Method for producing a grinding tool and grinding tool

Abstract

With a method for the production of a grinding tool, a tool base body is provided, which configures a three-dimensionally shaped adhesive sur-face by application of a bonding agent. The tool base body is positioned in a way that the adhesive surface is arranged in an electrostatic field, be-tween a first electrode and a second electrode. Into the electrostatic field, abrasive grains are introduced, which, due to the electrostatic field, move towards the adhesive surface and adhere to same. The grinding tool produced in this manner has a three-dimensionally shaped abrasive grain layer. The production of the grinding tool is simple, flexible and economical. The grinding tool has a randomly shaped abrasive grain layer and can be applied in a manifold manner with a high cutting performance and a long service life.

Claims

1. A method for the production of a grinding tool, comprising the steps: providing a tool base body, wherein the tool base body has at least one of a hub and a shaft in order to tension and rotatably drive the grinding tool around a central longitudinal axis and wherein the tool base body is at least section-wise rigid to rotate the grinding tool around the central longitudinal axis, generating a three-dimensionally shaped adhesive surface by applying a bonding agent onto the tool base body, positioning the tool base body in a way that the three-dimensionally shaped adhesive surface is arranged in an electrostatic field between a first electrode and a second electrode, and introducing abrasive grains into the electrostatic field in a way that the abrasive grains, due to the electrostatic field, move towards the three-dimensionally shaped adhesive surface and adhere to the three-dimensionally shaped adhesive surface in order to configure a three-dimensionally shaped abrasive grain layer, wherein the abrasive grains are directly applied onto the tool base body such that the tool base body configures a base and the three-dimensionally shaped abrasive grain layer is firmly bonded to the tool base body after the bonding agent is hardened, wherein the three-dimensionally shaped abrasive grain layer is curved in a radial direction and a circumferential direction with respect to the central longitudinal axis.

2. The method according to claim 1, wherein the three-dimensionally shaped adhesive surface is curved in order to configure the three-dimensionally shaped abrasive grain layer.

3. The method according to claim 1, wherein the tool base body is moved relative to at least one of the electrodes in order to configure the three-dimensionally shaped abrasive grain layer.

4. The method according to claim 1, wherein the central longitudinal axis of the tool base body is aligned in various directions relative to the first electrode in order to configure the three-dimensionally shaped abrasive grain layer.

5. The method according to claim 1, wherein the tool base body rotates around the central longitudinal axis in order to configure the three-dimensionally shaped abrasive grain layer.

6. The method according to claim 1, wherein the abrasive grains adhering to the adhesive surface, at least partially, are aligned towards the adhesive surface.

7. The method according to claim 1, wherein the abrasive grains are transported into the electrostatic field by means of a conveying device.

8. The method according to claim 7, wherein the conveying device comprises a conveyor belt.

9. The method according to claim 7, wherein the first electrode is arranged below a conveying area of the conveying device.

10. The method according to claim 1, wherein the abrasive grains are supplied by means of a dosing device.

11. The method according to claim 1, wherein an electric voltage between the electrodes is adjustable.

12. The method according to claim 1, wherein the tool base body configures the second electrode.

13. The method according to claim 1, wherein on the tool base body, at least one electroconductive layer is configured.

14. The method according to claim 1, wherein the applied bonding agent is electroconductive.

15. The method according to claim 1, wherein the tool base body, at least partially, is configured of an electroconductive material.

16. The method according to claim 1, wherein the tool base body and the second electrode are configured separately from one another.

17. The method according to claim 1, wherein the second electrode, at least section-wise, is shaped corresponding to the tool base body.

18. The method according to claim 1, wherein the second electrode, at least section-wise, abuts on the tool base body.

19. A grinding tool comprising: a tool base body, wherein the tool base body has at least one of a hub and a shaft in order to tension and rotatably drive the grinding tool around a central longitudinal axis and wherein the tool base body is at least section-wise rigid to rotate the grinding tool around the central longitudinal axis, and abrasive grains, wherein the abrasive grains are directly applied onto the tool base body and the tool base body configures a base, wherein the abrasive grains are bonded to the tool base body by a bonding agent and configure an abrasive grain layer, and wherein the abrasive grain layer is shaped three-dimensionally, wherein the three-dimensionally shaped abrasive grain layer is firmly bonded to the tool base body after the bonding agent is hardened, and wherein the three-dimensionally shaped abrasive grain layer is curved in a radial direction and a circumferential direction with respect to the central longitudinal axis.

20. The grinding tool according to claim 19, wherein the abrasive grain layer is curved.

21. The grinding tool according to claim 19, wherein the abrasive grains, at least partially, are aligned towards the tool base body.

22. The grinding tool according to claim 19, wherein the abrasive grains, respectively, have a maximum dimension D such that for at least 80%, of the abrasive grains: 1 μm≤D≤5000 μm.

23. The grinding tool according to claim 19, wherein the abrasive grains, respectively, have a maximum dimension D1 such that for at least 80% of the abrasive grains: 1 μm≤D1≤5000 μm.

24. The grinding tool according to claim 19, wherein the abrasive grains, respectively, have a maximum dimension D2 such that for at least 80% of the abrasive grains: 1 μm≤D2≤5000 μm.

25. The grinding tool according to claims 19, wherein a covering bond is applied onto the abrasive grain layer.

26. The method according to claim 1, wherein the tool base body is configured in a disc-like manner in an inner area and in a curved manner in a circumferential area around the inner area.

27. The method according to claim 26, wherein the at least one of the hub and the shaft is arranged in the inner area of the tool base body.

28. The grinding tool according to claim 19, wherein the tool base body is configured in a disc-like manner in an inner area and in a curved manner in a circumferential area around the inner area.

29. The grinding tool according to claim 28, wherein the at least one of the hub and the shaft is arranged in the inner area of the tool base body.

30. The grinding tool according to claim 1, wherein the three-dimensionally shaped adhesive surface and the three-dimensionally shaped abrasive grain layer are each curved from a first plane parallel to the tool base body towards a second plane perpendicular to the first plane.

31. The grinding tool according to claim 1, wherein the three-dimensionally shaped adhesive surface and the three-dimensionally shaped abrasive grain layer are each shaped in a curved manner between two transverse planes, one of which is perpendicular to the central longitudinal axis.

32. The grinding tool according to claim 1, wherein at least one non-electroconductive material of the tool base body is coated with abrasive grains.

33. The grinding tool according to claim 19, wherein at least one non-electroconductive material of the tool base body is coated with abrasive grains.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a schematic view of a device for the production of a grinding tool by coating a tool base body with abrasive grains by means of an electrostatic field between two electrodes,

(2) FIG. 2 shows an enlarged sectional view of the tool base body and the corresponding electrode in FIG. 1 according to a first embodiment,

(3) FIG. 3 shows a schematic sectional view of the finished grinding tool,

(4) FIG. 4 shows a sectional view of a tool base body and a corresponding electrode according to a second embodiment,

(5) FIG. 5 shows a sectional view of a tool base body configured as an electrode according to a third embodiment, and

(6) FIG. 6 shows a sectional view of a tool base body configured as an electrode according to a fourth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) In the following, a first embodiment of the invention is described with reference to FIGS. 1 and 3. A device 1 for the production of a grinding tool 2 comprises a handling device 3 for handling and positioning a tool base body 4, a first electrode 5 and a corresponding second electrode 6 for generating an electrostatic field E, a dosing device 7 for supplying abrasive grains 8, 9 to a conveying device 10.

(8) The conveying device 10 comprises an endless conveyor belt 11, which is tensioned by means of two pulleys 12, 13. The pulley 12, for example, is rotatably driven by means of an electric drive motor 14. A part of the conveyor belt 11, being arranged above the pulley 12, 13 in relation to the force of gravity F.sub.G, configures a conveying area 15, which extends in a horizontal x direction and a horizontal y direction.

(9) The dosing device 7 is arranged in front of the electrodes 5, 6, in a conveying direction 16. The first electrode 5 is configured in a plate-type manner and arranged below the upper part of the conveyor belt 11 or below the conveying area 15, in the direction of the force of gravity F.sub.G. On the other hand, the second electrode 6 is arranged above the conveyor belt 11 or the conveying area 15, in relation to the force of gravity F.sub.G. The second electrode 6 is thus spaced from the first electrode 5 in a vertical z direction, with the result that the conveying area 15 runs between the electrodes 5, 6. The x, y and z direction configure a Cartesian coordinate system.

(10) The functionality of the device 1 is described in the following:

(11) The second electrode 6 is configured separately from the tool base body 4 and shaped corresponding to the tool base body 4. The second electrode 6 is mounted to the handling device 3. The tool base body 4 is held by means of the handling device 3 in a way that the second electrode 6 essentially fully abuts on the rear side 17 of the tool base body 4. The handling device 3, holds the tool base body 4, for example, mechanically and/or pneumatically. Between the first electrode 5 and the second electrode 6, an electric voltage U is applied, which is generated by means of a voltage source 18 and is adjustable.

(12) The tool base body 4 has a three-dimensional shape. In an inner area 19, the tool base body 4 is configured in a disk-like manner and, for example, has a hub 20. Alternatively, the tool base body 4 can have a shaft instead of the hub 20. A configuration without a hub 20 or a shaft is possible, is well. In contrast to this, the tool base body 4 is configured in a curved manner, in a circumferential area 21 around the area 19.

(13) On a front side 22, turned away from the second electrode 6, first of all, a bonding agent 23 is applied, with the result that the bonding agent 23 arranged on the tool base body 4 configures a three-dimensionally shaped adhesive surface 24. The bonding agent 23, for example, is a resin, in particular phenolic resin. The tool base body 4 is made of a common material, such as, for example, vulcanized fiber or polyester. The bonding agent 23 is applied, for example, manually or by means of the handling device 3. For example, the tool base body 4 is immersed into the bonding agent 23 with the front side 22 by means of the handling device 3.

(14) Subsequently, the tool base body 4 is positioned above the first electrode in the z direction by means of the handling device 3, with the result that the adhesive surface 24 is partially arranged in the electrostatic field E, between the electrodes 5, 6. The field lines emerge perpendicularly out of the surface of the first electrode 5 and enter the surface of the second electrode 6 perpendicularly, with the result that the field lines essentially run perpendicularly through the adhesive surface 24. In FIG. 2, this is shown for the field lines f.sub.1, f.sub.2 and f.sub.3, as an example.

(15) By means of the conveying device 10, the abrasive grains 8, 9 are transported into the electrostatic field E in order to configure a three-dimensionally shaped abrasive grain layer 25. For this purpose, the dosing device 7, for example, provides a mixture of fine-grained abrasive grains 8 and of coarse-grained abrasive grains 9. The fine-grained abrasive grains 8, respectively, have a maximum dimension D.sub.1, provided that for at least 80%, in particular at least 90%, and in particular at least 95% of the abrasive grains 8: 1 μm≤D.sub.1≤5000 μm, in particular 5 μm≤D.sub.1≤500 μm, and in particular 10 μm≤D.sub.1≤250 μm. In contrast to this, the coarse-grained abrasive grains 9, respectively, have a maximum dimension D.sub.2, provided that for at least 80%, in particular at least 90% and in particular at least 95% of the abrasive grains 9: 1 μm≤D.sub.2≤5000 μm, in particular 150 μm≤D.sub.2≤3000 μm, and in particular 250 μm≤D.sub.2≤1500 μm. In particular, it is provided that D.sub.1≤D.sub.2. The abrasive grains 8, 9, in the mixture, thus have the maximum dimension D.sub.1 or D.sub.2, wherein the maximum dimension in the mixture is generally named as D. In the mixture, the abrasive grains 8, 9 thus have the maximum dimension D, provided that for at least 80%, in particular at least 90%, and in particular at least 95% of the abrasive grains 8, 9: 1 μm≤D≤5000 μm, in particular 10 μm≤D≤2500 μm, and in particular 100 μm≤D≤1000 μm.

(16) The abrasive grains 8, 9 are supplied to the conveyor belt 11 in a dosed manner by means of the dosing device 7, and they are distributed on same. By means of the, for example, electric drive motor 14, the conveyor belt 11 with the abrasive grains 8, 9 arranged thereon is moved in the conveying direction 16, with the result that the abrasive grains 8, 9 are introduced into the electrostatic field E. By means of the, for example, electric drive motor 14, the transport speed in the conveying direction 16 can be adjusted.

(17) Due to the electrostatic field E, the abrasive grains 8, 9 are moved against the force of gravity F.sub.G towards the adhesive surface 24, and they are aligned along the field lines, for example the field lines f.sub.1, f.sub.2 and f.sub.3. When the abrasive grains 8, 9 hit the adhesive surface 24, they adhere thereto. Due to the adhering abrasive grains 8, 9, the abrasive grain layer 25 is configured on the tool base body 4. In order to apply the abrasive grains 8, 9 evenly and homogeneously, the tool base body 4 is rotated around a central longitudinal axis 26 by means of the handling device 3. Between the coarse-grained abrasive grains 9, fine-grained abrasive grains 8 adhere to the tool base body 4, with the result that die abrasive grain layer 25 is configured homogeneously. The coarse-grained abrasive grains 9, in this case, configure main grains and the fine-grained abrasive grains 8 configure filler grains. The abrasive grain layer 25 is shaped three-dimensionally or in a curved manner, corresponding to the adhesive surface 24. Additionally, the tool base body 4, if needed, is moved in a way that the central longitudinal axis 26 is aligned in various directions towards the first electrode 5.

(18) After the application of the abrasive grain layer 25 onto the tool base body 4 has been finished, the tool base body 4, together with the bonding agent 23 and the abrasive grain layer 25, configures a semi-finished product. The semi-finished product is loosened from the handling device 3 and is arranged in a heating device, where the bonding agent 23 is hardened. Subsequently, at least one covering bond 27 as well as—if needed—a covering layer 31 are applied onto the abrasive grain layer 25 in the common manner. The covering bond 27, for example, has a bonding agent 23 with additional active grinding filler materials. The covering layer 31 is applied onto the covering bond 27. The covering layer 31 has a bonding agent 23 with additional active grinding filler materials, wherein the proportion of active grinding filler materials, preferably, is higher than the one in the covering bond 27. The covering bond 27 and the covering layer 31, for example, are applied manually. Subsequently, the covering bond 27 and the covering layer 31 are hardened in a heating device. The bonding agent 23, for example, comprises phenolic resin and chalk. The covering bond 27 and the covering layer 31, for example, comprise phenolic resin, chalk and cryolite. The atmospheric humidity during the production is for example 0% to 100%, in particular 35% to 80%. In FIG. 3, the finished grinding tool 2 is shown.

(19) In the following, a second embodiment of the invention is described with reference to FIG. 4. In contrast to the first embodiment, the second electrode 6 is configured smaller than the tool base body 4 and only covers a portion of the tool base body 4. In this portion, the second electrode 6 is shaped corresponding to the tool base body 4, with the result that the second electrode 6 essentially runs in parallel to the adhesive surface 24. The second electrode 6 does not abut on the rear side 17 of the tool base body 4, however is slightly spaced from same. The second electrode 6 is firmly connected with the handling device 3, whereas the tool base body 4 is rotated around the central longitudinal axis 26 by means of the handling device 3. The tool base body 4 thus is moved relative to the second electrode 6 by the rotation around the central longitudinal axis 26. The abrasive grains 8, 9 move in the direction of the adhesive surface 24 in the area of the electrostatic field E and, upon contact with the adhesive surface 24, adhere to same. As the tool base body 4 moves relative to the second electrode 6, i.e. rotates around the central longitudinal axis 26, the entire adhesive surface 24 is coated with the abrasive grains 8, 9. In view of the further setup of the device 1 as well as its functionality, and of the further setup of the grinding tool 2, reference is made to the preceding embodiment.

(20) In the following, a third embodiment is described with reference to FIG. 5. In contrast to the preceding embodiments, the tool base body 4 itself is configured as a second electrode 6. For this purpose, the tool base body 4 is made of an electroconductive material, in particular of a metal. The tool base body 4, for example, is made of aluminum. The tool base body 4 shown in FIG. 5, in addition to the even inner area 19 and the convexly curved area 21, shows a concavely curved area 28. The adhesive surface 24 thus is shaped three-dimensionally in a complex manner. The applied bonding agent 23 is electroconductive in order to avoid a block field and to optimize the electrostatic field E. The electroconductive bonding agent 23, for example, is a conductive varnish. The field lines f.sub.1 to f.sub.3 again run perpendicularly through the adhesive surface 24, with the result that abrasive grains 8, 9, despite the complexly shaped adhesive surface 24, are applied thereto in an aligned manner. The central longitudinal axis 26 essentially runs within the x-y plane, with the result that, by a rotation of the tool base body 4 around the central longitudinal axis, the inner area 19 as well as the areas 21 and 28 are reliably and homogeneously coated with the abrasive grains 8, 9. In view of the further setup of the device 1 as well as its functionality, and of the further setup of the grinding tool 2, reference is made to the preceding embodiments.

(21) In the following, a fourth embodiment of the invention is described with reference to FIG. 6. In contrast to the preceding embodiments, the tool base body 4 comprises a base body 29 made of a non-electroconductive material and an electroconductive layer 30 firmly connected with the base body 29. Due to the electroconductive layer 30, the tool base body 4 itself configures the second electrode 6. The layer 30, for example, is a copper foil. The bonding agent 23 is applied onto the electroconductive layer 30, with the result that the adhesive surface 24 is configured. The bonding agent 23 can be electroconductive. The tool base body 4 shows the inner area 19, the convexly curved area 21 and the concavely curved area 28. Between the inner area 19 and the convexly curved area 21, a chamfered area 32 or a chamfer is arranged. The chamfered area 32 and the inner area 19 form an angle α, provided that α≠180°. The chamfered area 32, for example, serves for rough machining or for two-dimensional treatment. The tool base body 4 rotates around the central longitudinal axis 26, with the result that the adhesive surface 24, despite the complex three-dimensional shape, is reliably and evenly coated with the abrasive grains 8, 9. The configured abrasive grain layer 25, due to the concave and convex curvature as well as the chamfer or the chamfered area 32, is shaped three-dimensionally in a complex manner. In view of the further setup of the device 1 as well as its functionality, and of the setup of the grinding tool 2, reference is made to the preceding embodiments.

(22) The method according to the invention has a low number of production steps and in particular avoids a transformation of coated abrasives. The method according to the invention allows for the production of grinding tools 2 including complexly three-dimensionally shaped abrasive grain layers 25 for a plurality of various applications. The cutting performance as well as the service life of the grinding tools 2, in this case, are comparable to grinding tools produced of coated abrasives. Due to the electrostatic application of the abrasive grains 8, 9, in particular, it is rendered possible that the abrasive grains 8, 9, with their respective longitudinal axis, are aligned perpendicularly to the adhesive surface 24 or the surface of the tool base body 4. This ensures a high cutting performance and a long service life. Additionally, the grinding tools 2 according to the invention, compared to coated abrasives, show lower noise and vibration exposure as well as lower effort in the application.