U.S. patent application number 17/635307 was filed with the patent office on 2022-09-29 for apparatus and method for cutting edge preparation.
The applicant listed for this patent is Timo Bathe, Technische Universitat Dortmund. Invention is credited to BATHE Timo.
Application Number | 20220305605 17/635307 |
Document ID | / |
Family ID | 1000006448406 |
Filed Date | 2022-09-29 |
United States Patent
Application |
20220305605 |
Kind Code |
A1 |
Timo; BATHE |
September 29, 2022 |
APPARATUS AND METHOD FOR CUTTING EDGE PREPARATION
Abstract
The invention describes an apparatus (1) for a cutting edge
preparation of cutting tools (5), in particular of drills or
milling tools or similar tools (5), in particular of hard-metal
cutting tools, wherein during a relative movement the cutting tool
(5) interacts in a machining fashion with a flexibly-bonded
grinding body (2) that is provided with abrasive particles, the
particles of the grinding body (2) influencing the edge geometry of
the cutting tool (5), wherein the grinding body (2) is adapted with
its dimensions substantially to the dimensions of the respective
cutting tool (5) that is to be prepared and is accommodated in an
exchangeable holder (4) which is arranged in a region of a
processing device, in particular of a tool grinding machine, and is
held such that it is machinable by the cutting tool (5) for the
cutting edge preparation. Furthermore, a corresponding method and a
corresponding grinding body (2) are given.
Inventors: |
Timo; BATHE; (Dortmund,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bathe; Timo
Technische Universitat Dortmund |
Dortmund
Dortmund |
|
DE
DE |
|
|
Family ID: |
1000006448406 |
Appl. No.: |
17/635307 |
Filed: |
August 10, 2020 |
PCT Filed: |
August 10, 2020 |
PCT NO: |
PCT/DE2020/000184 |
371 Date: |
February 14, 2022 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B 3/242 20130101;
B24D 5/063 20130101; B24B 19/04 20130101; B24B 27/0076 20130101;
B24B 3/021 20130101; B24D 13/02 20130101; B24B 3/18 20130101 |
International
Class: |
B24B 3/02 20060101
B24B003/02; B24B 3/18 20060101 B24B003/18; B24B 3/24 20060101
B24B003/24; B24B 19/04 20060101 B24B019/04; B24B 27/00 20060101
B24B027/00; B24D 5/06 20060101 B24D005/06; B24D 13/02 20060101
B24D013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 14, 2019 |
DE |
10 2019 005 692.2 |
Oct 7, 2019 |
DE |
20 2019 004 112.5 |
Claims
1. An apparatus (1) fora cutting edge preparation of cutting tools
(5), wherein during a relative movement the cutting tool (5)
interacts in a machining fashion with a flexibly-bonded grinding
body (2) that is provided with abrasive particles, the particles of
the grinding body (2) influencing the edge geometry of the cutting
tool (5), wherein the grinding body (2) is adapted with its
dimensions substantially to the dimensions of the respective
cutting tool (5) that is to be prepared and is accommodated in an
exchangeable holder (4) which is arranged in a region of a
processing device and is held such that it is machinable by the
cutting tool (5) for the cutting edge preparation.
2. The apparatus (1) according to claim 1, wherein the exchangeable
holder (4) is held in the workroom of a tool grinding machine.
3. The apparatus (1) according to claim 1, wherein the grinding
body (2) is implemented substantially in a cylindrical fashion.
4. The apparatus (1) according to claim 3, wherein the cylindrical
circumferential measurements of the grinding body (2) are
substantially adapted to the circumferential measurements of the
cutting tool (5) that is to be prepared.
5. The apparatus (1) according claim 1, wherein after complete
usage, the grinding body (2) can be simply replaced by a new
grinding body (2).
6. The apparatus (1) according to claim 1, whrerein the
rotationally symmetrical grinding body (2) can be manufactured and
be pressed into the exchangeable holder (4) with a very slight
allowance that is adapted to the diameter of the cutting tool (5)
that is to be prepared.
7. The apparatus (1) according to claim 1, wherein the exchangeable
holder (4) is insertable into a bore (11) in the grinding disk
receptacle (3).
8. The apparatus (1) according to claim 7, wherein the exchangeable
holder (4) comprises an outer thread (6), which can be screwed into
the bore (11) in the grinding disk receptacle (3) that is provided
with an inner thread, or of a different processing device.
9. The apparatus (1) according to claim 7, wherein that the
exchangeable holder (4) can be pressed or inserted into the bore
(11) in the grinding disk receptacle (3) and is held there in a
rotationally fix fashion.
10. The apparatus (1) according to claim 1, wherein a guide bushing
(12) is arranged in the region of the exchangeable holder (4) for
the grinding body (2), via which long-projecting asymmetrical
cutting tools (13), having a great length:diameter ratio, can be
guided and prepared, wherein the guide bushing (12) is arranged
relative to the exchangeable holder (4) in such a way that the
guide bushing (12) guides and supports the long-projecting cutting
tool (13) in front of the region of the machining of the grinding
body (2).
11. The apparatus (1) according to claim 1, wherein sensor
elements, which provide information on the progression of the
cutting edge preparation, are introducible in the exchangeable
holder (4), wherein the sensor elements are equipped with
accumulators, which are integrated in the exchangeable holder (4)
and can be charged in the grinding disk magazine or externally
while not in use.
12. The apparatus (1) according to claim 1, wherein the grinding
body (2) comprises abrasive particles and is successively
completely machinable by the cutting tools (5) which are to be
prepared.
13. The apparatus (1) according to claim 12, wherein the grinding
body (2) comprises a mixture of fine and coarse abrasive particles,
wherein a distribution of fine and coarse abrasive particles within
the grinding body (2) is implemented inhomogeneously.
14. The apparatus (1) according to claim 1, wherein the grinding
body (2) has an axially-extending perforation (15) which is adapted
to the cutting tool diameter (5) and within which the cutting tool
(5) is not affected by the particles of the grinding body (2).
15. The apparatus (1) according to claim 1, wherein the grinding
body (2) comprises sections (21, 22) having differing degrees of
hardness of the bonding.
16. A method for a cutting edge preparation of cutting tools (5),
wherein during a relative movement the cutting tool (5) interacts
in a machining fashion with a flexibly-bonded grinding body (2)
which is provided with abrasive particles, the particles of the
grinding body (2) influencing the edge geometry of the cutting tool
(5), wherein the grinding body (2) is adapted with its dimensions
substantially to the dimensions of the respective cutting tool (5)
that is to be prepared and is accommodated in an exchangeable
holder (4) which is arranged in the region of a processing device
and in which the grinding body (2) is successively completely
machined by the cutting tools (5) which are to be prepared.
17. The method according to claim 16, wherein the cutting edge
preparation is carried out in the same clamping arrangement,
directly following a first-time manufacturing of the shape of the
cutting tool (5) or following a regrinding of the cutting tool (5),
on the same processing device.
18. The method according to one of claim 16, wherein in the
machining of the grinding body a wide range of adaptation of the
cutting speeds is obtainable by the relative movement of grinding
body (2) and cutting tool (5).
19. The method according to claim 18, wherein the grinding body (2)
and the cutting tool (5) execute rotary movements during the
machining of the grinding body (2), wherein a superimposition of
the rotary movements of the grinding body (2) and of the cutting
tool (5) permits selective roundings of the cutting edge of the
cutting tool (5).
20. The method according to claim 18, wherein during the cutting
edge preparation the cutting tool (5) that is to be prepared
executes the necessary translational and rotary movements.
21. The method according to claim 16, wherein the grinding body (2)
creates variable roundings over the cutting region of the cutting
tools (5) by means of sections having different degrees of hardness
of the bonding.
22. The method according to claim 16, wherein due to an
axially-extending perforation (15), which is adapted to the cutting
tool diameter (5) and within which the cutting tool (5) is not
affected by the particles of the grinding body (2), the grinding
body (2) does not subject the axial regions of the cutting tool (5)
to a cutting edge preparation.
23. The method according to claim 16, wherein the grinding body (2)
has external measurements which are adapted to the cutting tool
diameter (5), such that only selected regions of the cutters of the
cutting tool (5) are subjected to a cutting edge preparation.
24. The method according to claim 16, wherein the cutting edge
preparation is carried out on new tools (5) or on cutting tools (5)
which were reground and are therefore already coated with a
hard-metal layer on certain functional surfaces.
25. The method according to claim 16, wherein the cutting tool (5)
having main cutters and secondary cutters successively machines--by
means of its main cutters, respectively secondary
cutters--respectively corresponding grinding bodies (2) which have
different characteristics and are allocated one by one.
26. A grinding body (2) for an execution of the method according to
claim 16, wherein the cylindrical circumferential measurements of
the grinding body (2) are substantially adapted to the
circumferential measurements of the cutting tool (5) that is to be
prepared.
Description
[0001] The invention concerns an apparatus and a method for cutting
edge preparation according to the preamble of claim 1 and a method
according to the preamble of claim 16 as well as a machinable
grinding body according to the preamble of claim 26.
[0002] In a manufacture with machining, for different processing
tasks tools are required which achieve high manufacturing accuracy
on the component together with a long lifespan in order to ensure
economic and competitive product manufacturing of the producing
enterprises. In addition to a good wear resistance of the tools,
predictable wear behavior is crucial for ensuring high-grade
procedural reliability. For the purpose of improving the practice
behavior of machining tools, in particular in the field of hard
metal tools so-called cutting-edge preparation has been established
as an essential process step in the production chain. Herein
fine-honing, in particular of the tool cutter, realized after the
grinding process for a production of the basic macro-shape of a
tool is referred to as cutting edge preparation. Due to the
brittle-hard material behavior of hard metals, microscopic defects,
like breakout along the cutting edge, are caused by the grinding
process. Cutting edge preparation permits remedying such defects as
well as creating a cutting edge shape that is adapted to the
specific machining process. In many application cases such a
load-adapted design of the cutting edge moreover allows augmenting
the stability of the cutting edges to such an extent that increased
machining volumes can be chosen without loss of service time. As a
result, economic efficiency of the production is significantly
increasable.
[0003] Customary well-known methods for cutting edge preparation,
some of which are well-established, are mainly based on methods
with a geometrically undefined cutter, like abrasive blasting,
magnetic finishing, drag grinding and flow grinding. Beyond these,
further separating methods are known, like brushing, spark erosion
and laser abrasion as well as the grinding of roundings, for the
preparation of cutting edges. The aforementioned methods share the
feature that their realization usually requires a special machine
or apparatus, which often means high investment costs. These
investment costs are a big obstacle, just for small and medium
tool-manufacturing enterprises. A further disadvantage in the
context of the aforementioned methods is a--sometimes
considerable--increase of the throughput time in tool
manufacturing. This, on the one hand, results from the additional
processing time required for the preparation process. On the other
hand, using a separate machine usually requires additional handling
efforts. For the sake of completeness it should be mentioned that
in the current prior art none of the above-described methods is
used for the preparation of reground tools. There being is no
opportunity for a preparation of cutting edges in a reground state,
these tools generally do not achieve the production quantities of
new tools.
[0004] Each of the aforementioned methods has specific advantages
and disadvantages regarding, on the one hand, the application of
the methods themselves but also the resulting shape of edges and
surfaces of the tools. Due to their considerable industrial
relevance, in the following only these methods will be discussed:
abrasive blasting, brushing, drag grinding, grinding, in particular
using elastically bonded grinding disks, as well as drill
polishing, which is similar to the above methods.
[0005] In abrasive blasting a blasting agent, consisting of an
abrasive medium and a carrier medium, is accelerated onto the
workpiece surface with huge kinetic energy via a blasting nozzle.
The abrasive medium is differentiated by grain type, grain size and
grain shape. The carrier medium is here often a liquid or air. The
most important process influences onto the method are, besides the
selection of the blasting agent, the blasting feed rate, the
blasting pressure and the blasting angle. The method permits
flexible guiding of the blasting nozzle or of the tool that is to
be prepared, thus enabling selective processing of individual
cutter regions. It is thus in particular suitable for creating
complex cutting edge shapes with rather smaller rounding
dimensions, wherein selective controlling of material abrasion is
quite difficult. In particular in the case of very small tool
diameters and with closely-situated cutters, there may be undesired
influence on further cutting edges which are not to be prepared,
due to so-called passive blasting. This will have a negative
influence on process accuracy and/or on the reproducibility of the
process result. On the free surfaces and machining surfaces which
adjoin the blasted cutting edge and come into contact with the
abrasive blast, a characteristic dimpled structure is formed, which
usually results in an optical matting of the surface.
[0006] A method that is also well established in an industrial
context is brushing. The material abrasion is brought about by
traversing a rotating brush provided with an abrasive medium along
the cutting edge of the tool. The method is suitable for efficient
production of rather large and asymmetric roundings.
Process-related influencing factors of the method are the cutting
speed, the feed rate, the feed motion, the pitch angle of the
cutting edge and the brushing duration. Tool-related influences are
the thread diameter, the grain size of the abrasive medium, the
bristle type and the bristle density. Due to this great number of
influencing factors, process controlling is complex and requires
accurate knowledge of the method and of the interactions for
precisely targeted implementation. In addition to process
controlling, process reliability is negatively affected by wear of
bristles. In the case of smaller tool diameters, the generation of
complex cutter shapes is also limited.
[0007] Drag grinding, which is a variant of vibratory grinding, is
a method that is also widely used in an industrial context.
Material abrasion is brought about by guiding the tools which are
to be prepared through a loose, usually resting abrasive medium.
Tool movement is herein mostly rotary. Above all, the rotation
speed, the rotation direction, the insertion depth, the processing
time and the selected abrasive medium are relevant for the
processing result. The method permits efficiently creating both
small and large roundings. Moreover, considerable improvement of
surface quality is obtainable. However, usage also has some
disadvantages. Due to the immersion of the tool in the abrasive
agent, there is a large contact area of the agent with the tool. In
all such contact zones there will be material abrasion, such that
selective preparation of individual cutter regions is almost
impossible. It is also difficult to adjust formation factors as
well and graded roundings and, in particular in the case of shaft
tools, in regions with larger diameters considerable material
abrasion will be induced by the rotary movement.
[0008] Cutting edge preparation may also be realized by a grinding
process. Usually a single or double bevel is created along the
cutting edge. In a more recent approach more than two bevels are
created, thus approximating the profile shape of the cutting edge
to a rounding. Beyond this the application of elastically bonded
grinding disks is also known in the field of tool preparation. One
field of application is the fine-honing of chip flutes of machining
tools.
[0009] From DE 10 2011 054 276 B4 a method for cutting edge
preparation of cutting tools is known, in particular of drills or
of milling tools, in particular of hard-metal cutting tools,
wherein following a generation of the desired cutting geometry, the
cutting tool is first of all adjusted and/or oriented with respect
to the required workpiece data of the cutting geometry and/or
cutting characteristics, the cutting tool is brought into a rotary
movement and is then introduced or bored, while maintaining the
rotary movement, into a grinding disk comprising silicon carbide
components, tungsten carbide components or diamond components and
is flexibly bonded with a rubber-containing bonding agent, to a
depth selected depending on the cutting edge geometry and in a
position on the circumference of the grinding disk selected for
this purpose. Herein a rotating tool is traversed into a grinding
disk with a defined drill path and pitch angle. However, as this
cinematic can be realized only on a very limited number of
machines, the method cannot be considered as a universal
preparation method. Moreover, this method does not allow an
adjustment of cutting edge roundings extending over the tool
diameter. In addition, due to drilling in full material, there will
always be considerable rounding of the cutter corner as well as of
the transverse cutter, for example in the case of a helical drill,
and after comprehensive usage the grinding body will have to be
redressed in a complicated fashion. Another disadvantage of this
method is in the preparation of tools having large projections,
because of the lack of guidance. In this method complex programming
needs to be done in order to identify the position of the bore, the
pitch angle between a workpiece, in this case the ground machining
tool, and the tool, i. e. the grinding disk that is to be machined.
Furthermore, after complete circumferential processing, the
grinding disk must be brought back to its initial state by methods
which must be executed externally. Furthermore, due to the mounting
of the grinding disk on a grinding mandrel, grinding disk magazine
places are occupied which may possibly be needed.
[0010] While it has been proven that cutting edge preparation is an
effective means of increasing performance and processing quality of
cutting tools, it often requires additional machines and
apparatuses. This results, on the one hand, in huge investment
costs for such apparatuses, on the other hand in additional
workpiece handling costs, which may constitute a decisive portion
of the preparation costs in a high-wage country like Germany. The
technological and economic aspects mentioned allow deducing the
demand for development of a further developed cutting edge
preparation method, which is in particular suitable to be used by
small and medium manufacturers of machining tools and in which in
particular the requirements of low investment costs and operation
expenses, simple realization and short tool preparation throughput
time are met.
[0011] The objective of the present invention is to provide a
simple and cost-efficient possibility for selectively preparing
cutting edges of rotationally symmetrical machining tools, which in
particular have a clamp shaft (shaft tools), in regard to their
microscopic shape, while avoiding additional investment costs for
machines for the tool-manufacturing enterprise.
[0012] The solution of the task of the invention lies in the
apparatus according to the characterizing features of claim 1, in
the method according to the characterizing features of claim 16 and
in the grinding body according to the characterizing features of
claim 26, in each case in combination with the features of the
respective preamble. Further advantageous implementations of the
invention will become apparent from the subclaims.
[0013] The invention concerning the apparatus is based on an
apparatus for cutting edge preparation of cutting tools, in
particular of drills or milling tools or similar tools, in
particular of hard-metal cutting tools, wherein during a relative
movement the cutting tool interacts in a machining fashion with a
flexibly-bonded grinding body that is provided with abrasive
particles, the particles of the grinding body influencing the edge
geometry of the cutting tool. According to the invention, such a
generic apparatus is developed further insofar as the grinding body
is adapted with its dimensions substantially to the dimensions of
the respective cutting tool that is to be prepared and is
accommodated in an exchangeable holder that is arranged in a region
of a processing device, in particular of a tool grinding machine,
and is held such that it is machinable by the cutting tool for a
cutting edge preparation. In contrast to known solutions for
cutting edge preparation, the dimensions of the grinding body are
in each case adapted to the dimensions, e. g. the circumferential
measurements, of the respective cutting tool that is to be
prepared, as a result of which on the one hand substantial saving
of grinding body material is achievable and, on the other hand, the
technological implementation of the cutting edge preparation can be
influenced and improved selectively. This requires only as much
material of the abrasive material that is to be made into the
grinding body as is actually necessary for carrying out the cutting
edge preparation, and hence the cutting edge preparation process is
realized in an economically efficient manner. Moreover, redressing
of large grinding disks, which is otherwise necessary between the
respective processes for cutting edge preparation, is dispensed
with. Furthermore, the dimensionally adapted grinding body is
accommodated in a corresponding exchangeable holder, which is
arranged, for example, in the workroom of a tool grinding machine
and is held such that it is machinable by the cutting tool for
cutting edge preparation. On the one hand, the exchangeable holder
enables a furnishing of the holder with respectively new or
different grinding bodies independently from the basic processing,
e. g. in the grinding machine, thus substantially decoupling the
re-furnishing of the grinding bodies from the actual processing. On
the other hand, the dimensionally adapted grinding body may be
accommodated--in a manner that is especially space-saving and thus
hardly interferes, for example, with a possible upstream grinding
process on the tool grinding machine--e. g. in the workroom of the
grinding machine, and may be kept available for an execution of the
cutting edge preparation. This substantially facilitates and
decomplicates, after the basic grinding of the cutting tool on the
tool grinding machine, an execution of the cutting edge preparation
on the same tool grinding machine, ideally in the same clamping
arrangement, as no or only little additional equipment is required,
e. g. at the tool grinding machine, such additional equipment
taking up only little or no additional space in the workroom of the
tool grinding machine. It is hence also for small tool grinding
outfits possible to offer not only basic tool grinding but also
cutting edge preparation without the necessity of investing in
expensive add-on devices for the tool grinding machine or of
acquiring additional machines. However, it is of course also
possible to apply and to constructionally provide the apparatus
also for processing devices other than a tool grinding machine, for
example for drilling machines, turning machines or the like, for
universal as well as for special machines, on which cutting tools
that are to be prepared are processed or used and on which the
cutting edge preparation may then be carried out close to the
process or depending on requirements in order to ensure defined
cutting conditions. The apparatus for cutting edge preparation may
also be used on any device, in particular any processing device,
which enables a relative movement between a cutting tool and a
grinding body and on which a cutting edge preparation may be
executed as well. In this light, the denomination of the processing
device shall be considered to be general and not limiting. If the
application of the apparatus on a tool grinding machine is
discussed here by way of example, other processing devices or
general devices are always also implied and comprised.
[0014] A particular advantage is given if the exchangeable holder
is held in the workroom of a tool grinding machine, preferably such
that it is insertable in a grinding disk receptacle of the tool
grinding machine. The construction space of the grinding disk
receptacle is a region of the grinding disk receptacle that has
normally no functional use and is usually arranged in a
prolongation of the clamping cone or of a similar clamp receptacle
in the region that is encompassed by the disk-shaped grinding disk.
This collar, which the grinding disk is plugged onto, is usually
embodied of a full material and is not used otherwise. Therefore,
it is just this space, which is arranged centrally in the workroom
of the tool grinding machine, that can now be used to form a
fitting-in space for the exchangeable holder with the grinding
body, in which the grinding body is held for being machined by the
cutting tool for cutting edge preparation. Hence in such an
arrangement of the grinding body, which is small in regard to
construction volume and is adapted to the dimensions of the cutting
tool, no additional construction space is required for the cutting
edge preparation; and the cutting edge preparation can moreover be
carried out in a region of the workroom of the tool grinding
machine that is easily accessible and does not require any change
of the cinematic for the movement of the grinding disk or of the
cutting tool. However, it is of course also conceivable to arrange
the grinding body, which is small in regard to construction volume
and is adapted to the dimensions of the cutting tool, in a
different place in the workroom of the tool grinding machine. Such
a position may be situated, for example, in the workroom of a tool
grinding machine, in particular in the region of the grinding
spindle, or in a different position. There may also be a variant
implemented as a space-saving pallet system, in which the
afore-described exchangeable holders, together with the grinding
bodies, are kept available with identical or differing diameters in
a magazine. In this way an interaction is enabled between the tool
that is to be produced and the grinding body for a plurality of
ground tools. The apparatus that is realizable as a pallet may be
implemented to be round, square or rectangular, and may--depending
on dimensions--accommodate a certain number of exchangeable holders
together with the grinding bodies. It is also conceivable to
provide the exchangeable holder in motion devices like spindles of
other processing devices, for example on the work spindle of a
turning machine or the like.
[0015] It is also advantageous if the grinding body is implemented
substantially in a cylindrical fashion. As the cutting tools which
are to be prepared usually also have at least principally
cylindrical dimensions, a cylindrical implementation of the
grinding body allows achieving a large extent of adaptation to
dimensions and shapes of the cutting tools, as a result of which
considerable saving of abrasive material of the grinding body is
achievable in the context of the dimensional adaptation of the
measurements of the grinding body to the measurements of the
cutting tools For this purpose, in a further implementation the
cylindrical circumferential measurements of the grinding body are
substantially adapted to the circumferential measurements of the
cutting tool that is to be prepared, such that in the course of
the--usually several--cutting edge preparations of cutting tools
which are to be processed one by one, the grinding body can be
machined successively and more or less completely, and therefore no
unused residue of the abrasive material needs to be disposed
of.
[0016] It is furthermore of essential advantage that after complete
usage, the grinding body can be simply replaced by a new grinding
body. As a result, times taken for processing a cutting tool will
be prolongated only slightly, and the cutting edge preparation does
not unnecessarily prolongate the time required for producing the
cutting tool by otherwise necessary refitting or the like.
[0017] In the first implementation the grinding body is simply
arranged exchangeably in the exchangeable holder, and is
preferentially pressed into the holder. For this purpose, the
rotationally symmetrical grinding body may for example be
manufactured and pressed into the exchangeable holder with a very
slight allowance that is adapted to the diameter of the cutting
tool that is to be prepared. As a result of the fitting-in, an
easily producible and sufficiently rotationally fix connection is
established between the grinding body and the exchangeable holder
so as to securely receive the processing forces during cutting edge
preparation.
[0018] In a particularly advantageous implementation, it is
conceivable that the exchangeable holder is realized in such a way
that it is insertable into a, preferably central, bore in the
grinding disk receptacle, preferably in the receiving collar of the
grinding disk. This easily accessible volume, which has up to now
been mostly unused as was described above, can be provided with
almost any tool grinding machine by a simple modification of a
customary grinding disk receptacle at a machine-side tensioning
element for the grinding disk, while changing the workroom of the
tool grinding machine not at all or only in an insubstantial
manner. It is possible in this aspect as well to provide a suitable
fitting-in space for inserting the exchangeable holder on other
processing machines, like in a spindle of a turning machine or a
similar processing device.
[0019] In a further implementation the exchangeable holder may
comprise an outer thread, which can be screwed into the bore in the
grinding disk receptacle that is provided with an inner thread. In
this way the exchangeable holder may be fitted and secured in the
bore in the grinding disk receptacle in a close-fitting and quick
manner. However, it is also conceivable to press or insert the
exchangeable holder into a, preferably central, bore in the
grinding disk receptacle and to hold it there in a rotationally fix
fashion, e. g. by something like a bayonet or a clamping or the
like.
[0020] In particular for a cutting edge preparation of
long-projecting cutting tools having a large length:diameter ratio,
a guide bushing may be arranged in the region of the exchangeable
holder for the grinding body, such that long-projecting cutting
tools, when guided via the guide bushing, can be prepared and thus
processed more accurately and more safely than without additional
guidance. Such long-projecting cutting tools may, for example, be
asymmetrical deep-drilling tools, deep-hole drills, helical drills
or the like, with a large length:diameter ratio, which otherwise
tend to deviate when processed or tend to vibrations during cutting
edge preparation because of their length. For this purpose, in a
further implementation the guide bushing can be arranged relative
to the exchangeable holder--preferably on the exchangeable holder
in a prolongation of the exchangeable holder--in such a way that
the guide bushing guides and supports the long-projecting cutting
tool in front of the region of the machining of the grinding
body.
[0021] It is also conceivable that electrical conductor paths
and/or sensor elements, which provide information on the
progression of the cutting edge preparation, are introducible in
the exchangeable holder. For example, it is additionally possible
that the course of processing is monitored and if applicable
influenced during the cutting edge preparation by means of
touch-free sensors or the like. In a further implementation it is
conceivable that for a voltage supply the sensor elements are
equipped with accumulators, which are integrated in the
exchangeable holder and can be charged in the grinding disk
magazine or externally while not in use. This allows, in
non-productive times in which the exchangeable holder is not in
use, to have sufficient energy stored in the accumulators so as to
enable an execution of the above-mentioned monitoring processes
during the cutting edge preparation, when the respective
exchangeable holder has been exchanged.
[0022] A special advantage is provided if the grinding body
comprises abrasive particles, which are in particular implemented
of silicon carbide, aluminum dioxide or diamond, and is
successively completely machined by the cutting tools which are to
be prepared. The machining behavior of the grinding body, and thus
the achievable cutting edge preparation, can be influenced over a
wide range of possibilities by the selection or mixture of the
abrasive particles which are respectively made into a grinding body
as well as, in a further implementation, by mixing fine and/or
coarse abrasive particles. It is herein also conceivable to
implement the distribution of fine and/or coarse abrasive particles
inhomogeneously withing the grinding body, for example in order to
induce different preparation behavior, for example in the core
region and the peripheral region of the grinding body, thus
allowing different preparation results in individual regions of the
cutting tool in adaptation to a respective geometry of the cutting
tool that is to be prepared.
[0023] It is furthermore conceivable that the grinding body has an
axially-extending perforation, which is adapted to the cutting tool
diameter and within which the cutting tool is not affected by the
particles of the grinding body. Thus it is advantageous, e. g. in
the cutting edge preparation of drills, to prepare the region of
the transverse cutter of the drill not at all or differently than
the region of the main cutter. If, due to the perforation, there is
no grinding body material present just in the region of the
transversal cutter, the region of the transversal cutter will not
be changed.
[0024] Beyond this it is conceivable that the grinding body
comprises sections having differing degrees of hardness of the
bonding, in particular radial annulus-shaped sections having
differing degrees of hardness. The bonding of the abrasive
particles of the grinding body has a direct effect on the machining
behavior of the grinding body and therefore on the local cutting
edge preparation of the cutting tool. By differing hardness or by
regions having different hardnesses of the bonding, a further
adaptation of the result of the cutting edge preparation to the
requirements of the respective cutting tool is achievable. For
example, the core of the grinding body may have a higher hardness
of the bonding than the peripheral region in order to obtain a
regular cutting edge rounding due to the elastic deformation of the
rotationally symmetrical grinding body.
[0025] The invention moreover concerns a method for cutting edge
preparation of cutting tools, in particular of drills or milling
tools or similar tools, in particular of hard-metal cutting tools,
wherein during a relative movement the cutting tool interacts in a
machining fashion with a flexibly-bonded grinding body which is
provided with abrasive particles, the particles of the grinding
body influencing the edge geometry of the cutting tool, i. e. a
method in which the grinding body is adapted with its dimensions
substantially to the dimensions of the respective cutting tool that
is to be prepared, and is accommodated in an exchangeable holder,
which is arranged in the region of a processing device, in
particular a tool grinding machine, for example in the workroom of
a tool grinding machine or of a different processing device, and in
which the grinding body is successively completely machined by the
cutting tools that are to be prepared. Essential characteristics
and advantages of the method are directly connected to the
apparatus described and explained above, hence the described
characteristics and advantages of this apparatus may be referred to
for a characterization of the method according to the
invention.
[0026] A special advantage is also given if the cutting edge
preparation can be carried out in the same clamping arrangement,
directly following a first-time manufacturing of the shape of the
cutting tool or following a regrinding of the cutting tool, on the
same processing device, for example a tool grinding machine, or an
a different processing device. In this way it is possible, on the
one hand, to do without additional devices for a separate cutting
edge preparation, which would otherwise be necessary, and also to
carry out the cutting edge preparation directly in the same
clamping arrangement and on the same tool grinding machine or
processing device which the basic shaping of the cutting tool is
executed on. The cutting edge preparation can moreover be also
carried out after regrinding of an already-used cutting tool, thus
benefiting from the advantages of the cutting edge preparation for
these reground cutting tools as well.
[0027] It is especially advantageous that in the machining of the
grinding body a wide range of adaptation of the cutting speeds is
obtainable by the relative movement of grinding body and cutting
tool, in particular by the superimposition of the rotation
directions and rotation speeds. Many parameters of the cutting edge
preparation are affected by the cutting speed of the cutting edge
preparation and may therefore be used selectively with a large
variety of possible cutting speeds for a controlling of the results
of the cutting edge preparation.
[0028] It is furthermore conceivable that the grinding body and/or
the cutting tool execute rotary movements during the machining of
the grinding body. Besides the usual rotation of the cutting tool,
the grinding body is also capable of rotating, if applicable
counter-rotating or rotating with different rotation speeds. In
this way, in particular by the superimposition of the rotary
movements of the grinding body and/or of the cutting tool,
roundings and/or tiltings of the cutting edge of the cutting tool
can be selectively induced, or a production of asymmetrical cutting
edge profiles and/or of cutting edge profiles which are variable
over the tool diameter may be enabled.
[0029] Beyond this it is conceivable that during the cutting edge
preparation only the cutting tool that is to be prepared executes
the necessary translational and rotary movements.
[0030] It is also conceivable that the grinding body has sections
with different degrees of hardness of the bonding and thus creates
variable roundings over the cutting region of the cutting tools. It
is possible, for this purpose, to produce the grinding body
selectively with locally or section-wise variable degrees of
hardness of its bonding, such that it is adapted to the respective
cutting tool that is to be prepared, thus influencing the local
machining by the cutting tool and thus the local cutting edge
preparation.
[0031] It is further conceivable that due to an axially-extending
perforation, which is adapted to the cutting tool diameter and
within which the cutting tool is not affected by the particles of
the grinding body, the grinding body subjects only defined regions
of a cutting tool, in particular for example the main cutters of a
drilling tool, to a cutting edge preparation while other regions,
in particular the transverse cutter of a drilling tool, are not
rounded.
[0032] The grinding body may also have external measurements which
are adapted to the cutting tool diameter, such that only selected
regions of the cutters of the cutting tool are subjected to a
cutting edge preparation.
[0033] For certain cutting tools that are to be prepared it is
conceivable that the cutting tool having main cutters and secondary
cutters, in particular milling tools, frictional tools and/or
sequential-drilling tools, successively machines--by means of its
main cutters, respectively secondary cutters--respectively
corresponding grinding bodies which have different characteristics.
Herein, for example, the main cutters of a reamer may be prepared
by means of a grinding body that is differently shaped or
dimensioned than a grinding body for the secondary cutters, thus
obtaining in each case the optimum preparation result for the main
cutters, respectively the secondary cutters.
[0034] The invention further concerns a grinding body for an
execution of the method according to claim 16, wherein the
cylindrical circumferential measurements of the grinding body are
substantially adapted to the circumferential measurements of the
cutting tool that is to be prepared.
[0035] A particularly preferred embodiment of the apparatus
according to the invention is shown in the drawing.
[0036] It is shown in
[0037] FIG. 1 in a principle-fashion illustration: the basic
construction and the function of an apparatus according to the
invention, arranged in the grinding disk receptacle of a grinding
disk before the cutting edge preparation of a drill,
[0038] FIG. 2 an apparatus according to the invention as shown in
FIG. 1, with an additional guide bushing before the cutting edge
preparation of a long-projecting deep hole drill,
[0039] FIG. 3a-3c views and sections through differently
implemented grinding bodies of the apparatus according to the
invention of FIG. 1,
[0040] FIG. 4a-4d detailed sectional views of the exchangeable
holder and grinding bodies arranged therein, for the cutting edge
preparation of different cutting tools,
[0041] FIG. 5 a pallet-like magazine at an apparatus according to
the invention, with places for receiving a plurality of
exchangeable holders and grinding bodies arranged therein.
[0042] In FIG. 1, in a principle-fashion illustration the basic
construction and the function of an apparatus 1 according to the
invention can be perceived, the apparatus 1 being exemplarily
arranged in the grinding disk receptacle 3 of a grinding disk 4
before the cutting edge preparation of a cutting tool 5, which is
in the present case embodied as a drill. The apparatus 1 is
arranged on a customary tool holder, which is in the present case
implemented as a cone-shaped receptacle 19 of a grinding disk 14,
of the kind usually used in customary tool grinding machines. The
actual implementation of the tool-grinding-machine-side receptacle
of the apparatus 1 is herein not relevant and may comprise any kind
of mechanical interface with the tool grinding machine.
Arrangements of this type may also be realized on other processing
devices, like for example drilling machines, turning machines or
other devices of that kind. The embodiment of the tool grinding
machine shown in the figures is herein only to be seen by way of
example and may be implemented in multiple modifications.
[0043] On the cone-shaped receptacle 10 in the workroom of the tool
grinding machine, a receiving collar 3 is arranged for receiving
the grinding disk 14, on which the grinding disk 14 is plugged with
its perforation and is then secured in a customary manner by a cap
nut 9 via a thread 8. This receiving collar 3 is usually made of a
full material and has no further task besides supporting the
grinding disk 14.
[0044] According to the invention, a portion of the receiving
collar 3 which is otherwise made of a full material and which is
situated centrally in the work region of the tool grinding machine,
is used for an accommodation of the apparatus 1 according to the
invention. For this purpose, from the work region of the tool
grinding machine a central longitudinal bore 11 is introduced into
the receiving collar 3 as a blind bore, which a sleeve-like, easily
exchangeable holder 4 for a grinding body 2--that will be described
in detail below--can be inserted in. As a result of this
arrangement of the apparatus 1, the apparatus 1 will not encumber
normal operation of the tool grinding machine while providing the
receptacle for a grinding body 2, which may be used for the cutting
edge preparation of a cutting tool 5.
[0045] The exchangeable holder 4 has such an outer diameter that it
is insertable into the longitudinal bore 11 of the receiving collar
3 in a largely tolerance-free manner. A fixing of the exchangeable
holder 4 in the longitudinal bore 11 can be brought about by an
end-side thread 6 on the outer surface of the exchangeable holder
4, which can be screwed into a corresponding counter-thread in the
longitudinal bore 11. It would also be conceivable to fix the
exchangeable holder 4 in the longitudinal bore 11 by pressing-in or
in another form-fit or force-fit manner if, on the one hand, a
rotationally fix fixation is ensured with easy exchangeability of
the exchangeable holder 4.
[0046] In the interior of the sleeve-like structured exchangeable
holder 4 there is also a bore 23 that a cylindrical grinding body
2, which may be used for an interaction with the cutters 7 of the
cutting tool 5 in the context of the cutting edge preparation of
the cutting tool 5, can be inserted into or pressed into in a
rotationally fix fashion. The grinding body 2 is implemented of a
flexibly bonded abrasive-particle matrix, for example of
rubber-like bonded abrasive particles which are made of hard
materials.
[0047] In regard to its cylindrical outer measurements, the
grinding body 2 is adapted to the circumferential measurements of
the cutting tool 5, in the present case the outer diameter of the
drill, and has an outer diameter that is slightly greater than the
outer diameter of the cutting tool 5, such that in the cutting edge
preparation the cutters of the cutting tool 5 in any case come into
contact only with the grinding body and not with the exchangeable
holder 4.
[0048] In order to carry out the cutting edge preparation of the
cutting tool 5, for example after basic grinding of the tool shape
by means of the grinding disk 14, the cutting tool 5 that is
embodied as a drill is positioned, in the longitudinal bore 11 of
the receiving collar 3, in front of the apparatus 1 in such a way
that the axis of the cutting tool 5 and the longitudinal bore 11,
and thus the exchangeable holder 4, are in alignment with one
another. The cutting tool 5 is then--during a relative rotation
between the cutting tool 5 and the grinding body 2--advanced to the
grinding body 2 in the feed direction until the cutters of the
cutting tool 5 interact in the designated manner with the grinding
body 2, machining the grinding body 2 and being thus prepared.
Herein the grinding body 2 is machined at least section-wise and is
thus shortened in a longitudinal direction. Following the cutting
edge preparation of the cutting tool 5, the cutting tool 5 is
re-traversed out of the exchangeable holder 4 against the feed
direction 24 and is ready for removal.
[0049] The process may then be repeated with the subsequent cutting
tool 5, as a result of which the grinding body 2 is more and more
machined away successively and, upon reaching a use-up limit, must
be replaced. For this purpose, the entire exchangeable holder 4
containing the remainder of the grinding body 2 is removed out of
the longitudinal bore 11 and is replaced by a exchangeable holder 4
that has been pre-equipped with a new grinding body 2. Due to the
quick exchangeability of the exchangeable holder 4 containing the
grinding body 2, work can be continued directly. Further
exchangeable holders 4 of the same type may, for example, be stored
in other grinding disk receptacles as a depot, to be used if the
preparation remains the same. This allows delaying the replacement
of the grinding body 2 until the job has been finished or until the
wear limits of the grinding disks 14 have been reached.
[0050] In FIG. 2 a modified apparatus 1 as shown in FIG. 1 is
illustrated, which has been modified for a cutting edge preparation
of a long-projecting cutting tool 13, in particular a deep hole
drill. As in a grinding process and also during cutting edge
preparation, such long-projecting cutting tools 12 tend to get
pushed sideways and to start vibrating, the cutting tool 13 is in
this case guided and supported by a guide bushing 12 that is
arranged at a front side of the exchangeable holder 4, thus
avoiding or substantially avoiding the negative effects of the long
projection.
[0051] FIGS. 3a to 3c present views and sections through
differently-structured grinding bodies 2 of the apparatus 1
according to the invention of FIG. 1, which constitute, by way of
example, conceivable modifications of the grinding body 2.
[0052] In FIG. 3a a grinding body 2 may be perceived of the kind
shown in FIG. 1, which is implemented homogeneously over the entire
machining region of the grinding body 2.
[0053] FIG. 3b shows a grinding body 2 having a central perforation
15, which may be used for example for the cutting edge preparation
of a drill as a cutting tool 5. The drill then does not interact
with the grinding body 2 in the region of the perforation 15 as
there is no abrasive material in this region. As a result, the
cutting tool 5 embodied as a drill is not affected in the region of
the sensitive transverse cutter and keeps the shape achieved by the
preceding grinding process with the grinding disk 14. Due to the
sleeve-like shape of the grinding body 2, the main cutters are
prepared only in the region of the main cutters.
[0054] It is also conceivable, as shown in FIG. 3c, that the
peripheral region 17 and the core region 16 of the grinding body 2
are made of different abrasive particles or of identical abrasive
particles having different bonding hardness and thus different
machining characteristics. For example, the core region 16 of the
grinding body 2 may have a higher bonding hardness than the
peripheral region 17 in order to achieve a minimization of elastic
deformations at the inner cutter of the cutting tool 5. Herein a
plurality of modifications of the grinding body 2 are conceivable,
depending on the cutting tool 5 that is to be prepared and its
shape.
[0055] In FIGS. 4a to 4d detailed sectional views are shown of the
exchangeable holder 4 and of grinding bodies 21, 22 for the cutting
edge preparation of different cutting tools 18, 19 and 20, which
are arranged in the exchangeable holder 4. All the tools 18, 19 and
20 have in common that they have different primary cutters and
secondary cutters which are to be prepared and which can be
prepared neither in a simple manner nor in a single run.
[0056] For example, the reamer 18 shown in FIG. 4a can be prepared
using the subregion 22 of the grinding body 2 on the primary
cutters and simultaneously using the subregion 21 of the grinding
body 2 on the secondary cutters. It is however also conceivable, as
is shown in FIG. 4b, to prepare the secondary cutters in an
individual processing, following the preparation of the primary
cutters, using only the subregion 21 of the grinding body 2 on the
secondary cutters.
[0057] In FIG. 4c the cutting edge preparation of a sequential
drill 19 is shown, whose two steps are prepared simultaneously on
two subregions 21 and 22 of the grinding body 2 which are, for
example, bonded in different manners.
[0058] FIG. 4d shows a cutting edge preparation of a milling tool
20 on the secondary cutters only, which interact with a subregion
21 of the grinding body 2.
[0059] FIG. 5 shows a conceivable implementation of a pallet-like
magazine 25 at an apparatus 1 according to the invention, with
receptacles 26 for receiving a plurality of exchangeable holders 4
and of grinding bodies 2 arranged therein. The exchangeable holders
4 with the grinding bodies 2 may be kept available in such a
pallet-like magazine 25 with identical diameters or with differing
diameters. This allows simple and automatizable exchanging of the
exchangeable holders 4 with the respectively required grinding
bodies 2, thus enabling a quick automatizable interaction between
the respective cutting tool 5 that is to be produced and the
suitable grinding body 2 for a plurality of ground tools 5. The
device that is here implemented exemplarily as a pallet-like
magazine 25 may be realized so as to be round, square or
rectangular, and may provide a certain number of receptacles 26 for
exchangeable holders 4 with grinding bodies 2, depending on
respective measurements.
[0060] In the following essential characteristics and advantages of
the invention will be briefly explained:
[0061] The basic idea of the method according to the invention is
the usage of a flexibly-bonded grinding body 2 implemented of
abrasive particles, which is here exemplarily installed in a
specifically developed grinding disk receptacle 3. In the defined
machining of such a grinding body 2, material abrasion will occur
on the cutting edge of the cutting tool 5, which may be used for a
selective preparation. This method is carried out, for example, on
a customary tool grinding machine and can thus be integrated at the
end of the process chain for tool production, respectively for tool
regrinding, without additional handling efforts. The material
abrasion that is necessary for the preparation is generated by the
relative movement between a grinding body 2 and a cutting tool 5.
The cylindrical grinding body 2 is herein, for example, clamped in
the grinding disk receptacle 3 in a positionally fixed manner while
the necessary translational and rotary movements are executed by
the cutting tool 5 that is to be prepared.
[0062] Furthermore, due to deliberate superimposition of the
rotational directions of the cutting tool 5 and the grinding disk
receptacle 3, there is in this case a possibility of selectively
adjusting roundings and tiltings of the cutting edge. It is further
possible, due to a construction of the grinding body 2 with
different degrees of hardness, to create variable roundings over
the cutter region of the cutting tool 5. A well-known problem is
the rounding of the transverse cutter of the cutting tool 5 brought
about by established preparation methods. The usage of a grinding
body 2 having a perforation 15 that is adapted to the tool diameter
5 provides possibilities of adapting the main cutters, for example
of a drilling tool 5, to the preparation process while avoiding a
rounding of the transverse cutter. The same applies in regard to
the accurate adaptation of the diameter of the grinding body 2 to
the diameter of the cutting tool 5 that is to be prepared.
[0063] Beyond this, due to the free process cinematic, there are
further fields of application, like for example the preparation of
reamers, micro-milling tools and sequential drilling tools.
[0064] The machining of the grinding body 2 results in a material
abrasion on the cutting edge of the cutting tool 5, which is thus
rounded. The advantage of the method according to the invention
lies in that the tool production (grinding of the macro-shape) and
a defined generation of the microscopic cutting edge shape can be
carried out, for example, on the same tool grinding machine or
processing device. Due to the machining of the grinding body 2, new
abrasive medium will always be available, as a result of which
there are constant preparation conditions for the duration of the
process. Influencing of the tools is herein limited to those
regions of the cutting tool 5 that come into contact with the
grinding body 2, which constitutes an advantage with respect to
other preparation methods, like drag grinding or abrasive blasting.
In addition to the low investment costs, preparation costs per tool
are small as the exchange of grinding bodies 2 can be brought about
in a quick and simple manner.
[0065] With the current state of the art, in particular the cutting
edge rounding of long-projecting cutting tools 13 having a high
length:diameter ratio (l/d ratio) requires special handling and
extensive process controlling if a suitable cutting edge
preparation is to be realized. The apparatus according to the
invention offers the potential of enabling a preparation of such
long-projecting cutting tools 13 by the simple cinematic and by
processing in one clamping arrangement and within existing
production procedures on the tool grinding machine or processing
device in a short time. However, besides cutting tools 13 having a
high l/d ratio customary rotationally symmetrical machining tools
may also be prepared by the present method with a slight
modification of the grinding bodies 2.
[0066] In addition to the cutting edge rounding of new tools 5, the
method according to the invention also enables a preparation of
cutting tools 5 which were reground and are therefore already
coated with a hard-material layer on certain functional surfaces.
According to currently available knowledge, this cannot be
selectively realized by currently available methods, such that the
performance of reground cutting tools 5 is mostly significantly
lower than the performance of new cutting tools 5.
[0067] For the implementation of the apparatus 1 according to the
invention, the accommodation of the exchangeable holder 4, for
example in the grinding disk receptacle 3, is crucial. The grinding
disk receptacles 3 normally used on tool grinding machines have
corresponding interfaces to the tool grinding machine spindle.
These are usually embodied as hollow-shaft cones (HSK), shaft cones
(SK) or as a further, mostly standardized, interface in order to
permit high flexibility and precision with the grinding disk
exchange. Herein for a tool grinding, the grinding disks are
usually put upon a mandrel 3, having for example a diameter d=20
mm, they are positioned by means of distance rings and are fixed
via a clamping nut 9. The core of the mandrel 3 has not had any
function up to now. Fitting-in the exchangeable holder 4, in the
present case into a bore 11 having an inner thread, provides the
mandrel 3 with an additional functionality and the grinding disk
receptacle 3 is considerably upgraded in regard to its
utilizability. Besides the fixation of the exchangeable holder 4
the connection, which can be screwed or can be joined otherwise,
might also permit an implementation of further functional elements
which are not involved in the cutting edge preparation. Moreover,
corresponding receptacles could be provided on other processing
devices, for example on turning machines, drilling machines, or
other specifically or universally applicable devices.
[0068] The grinding bodies 2 developed specifically for the
application in the cutting edge preparation have an elastic bonding
of the abrasive particles with a degree of hardness that must be
defined depending on the respective application case. This is a
rotationally symmetrical grinding body 2 containing fine or coarse
abrasive particles, for example silicon carbide, aluminum dioxide
or diamond, which is successively completely machined by the
cutting tools 5 which are to be prepared. The rotationally
symmetrical grinding bodies 2 are herein adapted to the diameter of
the cutting tool 5 that is to be prepared; they are produced with a
very small allowance and are pressed into the exchangeable holder
4. In this way rounding of the exposed cutter corners of the
cutting tools 5 can be avoided or can be significantly minimized in
comparison to existing methods. It is possible, besides the
rotationally symmetrical base bodies having a defined bonding
hardness, to produce grinding bodies 2 which have different degrees
of hardness and are thus correspondingly adapted to the application
case and to the diameters that are to be processed. In this context
in particular the possibility may be mentioned that with the
cutting tools 5 it may be necessary that the core 16 of the
grinding body 2 has a higher hardness than the peripheral region 17
in order to obtain a regular cutting edge rounding due to the
elastic deformation of the rotationally symmetrical grinding body
2.
[0069] Furthermore, the process cinematic offers additional
possibilities of covering a wide range of parameters in regard to
the cutting speeds when machining the grinding body 2, for example
by the superimposition of the rotation directions and rotation
speeds, independently from the performance capability of the
workpiece spindle and of the tool spindle. Moreover, by differently
oriented, counter-directional and co-directional movements of the
grinding disk receptacle 3 with the integrated grinding body 2 and
the cutting tool 5, influences regarding the cutting edge tilting,
of form factor K, may be enabled and adjusted. By way of the
introduction of perforations 15, the introduction of cores 16
having different hardnesses, abrasive particles and grain sizes,
and the flexible shaping of the grinding bodies 2, this method
provides an opportunity of a transfer to a great number of further
variants of machining tools 5. Beyond this, superimposition of the
axes of the grinding disk receptacle 3 allows developing and
realizing a different cinematic which approximates a milling
processing, thus enabling a preparation of different milling tools
selectively in regard to front cutters and/or circumferential
cutters.
[0070] In addition to the afore-described usage for grinding bodies
2 for a cutting edge preparation, the apparatus 1 may also be
extended by making use of measuring technology or of sensorics.
Introducing electrical conductor paths and sensors into the
exchangeable holder 4 even permits an implementation of an
electronical, accumulator-equipped surveillance electronics
arrangement, which may be charged with a suitable charging
technology in the grinding disk magazine or externally while not in
use.
[0071] Due to the integration of the apparatus 1 in the grinding
disk receptacle 3, only insignificantly higher acquisition costs
will be incurred in comparison to customary grinding disk
receptacles 3. This also means that due to the integration in the
grinding disk receptacle 3, the concept is applicable on almost any
tool grinding machine or processing machine. Therefore the
investment--necessary for most of already known methods--for
additional installations including the thus arising maintenance and
repair costs, as well as for the handling of the workpiece after
the grinding process. While the complete processing, for example on
the tool grinding machine, causes times when the machine cannot be
used for its primary purpose, such times are negligible due to the
very short processing periods of less than 5 s for each
preparation. Changing of tools is avoidable by an intelligent
composition of grinding disk packages on the grinding mandrel
and/or by furnishing each grinding disk receptacle 3 with the
apparatus 1 according to the invention, resulting in an overall
increase in productivity and in a considerable reduction of
production costs.
[0072] The adaptation of the grinding bodies 2 to the diameter of
the cutting tools 5 and the pre-defined maximum allowance of the
grinding body 2 that is to be machined ensure a nearly non-relevant
influencing of the cutter corners and of the secondary cutters of
the cutting tools 5. Moreover, as the contact area between the
cutting tool 5 and the grinding body 2 that is to be machined is
limited by the machining thickness, there will be no influencing of
the peripheral surfaces of the cutting tool 5. The defined length
of the rotationally symmetrical grinding body 2 within the
exchangeable holder 4 allows processing a number of cutting tools 5
that depends on a diameter and on a target rounding by using the
proposed concept until the grinding body 2 that is to be machined
is used up completely. Exchanging the exchangeable holder 4,
respectively changing to a further grinding disk receptacle 3
comprising an identical grinding body 2, allows continuous
processing close to the process chain. The free cinematic provided
by the mounting in the grinding disk receptacle 3 also offers the
potential of realizing a different process cinematic, similar to
milling, on the tool grinding machine. Thus opportunities arise of
preparing main cutters and secondary cutters of the cutting tools 5
with different cutting edge roundings and form factors.
[0073] In addition to the variation of the shape of the grinding
bodies 2 and of the bonding hardness, it is possible to create
different shapes of cutting edge rounding via an adaptation of the
cinematic engagement conditions. Herein the rotation direction of
the cutting tool 5, the rotation direction of the grinding body 2,
the dwell time at the bottom of the bore and the advancement per
turn are of particular relevance.
[0074] For long-projecting deep-drilling tools 13 having different
diameters a guiding of the tool tip is necessary for enabling
cutting edge preparation without getting the cutting tool 5
damaged. For this an adaptation of the exchangeable holder 4 is
necessary. The guiding of the cutting tool 5 must be dimensioned
such that the grinding body 2 coincides with the workpiece axis and
the elastic bending of the cutting tool 5 is compensated. Herein
the complexity of the preparation results from the requirements
regarding the cutting edge. In the case of an application with
deep-hole drilling tools, besides the more extensive rounding of
the outer cutter, a significantly smaller rounding of the inner
cutter must be achieved.
LIST OF REFERENCE NUMERALS
[0075] 1 apparatus according to the invention [0076] 2 grinding
body [0077] 3 receiving collar/grind disk receptacle [0078] 4
exchangeable holder [0079] 5 cutting tool [0080] 6 thread of
exchangeable holder [0081] 7 cutters of cutting tool [0082] 8
clamping thread [0083] 9 clamping nut [0084] 10 tool cone [0085] 11
bore in grinding disk receptacle [0086] 12 guide bushing [0087] 13
deep hole drill [0088] 14 grinding disk [0089] 15 perforation
[0090] 16 core having higher bonding hardness [0091] 17
circumferential region having lower [0092] bonding hardness [0093]
18 frictional tool [0094] 19 sequential drill [0095] 20 milling
tool [0096] 21 surrounding grinding body [0097] 22 inside-situated
grinding body [0098] 23 bore holder [0099] 24 feed direction [0100]
25 pallet-like magazine [0101] 26 receptacles
* * * * *