US20180071890A1

US20180071890A1 - 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

Info

Publication number: US20180071890A1
Application number: US15/700,249
Authority: US
Inventors: Jens Ketelaer
Original assignee: Sauer GmbH and Co KG
Current assignee: Sauer GmbH and Co KG
Priority date: 2016-09-09
Filing date: 2017-09-11
Publication date: 2018-03-15
Also published as: EP3292946A1; KR20180028964A; JP2018075704A; RU2017131507A; RU2017131507A3; CN107813192A; DE102016217251A1

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.

Description

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

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.
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.
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.
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.
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.
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.
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.
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.
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.
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

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.
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.
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.
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.
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.
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.
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.
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.
An advantageous development of the method is that the tool is a grinding tool.
The method can be developed in a particularly advantageous way when the grinding tool has a grinding wheel and/or a grinding pencil.
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.
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.
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.
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.
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.
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.
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.
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.
The method can advantageously be developed in such a way that the vibration generator comprises one or more piezoelectric actuators.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The method can advantageously be developed in such a way that the numerically controlled machine tool has at least five numerically controllable axes.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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

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;

FIG. 2a shows, by way of example, a tool-holding tool holder which can be used in the inventive method according to embodiments;

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;

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;

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;

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

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.
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.
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.
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).
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.
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.
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.
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.
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.
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.
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).
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.
Therefore, the sensor signal can be transmitted inductively from the tool holder 10 to a sensor signal evaluation device on the machine side.
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.
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).
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.
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.
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.
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.
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.
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).
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.
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).
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.
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.
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.
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.
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).
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.
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).
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.
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.
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).
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Examples and/or embodiments of the present invention and the advantages have been described above in detail with reference to the enclosed drawings.
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.

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.