US20070128994A1

US20070128994A1 - Electroplated abrasive tools, methods, and molds

Info

Publication number: US20070128994A1
Application number: US11/292,938
Authority: US
Inventors: Chien-Min Sung
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-12-02
Filing date: 2005-12-02
Publication date: 2007-06-07
Also published as: WO2007120224A2; WO2007120224A3; TW200800504A; CN101336147A

Abstract

The present invention provides for a mold that can position and hold abrasive particles, which are to be electrolytically attached to an electrically conductive substrate during an electrolytic process. The mold can include an insulating material with a molding surface suitable for holding the abrasive particles in place during this process. Additionally, a method for making an abrasive tool using such a mold is provided, as well as abrasive tools made thereby. In one aspect of this invention, abrasive tools can have abrasive particle tips that are arranged in accordance with a predetermined vertical pattern and/or a predetermined horizontal pattern in a manner that requires little or no post electrodeposition processing.

Description

FIELD OF THE INVENTION

The present invention relates generally to electroplated abrasive tools and methods and molds for making electroplated abrasive tools. Accordingly, the present invention involves the fields of electrochemistry, materials science, and physics.

BACKGROUND OF THE INVENTION

Abrasive tools have long been used in numerous applications, including the cutting, drilling, sawing, grinding, lapping, and polishing of materials. One common form of an abrasive tool is one that uses abrasive particles on a tool substrate to perform the cutting, grinding, polishing, etc.
Superabrasive particles, such as diamond, polycrystalline diamond (PCD), cubic boron nitride (CBN), and polycrystalline cubic boron nitride (PCBN) have been widely used for many materials removal applications due to their extreme hardness, atomic density, and high thermal conductivity. For example, dressing disks, grinding disks, saw blades, wire saws, and drill bits have all included superabrasive particles attached to a substrate.
Despite their apparent advantages, a number of issues continue to hamper the performance and usable life of many known superabrasive tools. For example, superabrasive particle placement and retention remain problematic. One additional issue is the height to which a superabrasive particle extends above the tool substrate. For many applications, it is advantageous to have all particles extend to a substantially uniform height above the tool substrate. In many instances, uniform particle height can help evenly distribute workload on the particles and therefor help improve particle retention. In other cases, it may be advantageous to have the particles extend to varying heights above the tools substrate according to a predetermined vertical pattern.
Many methods have been employed for the fabrication of superabrasive tools, such as brazing, hot pressing, infiltration, and electroplating among others. However, most of such methods are unable to produce a tool with the above-recited superabrasive particle placement characteristics. Further, tools made by most known methods require post fabrication processing in order to obtain a working surface with suitable characteristics, such as proper particle exposure.
As a result, abrasive tools and methods for making abrasive tools which allow accurate horizontal and vertical placement of abrasive particles, and that can achieve a suitable working surface with little or no post fabrication processing continue to be sought.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides abrasive tools having particles arranged according to both vertical and horizontal patterns, and which require little or no post production processing, as well as methods for the manufacture and use thereof. The present invention additionally provides devices for use as a part of such manufacturing processes.
In one aspect, the present invention provides a mold for the positioning and holding of abrasive particles, which are to be electrolytically attached to an electrically conductive substrate during an electrolytic process. The mold may include, or be made of an insulating material that has a molding surface suitable for holding the abrasive particles in place during the electrolytic deposition of a material that attaches the particles to the electrically conductive substrate.
In another aspect, methods are provided for making a tool that has a plurality of abrasive particles coupled to a substrate by an electrodeposited material. The method may include the steps of: 1) temporarily securing the plurality of abrasive particles to a molding surface of a mold, such as the molds described herein, 2) positioning the mold in an electrodeposition chamber with the molding surface oriented toward a substrate to which the abrasive particles are to be electrolytically attached, 3) electrolytically attaching the abrasive particles to the substrate with an electrodeposited material, and 4) removing the mold.
In yet another aspect, the present invention includes abrasive tools that, in some aspects, can be produced by the methods recited herein. Such tools generally include a substrate having a plurality of abrasive particles that are coupled to the substrate by an electrodeposited material. This plurality of abrasive particles can have tips arranged in accordance with a predetermined vertical pattern.
The above-recited features and advantages of the present invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a through 1 h are various views showing a series of steps for making a tool in accordance with an embodiment of this invention;
FIG. 1 a is a bottom view of a mold in accordance with an embodiment of this invention showing a molding surface of the mold;
FIG. 1 b is a sectional view taken along line A-A of FIG. 1 a in accordance with an embodiment of this invention;
FIG. 1 c is the sectional view of FIG. 1 b showing an adhesive coating on a molding surface of the mold in accordance with an embodiment of this invention;
FIG. 1 d is a bottom view of a mold showing placement of abrasive particles on the molding surface in accordance with an embodiment of this invention;
FIG. 1 e is the sectional view of FIG. 1 c showing placement of abrasive particles on the molding surface in accordance with an embodiment of this invention;
FIG. 1 f is a partial, sectional view of an electrodeposition chamber showing the orientation of a tool substrate and a mold in accordance with an embodiment of this invention;
FIG. 1 g is the partial, sectional view of FIG. 1 f showing abrasive particles coupled to the tool substrate by an electrodeposited material in accordance with an embodiment of this invention;
FIG. 1 h is a sectional view of a tool in accordance with an embodiment of this invention;
FIGS. 2 a through 2 c are various views showing a series of steps for making a tool in accordance with another embodiment of this invention;
FIG. 2 a is a sectional view of a mold showing placement of abrasive particles on the molding surface in accordance with another embodiment of this invention;
FIG. 2 b is the sectional view of FIG. 2 a showing a tool substrate and abrasive particles coupled thereto by an electrodeposited material in accordance with another embodiment of this invention;
FIG. 2 c is a sectional view of a tool in accordance with another embodiment of this invention.
The above figures are provided for illustrative purposes only. It should be noted that actual dimensions of layers and features may differ from those shown.

DETAILED DESCRIPTION

Before the present invention is disclosed and described, it is to be understood that this invention is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.
The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an abrasive particle” includes reference to one or more of such particles.

Definitions

In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set forth below.
As used herein, “insulating material” refers to a material or materials used to form a mold in a manner the effectively prevents accumulation of electrodeposited material on a molding surface of the insulating material. As explained herein, the insulating material may include electrically nonconductive and/or conductive materials.
As used herein, “molding surface” refers to a surface on the insulating material to which abrasive particles can be secured.
As used herein, “predetermined pattern” refers to a non-random arrangement of either abrasive particles or apertures that can be determined prior to fabrication of a tool or device including such particles or apertures.
As used herein, “horizontal pattern” refers to an arrangement of either abrasive particles or apertures across a surface to which they are, or are to be, attached or placed.
As used herein, “vertical pattern” refers to an arrangement of heights to which, the exposed tips of abrasive particles extend above the working surface of a tool or tool substrate.
As used herein, “working surface” refers to the surface of a tool or tool substrate that, during operation, faces toward, or comes in contact with a work piece that is being polished, grinded, sanded, etc.
As used herein, “lattice” refers to a horizontal pattern in which the abrasive particles are equidistant from neighboring abrasive particles or, in the case of apertures, the apertures are equidistant from neighboring apertures.
As used herein, “post electrodeposition processing” refers to the dressing or grinding required in some conventional methods to expose the working surface of a tool.
As used herein, “holding” or “temporarily securing” refers to the coupling or supporting of particles in order to prevent the particles from falling from and/or moving on the surface to which they are coupled or supported. For example, in some embodiments, gravity may be sufficient to couple or support the particles to the surface.
As used herein, “template” refers to a device with a plurality of apertures used for positioning abrasive particles onto a mold in a predetermined pattern. The predetermined pattern can be controlled by the configuration of the apertures on the template. In use, one side of the template is positioned against the molding surface of a mold, and diamond particles are spread over the other side. The apertures can be designed so that only one particle will fit in each aperture and fall through to contact the molding surface. The apertures can also be designed so that it accommodates only particles having a grit size in a specified range. The particles in the apertures can contact the molding surface so that they can be secured thereto. The remaining unsecured particles can be removed. The template can then be removed from the mold.
As used herein with respect to an identified property or circumstance, “substantially” refers to a degree of deviation that is sufficiently small so as to not measurably detract from the identified property or circumstance.
As used herein in connection with individual numerical numbers or numerical ranges, the term “about” refers to an actual number or range that is slightly above or below the actual value(s) articulated.
As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.
Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 1 to about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc.
This same principle applies to ranges reciting only one numerical value. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.

The Invention

The present invention encompasses electrodeposition methods of making abrasive tools that allow greater control in the arrangement and securing of abrasive particles according to both vertical and horizontal patterns on a tool substrate, and that require little or no post electrodeposition processing of the working surface of the tool. In other words, the working surface results from the electrodeposition process itself. Applicant has also developed a mold for use with this method as well as abrasive tools produced by this method.
Referring to FIGS. 1 a through 1 e, a mold 10 in accordance with the present invention is shown. The mold may be used in an electrolytic process for the positioning and holding of abrasive particles 22 to the molding surface 18 of the mold. FIGS. 1 f through 1 h show the mold configured for use in a partial view of an electrodeposition chamber 100 in accordance with an embodiment of this invention. Similarly, FIGS. 2 a through 2 c show other examples of a mold configured for use in accordance with an embodiment of the invention.
As shown in the Figures, the mold 10 includes an insulating material 14. This insulating material can effectively prevent the accumulation of electrodeposited material 58 on the molding surface 18. In the examples shown in FIGS. 1 f through 1 h and FIGS. 2 a through 2 c, the tips 42 of the abrasive particles form part of the working surface 49 of a tool 50, and these tips are held on the molding surface of the mold during electrodeposition. As such, the accumulation of electrodeposited material can be prevented from occurring on the particle tips and the working surface of the tool.
In one embodiment, the insulating material 14 has at least one aperture 26 extending through the insulating material. In another embodiment, as shown in FIGS. 1 a through 1 e, the insulating material has a plurality of apertures extending through the insulating material. The apertures can allow for circulation of an electrolytic fluid 30 from an area outside the mold 34 through the mold 10 and to the surface 56 of the tool substrate 54 in order to effect electrodeposition of the material used to secure the abrasive particles to the tool substrate. Such circulation can be advantageous as it is generally necessary to keep a sufficient concentration of the ions (not shown) in an electrolytic fluid at the location of electrodeposition. In the examples shown in FIGS. 1 g, 1 h, 2 b, and 2 c, the location of electrodeposition is on the surface 56 of the tool substrate 54.
In some embodiments, the plurality of apertures 26 can be arranged according to a predetermined pattern. For example, the predetermined pattern can be a lattice as shown in FIGS. 1 a and 1 d. A lattice pattern can help evenly distribute the ions of an electrolytic fluid 30 to the tool substrate 54. An even distribution of ions helps the electrodeposited material 58 build evenly across the surface of the tool substrate, which in turn can help secure abrasive particles 22 with an even amount of strength.
In other embodiments, the plurality of apertures 26 can be arranged in order to cause greater electrodeposition to occur in specific areas. For example, FIG. 2 b shows apertures located at the concave portions of the mold. A greater number of ions in the electrolytic fluid 30 may exist near the aperture causing more electrodeposited material 58 to form at that location.
The insulating material 14 may be formed in a variety of ways. In one embodiment, the insulating material can be formed of a resin material. For example, the resin material can be a synthetic resin or a polymeric material, such as polyimide. The resin material may also include epoxies, lacquers, varnishes, acrylic polymers, or mixtures thereof. In addition, the resin material may be a rubber material, including natural and synthetic rubbers, such as styrene-butadiene, polychloroprene elastomers, fluoroelastomers, ethylene propylene diene, nitrile elastomers such as Buna-N, and NBR, polysiloxanes, polyisobutylenes, and urethanes.
In other embodiments, the insulating material 14 may include electrically conductive components so long as the insulating material effectively, or substantially, prevents the formation of electrodeposited material 58 on the molding surface 18. For example, the insulating material may be a stainless steel substrate (not shown) covered with an insulating varnish (not shown).
The insulating material 14 also includes a molding surface 18 suitable for holding the abrasive particles 22 in place during the electrolytic deposition of a material 58 that attaches the abrasive particles to the surface 56 of an electrically conductive substrate 54, e.g. the tool substrate 54. The mold 10 can be configured for holding abrasive particles, such as diamond particles, in a variety of ways. For example, an adhesive material 38 can be adhered to the molding surface for holding the abrasive particles. The use of adhesive material can allow for the individual placement of abrasive particles. Other methods of holding the abrasive particles in place may include the forces of magnetism, friction, gravity, etc. For example, in one embodiment, the molding surface may include a plurality of grooves into which the abrasive particles are friction fitted.
In one embodiment, as shown in FIG. 1 e, the abrasive particles 22 are held so that they contact the molding surface 18 directly. Advantageously, the shape of a vertical pattern 62 to be imparted to a tool 50 can be controlled by configuring the shape of the molding surface. For example, as shown well in FIGS. 2 a through 2 c, the molding surface can be configured to have a shape that is inverse to a vertical pattern to be imparted to the abrasive particles on a tool substrate 54.
As such, the shape of the molding surface 18 can be adapted to suit many applications for abrasive tools 50. For example, the molding surface can be substantially flat (as shown in FIGS. 1 a through 1 g), concave, or convex, or it can include both convex and concave portions (as shown in FIGS. 2 a and 2 b). In another example, which can be particularly useful for chemical mechanical polishing (CMP) applications, the concave shape of the molding surface can have a slope of about 1/1000, or concavity of about 1/1000. This last example can impart a convex shape with a slope of about 1/1000 to the vertical pattern 62 of a polishing tool, which is often desired in CMP applications.
Additionally, in some embodiments where the abrasive particles 22 directly contact the molding surface 18, the tips 42 of the particles forming part of the working surface 49 of a tool can be set in a predetermined vertical pattern. This can help substantially with even dressing and good finish quality of the object being polished (not shown). Additionally, this can allow for specific dressing patterns on the object being polished.
In some embodiments, the molding surface 18 can hold the abrasive particles 22 in a predetermined horizontal pattern. Accordingly, the spacing between the particles on the surface 56 of the tool substrate 54 can be controlled. Such control can provide a number of advantages. For instance, controlled spacing of the abrasive particles can result in increased performance by reducing excessive frictional force (or drag) and heat generation caused during the polishing process. In some applications, it is desired to regularly distribute the abrasive particles over the surface of the tool substrate. For such applications, the molding surface can hold the abrasive particles in a lattice pattern.
Various techniques can be used to selectively position abrasive particles on the molding surface in a predetermined horizontal pattern. For example, the particles can be individually placed on the molding surface. Alternatively, a template (as defined above) can be used to more efficiently place particles on the molding surface. Other methods can include the use of transfer tape or other transfer medium, whereby particles are temporarily placed on the tape in a predetermined horizontal pattern and then transferred to the molding surface.
In one embodiment of the invention, the molding surface 18 can hold the abrasive particles 22 according to a predetermined pattern that is complimentary with the pattern of apertures 26. For example, both the abrasive particles and the apertures can each be arranged in lattice patterns as shown in FIG. 1 d. Advantageously, these complimentary patterns can provide for substantially equal concentrations of ions in the electrolytic fluid 30 to reach the site of electrodepostion around each abrasive particle. Thus, the amount of electrodeposited material 58 securing each abrasive particle can be substantially equivalent. This can help maximize particle retention by distributing substantially equal work load to each particle.
In other embodiments, the molding surface 18 can hold the abrasive particles 22 in a pattern that provides for at least one specified area on the molding surface that has a higher concentration of abrasive particles than the remainder of the molding surface. This can be particularly useful in CMP applications. For example, it may be desired to have a higher concentration of abrasive particles near the perimeter of a disc-shaped abrasive tool. The perimeter generally spins faster than the center of the disc-shaped tool and often there is more pressure on the leading edge of the disc. Additional patterns and configurations of abrasive particles may be found in Applicant's co-pending U.S. patent applications having Ser. No. 10/109,531 filed Mar. 27, 2002 and Ser. No. 10/954,956 filed Sep. 29, 2004, each of which are incorporated herein by reference.
In another aspect of the invention, a method is provided for making a tool 50 that has a plurality of abrasive particles 22 coupled to a substrate 54 by an electrodeposited material 58. As an initial step, abrasive particles can be temporarily secured to a molding surface 18 of a mold 10, as described herein. Next, the mold and the secured particles can be positioned into an electrodeposition chamber 100 with the molding surface oriented toward the substrate. Electrodeposition of a material on the surface 56 of the substrate 54 is then performed and the abrasive particles become electrolytically attached to the substrate with the electrodeposited material. The mold can then be removed, revealing a tool, or portion of a tool having abrasive particles attached to the surface of the tool substrate.
In one example, abrasive particles 22 can be temporarily secured to the molding surface 18 of a mold 10 with an adhesive material 38 as described above. With the molding surface oriented towards the substrate 54, electrodeposited material 58 can begin to form on the substrate until a portion of the abrasive particles is covered. The electrodeposited material can more firmly attach the particles to the adhesive material, and thus, the mold can be easily removed revealing the exposed tips of the abrasive particles.
In one embodiment, the substrate 54 can be an electrically conductive material, such as stainless steel. This can allow the substrate to act as one of the electrodes in the electrolytic process. The substrate can itself be the tool body (not shown). Alternatively, the substrate can be later secured to a tool body by other means.
In another embodiment of the invention, the electrodeposited material 58 can be a metallic material, such as a metal or a metallic composite material. For example, the electrodeposited material may be metals such as nickel, chromium, copper, titanium, tungsten, tin, iron, silver, gold, manganese, magnesium, zinc, aluminum, tantalum, or alloys or mixtures thereof. The metallic composite material may be a composite that includes one or more of these metals.
In another aspect of this invention, a tool 50 produced by the above-described method is provided. The tool can have a substrate 54 with a plurality of abrasive particles 22 that are coupled to the substrate by an electrodeposited material 58. The abrasive particles can be arranged such that the tips 42 of the particles have a predetermined vertical pattern. Additionally, the abrasive particles can have a portion exposed above the electrodeposited material which has never been covered by the electrodeposited material
For example, the abrasive particles 22 can each be set at a uniform height, or substantially uniform height above the substrate. The vertical pattern can also be convex, concave, or include both convex and concave areas.
In addition, the plurality of abrasive particles 22 can be arranged on the substrate 54 according to a predetermined horizontal pattern. For example, the abrasive particles can be arranged in a lattice as defined above. The abrasive particles can also be arranged such that there is a higher concentration of abrasive particles coupled to a specified area of the substrate than to the remainder of the substrate. Such vertical and horizontal patterns provide many advantages such as those described above.
In another embodiment of the invention, an abrasive tool 50 can be provided for that requires little or no post electrodeposition processing. In this embodiment, the electrodeposited material 58 forms on the substrate 54 of the tool, and does not occur on the finished working surface 49 of the tool. Because of this, the finished working surface does not require dressing to expose the tips 42 of the abrasive. particles like some other conventional methods. This helps prevent damage to the abrasive particles from the impact of dressing the working surface of the tool.

EXAMPLES

For a greater understanding of the present invention, examples will be provided below. These examples are in no way meant to serve as a limitation to the scope of the present invention.

Example 1

Manufacture of a CMP Pad Dresser

A mold of a polyimide layer (1 mm thick) that is stamped to contain a plurality of apertures arranged in a lattice pattern. The center of each aperture is separated from the center of neighboring apertures by a distance of 0.7 mm, and each aperture has a 0.5 mm diameter. One surface of the polyimide layer (i.e. the molding surface) is coated with an acrylic adhesive (50 microns thick). Diamond grits of 100/120 mesh are attached to the molding surface with each diamond grit located in the center of the four surrounding apertures. The diamond covered molding surface is placed against a disc-shaped stainless steel substrate (being 108 mm in diameter by 6.5 mm in thickness). The diamond grits are between the molding surface and the stainless steel substrate. The mold and the substrate are located in a plastic (PVC) ring 48 to hold them together during electrolytic process. The substrate is placed in contact with a cathode. NiSO₄solution is used as the electrolytic fluid. The plastic ring, mold, and substrate are submerged in the electrolytic fluid inside a PVC layer for sealing off the electrolytic fluid. Electrolysis is performed causing electrodeposition of the Ni on the substrate. Electrolysis continues until the Ni covers approximately about ⅔ of the average diamond grit size. The polyimide mold is then removed and the substrate with diamond grits attached by electrodeposited Ni is recovered.

Example 2

Thirty molds are made as follows:
Each mold is formed of a stainless steel disc that is about 120 mm in diameter and about 120 microns in thickness. Each disc is lithographically etched to form a plurality of apertures thereon distributed in a lattice pattern as described below. The apertures cover a generally circular area on a central portion of each disc of about 100 mm in diameter, leaving a width of about 20 mm around the perimeter of each disc without any apertures. Measuring from the approximate center points of adjacent apertures, (the “aperture separation”), a number of discs are formed with the following aperture separations:
1. Ten discs with an aperture separation of about 800 microns, each aperture about 400 microns in diameter;
2. Ten discs with an aperture separation of 600 microns, each aperture about 300 microns in diameter;
3. Ten discs with an aperture separation of 400 microns, each aperture about 200 microns in diameter.
Each disc is varnished coated, rubber coated, or otherwise coated with an inert or insulative material in order to improve its electrically insulating properties. However, this can be an optional step in certain applications where a less conductive, or non-conductive material is used for the mold itself. In some other cases, when the abrasive particles are insulating (e.g. diamond particles), the stainless steel, or other electrically conductive disc can be insulated by its separation from a cathodic substrate by the intervening insulating particles.
Using the above molds, the following procedure is used to make diamond pad conditioners:
1. Each mold is coated on both sides with an adhesive layer and assembled with an abrasive particle template on each side. The abrasive particle templates have been configured and selected to properly accommodate abrasive particles of a desired size, and to allow such particles to adhere between the holes in the mold on which the template is used (i.e. each aperture in each template will be placed so as to compensate for the holes in the mold and ensure that each abrasive particle will be adhered to the surface of the mold rather than falling through the apertures of the mold).
2. The mold and template assemblies are then fastened together with one or more dowel pins engaged in pin holes aligned and extending through each member of each assembly. However, it should be noted that other mechanisms, such as clamps, adhesives, etc., can be used in order to hold the templates and the mold together in an assembly.
3. Diamond particles (MBG-660 made by Diamond Innovations) of the appropriate size are then dispersed into the apertures of each template so that each template aperture accommodates and receives only a single abrasive particle which becomes adhered to the surface of the mold.
4. The excess diamonds are discarded by turning over, vibrating, shaking, etc., each mold/template assembly.
5. For each mold, the templates are removed leaving diamond particles adhered in the pattern dictated by the template on each surface of the mold. In some cases, the pattern dictated by the template may result in diamond particles located at the center between each set of four apertures on the mold.
6. Each mold is centered between two stainless steel substrates that are about 100 mm in diameter and about 6.5 mm in thickness, such that the diamond particles are sandwiched between the mold and the substrates. Since the diamond particles generally vary slightly in size, only some, if any of the larger diamond particles will contact the substrate.
7. For each mold, a heavy steel ring is pressed along the outer periphery of the mold to make sure that moving, shifting, or warping does not occur during the electrodeposition process. In some aspects, the ring may actually bend the periphery of the mold slightly to create a concave shape on each side of the mold. The amount of slope in the concavity may be controlled somewhat using this mechanism, and in some aspects the slope may be about 1/1000. This will cause the diamond particles on the periphery of the working surface of the substrate to be slightly lower (about 50 microns) than at the center of the substrate in the finished tool
8. Each of the mold/substrate assemblies is located in holes of a plastic rack. The bases of the substrates are connected to the cathode of a plating tank. The mold/substrate assemblies are covered with a NiSO₄electrolyte solution (i.e. placed in an electrolytic solution tank or bath, and as electricity passes through the substrate, nickel cations are reduced and nickel metal deposits onto the substrate. As the nickel builds in a layer on the substrate it grows toward the mold and the diamond particles attached to the mold eventually become surrounded by and embedded in the nickel layer to a selected degree. The depth to which the particles become buried can be controlled by the operator of the process. In one aspect, the depth of the layer may be from about ⅓ to ⅔ of the distance between the mold and the substrate. The building of the layer can be accomplished evenly and quickly because of the fact that the electrolytic solution is allowed to circulate through the apertures of the mold.
9. Since the mold is not electrically charged due to the intervening insulating diamond particles and the optional varnish coating or other insulating material, nickel does not deposit on the mold or the portions of the diamond particles near the molding surface.
10. Once the nickel layer has been completed, the tool and mold are removed from the electroplating solution and separated to reveal the working surface of the tool. The mold can then be reused.
Because the nickel layer builds from the substrate toward the mold, and the diamond particles become attached to the substrate as a result of the growth process, the profile of the exposed diamond particle tips on the working surface of the final tool will be dictated by the shape imparted by the molding surface of the mold. In this way, the diamond particle tips can be arranged in a predetermined vertical pattern on the working surface of the finished tool. Further, because of the nature of the process, no post fabrication finishing or work is required in order to provide a finished tool. In other words, in some aspects, a final tool which is ready for use may be produced as soon as the nickel layer is completed and the tool is removed from the electroplating bath.
Of course, it is to be understood that the above-described examples are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiments of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.

Claims

1. A mold for positioning and holding abrasive particles to be electrolytically attached to an electrically conductive substrate during an electrolytic process, comprising:

an insulating material having a molding surface suitable for holding the abrasive particles in place during electrolytic deposition of a material that attaches said particles to the electrically conductive substrate.

2. The mold of claim 1, further comprising an adhesive material adhered to the molding surface in order to hold the abrasive particles in place.

3. The mold of claim 1, wherein the insulating material has at least one aperture extending therethrough which allows circulation of an electrolytic fluid from an area outside the mold through the mold and to the molding surface.

4. The mold of claim 3, further comprising a plurality of apertures extending through the insulating material.

5. The mold of claim 4, wherein the plurality of apertures is arranged according to a predetermined pattern.

6. The mold of claim 5, wherein the predetermined pattern is a lattice.

7. The mold of claim 1, wherein the molding surface has a shape that is inverse to a vertical pattern to be imparted to the abrasive particles.

8. The mold of claim 7, wherein the molding surface is substantially flat.

9. The mold of claim 7, wherein the molding surface is concave.

10. The mold of claim 9, wherein the concave shape has a slope of about 1/1000.

11. The mold of claim 7, wherein the molding surface is convex.

12. The mold of claim 7, wherein the molding surface includes both convex and concave portions.

13. The mold of claim 1, wherein the molding surface holds the abrasive particles according to a predetermined horizontal pattern.

14. The mold of claim 13, wherein the pattern is a lattice pattern.

15. The mold of claim 5, wherein the molding surface holds the abrasive particles according to a predetermined pattern that is complimentary with the pattern of apertures.

16. The mold of claim 15, wherein the pattern of abrasive particles and the pattern of apertures are each lattice patterns.

17. The mold of claim 13, wherein the pattern provides for at least one specified area on the molding surface having a higher concentration of abrasive particles than a remainder of the molding surface.

18. The mold of claim 1, wherein the insulating material comprises a resin material.

19. The mold of claim 18, wherein the resin is a synthetic resin.

20. The mold of claim 18, wherein the resin material includes a polymeric material.

21. The mold of claim 18, wherein the resin material is a member selected from the group consisting of: epoxies, lacquers, varnishes, acrylic polymers, epoxies, and mixtures thereof.

22. The mold of claim 21, wherein the insulating material is a varnish.

23. The mold of claim 21, wherein the insulating material is an acrylic polymer.

24. The mold of claim 1, wherein the insulating material is a rubber material.

25. The mold of claim 24, wherein the rubber material is rubber is either a natural rubber or a synthetic rubber.

26. A method for making a tool having a plurality of abrasive particles coupled to a substrate by an electrodeposited material, comprising:

temporarily securing the plurality of abrasive particles to a molding surface of a mold as recited in claim 1;

positioning the mold in an electrodeposition chamber with the molding surface oriented toward a substrate to which the abrasive particles are to be electrolytically attached;

electrolytically attaching the abrasive particles to the substrate with an electrodeposited material; and

removing the mold.

27. The method of claim 26, wherein the substrate comprises an electrically conductive material.

28. The method of claim 27, wherein the electrically conductive material is stainless steel.

29. The method of claim 26, wherein the substrate is a tool body.

30. The method of claim 26, further comprising the step of removing the substrate from the electrodeposition chamber and attaching the substrate to a tool body.

31. The method of claim 26, wherein the electrodeposited material is a metallic material.

32. The method of claim 26, wherein the metallic material is a metallic composite material.

33. The method of claim 32, wherein the metallic composite material includes at least one member selected from the group consisting of: nickel, chromium, copper, titanium, tungsten, tin, iron, silver, gold, manganese, magnesium, zinc, aluminum, tantalum, alloys thereof, and mixtures thereof.

34. The method of claim 33, wherein the metallic composite material includes nickel.

35. The method of claim 31, wherein the metallic material consists of a metal.

36. The method of claim 35, wherein the metal is a member selected from the group consisting of: : nickel, chromium, copper, titanium, tungsten, tin, iron, silver, gold, manganese, magnesium, zinc, aluminum, tantalum, alloys thereof, and mixtures thereof.

37. The method of claim 36, wherein the metal is nickel.

38. A tool produced by the method of claim 26, comprising:

a substrate having a plurality of abrasive particles coupled to the substrate by an electrodeposited material, said plurality of abrasive particles having tips arranged in accordance with a predetermined vertical pattern and having a portion exposed above the electrodeposited material which has never been covered by the electrodeposited material.

39. The tool of claim 38, wherein the vertical pattern is a uniform height above the substrate.

40. The tool of claim 38, wherein the vertical pattern is a convex pattern.

41. The tool of claim 38, wherein the vertical pattern is a concave pattern.

42. The tool of claim 38, wherein the vertical pattern includes both convex and concave areas.

43. The tool of claim 38, wherein the plurality of abrasive particles are further arranged according to a predetermined horizontal pattern.

44. The tool of claim 43, wherein the horizontal pattern is a lattice.

45. The tool of claim 43, wherein the horizontal pattern provides for a higher concentration of abrasive particles coupled to a specified area of the substrate than to a remainder of the substrate.

46. The tool of claim 36, wherein the electrodeposition of the electrodeposited material provides a finished working surface without any post electrodeposition processing.

47. An abrasive tool comprising:

a substrate having a plurality of abrasive particles coupled thereto by an electrodeposited material, said abrasive particles being arranged according to a predetermined horizontal pattern, and having exposed portions extending above the electrodeposited material according to a predetermined vertical pattern, said electrodeposited material providing a working surface prepared by the electrodeposition process.