STRUCTURAL COMPONENT FOR A MACHINE TOOL AND METHOD FOR PRODUCING SAME

Abstract

A structural component for a machine tool is formed from a mineral casting and at least one sensor module is integrated into the structural component, wherein the sensor module is completely enclosed by the mineral casting and contains at least one sensor for detecting a mechanical load of the structural component during operation of the machine tool.

Claims

1. A structural component for a machine tool (1), wherein the structural component (2, 2′) is formed from a mineral casting and at least one sensor module (11-15) is integrated into the structural component (2, 2′), wherein the sensor module (11-15) is completely enclosed by the mineral casting and contains at least one sensor for detecting a mechanical load (S1-S5) of the structural component during operation of the machine tool.

2. The structural component according to claim 1, wherein the sensor module (11-15) is configured to detect a compressive force and/or a tensile force and/or an elongation and/or a compression and/or a bending and/or a torsion and/or a length change and/or a mechanical vibration.

3. The structural component according to claim 1, wherein the sensor module (11-15) is configured to detect mechanical loads as absolute value.

4. The structural component according to claim 1, wherein the sensor module (11-15) is configured to detect mechanical vibrations, the frequency of which corresponds at least to the lowest natural frequency of the structural component (2, 2′).

5. The structural component according to claim 1, wherein the sensor module (11-15) contains at least one temperature sensor (T1-T5) which is located in a defined position with respect to the at least one sensor for detecting a mechanical load (S1-S5).

6. The structural component according to claim 1, wherein the sensor module (11-15) is provided at a predetermined position in the structural component (2, 2′).

7. The structural component according to claim 1, further comprising at least one actuator (17, 18) provided on the structural component (2′) or integrated in the structural component (2′).

8. The structural component according to claim 1, wherein the structural component is a machine bed.

9. A machine tool, comprising the structural component (2, 2′) according to claim 1.

10. A method for producing a structural component (2, 2′) for a machine tool (1), the method comprising at least the following steps: Providing a casting mold for the structural component (2, 2′), providing at least one sensor module (11-15) in and/or on the casting mold, wherein the sensor module (11-15) contains at least one sensor for detecting a mechanical load (S1-S5), and introducing a liquid mineral casting into the casting mold.

11. The method according to claim 10, wherein the sensor module (11-15) is provided at a predetermined position in and/or on the casting mold.

12. The method according to claim 10, wherein the casting mold is removed from the structural component (2, 2′) after curing of the mineral casting.

13. The method according to claim 10, wherein during the method, sensor values are detected at least temporarily by the at least one sensor (S1-S5, T1-T5), and wherein at least one optimization value for the structural component (2, 2′) is calculated based on the detected sensor values.

14. A use of the structural component according to claim 1 in a machine tool (1), wherein during operation of the machine tool (1), sensor values are detected at least temporarily by the at least one sensor (S1-S5, T1-T5).

15. The use of the structural component according to claim 14, wherein natural vibrations of the structural component (2, 2′) and, at the same time, their effects are determined at a Tool Center Point (TCP) of the machine tool (1) by means of the detected sensor values.

Description

[0032] FIG. 1a is a schematic perspective view of a machine bed of a machine tool with integrated sensors according to one embodiment of the present invention, and FIG. 1b is a schematic illustration of an orthogonal projection of the sensors shown in FIG. 1a onto the upper side of the machine bed.

[0033] FIG. 2 is a schematic perspective view of the machine bed shown in FIG. 1a according to a refinement of the invention.

[0034] FIG. 3 shows schematically the steps of a method according to the invention for producing the machine bed shown in FIGS. 1a, 1b and 2.

[0035] In the following, an embodiment of the present invention is described with reference to FIGS. 1a, 1b. FIG. 1a shows a processing machine designed as a machine tool 1 with a structural element designed as a machine bed 2. The machine tool 1 is designed for machining and/or manufacturing a workpiece (not shown in the figures) by means of at least one tool (not shown in the figures), the workpiece being attached to or on the machine bed 2.

[0036] The machine bed 2 in FIG. 1a, purely as an example, is formed in a cuboidal manner and is made of mineral casting. The machine bed 2 has an upper side 3. On the upper side 3A, a first linear guide 4a and a second linear guide 4b are arranged parallel to each other at a distance d. A slide, which is not shown in more detail in the figures, can be attached to the linear guides 4a, 4b, on or to which slide the workpiece (not shown in the figures) can be secured. The slide (not shown) is provided to be movable along the linear guides 4a, 4b across the surface 3 of the machine bed 2.

[0037] Furthermore, a holding fixture 5 is provided in the machine bed 2, which is embedded in the mineral casting and projects upwardly above the upper side 3 of the machine bed 2. To simplify the illustration, FIG. 1a only shows the portion of the holding fixture 5 provided in the machine bed 2. The holding fixture 5 shown in FIG. 1a is shaped, purely as an example, in the form of a rod or tower and has a circular cross-section in the surface of the upper side 3. For example, the tool, which is not shown in the figures, for machining or manufacturing the workpiece (also not shown) can be secured on the holding fixture 5.

[0038] Furthermore, purely as an example, a Tool Center Point TCP is shown which is associated with the machine tool 1 and is located in FIGS. 1a and 1b on the upper side 3 of the machine bed 2. The Tool Center Point can also be provided at another location of the machine tool 1, in particular above the machine bed 2.

[0039] The machine bed 2 shown in FIG. 1a has, purely by way of example, five sensor modules 11, 12, 13, 14, 15 integrated in the machine bed, each of the sensor modules 11, 12, 13, 14, 15 being completely enclosed by the mineral casting, i.e., when viewing the machine bed 2, the sensor modules 11-15 are not visible from the outside. Each of the sensor modules 11, 12, 13, 14, 15 has a sensor configured as a strain sensor S1-S5 for detecting a mechanical load, and a temperature sensor T1-T5. The strain sensors S1-S5, for example, can comprise glass fibers integrated into the machine bed 2, the length of which is detected interferometrically. The strain sensor S1-S5 and the respective temperature sensor T1-T5 of each of the sensor modules 11-15 are in a defined position with respect to each other, i.e., have a predefined distance and a predefined orientation with respect to each other. Furthermore, each of the sensor modules 11-15 is provided at a predetermined position in the machine bed 2. As can be seen from FIG. 1a and the orthogonal projection of the sensor modules 11-15 onto the upper side 3 shown in FIG. 1b, the first and second sensor modules 11, 12 are each provided in the vicinity of the holding fixture 5, and the third, fourth and fifth sensor modules 13, 14, 15 are provided in the vicinity of the linear guides 4a, 4b. The strain sensors S3, S4 of the third and fourth sensor modules 13, 14 each extend substantially parallel to the linear guides 4a, 4b and can be provided substantially vertically below the respective linear guides 4a, 4b, as indicated by the dashed lines in FIG. 1a. In FIG. 1b, the strain sensors S3, S4 of the third and fourth sensor modules 13, 14 are arranged horizontally offset from the linear guides 4a, 4b. The strain sensor S5 of the fifth sensor module 15 extends substantially transverse to the linear guides 4a, 4b.

[0040] Optionally, the machine tool 1 comprises an evaluation unit, which is not shown in the figures, to which each sensor module 11-15 or each sensor T1-T5, S1-S5 is connected via a data link.

[0041] In the exemplary embodiment described above, five sensor modules 11-15 are integrated into the machine bed 2, each comprising a strain sensor S1-S5 and a temperature sensor T1-T5. The sensor modules 11-15 can also be provided at least partially without the temperature sensor and/or can comprise any other sensors for detecting a mechanical load, for example a sensor configured to detect a compressive force and/or a tensile force and/or an elongation and/or a compression and/or a bending and/or a torsion and/or a length change and/or a mechanical vibration, or a plurality of such sensors. The sensor modules can also be configured differently, i.e., they can include at least partially different sensors and/or more or less than five sensor modules can be provided.

[0042] According to a first refinement of the machine bed 2 shown in FIGS. 1a, 1b, at least one of the sensor modules 11-15 comprises at least one sensor S1-S5 which is configured to detect mechanical vibrations, the frequency of which corresponds at least to the lowest natural frequency of the machine bed 2.

[0043] FIG. 2 shows a second refinement of the machine bed 2 shown in FIGS. 1a, 1b, wherein for simplification of the illustration, the sensors S1-S5, T1-T5 of the sensor modules 11-15 shown in FIGS. 1a, 1b are not shown in FIG. 2. Two temperature control lines 17, 18 are integrated in the machine bed 2′, which have connections 17a, 17b, 18a, 18b for feeding and discharging a medium, for example water, which is used for cooling or heating (generally controlling the temperature) the machine bed 2′. Thus, the machine bed 2′ can be cooled or heated by feeding the medium through the temperature control lines 17, 18.

[0044] Alternatively or additionally to the temperature control lines 17, 18 shown in FIG. 2, the machine bed 2′ can have one or more further actuators (not shown), in particular actuators configured to at least partially compensate for or counteract mechanical loads detected by the sensors S1-S5 of the sensor modules 11-15. Preferably, the actuators are connected to a control unit (not shown) via which the actuators are controlled.

[0045] During operation of the machine tool 1, the workpiece not shown in the figures is attached to the slide (not shown) and machined and/or manufactured by the tool (not shown). In this case, sensor values can be detected by the sensors S1-S5, T1-T5 of the sensor modules 11-15 integrated in the machine bed 2, 2′ at least temporarily during and/or before and/or after operation of the machine tool. The sensor values are transmitted to the evaluation unit (not shown) and evaluated by the evaluation unit. Based on the detected and evaluated sensor values, for example, the actuator(s) can be controlled in such a manner that they at least partially compensate for or counteract the detected mechanical load and/or a detected heat input. Alternatively or additionally, it is possible, based on the detected and evaluated sensor values, to intervene in the operation of the machine tool 1 or to stop its operation.

[0046] Preferably, a modal analysis of the machine bed 2, 2′ is performed at least once. For this purpose, the machine bed 2, 2′ is subjected to vibrations by external excitation and the natural vibrations of the machine bed 2, 2′ are determined by means of the sensor values detected by the sensors S1-S5 of the sensor components 11-15. At the same time, the structural response of the machine bed 2, 2′ is determined at a reference point, for example at the Tool Center Point TCP, by means of another provided sensor (not shown in the figures), for example a vibration sensor, acceleration sensor, etc.

[0047] In the following, a method for producing the machine bed 2, 2′ shown in FIGS. 1a, 1b, 2 is described with reference to FIG. 3. In a first step 21, a casting mold (not shown in the figures) suitable for the machine bed 2, 2′ to be produced is provided. In a second step 22, the sensor modules 11-15 with the respective sensors S1-S5, T1-T5 are provided and attached in and/or to the casting mold. In doing so, the sensor modules 11-15 are positioned in such a manner that they are later located at the desired positions in the finished machine bed 2, 2′. Furthermore, in the second step 22, the holding fixture 5 is attached in and/or to the casting mold. If the machine bed is to be equipped with integrated actuators, for example the temperature control lines 17, 18 shown in FIG. 2, the actuators are also provided in the second step 22 and attached in and/or on the casting mold at the desired position.

[0048] Subsequently, in a third step 23, a liquid mineral casting is introduced into the casting mold. After the mineral casting has cured, the casting mold is removed from the machine bed 2, 2′ in a fourth step 24. In subsequent manufacturing and/or assembly steps (not shown in FIG. 3), the linear guides 4a, 4b can also be attached to the upper side 3 of the machine bed 2, 2′ and the machine bed 2, 2′ can be integrated into the machine tool 1 or further elements of the machine tool 1 can be attached to the machine bed 2, 2′.

[0049] During the production of the machine bed 2, 2′, for example for the purpose of quality control or process improvement, sensor values can be detected by the sensors S1-S5, T1-T5 at least temporarily, in particular during the curing or setting of the mineral casting. Based on the detected sensor values, at least one optimization value for the machine bed can be determined. The optimization value can be, for example, a weight and/or a material composition and/or a geometric shape and/or a dimensioning of the structural component.

[0050] Modifications of the machine tool described above are possible within the scope of the invention. Thus, the machine bed can also be provided without the holding fixture 5 described above with reference to FIGS. 1a, 1b, 2 and/or without the linear guides 4a, 4b. Alternatively or additionally, other structural elements can be provided on or embedded in the machine bed, in particular if the machine is a pick-and-place or packaging machine.

[0051] Although the present invention has been described with reference to a machine tool having a machine bed, it is not limited thereto. It can be applied to any machining devices having a structural component made of mineral casting. Preferably, the structural component of the machining devices is generally used for defined positioning of an object, i.e., a workpiece, to be machined with the machining device. As an alternative to the above-described design of the structural component as a machine bed, the structural component can be designed, for example, as a column, a gantry, a spindle suspension, a device body or the like.