JPWO2018149483A5 - - Google Patents

Description

The present invention relates to a method and a grinding tool for manufacturing a grinding tool.

Hand-handled abrasive tools (grinders) for surface working are manufactured with bonded abrasives (bonded abrasives) or with coated abrasives . For example, US Pat. No. 6,000,000 (which corresponds to US Pat. No. 6,000,000) discloses a rough grinding disk with a grinding body, ie, a bonded abrasive, which is bonded to a synthetic resin. On the other hand, from US Pat. No. 6,000,003 (which corresponds to US Pat. No. 6,000,000), a flap disc is known which includes a support plate provided with grinder lamellas. Grinder flakes are made from coated abrasive and contain abrasive grains bonded to a base by a bonding agent. Coated abrasives , in contrast to bonded abrasives , offer e.g. a higher cutting capacity and a longer service life as well as lower labor costs associated therewith with respect to the use of manually driven grinding tools, reduced labor during grinding , and has various advantages such as reduced noise and vibration load.

In the rough grinding disc known from DE 10 2005 020 002 A1 each of the grinder lobes is bent around the outer peripheral edge of the support plate, so that each of the grinder lobes is three-dimensional. to form an abrasive grain layer. This gives the rough grinding disc a high cutting capacity in a wide variety of abrasive applications. Disadvantages are that rough grinding discs are expensive in terms of production and that there is a risk of damage to the respective abrasive grain layer when bending the grinder lamella, so that it can only be used three-dimensionally to a limited extent. The point is that the formed abrasive grain layer cannot be produced.

WO 2009/138 114 A1 US 2011/0065369 A1 EP 2 130 646 A1 US 2009/0305619 A1

The present invention is based on the first problem of creating a method that allows the production of grinding tools with a randomly shaped abrasive layer and high cutting power in a simple, flexible and economical manner. there is

The present invention further addresses the second problem of creating a grinding tool that is simple to manufacture and flexible to use, with an optionally formed abrasive layer and with high cutting power. Based on

The first problem is solved by a method having the features of claim 1 of the appended claims. By applying (coating) the bonding agent to the tool base body, a three-dimensionally shaped bonding surface is created according to the shape of the tool base body or according to the shape of the base body surface of the tool base body. be. A tool base body having an adhesive surface is positioned in an electrostatic field, and abrasive grains are entrapped into the electrostatic field such that the tool base body is directly coated with abrasive grains in a layer. Abrasive grains entrained in the electrostatic field move along the lines of force in the direction of the bonding surface and remain adhered to the tool base body upon contact with the bonding surface or bonding agent, so that the abrasive grains adhere to the bonding surface. A corresponding three-dimensionally shaped abrasive layer is formed. A plurality of electrodes are formed from a conductive material to create an electrostatic field. Since the abrasive grains are applied directly to the tool base body, and thus the tool base body forms the foundation, the grinding tool is simple, flexible and economical compared to using coated abrasives . It is manufacturable. The abrasive layer can be produced by preparing the desired tool base body and applying an optionally three-dimensionally shaped abrasive layer to the bond in a flexible manner. Since the abrasive grains move along the lines of force, the abrasive grains are applied on the tool base body or the bonding surface in the desired manner depending on the extension of the lines of force and the positioning of the tool base body, resulting in , ensuring a high cutting capacity and a long service life of the grinding tool. Abrasive particles can move toward the bonding surface with or against gravity within an electrostatic field.

The tool base body can be constructed in a single layer or in multiple layers. The tool base body includes at least one material from the group consisting of vulcanized fibres, polyester, glass fibres, carbon fibres, cotton, plastics and metals. The tool base body may have a coated abrasive . The tool base body is elastic in at least one region and/or non-elastic in at least one region. The tool base body may have a hub or shaft for tensioning and for driving the grinding tool in rotation.

Binders are materials from the group consisting of thermosets, elastomers, thermoplastics, and synthetic resins. The binder is in particular a thermosetting plastic such as phenolic resin or epoxy resin. Phenolic resins are, for example, resoles and novolaks. The bonding agent can be applied on the tool base body in any desired manner.

The abrasive grain has a geometrically defined shape and/or a geometrically undefined shape. The abrasive grains comprise at least one material selected from the group consisting of ceramics, in particular corundum such as zirconium corundum, diamond, cubic boron nitride (CBN), silicon carbide and tungsten carbide.

The abrasive grains can be applied in a single layer or in multiple layers, so that the tool base body is provided with at least one layer of three-dimensionally shaped abrasive grains. If several layers of abrasive grains are to be formed, each lower abrasive layer is coated with a bonding agent and subsequent abrasive layers are applied using an electrostatic field in the manner described above. The bond thus forms a basic bond between the tool base body and the layer of abrasive grain applied thereon, and also forms an intermediate bond between the two layers of abrasive grain.

The bonding surface or abrasive layer may be three-dimensionally shaped in any manner, e.g., curved and/or with a plurality of planes juxtaposed, e.g., planes extending obliquely to each other. molded. A curved formation allows, for example, fillet weld processing and/or edge processing. With a plurality of planes extending obliquely to each other, the abrasive grain layer forms a chamfer that enables rough finishing (roughing) or flattening.

The method according to claim 2 ensures a simple, flexible and economical production. A curved bonding surface or curved abrasive layer makes it possible in particular to produce grinding tools for fillet weld processing and/or edge processing. The bonding surface or abrasive layer is in particular convexly and/or concavely curved. The direction of curvature is defined, for example, in relation to the longitudinal central axis of the tool base body and/or in relation to the tensioning side of the grinding tool directed towards the tool drive. The bonding surface or abrasive layer is, for example, cylindrically or spherically shaped.

The method according to claim 3 ensures a simple, flexible and economical production. The movement of the tool base body relative to at least one of the two electrodes ensures a reliable and even coating of abrasive grains on the bonding surface and thus an even grain layer. be. The movement changes the orientation, spacing and/or length with respect to at least one of the electrodes. The movement takes place, in particular, at least partially, while the abrasive grains are moving towards and adhering to the bonding surface. The tool base body is moved using, for example, a mounting device.

Also, the longitudinal central axis of the tool base body for forming the three-dimensionally formed abrasive layer may be oriented (aligned) in different directions with respect to the first electrode. This method ensures simple, flexible and economical production. By orienting the central longitudinal axis of the tool base body in different directions, it is possible to produce intricately shaped abrasive layers.

The method according to claim 4 ensures simple, flexible and economical production. Rotation of the tool base body about its central longitudinal axis allows a fast and even application of abrasive grains. This rotation is especially carried out during the application of the abrasive grains. In particular, the speed of rotation is adjustable, so that coating of the abrasive grains in a simple and flexible manner is possible. The speed of rotation is adjusted, for example, depending on the size and/or mass of the abrasive grains to be applied and/or the desired thickness of the abrasive grain layer.

The method according to claim 5 ensures a high cutting capacity and a long service life. The lines of force of the electrostatic field enter and exit perpendicular to the surface of the electrodes, so that the extension of the lines of force can be adjusted by the surface shape, length, and/or orientation of the electrodes. By properly positioning the bonding surface with respect to the lines of force, a plurality of abrasive grains are dispensed onto the bonding surface in a desired orientation. Due to the orientation, the grinding tool has a high cutting capacity and a long service life.

The method according to claim 1 ensures a simple, flexible and economical production. Using a transport device, the abrasive particles are automatically transported into the electrostatic field and from there are moved to the bonding surface due to the electrostatic field. The transport device can, for example, be driven continuously or intermittently (periodically). In particular, the transport device is driven as a function of the movement of the tool base body. For example, the transport device is synchronized with the movement of the tool base body. In particular, the transport speed of the transport device is adjustable.

Also, the transport device may include a transport belt. This method ensures simple, flexible and economical production. The conveyor belt allows the construction of a seamless (closed loop) conveyor in a simple manner. The transport belt is guided, for example, around at least two diverting wheels, thereby permitting, for example, a continuous drive of the transport device. The transport belt is preferably of electrically insulating design.

The method according to claim 1 ensures a simple, flexible and economical production. Due to the fact that the first electrode is arranged in the direction of gravity below the transport area, the abrasive grains are brought into the electrostatic field in a simple manner. The transport area is formed, for example, by the surface of the transport belt. The first electrode is arranged fixedly or displaceably. The first electrode is in particular plate-shaped. In particular, the plate-shaped electrodes extend essentially parallel to the transport belt.

The method according to claim 6 ensures simple, flexible and economical production. At least one metering device supplies abrasive grains directly to the electrostatic field and/or the conveying device. At least one metering device meters and dispenses abrasive grain to be applied. In particular, at least one metering device is arranged upstream of the conveying device and feeds abrasive grains to the conveying device. At least one metering device is used to supply an abrasive mixture, which preferably consists of abrasive grains (abrasive grain mixture). Within the abrasive mixture, the abrasive grains may vary in size, shape and/or material. The abrasive mixture can, for example, be mixed before being fed into the metering device, thus allowing the feeding of abrasive grains with just one metering device. Furthermore, a plurality of metering devices may be provided, each containing exactly one type of abrasive grain, so that the abrasive mixture can be supplied in a flexible manner. are mixed using a metering device. At least one metering device is used to orient, meter and/or dispense the abrasive grains.

The method according to claim 7 ensures simple, flexible and economical production. By adjusting the voltage, the electrostatic field is adapted to the abrasive grains to be applied.

The tool base body may also form the second electrode. This method ensures simple, flexible and economical production. By virtue of the tool base body itself forming the second electrode, the second electrode is optimally matched to the tool base body. Because the lines of force enter and exit the tool base body perpendicular to the bonding surface, the abrasive grains are directed in a simple manner onto the complex three-dimensionally shaped bonding surface. can be applied. The tool base body is electrically conductive at least partially or layer by layer. By virtue of the tool base body forming the second electrode, it is also possible to produce an abrasive layer that forms an undercut together with the tool base body. In other words, the tool base body or the second electrode remain on the grinding tool and need not be removed.

At least one electrically conductive layer may also be applied to the tool base body. This method ensures simple, flexible and economical production. Since the tool base body forms at least one electrically conductive layer, the tool base body itself forms the second electrode. The electrically conductive layer is arranged in particular on the surface of the base body, for example on the front side and/or on the back side of the tool base body and/or on the interior. The tool base body can, for example, be made entirely of electrically conductive material.

Also, the applied binder may be electrically conductive. This method ensures simple, flexible and economical production. The electrically conductive binder simplifies the coating of the abrasive grains, since the formation of block fields is avoided, and is particularly advantageous with the tool base body if it forms the second electrode. work together.

The tool base body can also be made at least partially of an electrically conductive material. This method ensures simple, flexible and economical production with high cutting capacity and long service life. Due to the electrically conductive material, the tool base body itself forms the second electrode.

The method according to claim 1 ensures a simple, flexible and economical production. Due to the fact that the second electrode is formed separately from the tool base body, it is possible to use the second electrode for producing a plurality of grinding tools. Using a separate second electrode, a tool base body made of any material, in particular a tool base body made of a non-conductive material, can also be abraded.

The method according to claim 8 ensures simple, flexible and economical production with high cutting power and long service life. Due to the fact that the second electrode is shaped in at least part of its area corresponding to the shape of the tool base body, the surface of the second electrode and the bonding surface extend substantially parallel to each other, so that The lines of force are oriented substantially perpendicular to the bonding surface. Thus, the abrasive grains can be oriented in a desired manner when adhering to the bonding surface, thereby enabling high cutting power and long service life. The second electrode is, for example, designed to correspond exactly to the tool base body and is arranged over the entire surface on the tool base body. Furthermore, the second electrode is shaped correspondingly to the tool base body, e.g. It substantially completely covers the adhesive surface especially during transfer.

The method according to claim 9 ensures simple, flexible and economical production with high cutting power and long service life. The abutment of the second electrode against the tool base body causes the surface of the second electrode to extend substantially parallel to and/or near the bonding surface, so that the abrasive grains are as desired. is applied to the adhesive surface with the orientation of This allows a high cutting capacity and a long service life.

The second problem is solved by a grinding tool having the features of claim 10 . The advantages of the grinding tool according to the invention correspond to the advantages of the manufacturing method according to the invention already explained. The grinding tool can also be developed in particular according to at least one feature of at least one of claims 1 to 9. The abrasive grain layer is three-dimensionally formed in any manner. For example curved and/or formed of a plurality of mutually coordinated planes, for example planes extending obliquely to each other. A curved shape allows, for example, the processing of fillet welds and/or the processing of edges. With multiple planes extending at an angle to each other, the abrasive layer forms chamfers that allow rough finishing (roughing) or flattening.

A grinding tool according to claim 11 can be used flexibly. A curved abrasive layer, in particular a convexly and/or concavely curved abrasive layer, allows the processing of fillet welds and/or the processing of edges in a flexible manner.

A grinding tool according to claim 12 ensures flexible use with high cutting power and long service life. Due to the orientation of the abrasive grains towards the tool base body, i.e. within the three-dimensionally formed abrasive layer, the grinding tool has a high cutting capacity and a long service life in different applications. .

Also, each of the abrasive grains has a maximum dimension D, and for at least 80%, especially for at least 90%, and especially for at least 95% of the abrasive grains, 1 μm≦D ≦5000 μm, especially 10 μm≦D≦2500 μm, and especially 100 μm≦D≦1000 μm may apply. This grinding tool guarantees flexible use with high cutting power and long service life. The size of the abrasive grains adjusts the grinding performance of the grinding tool in a desired manner. By means of an abrasive body mixture consisting of large or coarse-grained abrasive grains and small or fine-grained abrasive grains, in particular the targeted adjustment of the cutting space (tip space) and thus the cutting power and the grinding surface or the abrasive grain layer. can have a positive impact on Fine abrasive grains have a maximum dimension _D1 , while coarse grains have a maximum dimension _D2 . Between them, D ₁ ≤ D ₂ holds.

Also, each of the abrasive grains has a maximum dimension _D1 , and for at least 80% of the abrasive grains, especially for at least 90%, and especially for at least 95%, 1 μm≦ D ₁ ≦5000 μm, in particular 5 μm≦D ₁ ≦500 μm and especially 10 μm≦D ₁ ≦250 μm may apply. This grinding tool ensures simple production and flexible use. Abrasive grains are formed of fine particles. Fine-grained abrasive grains are utilized as fillers (filler granules), particularly in combination with coarse-grained abrasive grains. The fine-grain abrasive grains are applied before, with, and/or after the coarse-grain abrasive grains. Fine grain abrasives are applied electrically and/or mechanically. The coarse grain abrasive grains each have a maximum dimension D ₂ , and in particular D ₁ ≤ D ₂ .

Also, each of the abrasive grains has a maximum dimension _D2 , and for at least 80% of the abrasive grains, especially for at least 90%, and especially for at least 95%, 1 μm≦ D ₂ ≤ 5000 µm, in particular 150 µm ≤ D ₂ ≤ 3000 µm, and especially 250 µm ≤ D ₂ ≤ 1500 µm may apply. This grinding tool ensures simple production and flexible use. Coarse-grain abrasive grains are particularly applied (coated) in combination with fine-grained abrasive grains. In this case, the coarse-grained abrasive grains form the main granules and the fine-grained abrasive grains form the filler granules. The filler granules consist, for example, of brown alumina (usually corundum). Coarse-grained abrasive grains are made of, for example, ceramics. Each fine grain abrasive grain has a maximum dimension D ₁ , and in particular D ₁ ≤ D ₂ .

Grinding tools according to claims 13 and 14 ensure flexible use with high cutting power and long service life. After applying the abrasive layer, the abrasive tool or bond (base bond) is cured in a furnace in the usual manner. A bond is applied onto the abrasive layer to form at least one cover bond fixture and possibly additional cover layers. The cutting capacity and service life are improved by the cover joint fixture or the cover layer. The bonding agent is correspondingly configured, for example to form an adhesive surface, and in the usual manner contains abrasive capable fillers, such as cryolite or potassium tetrafluoroborate. You can The cover layer or the cover connection fixing is preferably hardened in a furnace.

Further features, advantages and details of the invention result from the following description of several embodiments.

1 shows a schematic diagram of an apparatus for manufacturing a grinding tool by applying an abrasive grain to a tool base body using an electrostatic field between two electrodes; FIG. 2 shows an enlarged cross-sectional view of the tool base body and associated electrodes of FIG. 1 according to a first embodiment; FIG. 1 shows a schematic cross-sectional view of a finished grinding tool; FIG. Fig. 3 shows a cross-sectional view of a tool base body and associated electrodes according to a second embodiment; FIG. 4 shows a sectional view of a tool base body formed as an electrode according to a third embodiment; FIG. 4 shows a sectional view of a tool base body formed as an electrode according to a fourth embodiment;

In the following, a first embodiment of the invention will be described with reference to FIGS. 1 and 3. FIG. An apparatus 1 for manufacturing a grinding tool 2 comprises a handling device 3 for handling and positioning a tool base body 4, a first electrode 5 and associated second electrodes for generating an electrostatic field E, a conveying device 10. It includes a dosing device (surveying device) 7 for feeding abrasive grains 8, 9 to the.

The transport device 10 comprises a seamless (closed loop) transport belt 11 which is tensioned by means of two diverting rollers 12,13. The diverting roller 12 is driven in rotation, for example by means of an electric drive motor 14 . The part of the transport belt 11 which is arranged above the diverting rollers 12, 13 with respect to the gravitational force _FG forms a transport area 15 extending in the horizontal x-direction and the horizontal y-direction.

The input device 7 is arranged upstream of the electrodes 5 , 6 in the transport device 16 . The first electrode 5 is formed in the form of a plate and is arranged under the upper member of the transport belt 11 or under the transport area 15 in the direction of the force of gravity _FG . Conversely, the second electrode 6 is arranged above the transport belt 11 or the transport area 15 with respect to the gravitational force _FG . The second electrode 6 is thus spaced from the first electrode 5 in the vertical z-direction, so that the transport area 15 extends between the electrodes 5,6. The x-, y-, and z-directions form a Cartesian coordinate system.

The functionality of the device 1 is described below.

The second electrode 6 is formed separately from the tool base body 4 and is shaped correspondingly to the tool base body 4 . A second electrode 6 is fixed to the handling device 3 . The tool base body 4 is held by means of the handling device 3 such that the second electrode 6 essentially rests over its entire surface against the rear face 17 of the tool base body 4 . The handling device 3 holds the tool base body 4, for example mechanically and/or pneumatically. A voltage U is applied between the first electrode 5 and the second electrode 6, which voltage U is generated by a power supply 18 and adjustable.

The tool base body 4 has a three-dimensional (stereoscopic) shape. In the inner region 19 the tool base body 4 is disc-shaped and has, for example, a hub 20 . Alternatively, tool base body 4 may have a shaft instead of hub 20 . Configurations without a hub 20 or shaft are also possible. In contrast, the tool base body 4 is of curved design in a region 21 surrounding region 19 .

The front surface 22 facing away from the second electrode 6 is first applied with a bonding agent 23 , so that the bonding agent 23 arranged on the tool base body 4 forms a three-dimensionally shaped bonding surface 24 . do. The binder 23 is for example a resin, in particular a phenolic resin. The tool base body 4 consists of customary materials, for example Vulcan fiber or polyester. The binder 23 is applied, for example, manually or by means of the handling device 3 . The tool base body 4 is dipped into the bonding agent 23 on the front face 22 using the handling device 3, for example.

The tool base body 4 is subsequently positioned above the first electrode 5 in the z-direction using the handling device 3, so that the bonding surface 24 is partially placed in the electrostatic field E between the electrodes 5,6. be. The lines of force emerge from the surface of the first electrode 5 and enter the surface of the second electrode 6 perpendicularly, so that the lines of force essentially extend through the bonding surface 24 perpendicularly. This is illustrated for f ₁ , f ₂ and f ₃ in FIG.

Using the transport device 10, the abrasive grains 8, 9 are transported into the electrostatic field E to form a three-dimensionally shaped abrasive grain layer 25. FIG. For this purpose, the dosing device 7 prepares, for example, a mixture of fine-grained abrasive grains 8 and coarse-grained abrasive grains 9 . Each of the fine-grained abrasive grains 8 has a maximum dimension _D1 and for at least 80% of the abrasive grains 8, especially for at least 90%, and especially for at least 95% 1 μm≦D ₁ ≦5000 μm, in particular 5 μm≦D ₁ ≦500 μm and especially 10 μm≦D ₁ ≦250 μm apply. In contrast, each of the abrasive grains 9 has a maximum dimension D2 of ₁ μm for at least 80%, especially for at least 90% and especially for at least 95% of the abrasive grains 9. ≦D ₂ ≦5000 μm, in particular 150 μm≦D ₂ ≦3000 μm and especially 250 μm≦D ₂ ≦1500 μm applies. In particular, D ₁ ≤ D ₂ holds. Abrasive grains 8, 9 therefore have a maximum dimension _D1 or _D2 within the mixture, the maximum dimension within the mixture being commonly referred to as D. Accordingly, the abrasive grains 8, 9 within the mixture have a maximum dimension D and for at least 80% of the abrasive grains 8, 9, especially for at least 90%, and especially for at least 95% 1 μm≦D≦5000 μm, in particular 10 μm≦D≦2500 μm and especially 100 μm≦D≦1000 μm.

A suitable amount of the abrasive grains 8 and 9 is charged using the charging device 7, supplied to the conveyor belt 11, and distributed thereon. For example, using an electric drive motor 14, the transport belt 11 is moved in the transport direction 16 with the abrasive grains 8, 9 arranged thereon, so that the abrasive grains 8, 9 are introduced into the electrostatic field E. For example, the electric drive motor 14 can be used to adjust the transport speed in the conveying direction 16 .

The electrostatic field E causes the abrasive grains 8, 9 to move against the gravitational force _FG toward the bonding surface 24 and be directed along the lines of force, for example along the lines of force f ₁ , f ₂ and f ₃ . . When the abrasive grains 8,9 hit the bonding surface 24, they remain bonded there. An abrasive grain layer 25 is formed on the tool base body 4 by the abrasive grains 8 , 9 adhering to it. In order to evenly and evenly apply the abrasive grains 8, 9, the tool base body 4 is rotated about its longitudinal central axis with the aid of the handling device 3. Between the coarser grains 9, the finer grains 8 are attached to the tool base body 4, so that the grain layer 25 is evenly formed. The coarser grains 9 then form the main grains and the finer grains 8 form the fill grains. Abrasive layer 25 is three-dimensionally shaped or curved to correspond to bonding surface 24 . Furthermore, the tool base body 4 is moved, if necessary, such that the central longitudinal axis 26 is oriented in a different direction with respect to the first electrode 5 .

The tool base body 4 together with the bonding agent 23 and the abrasive layer 25 forms a semi-finished product since the abrasive layer 25 has been applied on the tool base body 4 until completion. The semi-finished product is removed from the handling device 3 and placed in a heating device where the binder 23 is cured. Subsequently, at least the cover bond fixing 27 and optionally the cover layer 31 are applied to the abrasive layer 25 in the usual manner. The cover coupling fixture 27 comprises, for example, a bonding agent 23 together with an additional grind-active filler. A cover layer 31 is applied onto the cover coupling fixture 27 . The cover layer 31 has a binder 23 with additional grinding effective fillers. In this case, the proportion of filler material which is effective for grinding is in particular greater than the proportion at the cover coupling fixture 27 . The cover coupling fixture 27 and the cover layer 31 are applied manually, for example. Subsequently, the cover coupling fixture 27 and the cover layer 31 are cured in a heating device. Binder 23 includes, for example, phenolic resin and chalk. Cover bond fixture 27 and cover layer 31 include, for example, phenolic resin, chalk, and cryolite. Humidity during production takes, for example, values between 0% and 100%, in particular values between 35% and 80%. FIG. 3 shows the finished grinding tool.

A second embodiment of the present invention will be described below with reference to FIG. In contrast to the first exemplary embodiment, the second electrode 6 is made smaller than the tool base body 4 and overlaps only a partial area of the tool base body 4 . In this partial area, the second electrode 6 is shaped correspondingly to the tool base body 4 , so that the second electrode 6 extends essentially parallel to the bonding surface 24 . The second electrode 6 does not rest against the rear side 17 of the tool base body 4, but is slightly spaced therefrom. The second electrode 6 is fixedly connected to the handling device 3 , while the tool base body 4 is rotated about the central longitudinal axis 26 with the handling device 3 . The tool base body 4 thus moves relative to the second electrode 6 by rotation about the central longitudinal axis 26 . The abrasive grains 8, 9 move in the direction of the bonding surface 24 in the region of the electrostatic field E and remain adhered there when in contact with the bonding surface 24. FIG. As the tool base body 4 moves relative to the second electrode 6, ie rotates about the central longitudinal axis 26, the entire bonding surface 24 is covered with a layer of abrasive grains 8,9. As regards the further construction of the apparatus 1 and the function of the apparatus 1 and the further construction of the grinding tool 2 reference is made to the previous embodiments.

A third embodiment will be described below with reference to FIG. In contrast to the previous two embodiments, the tool base body 4 itself forms the second electrode 6 . For this purpose, the tool base body 4 consists of an electrically conductive material, in particular metal. The tool base body 4 is made of aluminum, for example. The tool base body 4 illustrated in FIG. 5 has a concavely curved region 28 in addition to the flat inner region (central side region) 19 and the convexly curved region 21 . The bonding surface 24 is therefore three-dimensionally shaped in a complex manner. The applied binder 23 is electrically conductive to avoid blocking fields and to optimize the electrostatic field E. Conductive binder 23 is, for example, a conductive varnish. The lines of force f ₁ to f ₃ again extend vertically through the bonding surface 24 so that the abrasive grains 8 , 9 are directed onto this bonding surface 24 despite the intricately formed bonding surface 24 . applied to the Since the central longitudinal axis 26 essentially extends in the xy plane, rotation of the tool base body 4 about the central longitudinal axis 26 ensures that the inner region 19 as well as the regions 21 and 28 grinds evenly. It is covered in layers by grains 8,9. With respect to the further structure and function of the device 1 and with respect to the further structure of the grinding tool 2, reference is made to the embodiments described above.

A fourth embodiment of the present invention will be described below with reference to FIG. As regards the differences from the above-described embodiments, the tool base body 4 comprises a base body 29 made of a non-conductive material and a conductive layer (membrane) fixedly connected to the base body 29. 30 included. Due to the electrically conductive layer 30 the tool base body 4 itself forms the second electrode 6 . Layer 30 is, for example, a copper film. A bonding agent 23 is coated onto the conductive layer 30 so that an adhesive surface 24 is formed. Binder 23 may be electrically conductive. The tool base body 4 has an inner region 19 , a convexly curved region 21 and a concavely curved region 28 . Between the inner region 19 and the convexly curved region 21 a chamfered region 32 or chamfer is arranged. The chamfered area 32 and the inner area 19 are joined at an angle α, where α≠180°. The chamfered area 32 is used, for example, for roughing or facing. As the tool base body 4 rotates about a longitudinal central axis 26, the bonding surface 24 is reliably and uniformly coated with abrasive grains 8, 9 in a layer despite its complex three-dimensional shape. The resulting abrasive layer 25 is three-dimensionally formed in a complex manner on the basis of convex and concave curvatures and on the basis of chamfers or chamfered areas. With respect to the further structure and function of the device 1 and with respect to the further structure of the grinding tool 2, reference is made to the embodiments described above.

The method according to the invention has a small number of manufacturing steps and in particular avoids deformation of the coated abrasive . The method according to the invention makes it possible to produce grinding tools 2 with complex three-dimensionally shaped abrasive layers for a number of different uses. The cutting power and service life of the grinding tools are in the case of the present invention comparable to grinding tools made from coated abrasives . By electrostatically applying the abrasive grains 8, 9 it is possible in particular that the abrasive grains 8, 9 are oriented with their respective longitudinal axes perpendicular to the bonding surface 24 or surface of the tool base body 4. becomes. This guarantees a high cutting capacity and a long service life. The grinding tool 2 according to the invention also involves less noise and vibration load and less effort in use compared to bonded abrasives .

4 tool base body 5 first electrode 6 second electrode 8 (fine-grained) abrasive grains 9 (coarse-grained) abrasive grains 10 transport device 11 transport belt 23 bond 24 bonding surface 25 abrasive layer 26 longitudinal central axis 27 Cover coupling fixing part 30 Conductive layer 31 Cover layer E Electrostatic field U Voltage

Claims (14)

By a method for manufacturing a grinding tool,
- providing the tool base body (4),
- applying a bonding agent (23) to said tool base body (4) resulting in a three-dimensionally shaped bonding surface (24),
- positioning said tool base body (4) such that said bonding surface (24) is located within the electrostatic field (E) between a first electrode (5) and a second electrode (6); ,
--wherein said first electrode (5) is arranged below the transport area (15) of the transport device (10),
--wherein said second electrode (6) is arranged above said transport area (15) of said transport device (10),
--wherein said tool base body (4) and said second electrode (6) are formed separately from each other, and
- bringing abrasive grains (8, 9) into said electrostatic field (E) such that said abrasive grains (8, 9) are driven by said electrostatic field (E) to said bonding surface (24); using the conveying device (10) so as to move toward and remain adhered to form a three-dimensionally shaped abrasive layer (25) across the bonding surface (24). conveying said abrasive grains (8, 9) into said electrostatic field (E), said non-conductive material of said tool base body (4) being applied with said abrasive grains (8, 9). A method according to claim 1, wherein said abrasive grains (8, 9) are applied directly to said tool base body (4) such that said tool base body (4) forms a foundation. The method of claim 1, wherein
A method, characterized in that said bonding surface (24) is curved to form said three-dimensionally shaped abrasive layer (25). 3. The method of claim 1 or 2,
A method, characterized in that said tool base body (4) for forming said three-dimensionally shaped abrasive layer (25) is moved relative to at least one of said electrodes (5, 6). . A method according to any one of claims 1 to 3, wherein
A method, characterized in that said tool base body (4) for forming said three-dimensionally shaped abrasive layer (25) is rotated about a central longitudinal axis (26). A method according to any one of claims 1 to 4,
The abrasive grains (8, 9) adhering to the bonding surface (24) are at least partially applied to the bonding surface (24) in a desired orientation along the lines of force of the electrostatic field (E). a method comprising: 6. A method according to any one of claims 1 to 5,
A method, characterized in that said abrasive grains (8, 9) are supplied using at least one dosing device (7). A method according to any one of claims 1 to 6,
A method, characterized in that the voltage (U) between said electrodes (5, 6) is adjustable. A method according to any one of claims 1 to 7,
A method, characterized in that said second electrode (6) is formed at least partially corresponding to the shape of said tool base body (4). 9. A method according to any one of claims 1 to 8,
A method, characterized in that said second electrode (6) rests at least partially against said tool base body (4). A grinding tool (2) comprising a tool base body (4) and abrasive grains (8, 9) , wherein the grinding tool (2) is tensioned about a central longitudinal axis (26). A hub (20) is configured in said tool base body (4) or a shaft is arranged in said tool base body (4) for rotationally driving the tool base body (4) said longitudinal In a grinding tool (2) having no resilience in at least some regions for rotating the grinding tool (2) about a central axis (26),
said abrasive grains (8, 9) being applied to said tool base body (4), said tool base body (4) forming a foundation;
said abrasive grains (8, 9) are bonded to said tool base body (4) with a bonding agent (23) to form an abrasive grain layer (25);
The abrasive layer (25) is three-dimensionally formed, and the tool base body (4) is entirely formed of a non-conductive material, the non-conductive material being the first A grinding tool (2) characterized in that said abrasive grains (8, 9) are applied by an electrostatic field (E) between an electrode (5) and a second electrode (6) . A grinding tool (2) according to claim 10, wherein
A grinding tool (2), characterized in that said abrasive layer (25) is curved. A grinding tool (2) according to claim 10 or 11, wherein
A grinding tool (2) characterized in that said abrasive grains (8, 9) are oriented with their respective longitudinal axes generally towards the surface of said tool base body (4). A grinding tool (2) according to any one of claims 10 to 12, wherein
Grinding tool (2), characterized in that said abrasive layer (25) is provided with a cover bond fixture (27) having a bond with an additional grinding-effective filler. A grinding tool (2) according to claim 13, wherein
Grinding tool (2), characterized in that said cover bond fixture (27) is provided with a cover layer (31) having a bond with an additional grinding-effective filler.