Note: Descriptions are shown in the official language in which they were submitted.
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Grinding tool and method for producing a grinding tool
The invention relates to a grinding tool and to a method for producing a
grinding tool.
A roughing grinding wheel is known from EP 1 543 923 Al. The roughing grinding
wheel has
two layers of bonded abrasive particles, the layers being reinforced by
external reinforcements
and internal reinforcements. An annular separating layer is arranged between
the inner rein-
forcements. The separating layer is formed by intermediate layers that rest
against one another
and are composed of paper or plastic film, for example. The separating layer
reduces the ampli-
tude of the vibration during grinding without making the structure of the
abrasive grit bound by
means of binder softer and without increasing abrasion.
It is the underlying object of the invention to provide a grinding tool which
is simple to produce
and can be used in a flexible manner and which has high vibration and noise
damping combined
with high cutting performance and a long life.
This object is achieved by means of a grinding tool having the features of
claim 1. By virtue of
the fact that the at least one fiber ply is arranged in the binder in a
partially movable manner, free
relative movement is achieved within the at least one fiber ply during
grinding, with the result
that the main body achieves high vibration and noise damping. To achieve the
free relative
movement within the at least one fiber ply, the amount of binder used in the
production of the
main body is, on the one hand, sufficiently large to ensure that the main body
has adequate sta-
bility and, on the other hand, sufficiently small to ensure that the at least
one fiber ply is not
bonded continuously and/or over its entire surface to the binder. The at least
one fiber ply is em-
bedded in the binder in such a way that a first region of the at least one
fiber ply is firmly con-
nected to the binder and a second region of the at least one fiber ply is
movable relative to the
binder and the first region. The at least one fiber ply preferably has at
least one yarn. The at least
one yarn is arranged in the binder in a partially movable manner. The at least
one yarn preferably
has a first yarn portion, which is arranged in such a way as to be immovable
relative to the bind-
er, and at least one second yarn portion, which is arranged in a movable
manner relative to the
binder. The second yarn portion is, in particular, arranged in a movable
manner relative to the
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first yarn portion. The binder is preferably a resin and/or an adhesive. The
binder is preferably a
thermoset, in particular phenolic resin or epoxy resin.
The main body and thus the grinding tool can be produced in any desired shape,
providing great
flexibility in the use of the grinding tool. The vibration- and noise-damping
design of the main
body does not have a disadvantageous effect on the abrasive layer. The
abrasive layer is arranged
directly and/or indirectly on the main body, which ensures high stability and
a long life by means
of the at least one fiber ply. The grinding tool is furthermore simple to
produce.
The abrasive layer is designed to match the intended use of the grinding tool.
The abrasive layer
preferably comprises an abrasive particle layer which is applied
electrostatically to the main
body. The abrasive particles of the abrasive particle layer are, in
particular, secured by means of
an adhesive agent on a surface of the main body. In particular, the abrasive
particles are at least
partially aligned with the main body and/or with respect to one another. The
abrasive particles
have a geometrically determined and/or a geometrically indeterminate shape.
The abrasive parti-
cles comprise at least one material selected from the group comprising
ceramics, corundum, in
particular zirconia corundum, diamond, cubic crystalline boron nitride (CBN),
silicon carbide,
and tungsten carbide. The abrasive particles can be applied in a single layer
or in multiple layers.
In the case where a plurality of abrasive particle layers are formed, an
adhesive agent is applied
to the respective abrasive particle layer situated underneath, and the
subsequent abrasive particle
layer is applied. The abrasive particle layer is secured on the main body or a
supporting layer,
which is connected to the main body. The abrasive layer comprises, in
particular, a base binding,
abrasive particles, and a top binding. The abrasive particles can be
introduced at different base
binding levels or applied to the main body.
The abrasive layer comprises, in particular, an abrasive fleece. The abrasive
fleece is secured by
means of an adhesive agent, for example, on a surface of the main body. The
abrasive layer fur-
thermore comprises an abrasive on a backing. The abrasive on a backing
comprises, in particular,
a supporting layer on which abrasive particles are secured. The abrasive on a
backing is designed
as abrasive flaps, for example. The abrasive particles used, in particular
diamond abrasive parti-
cles, can be used on a metal backing.
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The main body preferably has a hub or a shaft for clamping and rotary driving
of the grinding
tool. The grinding tool is, in particular, a grinding wheel.
A grinding tool as claimed in claim 2 ensures high vibration and noise
damping. By virtue of the
.. fact that the yarns of the respective fiber ply are arranged in a partially
movable manner relative
to one another and to the hinder, a movement of the yarns relative to one
another and thus a rela-
tive movement within the respective fiber ply are achieved. The main body
preferably has a plu-
rality of fiber plies, the respective yarns of which are embedded in the
binder in a partially mov-
able manner relative to one another.
A grinding tool as claimed in claim 3 ensures high vibration and noise
damping. The fiber plies
are preferably embedded one above the other in the binder. By virtue of the
fact that the fiber
plies are movable relative to one another in some region or regions, a
relative movement within
the respective fiber ply, on the one hand, and a relative movement between the
fiber plies, on the
other hand, are achieved. By virtue of the multi-ply construction, the main
body furthermore has
a high stability or strength and ensures a long life of the grinding tool. The
fiber plies comprise at
least one first region, which is connected firmly to the binder, and at least
one second region,
which is movable relative to the binder and to the at least one first region.
A grinding tool as claimed in claim 4 ensures high vibration and noise
damping. In particular,
the fiber plies are arranged one above the other. By virtue of the fact that
the yarns are arranged
in a partially movable manner relative to one another and to the binder, a
relative movement be-
tween the fiber plies and/or a relative movement within the respective fiber
ply are/is achieved.
A grinding tool as claimed in claim 5 ensures high vibration and noise damping
and a long life.
By virtue of the fact that the at least one fiber ply comprises at least one
woven fabric and/or at
least one non-crimp fabric, a vibration- and noise-damping relative movement
is achieved in a
simple manner within the main body. At the same time, the main body has a high
stability and
accordingly makes possible a long life. The at least one woven fabric and/or
the at least one non-
.. crimp fabric comprises at least one yarn, in particular a plurality of
yarns. In particular, the at
least one woven fabric comprises warp yarns and weft yarns. The at least one
yarn comprises a
first yarn portion, which is immovable relative to the binder, and at least
one second yarn por-
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tion, which is movable relative to the binder and relative to the first yarn
portion. For example,
the at least one woven fabric has a twill weave. The twill weave fabric allows
simple movements
of the warp yarns and/or of the well yarns within the woven fabric and thus
relative movement in
order to achieve high vibration and noise damping. The at least one woven
fabric and/or the at
least one non-crimp fabric are/is preferably produced from glass fibers,
carbon fibers, cotton
and/or polyester,
A grinding tool as claimed in claim 6 ensures high vibration and noise damping
in combination
with a long life. The more fiber plies the main body comprises, the higher the
degree of relative
movement that can be achieved within the main body is. Furthermore, the
stability of the main
body increases with the number of fiber plies, thereby ensuring a long life.
Conversely, the out-
lay on production increases with the number of fiber plies, and therefore
there is an optimum
range for the number of fiber plies.
A grinding tool as claimed in claim 7 ensures high vibration and noise damping
in combination
with a long life. The following applies to the ratio M: M = mB/mF, where mB
denotes the mass of
the binder, and mF denotes the mass of the at least one fiber ply. On the one
hand, the ratio M
ensures that the main body has sufficient stability and, in particular, is not
delarninated or does
not fold over in an unwanted manner during grinding. On the other hand, the
ratio M ensures that
the at least one fiber ply is not connected fully or over the full area with
the binder and that there
is no continuous bond with the binder, thus ensuring sufficient relative
movement within the
main body. The degree of relative movement within the main body is all the
greater, the smaller
the ratio M. Conversely, the degree of stability is all the greater, the
higher the ratio M.
A grinding tool as claimed in claim 8 ensures high vibration and noise
damping. The damping
particles are incorporated into the main body as a damping additive during
production. On the
one hand, the damping particles themselves have vibration- and noise-damping
properties. On
the other hand, the damping particles prevent the at least one fiber ply from
being connected ful-
ly or over the full area to the binder.
A grinding tool as claimed in claim 9 ensures high vibration and noise damping
in combination
with a long life. The binder ensures that the at least one fiber ply is
reinforced in some region or
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regions, and the binder itself preferably has damping properties. The binder
is a mixture of phe-
nolic resin and natural rubber, for example.
A grinding tool as claimed in claim 10 can be used in a flexible way and
ensures high vibration
and noise damping in combination with high cutting perfolinanee and a long
life. The main body
is of curved design in at least some section or sections of a working region,
In the working re-
gion, the abrasive layer is arranged on the main body. The abrasive layer is
of curved design in at
least some section or sections of the working region. This enables the
grinding tool to be used in
a flexible way, e.g. for fillet weld machining and/or for edge machining. The
main body and/or
the abrasive layer is of curved design, particularly in a radial direction
and/or in a circumferential
direction relative to an axis of rotation of the grinding tool. The curved
design is concave and/or
convex. The abrasive layer preferably comprises an abrasive particle layer,
which is secured di-
rectly on a surface of the main body by means of an adhesive agent. By virtue
of the curved de-
sign of the main body, forces that arise during grinding can be transferred
efficiently to the main
body and damped there, with the result that the grinding tool exhibits high
vibration and noise
damping. By virtue of the fact that the curved main body allows a curved
design of the abrasive
layer, the cutting performance in different applications is high.
A grinding tool as claimed in claim 11 can be used in a flexible way and
ensures high vibration
and noise damping in combination with high cutting performance and a long
life. The supporting
layer serves as an intermediate layer between the main body and the abrasive
layer and has ad-
vantageous properties, depending on the desired use. The supporting layer is
preferably connect-
ed monolithically to the main body. In particular, the supporting layer does
not form any under-
cuts with the main body. Abrasive particles are preferably applied immediately
or directly to the
supporting layer to form the abrasive layer. The abrasive particles are
secured by means of an
adhesive agent on a surface of the supporting layer, for example. The abrasive
particles are se-
cured by electrostatic application on the surface of the supporting layer, for
example. The sup-
porting layer is preferably formed from a metallic material,
A grinding tool as claimed in claim 12 ensures flexible usage capability in
combination with
high cutting performance. The three-dimensional shape of the abrasive layer is
dependent on the
desired use, and therefore high cutting performance and a long life are
achieved for the desired
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use. The abrasive layer is curved, for example, and/or is aligned in several
planes relative to one
another, e.g. in planes that extend obliquely relative to one another. The
abrasive layer is prefer-
ably of curved design in two directions extending perpendicularly to one
another, e.g. in a radial
direction and in a circumferential direction relative to the axis of rotation
of the grinding tool. A
.. curved design allows fillet weld machining and/or edge machining, for
example. By means of
planes extending obliquely to one another, the abrasive layer forms a chamfer
which allows
roughing or surface machining. The abrasive layer is preferably secured by
means of an adhesive
agent directly on a surface of the main body or on a surface of a supporting
layer connected to
the main body. In particular, the abrasive layer is produced by electrostatic
application of abra-
sive particles.
It is furthermore the underlying object of the invention to provide a method
for simple produc-
tion of a grinding tool which can be used in a flexible manner and which has
high vibration and
noise damping combined with high cutting performance and a long life.
This object is achieved by means of a method having the features of claim 13.
The advantages of
the method according to the invention correspond to the advantages of the
grinding tool accord-
ing to the invention that have already been described. In particular, the
method can also be re-
fined by means of features of the grinding tool, in particular by means of a
feature as claimed in
at least one of claims Ito 12.
A method as claimed in claim 14 ensures the production of the grinding tool
with high vibration
and noise damping in combination with a long life. The fiber plies are
arranged one above the
other and are connected to one another in such a way, by heating and then
cooling the binder,
that, on the one hand, the main body has sufficient stability and strength
and, on the other hand,
that a relative movement is achieved within the main body.
A method as claimed in claim 15 ensures the production of the grinding tool
with high vibration
and noise damping in combination with a long life. By virtue of the fact that
the at least one fiber
ply, preferably the plurality of fiber plies, is/are compressed during the
heating of the small
quantity of binder, the binder is distributed sufficiently to ensure that the
main body retains a
sufficient strength. By virtue of the small quantity of binder, however, no
continuous or full-area
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bond is formed within the respective fiber ply and/or between the fiber plies,
thus ensuring that a
relative movement is achieved within the main body during grinding. The
cooling of the binder
preferably also takes place under pressure.
A method as claimed in claim 16 ensures simple production of the grinding tool
with high vibra-
tion and noise damping in combination with a long life, By virtue of the fact
that the at least one
fiber ply is provided with the binder on only one side and/or only in some
region or regions on
two sides, no continuous or full-area bond is formed with the binder during
the production of the
main body. The respective fiber ply is impregnated with the binder, for
example. The impregnat-
ed fiber ply has been produced in an upstream production step, for example.
During the produc-
tion of the main body, a plurality of fiber plies provided with binder and
optionally at least one
fiber ply without binder are preferably arranged one above the other.
A method as claimed in claim 17 ensures simple production of the grinding tool
with high vibra-
tion and noise damping in combination with a long life. By virtue of the fact
that the fiber plies
with and without the binder are arranged adjacent to one another, no
continuous or full-area bond
with the binder is achieved during the production of the main body. The
desired relative move-
ment within the main body is thereby made possible. A plurality of first fiber
plies and a plurali-
ty of second fiber plies are preferably arranged alternately one above the
other. The respective
.. second fiber ply is preferably provided with the binder on one side or on
two sides. The respec-
tive second fiber ply is impregnated with the binder, for example.
A method as claimed in claim 18 ensures simple production of the grinding tool
with high vibra-
tion and noise damping in combination with a long life. As prepared, the at
least one fiber ply
does not have any binder. On the one hand, the layer of binder arranged
adjacent to the at least
one fiber ply gives the main body the required strength. On the other hand,
the at least one fiber
ply does not form a continuous or full-area bond with the binder, and
therefore the desired rela-
tive movement is achieved within the main body during grinding. The layer of
binder is prefera-
bly foiined as a binder film. One layer of binder, in particular a binder
film, is preferably provid-
ed between two fiber plies without binder. One fiber ply without binder and
one layer of binder,
in particular a binder film, are preferably provided alternately.
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A method as claimed in claim 19 ensures the production of the grinding tool
with high vibration
and noise damping in combination with high cutting performance and a long
life. The supporting
layer serves as an intermediate layer between the main body and the abrasive
layer. The support-
ing layer is formed according to the desired use. The supporting layer is
formed, for example,
.. from a metallic material, a woven supporting fabric and/or paper. In
particular, the supporting
layer is connected monolithically to the main body. The abrasive layer is
secured on the support-
ing layer or on one surface of the supporting layer. The abrasive layer can be
arranged or secured
on the supporting layer before and/or after the supporting layer is arranged
on the main body.
A method as claimed in claim 20 ensures simple production of the grinding tool
with the capaci-
ty for flexible use in combination with high cutting performance. The abrasive
layer comprises
an abrasive particle layer fainted by the applied abrasive particles. By means
of the electrostatic
application of the abrasive particles, the abrasive particle layer is secured
directly on the main
body or on a supporting layer arranged on the main body. Electrostatic
application makes possi-
ble a three-dimensional shape of the abrasive layer in a simple way, thus
allowing the grinding
tool produced to be used flexibly. Furthermore, electrostatic application
enables the main body
or supporting layer to be re-coated or re-covered. Thus, after consumption of
an abrasive layer,
the remaining grinding tool can be renewed by electrostatic application of a
new abrasive parti-
cle layer for repeated use. By electrostatic coating, the abrasive particles
are applied directional-
ly, in particular according to the course of the electrostatic field lines.
High cutting performance,
especially when using abrasive particles with a geometrically determined
shape, is thereby
achieved. In particular, the abrasive particles are secured on the main body
or the supporting
layer by means of an adhesive agent. The formation of the abrasive layer is
accomplished, in
particular, by multiple electrostatic applications of abrasive particles.
Further features, advantages and details of the invention will become apparent
from the follow-
ing description of a number of illustrative embodiments. In the drawings:
Figure 1 shows a sectional view of a grinding tool according to a
first illustrative embodi-
inent with a main body and an abrasive layer arranged thereon,
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Figure 2 shows an enlarged sectional view of the grinding tool in
figure 1 to illustrate a
structure of the main body with a binder and with fiber plies embedded in a
par-
tially movable manner in the binder,
Figure 3 shows a schematic illustration of the production of the main body
according to a
first method,
Figure 4 shows a schematic illustration of the production of the main
body according to a
second method,
Figure 5 shows a schematic illustration of the production of the main
body according to a
third method,
Figure 6 shows a schematic illustration of the production of the main
body according to a
fourth method,
Figure 7 shows a schematic illustration of the electrostatic
application of abrasive particles
to the main body,
Figure 8 shows a schematic sectional illustration of a grinding tool
according to a second
illustrative embodiment, and
Figure 9 shows a schematic illustration of the production of the main
body of the grinding
tool in figure 8.
A first illustrative embodiment of the invention is described below with
reference to figures I to
7. A handheld grinding machine (not illustrated specifically) is used in
operation to drive a
grinding tool 1 in rotation.
The grinding tool 1 is of disk-shaped design. The grinding tool I comprises a
main body 2 and
an abrasive layer 3 arranged thereon. In a clamping region 4, the main body 2
has a circular
opening 5 to receive a drive shaft of the grinding machine. The opening 5
defines an axis of rota-
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tion 6 of the grinding tool 1. As an alternative to the opening 5, the
grinding tool 1 can have a
shaft.
The grinding tool I comprises a working region 7, which surrounds the clamping
region 4 in a
ring shape. In the working region 7, the abrasive layer 3 is arranged on the
main body 2. The
working region 7 is divided into an inner region 8 and an outer region 9. The
inner region 8 is of
annular design and surrounds the clamping region 4. In the inner region 8, the
surface of the
main body 2 on which the abrasive layer 3 is arranged is of substantially
level design. The outer
region 9 is of annular design and surrounds the inner region 8. In the outer
region 9, the surface
of the main body 2 on which the abrasive layer 3 is arranged is of
substantially curved design. In
the outer region 9, the main body 2 is curved relative to the axis of rotation
6 along a radial di-
rection R and along a circumferential direction U. By virtue of the curvature
of the main body 2,
the abrasive layer 3 is formed in a correspondingly curved and three-
dimensional way.
The main body 2 comprises a number N of fiber plies, wherein the following
applies in general:
1 < N < 12, in particular 2 < N < 10, and in particular 4 < N < 8. The fiber
plies are denoted indi-
vidually by Fi, where i denotes a running index for the individual fiber plies
and depends on the
number N. By way of example, the grinding tool I illustrated in figure 1
comprises four fiber
plies, which are denoted individually by F1 to F4. The fiber plies Fi to F.4
are illustrated only
schematically in figure 1. The fiber plies F1 to F4 are designed as woven
fabric and/or non-crimp
fabric.
The main body 2 comprises a binder B, in which the fiber plies Ft to F4 are
embedded in such a
way that the fiber plies F1 to F4 are connected partially firmly to the binder
B and are arranged in
such a way as to be partially movable relative to the binder B and relative to
one another. To
achieve this, a mass ma of the binder B to a mass mE of the fiber plies F1 to
F4 is relatively small.
For a ratio M = ma/mF of the mass ma of the binder B to the mass mF of the
fiber plies Ft to F4,
the following applies: 1/25 < M < 1/2, in particular 1/20 < M < 1/3, in
particular 1/15 < M < 1/4,
and in particular 1/12 < M < 1/6. The binder B is an organic adhesive, in
particular phenolic res-
in, epoxy resin and/or natural rubber.
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Figure 2 illustrates the partially movable arrangement of the fiber plies F1
to F4 in the binder B.
The adjacent fiber plies F1 and F2 are illustrated by way of example in figure
2. The fiber plies F1
to F4 are designed as woven fabrics, for example, and each have a plurality of
weft yarns S and
warp yarns K extending transversely thereto. In figure 2, the weft yarns S1
and the warp yarns K1
of the first fiber ply Ft and the weft yarns Sz and the warp yarns K2 of the
second fiber ply F2 are
illustrated. Owing to the relatively small quantity of binder B, connection-
free regions V. in
which the fiber plies Fi to F4 are not connected by the binder B, are formed
in the main body 2.
In these connection-free regions V, the fiber plies F1 to F4 are movable in
themselves and relative
to the binder B. The fiber plies Ft to F4 embedded in the binder B are thus
movable in them-
selves and/or relative to one another in some regions. In the connection-free
regions V, the weft
yarns Si, S2 and/or the warp yarns Ki, K2 are movable relative to one another,
for example. The
connection-free regions V allow a relative movement of the fiber plies F1 to
F4 in some regions
within the main body 2.
The abrasive layer 3 comprises abrasive particles 10 with a geometrically
determined shape,
which are secured on the main body 2 by means of an adhesive agent 11. The
adhesive agent 11
is a resin, in particular phenolic resin, for example. The abrasive particles
10 are arranged direc-
tionally relative to one another and relative to a surface of the main body 2.
The abrasive parti-
cles 10 form an abrasive particle layer 12. A top binding 13 and a top layer
14 are arranged on
the abrasive particle layer 12 in the usual way. The top binding 13 and/or the
top layer 14 prefer-
ably have/has fillers with a grinding action.
By virtue of the fact that the fiber plies Ft to F4 allow a relative movement
in themselves and/or
relative to one another, forces which arise during grinding are absorbed by
the main body 2,
thereby ensuring high vibration and noise damping. The main body 2
nevertheless has sufficient
stability and strength, and therefore the grinding tool 1 has a long life. The
main body 2 can be
produced easily and in any geometrical shape, and therefore the grinding tool
I is flexible in ap-
plication. The abrasive layer 3 is easy to apply to the main body 2 shaped in
the desired manner,
and therefore the abrasive layer 3 ensures high cutting performance of the
grinding tool 1.
The production of the main body 2 is described below:
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A first production method is illustrated in figure 3. In the first production
method, the fiber plies
F1 to F4 arc prepared without binder. Layers of binder B are arranged between
the fiber plies F I
to F4 that are arranged one above the other. The layers of binder B are
designed as binder films.
The fiber plies F1 to F4 and the layers of binder B arranged therebetween are
then pressed against
.. a main body form G under a pressure p and heated in such a way that the
binder B becomes flu-
id. The hinder B connects the fiber plies F1 to F4 in the manner described.
The main body 2 is
formed by cooling the binder B.
A second production method for the main body 2 is illustrated in figure 4. In
the second produc-
tion method, fiber plies Fi and F4 are prepared without binder B, and fiber
plies F2 and F3 are
prepared with binder B. Fiber plies F2 and F3 are each impregnated with the
binder B on both
sides. The fiber plies Fi to F4 are arranged one above the other and pressed
against the main body
form G under a pressure p and heated in such a way that the binder B becomes
fluid. The binder
B connects the fiber plies Fl to F4 in the manner described. The main body 2
is formed after the
cooling of the binder B.
A third production method for the main body 2 is illustrated in figure 5. In
the third production
method, the fiber plies Fi to F4 are impregnated on one side with the binder B
during preparation.
The fiber plies F] to F4 are arranged one above the other and pressed against
the main body form
G under a pressure p and heated in such a way that the binder B becomes fluid.
The binder B
connects the fiber plies F1 to F4 in the manner described. The main body 2 is
formed after cool-
ing 4.
A fourth production method for the main body 2 is illustrated in figure 6. In
this production
method, the prepared fiber plies Fi to F4 are each provided in some region or
regions with the
binder B on two sides. The fiber plies Fi to 1-.4 are impregnated with the
binder B in some region
or regions. The fiber plies Fi to F4 are arranged one above the other, pressed
against the main
body form G under a pressure p and heated in such a way that the binder B
becomes fluid. The
binder B connects the fiber plies Fi to F4 in the manner described. After
cooling, the connected
fiber plies Fi to F4 form the main body 2.
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The production method and the fiber plies F1 to F4 prepared can be combined
with one another in
a desired manner.
The formation of the abrasive layer 3 on the main body 2 and the production of
the grinding tool
1 are described below:
By means of an application device 15, the abrasive particles 10 are applied
electrostatically to
the main body 2. The application device 15 comprises a handling device 16 for
handling and
positioning the main body 2, a first electrode 17 and an associated second
electrode 18 for getter-
ating an electrostatic field E, and a metering device 19 for feeding the
abrasive particles 10 to a
conveyor 20.
The conveyor 20 comprises an endless conveyor belt 21, which is tensioned by
means of two
deflection pulleys 22, 23. Deflection pulley 22 is driven in rotation by means
of an electric drive
motor 24. A part of the conveyor belt 21 arranged above the deflection pulleys
22,23 in relation
to the force of gravity Fci forms a conveying region 25, which extends in a
horizontal x direction
and a horizontal y direction.
The metering device 19 is arranged ahead of the electrodes 17, 18 in a
conveying direction 26.
The first electrode 17 is of plate-shaped design and is arranged below the
upper part of the con-
veyor belt 21 and below the conveying region 25 in the direction of the force
of gravity FG. In
contrast, the second electrode 18 is arranged above the conveyor belt 21 and
the conveying re-
gion 25 in relation to the force of gravity Fu. The second electrode 18 is
thus spaced apart from
the first electrode 17 in a vertical z direction, with the result that the
conveying region 25 extends
.. between the electrodes 17, 18. The second electrode 18 is secured on the
handling device 16. The
x, y and z directions form a Cartesian coordinate system.
The second electrode 18 is shaped to match the main body 2. The main body 2 is
held by means
of the handling device 16 in such a way that the second electrode 18 rests
substantially over the
full area against a rear side of the main body 2. The handling device 16 holds
the main body 2
mechanically and/or pneumatically, for example. An electric voltage UE, which
is generated and
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can be set by means of a voltage source 27, is applied between the first
electrode 17 and the sec-
ond electrode 18.
The adhesive agent 11 is first of all applied on a surface facing away from
the second electrode
18, with the result that the adhesive agent 11 arranged on the main body 2
folins a three-
dimensionally shaped adhesion surface, The adhesive agent 11 is applied
manually, for example,
or by means of the handling device 16. The surface of the main body 2 is
dipped into the adhe-
sive agent 11 by means of the handling device 16, for example.
The main body 2 is then positioned above the first electrode 17 in the z
direction by means of the
handling device 16, with the result that the adhesion surface is arranged
partially in the electro-
static field E between the electrodes 17, 18. The field lines emanate
vertically from the surface of
the first electrode 17 and enter the surface of the second electrode 18
vertically, with the result
that the field lines run substantially vertically through the adhesion
surface.
By means of the conveying device 20, the abrasive particles 10 for the
formation of the three-
dimensionally shaped abrasive particle layer 12 are transported into the
electrostatic field E. For
this purpose, the metering device 19 supplies the abrasive particles 10. The
abrasive particles 10
are fed to the conveyor belt 21 and distributed thereon in a metered manner by
means of the me-
tering device 19. By means of the electric drive motor 24, the conveyor belt
21 with the abrasive
particles 10 arranged thereon is moved in the conveying direction 26, thus
ensuring that the abra-
sive particles 10 are brought into the electrostatic field E. The speed of
transfer in the conveying
direction 26 can be set by means of the electric drive motor 24.
By means of the electrostatic field E, the abrasive particles 10 are moved to
the adhesive agent
11 and the adhesion surface counter to the force of gravity FG, and are
aligned along the field
lines. When the abrasive particles 10 touch the adhesion surface, they remain
stuck there. By
means of the adhering abrasive particles 10, the abrasive particle layer 12 is
formed on the main
body 2. In order to apply the abrasive particles 10 uniformly and
homogeneously, the main body
2 is rotated about a central longitudinal axis 28 by means of the handling
device 16.
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After the abrasive particle layer 12 has been fully applied to the main body
2, the main body 2
with the adhesive agent 11 and the abrasive particle layer 12 forms a
semifinished product. The
semifinished product is released by the handling device 16 and arranged in a
heating device,
where the adhesive agent 11 is cured. The top binding 13 and the top layer 14
are then applied to
.. the abrasive particle layer 12 in the usual way. In respect of further
details and features of the
grinding tool 1 and of the electrostatic application of the abrasive particles
10, attention is drawn
explicitly to WO 2018/149 483 Al, the contents of which are incorporated by
reference at this
point.
A second illustrative embodiment of the invention is described below with
reference to figures 8
and 9. In contrast to the previous illustrative embodiment, the main body 2
comprises damping
particles D. The damping particles D are natural rubber particles and/or foam
particles, for ex-
ample. The damping particles D are incorporated into the main body 2 during
the production of
the latter. The damping particles D form additional connection-free regions V
and themselves
have noise- and vibration-damping properties.
The grinding tool 2 furthermore comprises a supporting layer 29, which is
connected to the main
body 2 and provides a surface for the arrangement of the abrasive layer 2. The
supporting layer
29 is composed of a metallic material. The supporting layer 29 is connected
monolithically to the
main body 2. For this purpose, the supporting layer 29 is produced together
with the main body
2. This is illustrated in figure 9. The supporting layer 29 is covered
electrostatically with abrasive
particles 10 in the manner described before and/or after being connected to
the main body 2. In
respect of further aspects of the construction, production and operation of
the grinding tool 1,
attention is drawn to the previous illustrative embodiment.
In general, the following applies:
The grinding tool I according to the invention does not have continuous or
full-area bonding
with the binder within the main body 2, and therefore there are connection-
free free spaces or
.. regions within the main body 2, e.g. air inclusions. The main body 2 has a
quantity of binder B
such that, on the one hand, a relative movement is made possible within the
main body 2 but, on
the other hand, the main body 2 is sufficiently firm and does not delaminate
during grinding.
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This is achieved by means of insular or fine wetting of the fiber plies F1.
The free relative move-
ment within the fiber plies Fi or the respective fiber ply Fi allows high
vibration and noise damp-
ing. By virtue of the fiber plies Fi connected to one another by means of the
binder B and by vir-
tue of the possible relative movement within the respective fiber ply Fi, a
construction of the
main body 2 such that there are alternating hard and soft layers is achieved.
An additional rubber
ply is not required to achieve high vibration and noise damping, The fiber
plies F1 moving one
inside the other make possible the high vibration and noise damping but ensure
that there is no
wrinkling. The main body 2 can be produced with any desired three-dimensional
shape, in par-
ticular by draping the fiber plies F; and connecting the fiber plies Fl by
means of the binder B.
The respective fiber ply Fi has a connection on both sides to the binder B,
thus ensuring that
there is no delamination of the fiber plies F. The binder B connects the
individual fiber plies Fi,
which remain inherently flexible. The binder B is an elastomer, for example,
thereby assisting
the vibration and noise damping of the main body 2. The at least one fiber ply
Fi is padded, for
example. The at least one fiber ply F1 is coated, laminated, sheathed or
silanized with the binder
B, for example. The respective fiber ply Fi is designed as a woven fabric or
non-crimp fabric.
The fiber plies Fj within the main body 2 are designed as woven fabrics and/or
non-crimp fab-
rics. The woven fabric has a twill weave, for example. A twill weave ensures
movement or mo-
bility within the woven fabric and simplicity of draping. The fiber plies Fi
are arranged as inner
fiber plies and/or outer fiber plies in the main body 2. The abrasive layer 3
can comprise an abra-
sive particle layer 12 or an abrasive fleece. The abrasive particle 10 is a
coated ceramic particle,
for example. The supporting layer 29 serves as an intermediate layer between
the main body 2
and the abrasive layer 3. The supporting layer 29 can be designed as paper,
film and/or woven
fabric. The supporting layer 29 is composed of a metallic material, for
example. Abrasive parti-
cle 10 is preferably applied directly to the main body 2 or the supporting
layer 29.
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