, or by adding hollow glass and ceramic spheres to the composite. However, it has been found to be difficult to control the size and shape of the porosity in such abrasives and, if hollow spheres are used, it is difficult to prevent crushing the spheres during manufacture or use. While these porous abrasive tools are capable of trapping removed debris, they do not have any type of channel or pathway for clearing the debris from the tool itself. Therefore, additional mechanisms are required to move the abraded material away from the interface between the workpiece and the abrasive or the same clogging, smearing and overheating can occur.

The removal and containment of debris from various types of grinding/polishing operations may also raise various health and/or environmental issues. For example, the removal of asbestos, paint, silica, fiber composites and the like needs to be carefully controlled in a manner that minimizes the creation of any airborne contaminants that may be inhaled, released into the environment or become re-incorporated into the workpiece.

Accordingly, there is a need for an abrasive configuration that efficiently moves materials (i.e., coolant, air) to, and removes materials (i.e., heat, swarf) from, a workpiece during an abrading process.

Summary of the Invention

The needs remaining in the prior art are addressed by the present invention, which relates to an abrasive utilized to remove material from a workpiece and, more particularly, to an abrasive including fluid-dynamically-designed features that are configured to efficiently remove abraded material and waste from the surface of the workpiece. The direction of flow through the features may also be reversed in accordance with the present invention (i.e., toward the workpiece) to provide the introduction of cleaning fluids, coolants, process chemicals and the like.

In accordance with the present invention, an abrasive component (and/or backing plate) is formed to include fluid-dynamically-designed features which create an air flow stream/pressure differential that draws surface materials (including coolants or other process consumables) and the created debris (variously referred to as "swarf, meaning in general any material removed by an abrading tool) away from the grinding surface. Various other features formed within the abrasive may be specifically designed to introduce materials onto the workpiece surface. The abrasive component itself may take the form of a disk, belt, drum, wheel or any other suitable design. The fluid- dynamically-designed features include elements such as apertures, air foils, blower vanes and the like.

It is an advantage of the fluid-dynamic design of the inventive fluid-dynamic abrasive that the created flow properties are used to control environmental properties such as the velocity, pressure, density (including abrasive particle density), chemistry, cleanliness and temperature at the workpiece surface. The included features function individually to remove localized debris, while the entirety functions globally to manage the environmental conditions across the workpiece and abrasive tool surface. By removing the by-products of the abrasive process (mechanical, chemical, heat, etc.) before they can interact with the workpiece (or the abrasive), the chance of workpiece contamination (or abrasive clogging/blockage) is significantly reduced. Also as mentioned above, a conventional grinding process creates heat at the workpiece area. The ability to lower the temperature via the inventive fluid-dynamic abrasive prevents overheating of the material. The apertures and associated pressure differential associated with the fluid- dynamic abrasive also allow for a more uniform flow over the contact area and localized control of the workpiece/abrasive interface (balancing waste entrainment and abrasive contact area). The use of a large number of apertures allows the abrasive to function in the manner of a serrated cutting tool, creating swarf of minimal chip size, while maximizing 'cutting tool' clearance. In particular, the aperture dimensions and configuration are designed to result in a predictable flow pattern at a finite granularity/resolution in conjunction with macroscopic or collected vortices to: move debris from the surface in a preferred direction (e.g., flow from the edge of a disk/drum/wheel to the center, from the center to the edge, a radial flow around a disk, a lifting flow above an abrasive belt, etc.). A backing plate may be configured to include a plurality of containment channels to balance exhaust and/or coolant flow from the center of an abrasive element to its outer periphery.

Advantageously, the unique configuration of the subject abrasive components, which incorporates various principles of fluid dynamics, has provided the following features: the overall process is "cleaner" than prior art arrangements since the constant movement (rotational or translational) of the abrasive itself creates the 'pull' to remove the debris from the surface without allowing re-entry or "clogging" of the work area or abrasive surface; the overall process is "cooler" since the same increased air flow also functions to remove heat as it is created; the overall process is "uniform" in terms of providing the same abrading function and balanced cooling across the entire face of the workpiece (regardless of the degree of contact between the workpiece and the abrasive) in a manner such that the waste or by-products are not permitted to interact with, damage or taint the freshly-exposed surfaces; the overall process is more economical than prior art systems requiring utilization and maintenance of a separate vacuum source; and the overall process provides a higher quality result, since any potential contaminants are immediately and continuously removed from the work area, significantly reducing any potential environmental, health or workproduct contamination concerns.

Other and further advantages and features of the present invention will become apparent during the course of the following discussion and by reference to the accompanying drawings.

Brief Description of the Drawings Referring now to the drawings,

FIG. 1 illustrates a prior art tool including an abrasive disk and vacuum system for removing debris from the work area;

FIG. 2 is a side view of a prior art conditioning head for a chemical mechanical planarization (CMP) system, illustrating the apertured abrasive disk included within the conditioning head;

FIG. 3 is an exploded view of a portion of the arrangement in FIG. 2, illustrating in particular the impeller and apertured abrasive disk components of the conditioning head; FIG. 4 is a top view of one exemplary fluid-dynamically-designed abrasive disk formed in accordance with the present invention;

FIG. 5 illustrates an alternative embodiment of the present invention where the geometry of the apertures within the abrasive disk are themselves configured to provide the fluid dynamic improvements in debris removal;

FIG. 6 shows yet another embodiment of the present invention, where the disk apertures are tilted to create the desired pressure differential and directional force component;

FIG. 7 illustrates another fluid-dynamic-based abrasive disk design of the present invention;

FIG. 8 contains an illustration of yet another fluid-dynamic-based abrasive disk configuration formed in accordance with the present invention;

FIG. 9 contains an isometric perspective view of an exemplary fluid- dynamically-designed impeller (backing plate) for use with an abrasive disk in accordance with the present invention;

FIG. 10 illustrates an alternative fluid-dynamically-designed impeller configuration;

FIG. 1 1 illustrates an exemplary fluid-dynamically-designed abrasive belt formed in accordance with the present invention; FIG. 12 illustrates an exemplary fluid-dynamically-designed abrasive drum formed in accordance with the present invention; and

FIG. 13 illustrates an exemplary fluid-dynamically-designed abrasive wheel formed in accordance with the present invention.

Detailed Description

The fluid-dynamic based abrasive component of the present invention is intended to find use in a variety of applications, where any specific application mentioned in the following discussion is intended to merely provide a full illustration of the various features of the inventive abrasive component. Indeed, abrasives are used in grinding/polishing many different surfaces (metals, glass, ceramic and the like) in a variety of heavy-duty industrial and/or commercial applications. In industrial applications, abrasives are typically driven at speeds in the range of 1750 — 3200 rpm. The generated swarf will follow the path of abrasive grit impact. Other applications may utilize a higher speed abrasive or a lower speed abrasive. For example, a lower speed abrasive is typically used in semiconductor industry applications when polishing/treating the surface of semiconductor wafers and in particular conditioning the polishing pads used to perform the polishing operations. Regardless of the application, the configuration of the subject abrasive is not considered to be dependent upon its field of use. Rather, the fluid dynamic properties of the abrasive are designed specifically for the operating speeds, fluid properties (viscosity, volume, containment, lift, flow direction, pressures, etc.) and the like.

Prior to describing the details of the inventive abrasive, an overview of a conventional prior art abrasive disk will be described in order to provide a sufficient knowledge base for gaining the best understanding of the features of the present invention.

FIG. 1 is a cut-away side view of an exemplary prior art sanding head 1 that requires the use of a separate, stand-along vacuum system (not shown) for removing debris from the surface of the workpiece being sanded. Sanding head 1 includes a shaft 2 rotatably mounted in a casing 3 and mechanically connectible to a drive motor of an electric drill (not shown). Shaft 2 is also connected at one end to a backing plate 4. Backing plate 4 has in its center, as is known, a hollow cylindrical element 5 which is closed at its lower end by an end wall 6. An abrasive disk 7 is attached to shaft 2 in a ^' manner that allows abrasive disk 7 to rotate and perform the sanding operation. The application of a vacuum to a vacuum port 8 then allows for the sanding debris to be drawn up around the periphery of abrasive disk 7, through an inner chamber 9 of sanding head 1 , then through vacuum port 8 and into a collection unit (not shown). In particular, the debris generated by abrasive disk 7 is projected by centrifugal force towards the periphery of disk 7. As shown by the arrows in FIG. 1, the vacuumed debris along the periphery is then drawn upward into inner chamber 9 and through port 8 to the separate vacuum system.

One problem with this arrangement, however, is that the removal of debris relies on the separate vacuum system capturing all of the material that has moved to the periphery of the disk. Clearly, some of the debris will always remain in a central portion of the abrasive disk. Also, as mentioned above, this approach is also problematic in situations where less than full face abrasive contact is maintained (i.e., edge grinding) and the vacuum flow is formed only at the periphery of the disk. While the prior art arrangement of FlG. 1 shows a conventional sanding head as used for many diverse applications, there are also specialized applications as mentioned above that require the use of an abrasive for operations such as fine polishing of glass, planarizing of semiconductor wafers and, even more particularly, re-conditioning the polishing pad surface of the material used to planarize semiconductor wafers. As is well- known in the art, chemical mechanical planarization (CMP) systems use an abrasive disk to remove collected debris and planarizing fluids from the surface of a polishing pad (referred to as a "conditioning" process). FIG. 2 is a cut-away side view of an exemplary prior art CMP conditioning head 20, and FIG. 3 contains an exploded view of certain of the pertinent elements within conditioning head 20. US Patent 6,508,697, issued on January 21 , 2003 to the assignee of this application contains a complete description of such a conditioning arrangement and is herein incorporated by reference.

For the purposes of understanding the benefits of the fluid-dynamic abrasive of the present invention, the aspects of conditioning head 20 related to its abrasive disk will be briefly described. Referring to both FIGs. 2 and 3, prior art conditioning head 20 comprises an outer housing 22 including an inlet port 24 for dispensing conditioning/cleaning agents onto a polishing pad 26 and a vacuum outlet port 28. An abrasive conditioning disk 30 is disposed at the bottom of conditioning head 20 and functions to rotate against the surface of polishing pad 26, sufficiently abrading the surface to remove any embedded particulates. As fully described in the above- referenced patent, abrasive conditioning disk 30 includes a plurality of apertures 32 formed across the entire surface. The exploded view of FIG. 3 best illustrates the placement and size of apertures 32. In this particular embodiment, an impeller 34 is disposed between abrasive disk 30 and outer housing 22, where impeller 34 is used to provide the rotational motion to abrasive disk 30.

The application of a vacuum force through port 28, as shown by the arrows in FIG. 2, allows for the dislodged debris and other effluent materials to be pulled off of polishing pad 26, through apertures 32 of abrasive disk 30 and along blades 36 of impeller 34 into vacuum port 28. Impeller blades 36 function to sectionalize the vacuum. This improves the localized pressure and corresponding removal of the effluent and, in some embodiments, may also include apertures for either dispensing conditioning materials or evacuating debris (or both). While the use of an apertured abrasive disk has been successful in improving the removal of effluent from the pad's surface, improvements in flow efficiency, containment, and partial-contact cleaning ability (i.e., just beyond the edge of the pad 12 where the vacuum force will be broken) are desirable.

By incorporating fluid dynamic considerations into the configuration of an apertured abrasive component (e.g., disk, belt, drum, wheel or the like), the various embodiments of the present invention, as described below, will create an extremely localized pressure differential (i.e., a pressure differential in the region of the aperture, also referred to variously as a "venturi") that assists or replaces the vacuum removal operation, balance flow across the radial direction and direct flow toward the periphery, thereby improving the performance of the abrasive. Indeed, the fluid-dynamic design is useful in any abrasive application, from industrial heavy-duty abrasive tasks to the highly-specialized pad conditioning of polishing pads in the semiconductor industry.

FIG. 4 is a top view of one exemplary fluid-dynamicaliy-designed abrasive disk 100 formed in accordance with the present invention. Similar to prior art abrasive disk 20 described above, fluid-dynamic abrasive disk 100 includes a plurality of apertures 1 10 formed therethrough to allow for the abrading debris to be drawn away from the workpiece surface (not shown). In accordance with the fluid dynamic principles of the present invention, a plurality of blower vanes 120 are disposed around the outer periphery of disk 100, as shown in FIG. 4. Between each pair of adjacent blower vanes, a vacuum outlet channel 130 is formed. Accordingly, when abrasive disk 100 is rotated (illustrated by the arrows labeled "R" in FIG. 4) the presence of blower vanes 120 creates a pressure differential across the surface of abrasive disk 100. That is, the pressure in the central area of disk 100 is greater than the pressure around the periphery of disk 100, forcing the evacuated debris into vacuum outlet channels 130. In this particular embodiment, the configuration of apertures 1 10 remains similar to those of prior art designs. More generally, it is conceivable that such a fluid dynamic abrasive disk of this embodiment of the present invention may utilize fewer apertures (or apertures of varying size - smaller toward the center to balance flow and abrasive particle engagement as a function of revolution), relying on the pressure differential created by blower vanes 120 to move the debris from the workpiece surface into channels 130. It is to be understood that a variety of different factors are involved in determining the pressure differential created by the fluid-dynamic abrasive of the present invention. Some of the factors include, but are not limited to, the rotational/translational speed of the abrasive, the size, shape, and number of blower vanes/airfoils, the distribution of blower vanes/airfoils on the abrasive, the size and number of outlet channels, and the like. Any or all of these factors (and others) may be considered when implementing the inventive fluid-dynamic abrasive for a particular purpose. Further, the abrasive of the present invention may be formed to include only a surface layer of abrasive material or a distributed volume of abrasive throughout a cast or sintered abrasive material. In these arrangements using only a surface abrasive layer, the fluid- dynamic-based attributes are formed as part of the 'substrate' or backing plate upon which the abrasive layer is affixed.

As shown in FIG. 4 and more particularly described in association with the remaining figures, the fluid-dynamic-based abrasive of the present invention functions to increase the amount of waste material removed from the workpiece surface, and provides the additional benefit of also removing heat from the work area. By specifically incorporating fluid dynamic principles into the configuration of the apertured abrasive, various types of directed flow may be created. That is, the abrasive apertures may be configured to direct the flow upward away from the work area (lift), between the abrasive and workpiece (flush), or from the center to edge of the disk/drum/wheel, or vice versa (radial). The apertures may also be configured to improve the evacuation of abraded material from the center portion of the abrasive, relative to prior art arrangements, thus improving the cleanliness of the abraded workpiece surface, as well as the abrasive itself and aiding in the collection/containment from otherwise uncontrolled waste dispersion.

FIG. 5 illustrates an alternative disk embodiment of the present invention where the geometry of the apertures within the abrasive disk is specifically configured to provide the improvements in debris removal. In the cut-away side view of FIG. 5, an exemplary fluid-dynamic abrasive disk 200 is shown as including a plurality of apertures 210. In accordance with this embodiment of the present invention each aperture 210 tapers outwardly from a first diameter Dl along bottom surface 230 of abrasive disk 200 to a second, larger diameter D2 along top surface 240 of abrasive disk 200. In accordance with the present invention, the tapered apertures (increasing from Dl to D2) create an inverse pressure gradient as disk 200 is rotated (again, the magnitude of the gradient being a function of factors such as taper design, disk rotation speed, etc.). This pressure gradient, illustrated by the references +P and -P in FIG. 5, is created locally at each aperture 210, thus providing instantaneous and offsetting forces for particle entrainment. The various, localized venturi will force the removed debris from the central portion of the workpiece being abraded (not shown) upward, through and outward toward the periphery of the abrasive disk and thereafter into the waste stream. By utilizing the inventive fluid-dynamically-configured apertures, the process of removing debris is significantly accelerated when compared to standard prior art structures; indeed, the aggregate airflow can be sufficient to eliminate the need for an external vacuum source. Since the pressure differential is localized, the removal forces and effectiveness are not affected by the workpiece size or abrasive contact area. For example, in the field of CMP pad conditioning, the use of the localized venturi complement separately applied flows and will allow for a sufficient vacuum to be maintained as the abrasive moves outward over the edge of the polishing pad (a situation which, in the past, would cause the applied vacuum force to "break" and allow the debris to remain in the peripheral region of the pad). By localizing the pressure differential at the point where abrasion is occurring and containing it within a backing plate, the swarf can therefore be directed in a more predictable manner. The localized aspect of the created flow is also useful from a mechanical point of view, in terms of allowing for localized introduction of coolants, removal of heat, and the ability to control the stream direction for both introduced and removed elements.

Instead of creating apertures of tapered geometry, the plurality of apertures themselves may be tilted to create a similar pressure differential, as shown in the embodiment of FIG. 6. In this case, a fluid-dynamically-configured abrasive disk 300 includes a plurality of apertures 310. Each aperture 310 has essentially the same diameter D, as illustrated along bottom surface 320 and top surface 330 of abrasive disk 300. However, the apertures are shown as tilted to a predetermined angle θ, where the angled arrangement will create the desired pressure differential or impart a predetermined directional force vector at a predetermined radial position.

The scope of the present invention is intended to cover any fluid-dynamically configured arrangement of features within an abrasive component. FIGs. 7 and 8 illustrate two more exemplary arrangements, also shown in the form of an abrasive disk. FlG. 7 illustrates a fluid-dynamic abrasive disk 400 where each aperture 410 is formed to comprise a first diameter dl through a certain predetermined thickness of disk 400, and thereafter taper outward, as shown by opening 420, to a final diameter d2. The resultant structure exhibits a funnel-like configuration. Again, the difference in diameter from dl to d2 will provide the pressure differential sufficient to force the debris upward and away from the workpiece surface (venturi action). The apertures need not comprise linear sidewalls, as shown by the embodiment of FIG. 8, where a fluid-dynamic abrasive disk 500 includes apertures 510 having a curved or 'airfoil' -shaped sidewall(s) 520. As described above, the rotation of abrasive disk 500 will draw the material from the workpiece surface and into a collection system (not shown).

In arrangements that utilize an impeller (or backing plate) in conjunction with an abrasive disk, the impeller blades themselves may be configured to improve the flow of debris from the workpiece surface to the waste system. It is possible to design both the abrasive disk and impeller to exhibit fluid dynamic attributes or, alternatively, so design one or the other component. Indeed, by incorporating fluid-dynamic features into the impeller design, additional advantages may be obtained. For example, the movement of air will function to cool the surface of the workpiece being abraded (thus preventing overheating). Moreover, the application of cleaning materials (in conjunction with the abrading process) will be considerably more uniform across the workpiece surface by virtue of the specific impeller configuration. Additionally, the impeller can be designed to contain the removed waste material or alternatively pump 'coolant' back into the workpiece for additional process benefits.

FIG. 9 contains an isometric perspective view of an exemplary fluid-dynamic impeller 600 formed to include a plurality of impeller blades 610. In accordance with the present invention, each blade 610 is specifically designed to exhibit an airfoil-like structure (i.e., curvedly tapering inward from the outer periphery 620 of impeller plate 630 toward the central region 640 of impeller plate 630). The curvature of blades 610 in the manner shown will improve the pressure balance and flow of debris from a workpiece surface toward an associated outlet port. An alternative impeller configuration is shown in FIG. 10, where a two-dimensional modification of the blade profile (compared to the prior art blade shown in FIG. 3) will provide fluid-dynamically- based improvement in the movement of debris material from the workpiece surface. In this arrangement, an impeller 700 comprises a set of impeller blades 710 disposed in a type of "pinwheel" configuration such that as the impeller is rotated, the created pressure differential will force the debris to the periphery of the system.

While the embodiments of the present invention discussed thus far have illustrated the formation of a fluid-dynamic abrasive disk, it is to be understood that the abrasive may also take the form of a belt, drum, wheel, or any other abrasive configuration suitable for a specific purpose. FIG. 1 1 illustrates an exemplary fluid- dynamically-designed abrasive belt grinder 800, including a belt 810 that moves in a linear direction with respect to the workpiece being abraded, this translational movement indicated by arrow L in FIG. 1 1. A plurality of apertures 820 are formed in belt 810 that create a pressure differential between bottom surface 830 and top surface 840 of belt 810, directing the swarf upward and away from a workpiece (a lifting force). Thereafter, the swarf is drawn through apertures 845 in a vacuum plenum 850 and ultimately directed into a containment vessel (not shown). Importantly, the fluid-dynamically- designed arrangement of FIG. 1 1 will draw substantially all of the swarf/debris from the workpiece. As mentioned above, there are many situations where the workpiece being abraded includes a hazardous material that will be introduced into the exhaust flow. The ability to provide an efficient and complete containment of this material in accordance with the fluid dynamic aspects of the inventive abrasive greatly diminishes the potential for contamination of the environment, inhalation by a worker, and/or re-incorporation of the material into the workpiece.

FIG. 12 illustrates an exemplary abrasive drum embodiment of the present invention. As shown, a drum 900 is formed to include at least an outer surface 910 of abrasive material (alternatively, the abrasive grit may be disposed through the thickness / of the drum), with a plurality of apertures 920 formed therethrough. The number and configuration of the apertures is considered to be a matter of design choice. In accordance with the present invention, a plurality of airfoils 930 are disposed on an inner surface 940 in the manner shown in FIG. 12. As drum 900 rotates (shown by arrow r in FIG. 12), the presence of the airfoils will pull any swarf created by the abrading process through apertures 920 and toward the center 950 of drum 900. A central vacuum attachment (not shown) may then be used to remove the entrained swarf.

Yet another embodiment of the present invention is shown in FIG. 13, in this case in the form of an abrasive wheel 1000, having an abrasive outer surface 1 100. Abrasive wheel 1000 is shown as having a thickness T , with a plurality of apertures 1200 formed through the thickness thereof. A plurality of airfoils 1300 are disposed around the inner periphery 1400 of wheel 1000. As wheel 1000 rotates, the combination of apertures 1200 and airfoils 1300 will draw the swarf towards the center of wheel 1000. In this particular embodiment, a containment shroud 1500 is included and disposed around the central portion of wheel 1000 to collect the swarf. Having thus described various embodiments of the present invention, it is to be appreciated that there are many other variations, alterations, modifications and improvements of the specifically-described embodiments that may be made by those skilled in the art. Such variations, alterations, modifications and improvements are intended to be part of this disclosure and thus also intended to be part of this invention. Accordingly, the foregoing description and drawings are by way of the example only, and the scope of this invention is rather defined by the claims appended hereto.

Claims

What is claimed is:

1. An abrasive tool incorporating fluid-dynamically-designed features to improve removal of waste material from a workpiece, the abrasive tool comprising: a substrate having a working surface and a backing surface, wherein at least the working surface has a coating of an abrasive composition; and a plurality of features formed on or through the substrate, wherein the plurality of features are configured to create a pressure differential between the working surface and the backing surface of the substrate during the abrading process.

2. An abrasive tool as defined in claim 1 wherein the substrate comprises a circular disk and the plurality of features comprises a plurality of blower vanes attached to the substrate working surface and disposed downwardly therefrom, the plurality of blower vanes for channeling waste material directed to the periphery of the circular disk substrate as the abrasive tool is rotated.

3. An abrasive tool as defined in claim 1 wherein the plurality of features comprise a plurality of apertures formed through the thickness of the substrate.

4. An abrasive tool as defined in claim 3 wherein at least some of the plurality of apertures are formed to comprise a working surface diameter, which is less than an associated backing surface diameter, creating a pressure differential upon use of the abrasive tool.

5. An abrasive tool as defined in claim 4 wherein a sidewall of the least some of the plurality of apertures is formed to include a curved surface.

6. An abrasive tool as defined in claim 3 where at least one of the plurality of apertures is tilted with respect to the thickness of the substrate, the tilted apertures creating a pressure differential when the abrasive tool is used.

7. An abrasive tool as defined in claim 1 wherein the substrate comprises a linear belt.

8. An abrasive tool as defined in claim 1 wherein the substrate comprises a drum component.

9. An abrasive tool as defined in claim 8 wherein the substrate includes a plurality of apertures formed therethrough and a plurality of airfoils disposed on an inner perimeter thereof to create the desired pressure differential upon rotation of the drum.

10. An abrasive tool as defined in claim 1 wherein the substrate comprises a wheel component.

11. An abrasive tool as defined in claim 10 wherein the substrate includes a plurality of apertures formed therethrough and a plurality of airfoils disposed on an inner perimeter thereof to create the desired pressure differential upon rotation of the wheel.

12. An abrasive system including an abrasive component having a working surface and a backing surface, at least the working surface having a coating of an abrasive composition; a plurality of apertures formed through the thickness of the abrasive component; and an impeller coupled to the abrasive component for imparting motion to the abrasive component, the impeller including a plurality of spaced-apart impeller blades coupled to the backing surface of the abrasive component, wherein the plurality of apertures and/or the plurality of spaced-apart impeller blades are configured to create a pressure differential between the working surface and the backing surface of the abrasive component upon movement of said abrasive disk.

13. An abrasive system as defined in claim 12 wherein the impeller blades are configured to exhibit an airfoil geometry for creating the pressure differential between the abrasive component working and backing surfaces upon movement.

14. An abrasive system as defined in claim 12 wherein the impeller blades are configured to exhibit an airfoil geometry for removing heat from the abrasive component during use.

15. An abrasive system as defined in claim 12 wherein the impeller blades are configured to exhibit a pinwheel-like structure for creating the pressure differential between the abrasive component working and backing surfaces upon movement.

16. An abrasive system as defined in claim 12 wherein the impeller blades are configured to exhibit a pinwheel-like structure for removing heat from the abrasive component during use.

17. An abrasive system as defined in claim 12 where at least one of the plurality of apertures is formed to comprise a working surface diameter less than an associated backing surface diameter, creating a pressure differential upon movement of the abrasive disk.

18. An abrasive system as defined in claim 12 wherein a sidewall of at least one of the plurality of apertures is formed to include at least one curved surface.

19. An abrasive system as defined in claim 12 where at least some of the plurality of apertures are tilted with respect to the thickness of the abrasive component, the tilt creating a pressure differential when said abrasive component is moved.

20. An abrasive tool incorporating fluid-dynamically-designed features to contain waste material from a workpiece, the abrasive tool comprising: a substrate having a working surface and a backing surface, wherein at least the working surface has a coating of an abrasive composition; a plurality of features formed on or through the substrate, wherein the plurality of features are configured to create a pressure differential between the working surface and the backing surface of the substrate during the abrading process so as to draw waste material away from the workpiece; and a containment channel coupled to the substrate to contain the removed waste material in a isolated manner such that re-entry of the waste material onto the workpiece is prevented.