WO2018095470A1

WO2018095470A1 - Processing tool for a processing machine

Info

Publication number: WO2018095470A1
Application number: PCT/DE2017/100976
Authority: WO
Inventors: Klaus Daut
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2016-11-23
Filing date: 2017-11-16
Publication date: 2018-05-31
Also published as: DE102016223201A1

Abstract

The invention relates to a processing tool (2) for a processing machine which, in an intended processing state (B), can be acted on by a processing force (F) along a forces path (12), contains a force sensor (14), which is coupled in terms of measurement to the force path (12) in order to sense a measured variable (M) correlated with the processing force (F), and contains an interface (16) connected to the force sensor (14) for transmitting the measured variable (M) to a mating interface (36), wherein the force sensor (14) is attached fixedly and non-detachably to the processing tool (2).

Description

Machining tool for a processing machine

The invention relates to a machining tool for a processing machine.

Machining tools, e.g. Indexable inserts are used worldwide for machining workpieces, in particular for machining. Tools, especially indexable inserts, are used e.g. manufactured according to DIN by many manufacturers. From practice it is known to monitor processing tools during their operation in a processing machine. For this, e.g. a use of thermal imaging cameras, monitoring the power consumption of feed or spindle motors or a photo surveillance known. From DE 35 35 474 A1 discloses a method for detecting Grenzverschleiss and / or cutting edge breakage in tools with a in the cutting material or the wear material, z. B. in the insert, embedded insulated track, which communicates with a voltage source in communication and forms part of a circuit which serves to trigger a signal to cancel the machining operation. At least two tracks are provided, one of which is part of a closed circuit, while the other forms part of an open circuit, and the signal for canceling the operation then arises when either the track is broken in the closed circuit or the track in the open circuit Circuit is closed.

The object of the invention is to improve the monitoring of machining tools. The object is achieved by a machining tool according to claim 1. Preferred or advantageous embodiments of the invention and others Categories of the invention will become apparent from the further claims, the following description and the accompanying drawings.

The processing tool is one for a processing machine. The machining tool is acted upon in an intended processing state with a processing force along a force path. The intended processing state is that when the machining tool is operated according to its design or application specifications in a processing machine provided for this purpose.

The machining tool contains at least one force transducer. The force transducer is metrologically coupled to the force path. The coupling serves to detect a measured variable. The measured variable is correlated with the processing force. The correlation is, in particular, that a large part of the processing power is absorbed by the load cell. In particular, it is known (for example by simulation or experiments) that the measured variable is proportional to the actual machining force. Thus, at least one relative, in particular an absolute value of the processing force can be recalculated or re-calculated from the measured value. The editing tool contains at least one interface. The interface is connected to the load cell or each load cell is connected to at least one interface. The connection is used to transfer the measured variable from the load cell to the interface. In particular, the connection also serves a power supply of the force transducer. The interface is designed to transmit the measured variable to a counter-interface. The force transducer is fixed and permanently attached to the machining tool. In particular, the force transducer is attached to the production or even before the final completion of the machining tool on this. In particular, the load cell forms an integral part of the machining tool.

From the counter-interface, the signal or the measured variable is then forwarded to a remote station, where the measured variable is further processed. The transfer from the counter-interface to the remote site takes place in particular at least partially wirelessly, for example by means of RFID.

According to the invention, a sensorized machining tool results, which contains its own, ie integrated, force transducer in order to measure the force (at least one measured variable correlated therewith) in the force path with which the machining tool is loaded at the time of measurement. The force transducer is in particular a so-called SENSOTECT® ¹ force transducer, ie it may contain or consist of such a coating. The transmission of the measured variable to the counter-interface is designed in particular as an electrical contact. Due to the combined measuring and interface unit, there is the advantage of being able to make statements about the processing force currently available on the machining tool at the machine at any time or permanently. Since the measured variable is correlated with the machining force, it is possible to draw conclusions about the currently measured machining force from the measured variable.

The measurement results, that is to say the determined measured variable or processing force, can in particular be continuously recorded by a software and compared with each other. Now wear the machining tool, e.g. an indexable insert also increases the force required and can - e.g. in a diagram - to be judged. Limits can be defined and the worker is prompted to swap the machining tool. Another effect can be used or e.g. be achieved by software. Areas (time windows, process sections, etc.) can be defined in which, in error-free operation, no introduction of force into the machining tool should or may take place, if e.g. In the machine program the rapid traverse is activated or the worker engages by hand into the machine. In this case, no force should be on the

"SENSOTECT" is a registered trademark of Schaeffler Technologies AG & Co. KG, 91074 Herzogenaurach, Germany Machining tool, in particular the cutting edge act. If there is still an application of force, the processing tool or the cutting edge had foreign contact. This can be documented and the source of interference can be determined.

According to the invention, a sensorized machining tool results. Loads on the machining tool, e.g. Indexable insert loads can be monitored and wear can be detected. In a preferred embodiment, the force transducer is a sensor layer applied to the surface of the machining tool. On the machining tool, e.g. Standardized indexable inserts, a layer, in particular a SENSOTECT® layer is applied. The effective direction is thereby aligned in particular to the force introduction direction. Upon initiation of a force (e.g., cutting operation), the resistance within the (SENSOTECT®) layer now changes. Thus, the measured variable correlated with the processing force can be detected.

In a preferred embodiment, the force transducer is arranged in the interior of the (in particular one-piece force-transmitting part of) machining tool. The arrangement in the interior takes place, for example, by receiving in a cavity of the machining tool. The cavity is in particular sealed to the outside, so that the components arranged in the interior of the machining tool are protected against environmental influences such as chips, coolant, etc. In a preferred embodiment, the force transducer is arranged in a recess introduced into the machining tool. Such a recess is usually easier to introduce into the machining tool as a cavity. The recess is in particular a blind hole or a depression which is accessible from the surface of the machining tool, in particular a bore.

The recess for the force sensor is located in particular at a location of the machining tool, that of the force path or a large part of the force path would go through if the recess would not exist. In other words, a region of the one-piece or solid material is sought in the machining tool, which is traversed by the force path. There, the corresponding Ausnehm is introduced for the force sensor. Thus, the force sensor can be introduced in the force path.

In a preferred variant of this embodiment, the force transducer is designed as a fitting element for the recess. The fit of the fitting element is in particular carried out so that, by inserting the fitting element, the force path through the recess and through the fitting element is at least partially closed again, as would be the case with solid material. Thus, the force path passes through the force transducer. The load cell is designed, in particular, as a force measuring pin, which can be pressed into an appropriate bore as a recess, or alternatively as a sensor layer, in particular as a SENSOTECT® layer. So the load cell sits as well as possible in the power path and the power path is closed again at this point and is used for power transmission. This results in particular in a SENSOTECT® indexable insert. In a preferred embodiment, the force transducer is arranged in the region of a designated force introduction point of the machining tool. "Point" is to be understood here broadly: It can also be a line or area force application area. The force application point refers back to the intended processing state or operating state of the machining tool. At the force application point or in its area, the force path is most concentrated, which is why a force transducer placed there can absorb as much of the actually acting force as possible. The measured variable generated by the force transducer thus has the largest possible amplitude and is particularly well correlated with the actually transmitted by the tool holder machining force. The force introduction point is in particular a processing zone of the machining tool. In particular, the load cell is arranged on an open space below (seen in the direction of force) of the processing zone. In particular, the force introduction point is a processing zone of the machining tool, in particular a cutting edge. Processing zones, especially cutting, are easy to identify on the tool, resulting in easy placement of the force sensor.

In a preferred embodiment, the processing zone is subject to material removal, and the processing zone has a wear limit for maximum permissible material removal, wherein the force transducer is arranged in the region of the sealing limit. The force transducer, in particular as a layer, is located in particular in the area of the free surface of the cutting edge and is applied in particular only by a regular distance measure (wear limit, eg approx. 0.2 mm, possibly plus a safety distance) below the main cutting edge of the tool. Normal wear of a machining tool, in particular a turning (cutting) plate leads to a burn in the area of the free surface on which in particular the force sensor or the sensor layer (eg SENSOTECT®) is located. Normal wear should not exceed the clearance or wear limit (eg between 0.15mm and 0.2mm). From this amount, the dimensional jumps and the surface usually become so bad that the tool has to be replaced. The force transducer is then as close as possible to the force application point without this being destroyed in normal operation. Such distance dimensions are in particular maximum 0.05 mm, 0, 1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or 1, 2, 3, 5 or 10 mm, depending on the application. In a preferred variant of this embodiment, the force transducer includes an electrical line which is arranged at the wear limit, so that it is removed when the wear exceeds the wear limit. At the wear limit, the tool would have to be exchanged at the latest. If this is not done by the operator, then the line, eg a line, of the (SENSOTECT®) sensor layer is attacked and destroyed. The flow of current through the line is interrupted. An evaluation circuit, eg a software, can now detect this, since no signal is passed through and can stop the machine. The worker is requested to change the machining tool. In a preferred embodiment, the machining tool is a turning tool (turning tool), an indexable insert, a drill or a milling cutter. Such components are particularly common or widely used and can serve according to the invention as a monitored tool holder. This results in particular a sensorized insert for turning-drilling and milling.

In a preferred embodiment, the interface is arranged in a contact region of the machining tool, with which the machining tool can be applied to a tool holder or a portion thereof in which a mating interface is present. The described location or contact area on the machining tool is that on which a portion of the tool holder rests during normal operation, e.g. a contact surface containing the counter interface. At this section, the mating interface (e.g., mating contacts) is then attached to the interface on the toolholder. Thus, via the interface and the counter interface at this location, a communication connection to the tool holder receiving the machining tool can be established, and thus the measured variable can be forwarded or directed away from the machining tool. In particular, two poles of an interface (end contacts of a conductor loop of the force transducer) are passed around a corner of the machining tool (e.g., insert) to an area where the tool seat (insert face) of the tool holder begins. In this area of the tool holder is the contact area, there can now be the preparation of the contact between the force transducer and a further in the machine connecting line o.ä. respectively.

In a preferred embodiment, the interface contains at least one electrical contact. This results in a particularly simple way of connecting the interface to a counter-interface in order to establish a signal-conducting connection.

In a preferred embodiment, the machining tool is a turning tool having at least two tool sections, and each of the Tool sections is associated with a force transducer. In particular, an interface is also assigned to each of the sections. This is in particular a geometrically identical arrangement, for example, relative to a cutting edge or a tool holder. The multiple arrangements of load cell, interface, cables, etc. are thus "copied" to themselves and, for example, shifted or rotated. For example, a reversing plate with two rotational positions for insertion into a tool holder has two cutting edges which are rotated by 180 °. The force transducer (eg a SENSOTECT® layer) is thus applied twice on the insert. The two structures are "mirrored" by 180 ° or copied and twisted).

The object of the invention is also achieved by a measuring device. The measuring device is a measuring device for a machining tool of a processing machine. The measuring device contains at least the force sensor and the interface connected thereto (thus also the connecting means necessary for this, in particular at least one connecting line) of the machining tool according to the invention. The measuring device also contains a counter interface for receiving the measured quantities transmitted by the interface. Such a counter-interface can be installed, in particular in the processing machine, on a holder for the processing tool. The measuring device and at least a part of their embodiments and the respective advantages have been explained analogously already in connection with the machining tool according to the invention. The invention is based on the following findings, observations or considerations, wherein in this context as "invention" also embodiments of the invention are mentioned, the parts or combinations of the above embodiments correspond and / or optionally also include previously not mentioned embodiments.

The invention is based on the consideration that indexable inserts or tools can be monitored in general, for example by thermal imaging cameras. Another way of monitoring is monitoring the power consumption the feed or spindle motors. However, this is inaccurate because between the active site of cutting and power on the engine many power losses such as friction are not detected. Another monitoring option is the photo surveillance in which the wear takes place via an image recognition. However, this is prone to failure, because chips and other media can make image recognition difficult. The monitoring by means of structure-borne noise is difficult when turning, because turning tools have different pressure angles during machining.

The aim of the invention is the economic monitoring of the cutting forces according to the Industrie 4.0 idea. Here, the power should be documented for each machining process. It should also be possible to achieve a message or a conclusion when reaching an upper limit of wear.

The invention can be used in a large part of machining tools. This type of tool is produced and consumed 100,000 times a day. The invention is thus widely used.

The invention can be used in the majority of tool manufacturers and is also widely applicable in this regard.

Further features, effects and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. 1 shows a sensorized processing tool in a side view, FIG.

FIG. 2 shows a tool holder with the machining tool from FIG. 1 in FIG

Top view,

FIG. 1 shows a machining tool 2, here an indexable insert in side view (direction of the arrow I in FIG. 2). Figure 2 shows a tool holder 4 in the form of an indexable insert holder with the held on this or fixed machining tool 2 in plan view, ie in the direction of the arrow II in Fig. 1st

On the tool holder 4, the machining tool 2 is fixed with a screw not explained in detail. The tool holder 4 is held in a processing machine, not shown here, here a lathe. The tool holder 4 is in a processing state B, that is, with the aid of the tool holder 4 and the machining tool 2, a workpiece, not shown, is processed.

During machining of the workpiece, a processing force F occurs, which is introduced from the workpiece into the machining tool 2 or its machining tip 6. An opposing force in the form of a (possibly deviating) machining force F is introduced via a shank 7 of the tool holder 4 which is not explained in more detail. In the processing tool 2, the processing force F runs along a force path 12, which is indicated only symbolically in FIG.

The machining tool 2 includes a force transducer 14. The force transducer 14 is metrologically coupled to the force path 12 in order to detect the machining force F (or a certain proportional component of this) in the form of a symbolically indicated measure M. The machining tool 2 also includes an interface 16 which is connected to the force transducer 14 to transmit the measurand M from the force transducer 14 to the interface 16. The interface 16 is designed to transmit the measured variable M to a counterpart interface 36. This transmission is wired, here by means of electrical contacts 17th

The force transducer 14 and the interface 16 are arranged on the surface of the machining tool 2. The force transducer 14 is in this case arranged so that a force transmission along the force path 12 (at least a part) of the machining force F takes place over the region of the machining tool 2, on which the force transducer 14 is arranged. So can the force transducer 14 record the respective processing force F or its portion in the form of the measured variable M.

The force transducer 14 is placed such that it is in each case arranged in the region of a designated force introduction point 24a of the machining tool 2. In the example, the force introduction point 24a (or introduction surface) is a processing zone 25a, here a cutting edge, of the machining tool 2.

The connection of load cell 14 and interface 16 via a connecting line 30. The connecting line 30 is disposed on the surface of the machining tool 2 and its free surface 33.

Together with the counter-interface 36 of the force transducer 14, the interface 16 and the two connecting elements connecting electrical connection line 30 forms a measuring device 28 for the processing tool 2 of the processing machine. The counter-interface 36 is in this case installed on the tool holder 4 for the machining tool 2 in the processing machine. The counter-interface 36 thus serves to receive the transmitted from the interface 16 parameter M.

Here, the force transducer 14 is a sensor layer in the form of a SENSOTECT® layer or structure, which is applied to the surface of the machining tool 2 during its production. The processing zone 25a is subject to a material removal in regular operation, which may take place up to a wear limit 34. The distance A between the wear limit 34 and the processing zone 25a in a new machining tool 2 is 0.2 mm. The permitted material removal is also limited to 0.2mm. The force transducer 14 is arranged in the region of the wear limit, here in the direction of removal directly adjacent to it below (in the direction of the processing force F). The force transducer 14 includes a plurality of series-connected electrical lines 35, here sections of a sensor coil. These are arranged directly on or on the wear limit 34. The lines 35 are therefore removed when the wear exceeds the wear limit. Thus, the exceeding of the wear limit 34 can be detected by interrupting at least one of the lines 35.

The interface 16 or the contacts 17 are arranged in a contact region of the machining tool 2. With this contact region, the machining tool 2 on the tool holder 4 or on a contact surface thereof, in the region of a counter-interface 36 can be applied. Thus, the contacts 17 (shown symbolically within the tool in FIG. 2) abut mating contacts 38 of the mating interface 36 on the tool holder 4 in order to produce an electrical connection to a signal line 40 on the tool holder 4. The measured value M can then be forwarded via the signal line 40 to a remote station 18. This signal path is in particular at least partially wirelessly.

The machining tool 2 is a turning tool. By a rotation through 180 ° about the rotation axis 42, a second processing zone 25b is brought to the location of the processing zone 25a shown in FIG. Also at the processing zone 25b (identical to the processing zone 25a) a force transducer 14 with signal line 30 and interface 16 is attached. The two load cells 14 are shown symbolically in FIG. 2 in the interior of the machining tool 2. 1 identically shows a side view in the direction of the arrow Γ in FIG. 2, except that the processing zone 25b would then be visible instead of the processing zone 25a. The force introduction point 24a then becomes the force introduction point 24b.

The processing zone 25a with associated load cell 14, connecting line 30 and interface 16 therefore forms a tool section 44a. The processing zone 25b with the associated respective components forms a tool portion 44b. Reference character list Editing tool

toolholder

processing tip

shaft

12 power path

14 load cells

16 interface

17 contact

18 remote station

4a, b force application point

5a, b processing zone

8 measuring device

30 connecting line

33 open space

34 Wear limit

35 line

36 counter-interface

38 mating contact

40 signal line

42 axis of rotation

44a, b tool section

F processing power

B processing state

M measured variable

A distance

Claims

claims

1 . Machining tool (2) for a processing machine, wherein the machining tool (2) in an intended processing state (B) with an operating force (F) along a force path (12) is acted upon, characterized in that the machining tool (2) has a force transducer (14) contains, which is metrologically coupled to the force path (12) for detecting a correlated with the processing force (F) metric (M), and the machining tool (2) connected to the force transducer (14) interface (16) for transmitting the measured variable (M ) to a mating interface (36), wherein the force transducer (14) fixed and non-detachable on the machining tool (2) is mounted.

2. machining tool (2) according to claim 1, characterized in that the force transducer (14) on the surface of the machining tool (2) applied sensor layer.

3. Machining tool (2) according to one of the preceding claims, characterized in that the force transducer (14) in the region of an intended force introduction point (24a, b) of the machining tool (2) is arranged.

4. machining tool (2) according to claim 3, characterized in that the force introduction point (24 a, b) is a processing zone (25 a, b) of the machining tool (4).

5. machining tool (2) according to one of claims 3 to 4, characterized in that the processing zone (25 a, b) is subject to material removal, and the processing zone (25 a, b) has a wear limit (34) for maximum allowable material removal, wherein the Force transducer (14) in the region of the wear limit (34) is arranged.

6. machining tool (2) according to claim 5, characterized in that the force transducer (14) includes an electrical line (35) which is disposed at the wear limit (34), so that the line (35) is removed when the wear exceeds the wear limit (34).

7. machining tool (2) according to one of the preceding claims, characterized in that the machining tool (2) is a rotary tool, an indexable insert, a drill or a milling cutter.

8. machining tool (2) according to one of the preceding claims, characterized in that the interface (16) in a contact region of the machining tool (2) is arranged, with which the machining tool (2) on a tool holder (4) in the region of a counter Interface (36) can be applied.

9. machining tool (2) according to one of the preceding claims, characterized in that the interface (14) contains at least one electrical contact (17).

10. machining tool (2) according to any one of the preceding claims, characterized in that the machining tool (2) is a turning tool with at least two tool sections (44 a, b), and each of the tool sections (44 a, b) is associated with a force transducer (14) ,