U.S. patent application number 15/700249 was filed with the patent office on 2018-03-15 for method for processing a workpiece made of hard metal for producing a tool main body on a numerically controlled machine tool with tool-carrying work spindle.
This patent application is currently assigned to SAUER GMBH. The applicant listed for this patent is SAUER GMBH. Invention is credited to Jens KETELAER.
Application Number | 20180071890 15/700249 |
Document ID | / |
Family ID | 59799251 |
Filed Date | 2018-03-15 |
United States Patent
Application |
20180071890 |
Kind Code |
A1 |
KETELAER; Jens |
March 15, 2018 |
METHOD FOR PROCESSING A WORKPIECE MADE OF HARD METAL FOR PRODUCING
A TOOL MAIN BODY ON A NUMERICALLY CONTROLLED MACHINE TOOL WITH
TOOL-CARRYING WORK SPINDLE
Abstract
A method for processing a workpiece made of hard metal for
producing a tool main body on a numerically controlled machine tool
with tool-carrying work spindle, comprising: accommodating a tool
holder that holds a tool on a tool support of the work spindle of
the machine tool, wherein the tool holder comprises a vibration
generator for generating a vibration of the tool, and processing
the workpiece which is clamped on the machine tool and is made of
hard metal by the vibrating tool held on the tool holder for
working out one or more recesses at the workpiece for producing the
tool main body.
Inventors: |
KETELAER; Jens; (Wiesbaden,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAUER GMBH |
Stipshausen |
|
DE |
|
|
Assignee: |
SAUER GMBH
Stipshausen
DE
|
Family ID: |
59799251 |
Appl. No.: |
15/700249 |
Filed: |
September 11, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23B 2270/10 20130101;
B24B 51/00 20130101; B23P 15/28 20130101; B24B 49/10 20130101; B23B
31/02 20130101; B24B 1/04 20130101; B24B 49/00 20130101; B23B
2260/108 20130101; B24B 41/06 20130101; B23P 25/00 20130101 |
International
Class: |
B24B 51/00 20060101
B24B051/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2016 |
DE |
10 2016 217 251.4 |
Claims
1. A method for processing a workpiece made of hard metal for
producing a tool main body on a numerically controlled machine tool
with a tool-carrying work spindle, comprising: accommodating a tool
holder holding a tool at a tool support of the work spindle of the
machine tool, wherein the tool holder comprises a vibration
generator for generating a vibration of the tool, and processing
the workpiece which is clamped on the machine tool and made of hard
metal by means of the vibrating tool held on the tool holder for
working out one or more recesses at the workpiece for producing the
tool main body.
2. The method according to claim 1, wherein the tool is a grinding
tool.
3. The method according to claim 2, wherein the grinding tool
comprises a grinding wheel and/or a grinding pencil.
4. The method according to claim 1, wherein the vibration generator
generates vibrations of the tool in a direction axial to the
spindle axis direction of the work spindle, in a direction radial
to the spindle axis direction of the work spindle and/or in the
circumferential direction about the spindle axis of the work
spindle.
5. The method according to claim 1, wherein the vibrations of the
tool that are produced by the vibration generator are in the
ultrasonic range, in particular at frequencies of greater than 10
kHz.
6. The method according to claim 1, wherein a work signal for
generating the vibration of the tool is transferred to the
vibration generator in a contactless fashion.
7. The method according to claim 1, wherein the vibration generator
comprises one or more piezoelectric actuators.
8. The method according to claim 1 wherein the working-out of one
or more recesses at the workpiece comprises: working out one or
more chip flutes of the tool main body to be produced, working out
one or more plate seats of the tool main body to be produced,
working out one or more cooling channels of the tool main body to
be produced, working out one or more chamfers out of the tool main
body to be produced, working out one or more clearance angles of
the tool main body to be produced, and/or working out one or more
cutting edges of the tool main body to be produced.
9. The method according to claim 8, wherein working out one or more
chip flutes of the tool main body to be produced, working out one
or more plat seats of the tool main body to be produced, working
out one or more cooling channels of the tool main body to be
produced, working out one or more chamfers of the tool main body to
be produced, working out one or more clearance angles of the tool
main body to be produced and/or working out one or more cutting
edges of the tool main body to be produced is done while the
workpiece is clamped on the machine tool.
10. The method according to claim 8, wherein working out one or
more chip flutes of the tool main body to be produced, working out
one or more plat seats of the tool main body to be produced,
working out one or more cooling channels of the tool main body to
be produced, working out one or more chamfers of the tool main body
to be produced, working out one or more clearance angles of the
tool main body to be produced and/or working out one or more
cutting edges of the tool main body to be produced is carried out
in each case by means of different tools, in particular grinding
tools.
11. The method according to claim 10, further comprising exchanging
the tool holder for a second tool holder holding another tool,
wherein the second tool holder comprises a second vibration
generator for generating the vibration of the other tool, and
processing the workpiece which is clamped on the machine tool and
is made of hard metal by means of the vibrating other tool held on
the second tool holder for working out one or more further recesses
on the workpiece for producing the tool main body.
12. The method according to claim 11, wherein one or more chip
flutes are worked out with the other tool, in particular when one
or more plate seats, one or more cooling channels, one or more
chamfers, one or more clearance angles and/or one or more cutting
edges have been worked out with the previously introduced tool, one
or more plate seats are worked out with the other tool, in
particular when one or more cooling channels, one or more chip
flutes, one or more chamfers, one or more clearance angles and/or
one or more cutting edges have been worked out with the previously
introduced tool, one or more cooling channels are worked out with
the other tool, in particular when one or more chip flutes, one or
more plate seats, one or more chamfers, one or more clearance
angles and/or one or more cutting edges have been worked out with
the previously introduced tool, one or more chamfers are worked out
with the other tool, in particular when one or more plate seats,
one or more cooling channels, one or more chip flutes, one or more
clearance angles and/or one or more cutting edges have been worked
out with the previously introduced tool, one or more clearance
angles are worked out with the other tool, in particular when one
or more cooling channels, one or more chip flutes, one or more
chamfers, one or more plate seats and/or one or more cutting edges
have been cut worked out the previously introduced tool, or one or
more cutting edges are worked out with the other tool, in
particular when one or more chip flutes, one or more plate seats,
one or more chamfers, one or more clearance angles and/or one or
more cooling channels have been worked out with the previously
introduced tool.
13. The method according to claim 11, wherein the exchange of the
tool-holding tool holder on the tool support of the work spindle of
the machine tool is carried out by a tool change device set up for
this purpose.
14. The method according to claim 1, wherein the numerically
controlled machine tool has at least five numerically controllable
axes.
15. A control apparatus of a numerically controlled machine tool
with a tool-carrying work spindle and a tool holder which holds the
tool and which can be accommodated on a tool support of the work
spindle, wherein the control apparatus is configured to control the
method according to claim 1 on the machine tool.
16. The control apparatus according to claim 15, further comprising
a control panel configured to manually input data associated with
the tool main body to be produced as a data set via the control
panel.
17. The control apparatus according to claim 16, wherein the
control panel is configured in such a way that the manual input of
the data associated with the tool main body to be produced as a
data set comprises a menu-guided manual input of the data
associated with the tool main body to be produced as a data
set.
18. The control apparatus according to claim 15, further comprising
an interface configured to receive a data set associated with the
tool main body.
19. The control apparatus according to claim 16, wherein the data
set comprises parameters relating to a geometry of the tool main
body to be produced and optionally admissible tolerance ranges of
the geometry of the tool main body to be produced.
20. The control apparatus according to claim 16, wherein the data
set comprises model data which indicates a three-dimensional
geometry model of the tool main body to be produced.
21. The control apparatus according to claim 16, wherein the data
set comprises material data, which indicates the material
properties of the tool main body to be produced.
22. The control apparatus according to claim 16, wherein the
control apparatus is configured to obtain the data set associated
with the tool main body by reception or manual input and to control
the method on the basis of the received data set or of the data set
inputted manually via the control panel in a semi-automatic or
fully automatic way on the machine tool.
23. A computer program product with a computer program stored on a
computer-readable data storage medium, which can be carried out on
a numerical control apparatus or a numerically controlled machine
tool having a tool-carrying work spindle and a tool holder which
holds a tool and can be accommodated on a tool support of the work
spindle, or in a computer connected to the control apparatus of the
numerically controlled machine tool, and which is configured to
control on the machine tool a method according to claim 1.
Description
[0001] The present invention relates to a method for processing a
workpiece made of hard metal for producing a tool main body on a
numerically controlled machine tool with a tool-carrying work
spindle. The present invention also relates to a control apparatus
of a numerically controlled machine tool and a computer program
product serving to control the above mentioned method.
BACKGROUND OF THE INVENTION
[0002] In general, it is not possible to use conventional machining
methods, such as milling, for processing workpieces made of hard
metal. The tool wear would not be in economic proportion to the
material removed from the workpiece if one attempted to process
hard metal by means of a milling cutter. This is why grinding
methods are used since it is thereby possible to use different tool
materials (e.g. diamond) and process the workpiece in a more
economical way.
[0003] In order to produce a tool main body from a workpiece made
of hard metal, in particular special machines are known which by
means of grinding tools provide the workpiece with contours and
recesses.
[0004] The resulting tool main body is also known as a carrier
tool. It usually serves to accommodate even firmer cutting edges
which are specifically hardened for the particular case of
application, such as screwed-on indexable cutting inserts or
cutting inserts made of PCD (polycrystalline diamond), which are
fixedly attached to the tool main body by soldering. In addition,
the tool main body is usually provided with chip chambers/grooves
for accommodating the chips and recessed chambers which can
accommodate clamps for clamping the cutting edges. The tool main
bodies can have all kinds of designs, e.g. be made as a cutter
head.
[0005] This design of tool main body and individually attached
cutting edges has the decisive advantage that when the cutting
edges have been worn, it is not the entire tool assembly (cutting
edges and tool main body) that have to be exchanged but merely the
cutting edges have to be replaced. For example, indexable cutting
inserts, which are screwed e.g. to the tool main body, can easily
be removed and be substituted with new cutting inserts. However, it
is also possible that e.g. the cutting edges attached by soldering
(such as PCD cutting inserts) have to be resharpened by
grinding.
[0006] In order to mount the cutting edges and simultaneously also
feed coolant to the corresponding cutting edges and thereby
increase the service life of these tools, the tool main bodies are
often provided with internal coolant bores which are introduced
into the tool main body.
[0007] For this purpose, it has so far been necessary to process
the prepared workpieces in a special machine by means of grinding
and additionally clamp them in an electrical discharge machine as
well as to cut the cooling channels into the tool main body, e.g.
by means of electrical discharge sinking or electrical discharge
drilling.
[0008] As far as the manufacture is concerned, this means that a
plurality of different machines has to be used and that some of the
processes that have to be employed, such as electrical discharge
machining, are highly complex.
[0009] The drawbacks of electrical discharge machining show inter
alio that long preparation times are necessary for the electrode
production. Different cooling channels each require different
electrodes which have to be defined, designed and manufactured. In
addition, the time required for setting up the machine is long
(measuring the electrode with respect to center displacement,
rotation, length). Furthermore, the already high wear of the
electrode produced in a complex way will be further increased when
the voltage level increases or the voltage pulse frequency
increases in order to raise the removal rates of the material to be
electrically discharged.
[0010] Therefore, it is important to avoid the electrical discharge
machining when a workpiece made of hard metal is processed for
producing a tool main body and to manufacture this body while
clamped on the machine instead. Furthermore, the stock removal rate
of the processing method and simultaneously the service life of the
tool shall be increased.
[0011] All in all, this shall serve to considerably lower the
energy required and also the time for producing a tool main body
made of hard metal.
SUMMARY OF THE INVENTION
[0012] Therefore, an object of the present invention is to provide
a method for processing a workpiece made of hard metal for
producing a tool main body on a numerically controlled machine tool
with tool-carrying work spindle, by means of which the above
problems can be avoided.
[0013] A further object of the present invention is to provide a
control apparatus and a computer program product, by means of which
the method according to the invention can be controlled.
[0014] These objects are achieved by a method according to claim 1,
a control apparatus according to claim 15 and a computer program
product according to claim 21. The dependent claims each refer to
advantageous embodiments of the method according to the invention
or the control apparatus according to the invention.
[0015] The inventive method for processing a workpiece made of hard
metal for producing a tool main body on a numerically controlled
machine tool with tool-carrying work spindle comprises the steps
of: accommodating a tool holder holding a tool at a tool support of
the work spindle of the machine tool, wherein the tool holder
comprises a vibration generator for generating a vibration of the
tool, and processing the workpiece which is clamped on the machine
tool and is made of hard metal by means of the vibrating tool held
on the tool holder and serving to work out one or more recesses at
the workpiece in order to produce the main body of the tool.
[0016] Through the use of the vibration generator, it is possible
that, in the described method, the tool is rotationally driven as
usual and also a vibration is introduced into the tool, which
supports the removal of the hard metal material on the
workpiece.
[0017] The inventors have surprisingly found that due to the
vibrating of the tool, up to two times the amount of hard metal
material can be removed in the removal process in the same amount
of time as compared to the non-vibrating movement of the tool.
[0018] Furthermore, there are advantages as regards the use of the
previously described method since the workpiece can remain in its
set-up position (clamping) while all kinds of recesses for e.g.
mounting possibilities for cutting elements or recesses, some of
which can be produced only with difficulty by common methods, are
worked into the workpiece. In addition, the tools can be exchanged,
if required, if this is necessary due to the different
recesses.
[0019] However, the optimized removal rate can also be used for
reducing the process forces on the tool. The lower process forces
reduce the temperature developing on the tool and on the workpiece
and can thus considerably reduce the wear of the tool.
[0020] An advantageous development of the method is that the tool
is a grinding tool.
[0021] The method can be developed in a particularly advantageous
way when the grinding tool has a grinding wheel and/or a grinding
pencil.
[0022] The use of the vibration generator can advantageously be
used for processing materials, in particular very hard materials,
by means of grinding tools according to the described method.
Grinding tools often remove markedly less material than tools
having a geometrically defined cutting edge, such as a milling
cutter. However, these tools can be equipped with special charge
materials (e.g. diamonds) which make them particularly resistant
and durable when they are used for very hard materials, such as
hard metal. Due to the introduction of the vibration into the
grinding tool by the vibration generator, it is possible to
compensate for part of the lower removal rates of the workpiece
material.
[0023] Furthermore, the method can advantageously be developed in
such a way that the vibration generator produces vibrations of the
tool in a direction axial to the spindle axis direction of the work
spindle, in a direction radial to the spindle axis direction of the
work spindle and/or in a circumferential direction about the
spindle axis of the work spindle.
[0024] The vibration generator is not limited to only produce a
vibrational motion of the tool axially to the spindle axis
direction of the work spindle. The vibration generator can rather
also be used for creating a vibrational motion of the tool in a
radial direction relative to the spindle axis direction of the work
spindle. The two vibrational motion patterns of the tool
considerably support the removal of material on the workpiece.
[0025] A special case is the vibrating (or oscillating) motion of
the tool in the circumferential direction about the spindle axis of
the work spindle. This type of tool motion can dispense with the
rotational drive of the tool by a further actuator and can
exclusively use the vibration generator as a tool drive instead.
This type of tool motion is particularly well suited for tools
having a geometrically undetermined cutting edge, as in the case of
grinding tools.
[0026] An advantageous development of the method is that the tool
vibrations produced by the vibration generator are in the
ultrasonic range, in particular at frequencies of greater than 10
kHz, more preferably of greater than 15 kHz.
[0027] Due to a particular high-frequency vibrational motion of the
tool, it is possible to increase the material removal to a
particularly high degree since the tool performs more machining
motions and the removal of the chips is additionally supported by
the high-frequency vibration.
[0028] The method can advantageously be developed further by
transmitting a work signal for generating the vibration of the tool
in contactless fashion to the vibration generator.
[0029] This type of contactless signal transmission has the
advantage that no additional circuitry or energy supply is
necessary in the tool holder or power supply to transmit the work
signal into the tool holder since the inductive transmission does
not require any further energy.
[0030] The method can advantageously be developed in such a way
that the vibration generator comprises one or more piezoelectric
actuators.
[0031] The advantage of a piezo-actuator system is that extremely
high frequencies (ultrasound) can be produced by the highly dynamic
behavior of the piezo crystals, wherein the piezo elements
simultaneously have a great robustness and good linear control
behavior.
[0032] A particularly advantageous development of the method is
that the working out of one or more recesses at the workpiece
comprises the following steps: working out one or more chip flutes
of the tool main body to be produced, working out one or more plate
seats of the tool main body to be produced, working out one or more
cooling channels of the tool main body to be produced, working out
one or more chamfers of the tool main body to be produced, working
out one or more clearance angles of the tool main body to be
produced and/or working out one or more cutting edges of the tool
main body to be produced.
[0033] Due to the use of the vibration generator and the
advantageous effect of a vibration introduced into the tool, as
already described above, it is now not only possible to grind plate
seats and/or chip flutes, as is common practice in special machines
for producing tool main bodies, but also to introduce the cooling
channels in a machine tool into the workpiece to be processed.
Thus, the use of an additional machine (such as an electrical
discharge machine) is no longer necessary and all necessary
processing steps to be performed on the tool main body to be
produced can be carried out efficiently, e.g. while it is clamped
in a machine tool.
[0034] In addition to the processing of the tool main body to be
produced for working out plate seats, chip flutes and/or cooling
channels while clamped, it is now also possible to work out
chamfers, clearance angles and cutting edges by means of the
described method while the tool main body to be produced remains
clamped.
[0035] The method can be developed in a particularly advantageous
way by working out one or more chip flutes of the tool main body to
be produced, working out one or more plate seats of the tool main
body to be produced, working out one or more cooling channels of
the tool main body to be produced, working out one or more chamfers
of the tool main body to be produced, working out one or more
clearance angles of the tool main body to be produced and/or
working out one or more cutting edges of the tool main body to be
produced while the workpiece is clamped on the machine tool.
[0036] Thus, it is possible to carry out all necessary processing
steps on the tool main body to be produced without having to
unclamp the workpiece to be processed and insert it in another,
additional machine or reclamp the workpiece to be processed in the
same machine tool.
[0037] As a result, various additional set-up times, be it those
required for the additional machine or those resulting from the
reclamping of the workpiece to be processed in the same machine
tool, are totally omitted. Furthermore, the dimensional stability
of the resulting tool main body is improved since the reference
points on the workpiece are not lost as the workpiece to be
processed remains in its original clamping position. Therefore, the
tool-carrying work spindle can position the cooling channels at the
locations intended for this purpose with very high precision.
[0038] The method can advantageously be developed in such a way
that the working out of one or more chip flutes of the tool main
body to be produced, the working out of one or more plate seats of
the tool main body to be produced, the working out of one or more
cooling channels of the tool main body to be produced, the working
out of one or more chamfers of the tool main body to be produced,
the working out of one or more clearance angles of the tool main
body to be produced and/or the working out of one or more cutting
edges of the tool main body to be produced is carried out in each
case by means of different tools, in particular grinding tools.
[0039] Thus, the individual processing steps serving to introduce
all necessary recesses into the workpiece to be processed are not
limited to one tool. Instead, it is possible to use all kinds of
tools, such as grinding wheels having different diameters and
widths and grinding pencils having different diameters and
lengths.
[0040] The method can be developed in a particularly advantageous
way by the following steps: exchanging the tool holder for a second
tool holder holding another tool, wherein the second tool holder
comprises a second vibration generator for generating a vibration
of the other tool, and processing the workpiece which is clamped on
the machine tool and is made of hard metal by means of the
vibrating other tool which is held on the second tool holder and
serves to work out one or more further recesses from the workpiece
in order to produce the tool main body.
[0041] Thus, the tool holder to be used can be exchanged with the
tool and corresponding vibration generator in the described method,
even while the workpiece remains clamped. The advantage is that the
tool and also the vibration generator can be adapted to
corresponding processing conditions by an exchange without a change
to another machine tool or the like being necessary. The workpiece
can again remain clamped and its reference points can be maintained
for the further processing.
[0042] The method can advantageously be developed in such a way
that one or more chip flutes are worked out by means of the other
tool, in particular when one or more plate seats, one or more
cooling channels, one or more chamfers, one or more clearance
angles and/or one or more cutting edges have been worked out by
means of the previously introduced tool, one or more plate seats
are worked out by means of the other tool, in particular when one
or more cooling channels, one or more chip flutes, one or more
chamfers, one or more clearance angles and/or one or more cutting
edges have been worked out by means of the previously introduced
tool, one or more cooling channels are worked out by means of the
other tool, in particular when one or more chip flutes, one or more
plate seats, one or more chamfers, one or more clearance angles
and/or one or more cutting edges have been worked out by means of
the previously introduced tool, one or more chamfers are worked out
by means of the other tool, in particular when one or more plate
seats, one or more cooling channels, one or more chip flutes, one
or more clearance angles and/or one or more cutting edges have been
worked out by means of the previously introduced tool, one or more
clearance angles are worked out by means of the other tool, in
particular when one or more cooling channels, one or more chip
flutes, one or more chamfers, one or more plate seats and/or one or
more cutting edges have been worked out by means of the previously
introduced tool, or one or more cutting edges are worked out by
means of the other tool, in particular when one or more chip
flutes, one or more plate seats, one or more chamfers, one or more
clearance angles and/or one or more cooling channels have been
worked out by means of the previously introduced tool.
[0043] A major advantage of the method is that for introducing the
particular recesses the workpiece does not have to be processed in
any defined sequence. Depending on the requirements of the tool
main body to be produced, a sequence of the processing stages can
rather be chosen freely, which additionally increases the
flexibility and, as a result, the productivity of the production
process.
[0044] An advantageous development of the method is that the
exchange of the tool-holding tool holder is carried out on the tool
support of the work spindle of the machine tool by a tool change
device set up for this purpose.
[0045] It is thus possible to exchange the tool holder with the
tool and vibration generator in fully automatic or semi-automatic
fashion. In addition, such a tool change device adds to the safety
of the operator since the latter can be hurt in a manual tool
change and in handling the machine tool by existing metal chips or
flashes protruding from the workpiece.
[0046] In addition, the method can advantageously be developed by
exchanging the workpiece disposed on the clamp of the machine tool
by a workpiece change device set up for this purpose.
[0047] The workpiece change device additionally supports the
automation of the processing procedure and can be used for
exchanging already processed tool main bodies with still
unprocessed or only partially processed workpieces (or unfinished
parts/blanks) in order to (further) process them. In addition, such
a device and also the above mentioned tool change device add to the
safety of the operator for the above mentioned reasons.
[0048] The method can advantageously be developed in such a way
that the numerically controlled machine tool has at least five
numerically controllable axes.
[0049] In order to process the tool main body to be produced as
efficiently as possible and to also get at only hard-to-reach
locations of the tool main body to be produced, it is recommended
that the machine tool has at least five axes which can be
independently controlled numerically.
[0050] An inventive control apparatus of a numerically controlled
machine tool having a tool-carrying work spindle and a tool-holding
tool holder, which can be accommodated on a tool support of the
work spindle, is configured to control on the machine tool a method
for processing a workpiece made of hard metal for producing a tool
main body on a numerically controlled machine tool with
tool-carrying work spindle.
[0051] As a result of the control apparatus according to the
invention, the above described method and all its developments can
be performed and controlled on the machine tool.
[0052] The control apparatus can advantageously be developed by the
following features: a control panel which is configured to manually
input data associated with the tool main body to be produced via
the control panel.
[0053] This provides the user with the possibility of directly
inputting data relevant to the processing of the workpiece into the
control apparatus and manually adapting the processing steps
appropriately.
[0054] Thus, the control apparatus can advantageously be developed
by configuring the control panel in such a way that the manual
input of the data associated with the tool main body to be produced
comprises as a data set a menu-guided, manual input of the data
associated with the tool main body to be produced as a data
set.
[0055] The menu-guided, manual input helps the user to input the
corresponding data in a logical sequence and to prepare it in such
a way that it can be read by the control apparatus. This saves the
user time and makes possible that users with little EDP and/or CNC
program language knowledge can input data associated with the tool
main body into the control apparatus and thus can adjust the
production process.
[0056] The control apparatus can advantageously be developed by the
following features: an interface which is configured to receive a
data set associated with the tool main body.
[0057] This gives the user the opportunity to send data relevant
for processing the workpiece to the control apparatus in a rapid
and efficient way and correspondingly adapt the processing steps by
the received data.
[0058] The control apparatus can advantageously be developed such
that the data set comprises parameters relating to the geometry of
the tool main body to be produced and optionally admissible
tolerance ranges of the geometry of the tool main body to be
produced.
[0059] Furthermore, the control apparatus can advantageously be
developed such that the data set comprises model data which
indicate a three-dimensional geometry model of the tool main body
to be produced and/or the data set comprises material data which
indicates material properties of the tool main body to be
produced.
[0060] The adjustment of the processing method for producing a tool
main body in a rapid and efficient way can be carried out by the
interface of the control apparatus and the design of the data set
by all kinds of parameters.
[0061] A particularly advantageous development of the control
apparatus is obtained when the control apparatus is configured to
receive the data set associated with the tool main body by
reception or manual input and to control the method for processing
a workpiece made of hard metal for producing a tool main body on a
numerically controlled machine tool with tool-carrying work spindle
on the basis of the received data set or the data set manually
inputted via the control panel on the machine tool in a
semi-automatic or fully automatic fashion.
[0062] Due to the use of a mostly automatic control of the machine
tool and the use of automatable devices, such as the tool change
device, the method for producing a tool main body can also be
mostly automated, which further increases the efficiency of this
production or manufacture.
[0063] A computer program product according to the invention has a
computer program which is stored on a computer-readable data
storage medium and can run on a numerical control apparatus of a
numerically controlled machine tool with tool-carrying work spindle
and a tool-holding tool holder that can be accommodated on a tool
support of the work spindle or in a computer connected to the
control apparatus of the numerically controlled machine tool, and
which is configured to control on the machine tool a method for
processing a workpiece made of hard metal for producing a tool main
body on a numerically controlled machine tool with tool-carrying
work spindle.
[0064] The above described method and all its developments can be
carried out and controlled on the machine tool by means of the
control apparatus using the computer program product according to
the invention.
[0065] In summary, a tool main body comprising a workpiece made of
hard metal can be produced by the described method in a machine
tool (e.g. a universal machine), wherein the workpiece can remain
clamped in all processing steps while sometimes complex recesses,
such as cooling channels, are worked into the tool main body to be
produced since the machine tool has a corresponding system which
supports the removal of material and simultaneously reduces the
process forces during the processing of the workpiece and thus
considerably reduces the wear of the tool when hard-metal materials
are used.
[0066] Further aspects and the advantages thereof as well as
advantages and more specific design possibilities of the above
described aspects and features are described in the following
descriptions and explanations of the attached drawings, which
should, however, by no means be considered limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] FIG. 1 shows, by way of example, a sectional view of a tool
holder which can be used in the inventive method according to
embodiments;
[0068] FIG. 2a shows, by way of example, a tool-holding tool holder
which can be used in the inventive method according to
embodiments;
[0069] FIG. 2b shows, by way of example, a tool-holding tool holder
processing a workpiece made of hard metal for producing a tool main
body which can be used in the inventive method according to
embodiments;
[0070] FIG. 3a shows, by way of example, a processed tool main body
having chip flutes, plate seats and cooling channels, which was
produced by the method according to the invention;
[0071] FIG. 3b shows, by way of example, a sectional view of a tool
main body which is processed by the method according to the
invention and is provided with chip flutes, plate seats and cooling
channels;
[0072] FIG. 4 shows, by way of example, a schematic diagram of a
machine tool which has a tool holder and can be used in the
inventive method according to embodiments.
DETAILED DESCRIPTION OF THE DRAWINGS AND PREFERRED EMBODIMENTS OF
THE PRESENT INVENTION
[0073] Examples and/or embodiments of the present invention are
described in detail below with reference to the enclosed drawings.
The same or similar elements in the drawings can here be designated
by the same reference signs but sometimes also by different
reference signs.
[0074] However, it should be noted that the present invention is by
no means limited or confined to the below described embodiments and
the design features thereof but additionally comprises
modifications of the embodiments, in particular those which are
comprised by modifications of the features of the described
examples and/or by combination of individual or a plurality of the
features of the described examples on the basis of the scope of
protection of the independent claims.
[0075] FIG. 1 shows, by way of example, an exemplary assembly of a
tool holder 10, which can be used in the method according to the
invention.
[0076] One end of the tool holder 10 accommodates a tool support
portion 11 for accommodating a tool 90 (not shown in FIG. 1; see
FIGS. 2a, 2b and 4). As an example, a plurality, e.g. six,
perforated disk-shaped first piezo elements 21 are arranged e.g. in
stacked fashion in the tool holder 10, said piezo elements being
connected to the tool support portion 11 e.g. via a transmission
portion 12 and forming, by way of example, a vibration generator 20
(ultrasound generator/actuator) for converting an electric voltage
into a mechanical vibration (e.g. with a frequency in the
ultrasonic range).
[0077] As an example, the mechanical vibration of the first piezo
elements 21 is transferred to the tool 90 via the transfer portion
12. The first piezo elements 21 can e.g. be made as piezo ceramic
disks having electrodes mounted therebetween.
[0078] The vibration generator 20 is supplied with energy and/or
actuated e.g. via a transformer (first transformer) which, as an
example, comprises on the machine side a first pot core 31 and a
primary winding 32 (transmitter unit/transmitter coil) (not shown
in FIG. 1) and e.g. comprises on the tool side a second pot core 33
and a secondary coil 34 (receiver unit/receiver coil) which, as an
example, are arranged as ring elements on the outer side of the
tool holder 10.
[0079] On a side of the stack made of first piezo elements 21,
which faces away from the tool support portion 11, e.g. a
perforated disk-shaped piezoelectric sensor element 40 is arranged
which comprises e.g. a piezo element 41 and two contacts 42 and is
coupled e.g. mechanically to the first piezo elements 21 but is
electrically insulated by an insulating element 43, which can
consist of a ceramic perforated disk, from the first piezo elements
21. The piezoelectric sensor element 40 is electrically insulated
by a further insulating element 43, e.g. from a fastening element
13, e.g. a fastening nut.
[0080] The fastening element 13 serves to fasten the piezoelectric
sensor element 40 to the vibration generator 20 (ultrasonic
generator/actuator) and the bias of the first piezo elements 21 due
to the dynamic load.
[0081] The first piezo elements 21 and the piezoelectric sensor
element 40 have the same orientation, thereby rendering possible,
on the one hand, the generation and the detection of the vibration
in the same direction and achieving, on the other hand, a
space-saving arrangement of the elements in the tool holder 10.
[0082] The piezoelectric sensor element 40 changes the mechanical
vibrations of the system capable of vibration, comprising the tool
90, the transfer portion 12, the vibration generator 20 and the
piezoelectric sensor element 40, into a sensor signal which is
transmitted e.g. as an electric voltage via a wire connection 50
from the piezoelectric sensor element 40 through the tool holder 10
to a sender element on the outer side of the tool holder 10.
[0083] The sensor signal is transmitted e.g. in contact-free manner
from the sender element 61 and 62 at a bore 70 to a receiver
element on the machine side (not shown in FIG. 1).
[0084] The sender element 61 and 62 is e.g. part of a further
transformer (second transformer) and comprises e.g. a first ferrite
core and a primary winding; the receiver element is also part of
the second transformer and comprises a second ferrite core and a
secondary winding. However, it is also possible to provide an
optical sender element.
[0085] Therefore, the sensor signal can be transmitted inductively
from the tool holder 10 to a sensor signal evaluation device on the
machine side.
[0086] FIG. 2a shows, by way of example, a tool holder 10, which
holds the tool 90 (here a grinding pencil) and can be used in the
method according to the invention.
[0087] The tool 90 is connected to the tool holder 10 via the tool
support portion 11. The resulting unit can be accommodated in a
tool support 1041 of a work spindle 1040 of a machine tool 1000
(both not shown in FIG. 2a; see FIG. 4). This unit can be
accommodated both manually and in automated fashion by a tool
change device 1060 (not shown in FIG. 2a; see FIG. 4).
[0088] As an example, FIG. 2b shows a tool holder 10 holding a tool
90 (here a grinding pencil) processing a workpiece WS made of hard
metal for producing a tool main body which can be used in the
method according to the invention.
[0089] In this case, the tool 90 and the tool holder 10 again form
a unit, wherein the vibration generator 20 (not shown in FIG. 2b
see FIG. 1) causes the tool 90 to vibrate in order to increase the
removal rate on the workpiece WS and, at the same time, minimize
the process forces and thus the tool wear.
[0090] FIG. 3a shows e.g. a processed tool main body which has chip
flutes SN, plate seats PS and cooling channels KK and was made by
the method according to the invention.
[0091] This figure shows clearly the plate seats PS and chip flutes
SN, which are worked out by the tool 90 and which are typically
produced in tool main bodies. They serve for the mounting
possibility of cutting edges (e.g. indexable cutting inserts) and
later on, when the tool main body with cutting edges is used in
e.g. machine tools, for the removal of the accumulating chips
during the processing of workpieces. The worked-out recesses shown
in FIG. 3a, such as plate seats PS, chip flutes SN and cooling
channels KK, can be supplemented by chamfers F, clearance angles FW
and/or cutting edges SK.
[0092] FIG. 3b shows, by way of example, a tool main body processed
by the method according to the invention in a sectional view with
chip flutes SN, plate seats PS and cooling channels KK.
[0093] This figure shows particularly well the incorporated cooling
channels KK, which can be divided into a main channel of larger
diameter (along the central axis of the tool main body/workpiece)
and side channels of smaller diameter (branching off the main
channel).
[0094] FIG. 4 shows, by way of example, a schematic diagram of a
machine tool which has a tool holder and can be used in the
inventive method according to embodiments.
[0095] The machine tool 1000 can be made e.g. as a numerically
controllable milling and/or grinding machine, numerically
controllable universal milling and/or grinding machine or as a
numerically controllable machining center. In order to control a
relative movement between tool and workpiece, the machine tool can
have a plurality of controllable linear axes (as a rule e.g.
designated as X-axis, Y-axis and/or Z-axis) and/or one or more
rotary or rotational axes (usually e.g. designated as A-axis,
B-axis and/or C-axis).
[0096] For example, the machine tool 1000 has a machine bed 1010, a
machine column 1020 and a spindle head 1030, wherein the machine
bed 1010 supports e.g. a workpiece table 1050 and the spindle head
1030 supports e.g. a work spindle 1040. Furthermore, the machine
tool 1000 can have a tool change device 1060 and a workpiece change
device 1070 or a combination of tool change and workpiece change
device.
[0097] The tool table 1050 is e.g. horizontally mounted in a
linearly movable fashion on horizontal linear guideways 1050, which
are arranged on the machine bed 1010 in a horizontal direction, and
can be movably controlled via a linear drive 1052 of a first linear
axis of the machine tool 1000. For example, a workpiece WS is
clamped in a workpiece clamping device 1053 on the tool table.
[0098] The spindle head 1030 is e.g. vertically mounted in a
linearly movable fashion on vertical linear guideways 1050, which
are arranged on the machine column 1020 in a vertical direction,
and is movably controllable via a linear drive 1032 of a second
linear axis of the machine tool 1000, such that the work spindle
1040, which accommodates a tool holder 10 holding a tool 90, is
also vertically movable.
[0099] In further embodiments, one or more further linear axes can
also be provided, e.g. to additionally render possible a linear
movement of the workpiece relative to the tool in a direction
perpendicular to the drawing plane of FIG. 4.
[0100] In addition, one or more rotational and/or rotary axes can
be provided, e.g. a rotary axis with a rotary axis drive for
rotating the tool table 1050 (so-called rotary table).
[0101] Using the above described linear and optionally rotary
and/or rotational axes and/or the drives thereof, a relative
movement of the tool 90 can be controlled relative to the workpiece
WS.
[0102] For this purpose, a control apparatus 1100 of the machine
tool 1000 has a machine control device 1110, which comprises e.g. a
CNC and/or NC control device 1112, which is configured to control,
e.g. on the basis of NC data stored in a storage apparatus 111, the
functions and/or processing procedures on the machine tool 1000.
Furthermore, the machine control device 1110 has e.g. a PLC or SPS
device 1113 ("PLC" stands for programmable logic controller and
"SPS" for storage programmable controller).
[0103] The PLC and/or SPS device 1113 is more preferably configured
to send control signals to actuators of the machine tool on the
basis of control commands of the NC control device 1112 or also
optionally independently of the NC control device 1112, e.g. to the
linear drives 1052 or 1032 of the linear axes and/or generally to
drives of the machine axes or also to the spindle drive 1042 of the
work spindle 1040.
[0104] In addition, the PLC and/or SPS device 1113 is configured to
receive or read out sensor signals from position measurement
sensors (not shown) of the machine tool 1000, which indicate the
actual positions of the drives and/or machine axes in real time
during processing, and, where appropriate, pass them on to the NC
control device 1112. The PLC and/or SPS device 1113 can also be
configured to enable machine-internal and/or external devices or
apparatuses to read out positional data on the PLC and/or SPS
device 1113, which indicate the actual positions of the drives
and/or machine axes.
[0105] The work spindle 1040 has the above already mentioned
spindle drive 1042 and also a tool support 1041 (tool support
portion), where the tool holder 10 is accommodated and can be
rotationally driven by means of the spindle drive 1042 (in
particular for producing the cutting and/or grinding movement).
[0106] The tool holder 10 is merely shown schematically and has
e.g. a tool connection body 14 (e.g. a machine taper and/or steep
taper or hollow shank taper, or also a Morse taper or other tool
connection), by means of which the tool holder 10 is accommodated
on the tool support 1041 of the work spindle 1040. For example, the
tool holder 10 can be designed in analogy to FIG. 1.
[0107] The tool holder 10 has e.g. an inductive receiver unit 32
(e.g. analogous to the secondary coil and/or winding 34 of FIG. 1)
for receiving in contactless and/or inductive fashion a control
signal from the sender unit 32 (primary coil or winding) which is
attached to the spindle head 1030 (and/or the spindle).
[0108] For example, the tool holder 10 also has an actuator 20
(e.g. ultrasonic transducer and/or ultrasound generator, optionally
e.g. including one or more piezo elements), which is configured to
cause the tool holder 10 and/or the tool 90 accommodated in the
tool holder 10 to vibrate on the basis of the control signal,
preferably in particular in the ultrasonic range, i.e. in
particular at ultrasonic frequencies and/or at frequencies above 10
kHz and/or in particular e.g. above 15 kHz and e.g. up to 60
kHz.
[0109] The tool holder 10 also has the tool support portion 11,
where the tool 90 is accommodated and/or held, wherein the tool 90
is rotationally driven via the spindle drive 1042.
[0110] In order to drive the actuator 20 and/or to control the
vibration of the tool 90, the control apparatus 1100 of the machine
tool 1000 has a further control device 1120, which produces the
control signal and outputs it via the sender unit 32 to the tool
holder 10 for transmission to the receiver device 34 for the
actuator 20. In further embodiments, the control device 1120 can
also be integrated in the machine control device 1110 and/or
comprise an external data processing apparatus, e.g. a computer,
and/or be made by an externally connected data processing
apparatus, e.g. a computer.
[0111] The control device 1120 comprises e.g. a generator 1124 for
producing a high-frequency carrier signal. The high-frequency
carrier signal can be e.g. a substantially periodic and/or
preferably substantially sinus-shaped carrier signal, which
preferably has a defined frequency and/or a defined amplitude. The
frequency of the carrier signal has a high frequency (i.e. in
particular a frequency of greater than 10 kHz, preferably greater
than 15 kHz) and is preferably in the ultrasonic range.
[0112] The control device 1120 comprises e.g. also a storage device
1121 for storing geometry data, tolerance values of the geometry,
model data and material data of the tool main body to be
produced.
[0113] The control device 1120 comprises e.g. also a data
processing device 1122 configured to read out the data from the
storage device 1121 and can additionally read out positions, in
particular axis positions, from the machine control apparatus 1110.
This can preferably be done in real time while the workpiece WS is
processed, wherein, on the one hand, current actual positions of
the axes and drives of the machine tool 1000 can preferably be read
out e.g. of the PLC and/or SPS control device 1113 (and/or out of
the NC control system 1112) in real time or, on the other hand,
current target positions can be read out of the NC control system
1112.
[0114] In particular, the data processing device 1122 is preferably
configured, on the basis of the read-out positional data of the
machine control, to calculate the position of the tool 90 relative
to the workpiece WS.
[0115] Alternatively, it is also possible for the position of the
tool 90 to be calculated in the NC control system 1112 and to be
read out of the data processing device 1122.
[0116] On the basis of the calculated or read-out position of the
tool 90 relative to the workpiece WS and in comparison with the
data of the storage apparatus 1121, the data processing device 1122
is configured to determine and/or to calculate a currently desired
deflection of the tool 90 on the basis of the desired tool main
body geometry on the current tool position and to pass it to a work
signal generator 1123 as a target value.
[0117] Furthermore, the control apparatus 1120 comprises an
interface 1126 for receiving data. In this connection, the data can
have e.g. a data set with which the tool main body can be
associated, which, in turn, has e.g. geometry data of the tool main
body to be produced and/or admissible tolerance values/ranges for
the manufacture of the tool main body to be produced. For example,
it is also possible to insert further data which are relevant to
the control of the machine tool 1000, such as a three-dimensional
model of the tool main body to be produced or to define information
on the material of the tool main body to be produced. The
possibilities of the data and information, which can be received,
do not exhaust themselves in the above mentioned possibilities.
[0118] In addition, the interface 1126 can also send data from the
machine tool. This data can also comprise e.g. information on the
duration of processing or outstanding process steps and also visual
information, e.g. from an image-processing device within the
machine tool. However, it is also possible to send information,
e.g. on the tool wear or coolant and/or lubricant levels (and
optionally shortages of these process materials) by means of the
interface 1126. The possibilities of the data and information,
which can be sent, do not exhaust themselves in the above mentioned
possibilities.
[0119] Thus, the interface 1126 is not limited to a design and can
be realized e.g. as a USB interface (e.g. for using USB sticks as
data transfer medium). It can also be regarded as an interface 1126
to an existing network and therefore be realized in such a way that
it is connected to the existing network both by wiring (e.g. LAN)
and wirelessly. The above mentioned possibilities for further
embodiments of the interface 1126 are not exhausted here as
well.
[0120] The control device 1120 also comprises a control panel 1127
for manually inputting data. It is here particularly advantageous
for the manual input of data to be menu-guided. It is thus ensured
that the user does not necessarily have to have programming
language knowledge of e.g. CNC control systems to adapt the
production process of the tool main body to be produced.
[0121] The manually inputted data can e.g. include geometry data of
the tool main body to be produced and/or admissible tolerance
values/ranges for the manufacture of the tool main body to be
produced. For example, the data can also define further data
relevant to the control of the machine tool 1000 or details on the
material for the tool main body to be produced. The possibilities
of the data and information, which can be manually inputted via the
control panel and thus can be provided to the control device 1120
for processing the tool main body to be produced, do not exhaust
themselves in the above mentioned possibilities.
[0122] The tool change device 1060 functionally connected to the
machine tool 1000 is configured in such a way that, in the case of
a requested tool change on the part of the control apparatus 1100,
the unit which is accommodated by the tool support 1041 of the work
spindle 1040 and includes the tool holder 10 (including vibration
generator/actuator 20) and the tool 90 is removed from the tool
support 1041 (after the unit is either released by manual actuation
or in automated fashion) and to pass it on to an existing tool
magazine 1061, wherein the tool magazine 1061 again accommodates
the unit including the tool holder 10 and the tool 90 and stores it
at a corresponding location. Thus, an information signal can be
sent from the tool magazine 1061 to the control apparatus 1100,
which provides information about the storage location of the just
accommodated unit to later find this unit including the tool holder
10 and the tool 90 in the tool magazine 1061 again.
[0123] After the above mentioned step, the tool magazine 1061
provides another unit consisting of another tool holder 10
(including another vibration generator/actuator 20) and another
tool 90 (depending on the particular control signal of the control
apparatus 1100), which is accommodated by the tool change device
1060 and supplied to the tool support 1041 of the work spindle
1040. Having locked the other unit in the tool support 1041 (this
can again be done correspondingly in manual or automated fashion),
the tool change device 1060 returns to a rest position and again
releases the processing space of the machine tool 1000 for the
further processing of the workpiece WS.
[0124] Furthermore, the workpiece change device 1070, which is in
functional connection to the machine tool 1000, is configured in
such a way that, in the case of a demanded workpiece change by the
control apparatus 1100, the workpiece WS accommodated in the
workpiece clamping device 1053 is removed from the workpiece
clamping device 1053 (after releasing the workpiece WS either by
manual actuation or in automated fashion) and is passed to an
existing workpiece magazine 1071, wherein the tool magazine 1017
again accommodates the workpiece and stores it at an appropriate
location. Thus, an information signal can be sent from the
workpiece magazine 1071 to the control apparatus 1100, which
provides information about the storage location of the just
accommodated workpiece WS to subsequently find this workpiece WS in
the workpiece magazine 1071 again.
[0125] In addition, the workpiece magazine 1071 can provide
another, still unprocessed or only partly processed workpiece WS
(and/or blank part/blank) after the above mentioned step (depending
on the particular control signal of the control apparatus 1100),
which is accommodated by the workpiece change device 1070 and
supplied to the workpiece clamping device 1053. Having locked the
other workpiece WS in the workpiece clamping device 1053 (this can
again be done manually or in automated fashion), the workpiece
change device 1070 returns to a rest position and again releases
the processing space of the machine tool 1000 for a (new)
processing of the other workpiece WS.
[0126] Examples and/or embodiments of the present invention and the
advantages have been described above in detail with reference to
the enclosed drawings.
[0127] However, it is pointed out again that the present invention
is by no means limited or restricted to the above described
embodiments and the design features thereof but further comprises
modifications of the embodiments, in particular those comprised by
modifications of the features of the described examples and/or by
combination of individual or a plurality of the features of the
described examples on the basis of the scope of the independent
claims.
* * * * *