Two-side or one-side machining tool

Abstract

The invention relates to a two-side or one-side machining tool, comprising a preferably annular first working disk and a counter-bearing element, and comprising a rotary drive having a drive shaft for rotating the first working disk and / or the counter-bearing element, wherein a working gap is formed between the first working disk and the counter-bearing element for machining both sides or one side of flat workpieces, wherein a sensor is provided which is designed to monitor the orientation of the drive shaft during operation of the two-side or one-side machining tool.

Description

[0001] Double- or single-sided machining machine

[0002] The invention relates to a double- or single-sided machining machine comprising a preferably annular first working disk and a counter bearing element, and comprising a rotary drive with a drive shaft for rotating the first working disk and / or the counter bearing element, wherein a working gap is formed between the first working disk and the counter bearing element for machining flat workpieces on both or one side.

[0003] For example, in double-sided machining centers, flat workpieces, such as wafers, are machined simultaneously on both sides. These machines have an upper and a lower working disk, between which a typically annular working gap is formed, in which the workpieces to be machined are guided during processing. The upper working disk is usually attached to an upper support disk, and the lower working disk is usually attached to a lower support disk. For machining, a relative rotation between the working disks is achieved by rotating at least one of the working disks, particularly together with its support disk. Double-sided machining centers are known in which so-called runner disks are guided in the working gap. The runner disks typically hold the workpieces to be machined in a floating manner within circular openings.A suitable kinematic system ensures that the rotor discs also rotate within the working gap as the working discs rotate relative to each other. This causes the workpieces to move along cycloidal paths within the working gap, resulting in a particularly uniform surface finish. The machining can be performed, for example, by grinding, lapping, or polishing. In double-sided polishing machines, for instance, multiple silicon wafers, such as more than ten with a diameter of 300 mm, can be processed simultaneously.

[0004] The machining of workpieces in a given machining step should be carried out under the most stable possible load over time, with the load being distributed as homogeneously as possible across the entire surface of the machining disc. An ideal homogeneous distribution is achieved, in particular, when the lower machining disc is perfectly horizontal and the drive shafts of both discs are parallel, ideally coaxial. The alignment of the machining discs depends on a number of factors, such as the manufacturing tolerances of the individual components, in total. Another factor is the flatness of the disc surface. The more uneven the surface of the disc, the lower the resulting workpiece quality. The machine's installation location is also a factor. For example, an uneven installation surface leads to misalignment between the machining discs, which requires complex correction.Regarding manufacturing tolerances, every effort is made to minimize permissible manufacturing defects in individual components. The surface flatness of the work discs is improved through suitable dressing processes. To compensate for unevenness in the floor at the machine's installation site, height-adjustable feet on the machine base supporting the work discs are a known practice. Such feet may be equipped with damping.

[0005] The primary goal when adjusting the feet is to achieve horizontal alignment of the lower work disc. Once this is accomplished, the upper work disc or a counter bearing element is aligned with the surface of the lower work disc, particularly with its drive shaft. However, this alignment of the lower work disc, set during the machine's initial setup for operation, is not stable over an indefinite period but is subject to change due to various factors. For example, damping elements in the feet are not stable over time but lose elasticity, especially with age and use. Furthermore, the floor of a production area supporting the machine is typically not uniform, necessitating realignment if the machine is repositioned. Moreover, such a floor is often not stable over time either.This is particularly true for cleanroom floors with columns or installations on higher floors. Over time, changes in the floor surface can occur, affecting the alignment of the machining center's work discs. The alignment of the work disc drive shafts is also influenced by loads, such as those from the feet, which can lead to unforeseen shifts in the alignment of the lower work disc. Such changes in work disc alignment are not externally detectable but only become apparent as a deterioration in workpiece quality after a production process, despite consistent process parameters. Consequently, deviations from the ideal range of process parameters and work disc alignment are often detected late, resulting in significant scrap.

[0006] Misalignment can also result from both a tilting of the work discs relative to each other and a non-coaxial alignment of the work discs. A further problem arises, for example, with double-sided machining centers where an upper work disc can be moved between a position above the lower work disc and a position pivoted away from it by means of a swivel arm. Here, on the one hand, an undesirable change in the alignment between the work discs can occur during the swiveling movement when they are pivoted back to the position above the lower work disc. On the other hand, such machining centers often have an asymmetrical weight distribution due to the swivel arm arrangement, which further complicates the alignment of the work discs relative to each other.This is especially true given the considerable total weight of such machines, exceeding 10 t, for example approximately 20 t.

[0007] The problems described above, caused by a changing orientation of the lower work disk, are addressed through appropriate countermeasures. However, even with the lower work disk's orientation assumed to be constant and correct, the load during a machining process can dynamically alter the alignment between the lower work disk and an upper counter-bearing element, particularly an upper work disk. Furthermore, the design of the aforementioned machining centers with a swivel arm causes the axis of an upper counter-bearing element or an upper work disk, which is coaxially aligned in a static state, to tilt under load. This tilting is unavoidable with a rigid design. To some extent, this effect can be mitigated by deliberately misaligning the work disks before the start of the process.This deliberate misalignment can be used for a single load in the process to ensure coaxial alignment. However, as soon as multiple loads are used in a process, only one of these loads will have perfect coaxial alignment, while the others will have a detrimental misalignment. Similarly, only one optimal process can be run on a machine, even with only one load—namely, the one that corresponds to the deliberate misalignment. This severely restricts the machine's flexibility. The rotational movement between the work disks can also lead to further misalignment, which can, in principle, be statically pre-compensated, but with the disadvantages described above.

[0008] Also known is the use of a somewhat flexible connecting element between a drive shaft and the shaft passing through it.

[0009] ... / 5 driven work disc, for example, a curved-tooth coupling. Such a connecting element is intended to compensate for imperfect alignment of the drive shaft. However, each element of this type has only a limited working range. If the misalignment exceeds this range, the corresponding error is transferred to the workpieces being machined. Furthermore, such connecting elements also react differently to the applied load under which the workpieces are machined. Consequently, any pre-compensation for a change in alignment between the work discs occurring under load is only fully valid for a specific process with specific process parameters, such as rotational speed, load, and the machining tool used, particularly slurry. This is a dynamic problem that changes depending on the operating point of the double- or single-sided machining center.

[0010] Based on the prior art described above, the invention aims to provide a double- or single-sided machining machine of the type mentioned above, with which workpieces can be machined reliably and cost-effectively with high quality and reduced scrap.

[0011] The invention solves the problem through the subject matter of independent claim 1. Advantageous embodiments can be found in the dependent claims, the description and the figures.

[0012] For a double- or single-sided machining machine of the type mentioned above, the invention solves the problem by providing a sensor designed to monitor the orientation of the drive shaft during operation of the machine. The machining machine can be, for example, a polishing machine, a lapping machine, or a grinding machine. The workpieces being machined can be, for example, wafers. A working gap is formed between the first working disk and a counter bearing element, for example, a simple weight or pressure cylinder in single-sided machining machines, or a second working disk in double-sided machining machines. In this gap, the workpieces to be machined are processed on both sides or on one side only. In a double-sided machining machine, simultaneous processing of the top and bottom sides of the workpieces can take place in the working gap.Accordingly, both work discs can have a working surface that processes the workpiece surface. In contrast, with a single-sided machining center, only one side of the workpiece is machined, for example, the underside, by the lower work disc. In this case, only one work disc has a working surface that processes the workpiece surface. The counter bearing element then serves only to provide a corresponding counter bearing for the machining process by the work disc.

[0013] The workpieces can be mounted in openings of rotor discs arranged in the working gap in a manner known per se. During operation, the first working disc and the counter bearing element are driven to rotate relative to each other, for example, via a first and / or a second drive shaft and at least one drive motor. Both the counter bearing element and the first working disc can be driven to rotate, for example, in opposite directions. However, it is also possible to drive only one of the counter bearing element and the first working disc. For example, in a double-sided machining center, suitable kinematics can also cause the rotor discs to rotate through the working gap during this relative rotation, so that workpieces arranged in the rotor discs describe cycloidal paths in the working gap. For example, the rotor discs can be driven at their... / 7 outer edge and / or on its inner edge have a toothing that engages with an associated toothing, for example, of the first working disk. Such machines with so-called planetary kinematics are known per se.

[0014] The first working disc can be ring-shaped. The counter bearing element or the second working disc can also be ring-shaped. The first working disc and the counter bearing element, for example, the second working disc, then have opposing, ring-shaped working surfaces, between which the ring-shaped working gap is formed. The working surfaces can be covered with a working material, for example, polishing cloths. Any support discs holding the working discs can also be ring-shaped or at least have ring-shaped support sections to which the working discs are attached. More than one support disc per working disc can also be provided. The first working disc and / or the counter bearing element can be single-layered or multi-layered. The same applies to a support disc that carries the first working disc or the counter bearing element.

[0015] Temperature control channels can be formed in the first working disk and / or the counter bearing element and / or in a first support disk supporting the first working disk and / or a second support disk supporting the counter bearing element, through which a temperature control fluid, for example a temperature control liquid, is guided during operation to temperature control the respective components.

[0016] As explained at the beginning, the drive shaft can be coupled to the first working disc or the counter bearing element via a connecting element that compensates for misalignment, for example a curved tooth coupling.

[0017] According to the invention, a sensor is provided which monitors the alignment of the drive shaft during operation of the double- or single-sided machining machine.

[0018] 8. If two drive shafts are provided, namely one drive shaft for the first work disk and one drive shaft for the counter bearing element or a second work disk, the alignment of both drive shafts can be monitored by a suitable sensor. The sensor repeatedly records measured values ​​characterizing the drive shaft alignment, for example at specific intervals or continuously, during operation of the double- or single-sided machining center. In this way, any change in the drive shaft alignment that may occur during operation can be detected early, i.e., dynamically, and thus the risk of deteriorating workpiece quality can be identified early on and counteracted in a timely manner with suitable countermeasures in order to minimize scrap.For example, an operator can be alerted to a deviation of the alignment from a predetermined orientation, so that appropriate countermeasures can be taken in a timely manner to further ensure the desired workpiece quality. Thus, according to the invention, it is ensured in a simple and reliable manner that the workpiece quality is maintained at all times, even in the case of the changes in influencing factors affecting the alignment of the drive shaft described above.

[0019] The double- or single-sided processing machine can be, in particular, a double- or single-sided polishing machine, a double- or single-sided lapping machine, or a double- or single-sided grinding machine.

[0020] In one embodiment, the counter bearing element can be formed by a preferably annular second working disk, wherein the working gap for machining flat workpieces from one or both sides is formed between the first and second working disks. Particularly with correct alignment, the first and second working disks can be arranged coaxially to each other. The first working disk can be attached to a first support disk and / or the second working disk can be attached to a second support disk.

[0021] In a further embodiment, the first working disk or the counter bearing element can be arranged on a pivot arm and pivoted relative to the other first working disk or counter bearing element with the pivot arm. A rotary drive for the first working disk or the counter bearing element arranged on the pivot arm can be integrated into the pivot arm. As explained at the outset, particularly with such machine tools, which have an asymmetrical weight distribution, there are special challenges regarding the alignment between the first working disk and the counter bearing element, especially the reliable maintenance of the correct alignment, which can be reliably addressed according to the invention. The rotary drive and the drive shaft can be arranged on the pivot arm, and in particular, integrated into the pivot arm.

[0022] In a further embodiment, the double- or single-sided machining machine can have a machine base with feet that allow the machine base to stand on the floor of a production area when the machine is assembled. The machine base supports the first working disk and the counter bearing element. The machine base supporting the first working disk and the counter bearing element can be designed as a housing. It can also support a rotary drive for rotating the first working disk and / or the counter bearing element. Likewise, the machine base can support a swivel arm, if provided, for pivoting the first working disk and / or the counter bearing element. The machine base can also support first and / or second support disks, if provided. The feet can have dampers. They can be height-adjustable. During operation, the alignment of the feet can change, for example... / 10 Example: a loss of damping effect from the dampers. This can change the alignment of the drive shaft.

[0023] In a further embodiment, the sensor can include a distance sensor for measuring the distance to the drive shaft during operation of the double- or single-sided machining center. The distance sensor can be a mechanical distance sensor, for example, a position probe, and / or an inductive distance sensor and / or an optical distance sensor. With this particularly practical embodiment, the orientation of the drive shaft during operation of the double- or single-sided machining center can be detected in a particularly simple and reliable manner.

[0024] The double- or single-sided machining center can also include an evaluation unit that receives the measurement data from the sensors. This evaluation unit can be configured to issue a warning signal if a deviation of the drive shaft's alignment from a predefined orientation is detected. Based on such a warning signal, an operator can take measures to restore the drive shaft to its optimal alignment. This could involve, for example, changing the position of the first working disc and / or the counter bearing element, such as a vertical, lateral, and / or tilting movement, and / or adjusting the feet, such as a vertical movement of the feet. Changing the position of the first working disc and / or the counter bearing element could therefore, for example, involve a vertical adjustment and / or a lateral adjustment.This can also involve a tilting of the first working disk and / or the counter bearing element, for example, to correct a non-coaxial alignment of the rotational axes of the first working disk and the counter bearing element. The specified alignment can be an alignment of the drive shaft set during the setup of the double- or single-sided machining center for operation. The first working disk or the counter bearing element, in particular its drive shaft(s), are thus optimally aligned relative to each other before a machining process, and this alignment is adopted as the target alignment. If the sensor detects a change from this target alignment, countermeasures can be taken as described above.

[0025] The evaluation unit can, in a further embodiment, be configured to infer the orientation of the drive shaft from the vibration amplitude of the distance measurement signals detected by the distance sensor. During repeated, for example, continuous measurement of the distance between the distance sensor and the drive shaft, an undesired tilt relative to a coaxial (e.g., vertical) orientation of the drive shaft, for instance, results in a periodic change in distance with rotation, which is measured as a vibration signal by the distance sensor. The amplitude of the vibration should be minimal, ideally zero, when the drive shaft is optimally aligned. Accordingly, the vibration amplitude of the measured values ​​can be used to infer the orientation of the drive shaft, and in particular, to detect any deviation of the orientation from a predefined orientation.

[0026] In a further embodiment, the evaluation unit can be configured to control the double- or single-sided machining center upon detecting a deviation of the drive shaft from a predetermined orientation, so that the drive shaft's orientation again corresponds to the predetermined orientation. In this embodiment, an automatic realignment can thus occur upon detection of a deviation from the predetermined orientation, ensuring optimal workpiece quality at all times. For this purpose, the evaluation unit can control suitable adjustment devices with which the drive shaft's orientation can be adjusted as described above. In a further embodiment, the drive shaft and / or a support element carrying the first drive shaft and / or the first working disk and / or a first support disk carrying the first working disk and / or the counter bearing element and / or a second support disk carrying the counter bearing element can be provided with an adjustment device that can be controlled by the evaluation unit so that the orientation of the drive shaft corresponds again to the specified orientation. The support element carrying the drive shaft can, for example, comprise a support element carrying a rotary drive and / or a gearbox of a rotary drive and thus the drive shaft connected to the rotary drive or the gearbox. This support element can be a section of a pivoting arm for pivoting the first working disk and / or the counter bearing element.

[0027] In a particularly practical embodiment, the adjusting device can comprise at least one adjusting element that is translationally movable by means of an adjusting drive, by means of whose translational movement the drive shaft and / or a support element supporting the first drive shaft and / or the first working disk and / or a first support disk supporting the first working disk and / or the counter bearing element and / or a second support disk supporting the counter bearing element can be adjusted in height and / or laterally and / or tilted. In particular, several such adjusting elements can be provided.

[0028] According to a further, particularly practical embodiment, the adjusting element can comprise an adjustable threaded rod. The adjustable threaded rod can be driven by an electric or hydraulic actuator, or by a piezoelectric element. Compared to manually adjusting the drive shaft's alignment, for example by using shims of varying thicknesses, the aforementioned embodiment is less complex, especially since it eliminates the need to disassemble and reassemble numerous parts of the double- or single-sided machining center.

[0029] With the above-described designs, adjustment can be carried out particularly easily, either manually or automatically via the evaluation unit, using suitable screw points.

[0030] Exemplary embodiments of the invention are explained in more detail below with reference to the figures. They schematically show:

[0031] Fig. 1 shows a double-sided machining machine according to the invention in a side view in a first operating state,

[0032] Fig. 2 shows the double-sided machining machine from Figure 1 in a second operating state,

[0033] Fig. 3 shows a top view of the double-sided machining machine according to Figure 1 in the operating state of Figure 2,

[0034] Fig. 4 shows the representation from Figure 3 in a further operating state,

[0035] Fig. 5 shows a part of the double-page spreads shown in Figures 1 to 4.

[0036] Machining machine in a partially cut-away side view

[0037] Fig. 6 shows another part of a double-sided machining machine shown in Figures 1 to 4, with a first adjusting device,

[0038] Fig. 7 shows a representation corresponding to Figure 6 with an additional adjustment device,

[0039] Fig. 8 shows a measurement diagram taken with the double-sided machining machine according to the invention,

[0040] Fig. 9 shows a further representation of the double-sided machining machine according to the invention in a first operating state,

[0041] Fig. 10 shows the representation from Figure 9 in a second operating state, Fig. 11 shows the representation from Fig. 9 in the first operating state with a changed orientation of the drive shaft of the upper working disc, and

[0042] Fig. 12 shows the representation from Fig. 11 in the second operating state.

[0043] Unless otherwise stated, the same reference symbols in the figures denote the same objects.

[0044] The double-sided machining machine shown in Figures 1 to 4, by way of example only, has a machine base 10 that rests on a floor 14 of a production area via a plurality of feet 12. The machine base 10, which is designed, for example, as a housing, carries an annular first support disk 16, which in turn carries an annular first working disk 18. Furthermore, the machine base 10 carries a pivot arm 22 arranged on a swivel housing 20, which carries an annular second support disk 24, which in turn carries an annular second working disk 26. The upper second support disk 24, together with the second working disk 26, can be rotated about a drive shaft 28, for example, by means of a rotary drive arranged in the pivot arm 22.By means of a rotary drive (not shown) and a drive shaft (also not shown), the lower first carrier disk 16 and with it the first working disk 18 are preferably rotatable, for example in the opposite direction to the second carrier disk 24 with the second working disk 26. An annular working gap is formed between the working disks 18 and 26, with Figure 1 showing the working disks 18 and 26 in a state moved apart axially, for example for loading workpieces to be processed, such as wafers, onto runner disks arranged on the lower working disk 18. Figure 2 shows the working disks 18 and 26 in a position facing each other. By rotating the working disks 18 and 26 in opposite directions, the workpieces, which are, for example, floatingly mounted in runner disks, can be moved into position in a manner known per se. / 15 the annular working gap can be machined, for example by grinding, lapping or polishing.

[0045] As can be seen from a comparison of Figures 1 and 2, the swivel arm 22 can be moved vertically to adjust between the operating states shown in Figures 1 and 2. Figures 3 and 4 also show that the swivel arm 22 can be pivoted together with the swivel housing 20 to pivot the second, upper carrier disc 24 and with it the second, upper working disc 26 between a position opposite the first, lower working disc 18 and a position further away from it, particularly for loading runner discs with workpieces to be machined.

[0046] The feet 12 can include dampers 30. The double-sided machining machine also includes an evaluation unit 32, which receives, among other things, measured values ​​from a sensor that will be explained in more detail below.

[0047] The following section will explain the design of a sensor according to the invention for monitoring the alignment of the drive shaft 28 of the second work disk 26 during operation of the double-sided machining center, using the second work disk 26 as an example. A corresponding sensor is provided for monitoring the alignment of the drive shaft of the first work disk 18. The following explanations also apply accordingly to the sensor assigned to the drive shaft of the first work disk 16. Of course, it would also be possible to provide a corresponding sensor for only one of the drive shafts or work disks.

[0048] Figure 5 shows that the drive shaft 28 is connected to the second working disk 26 (shown in a highly schematic way) via a curved-tooth coupling 34. The curved-tooth coupling 34 can compensate for undesired tilting of the drive shaft 28 to a certain extent. However, if a working range of the curved-tooth coupling 34 is exceeded, such compensation can no longer be effective. Therefore, the double-sided machining center has a sensor 36, in this case a distance sensor 36. The distance sensor 36 can, for example, be a mechanical, inductive, or optical distance sensor. It measures a distance to the drive shaft 28. The measured values ​​of the distance sensor 36 are available at the evaluation unit 32.

[0049] Figure 8 shows an example of a corresponding measurement diagram. A measurement signal (displacement) recorded by the distance sensor 36 is plotted against time in arbitrary units as a solid line. The diagram in Figure 8 shows a stepwise increase in the load applied by the second working disc 26 to the first working disc 18, represented by a dashed line. It can be seen that the distance sensor 36 measures a vibration signal whose amplitude increases with increasing load. For optimal alignment of the drive shaft 28, the lowest possible vibration amplitude is desirable. A higher amplitude indicates an undesirable tilting of the drive shaft 28.

[0050] Based on the measured values ​​obtained from the distance sensor 36, the evaluation unit 32 can monitor the alignment of the drive shaft 28 during operation of the double-sided machining center. If an impermissible deviation of the alignment from a predetermined alignment is detected—for example, an alignment set during the setup of the double-sided machining center, or compared to an initial operating position—the evaluation unit 32 can issue a warning signal. Based on this, an operator can, for example, correct the alignment of the drive shaft 28. If a suitable adjustment device is provided, the evaluation unit 32 can also perform an automatic correction of the alignment of the drive shaft 28, as explained in more detail below.

[0051] Figure 6 schematically shows a first adjustment device for the manual adjustment of the drive shaft 28 by an operator. For this purpose, four screw points 40 are provided, for example, for aligning a rotary drive 42 connected to the drive shaft 28, for example, via a gearbox, and thus for aligning the drive shaft 28 itself relative to the second working disk 26 with washers, of which only two are visible in Figure 6. The other two screw points are located behind the visible screw points 40, within the plane of Figure 6. In this way, any misalignment of the drive shaft 28 that may be detected can be manually corrected by selecting suitable washers.

[0052] Figure 7 shows another example of an adjusting device, which is a further development compared to the adjusting device of Figure 6 in that no complex disassembly is required, for example, for inserting washers. The adjusting device again comprises four pairs of adjusting threaded rods 44 driven by an adjusting actuator and fixing screws 46, of which two are visible and two are concealed in Figure 7. The adjusting threaded rods 44 can be driven by an electric or hydraulic adjusting actuator or by piezoelectric elements, controlled in particular by the evaluation unit 32, so that it can automatically make a corresponding correction if a misalignment of the drive shaft 28 is detected.

[0053] Figures 9 and 10 illustrate the effect of a change in the orientation of the upper drive shaft 28 under load. Figure 9 shows the working discs 18 and 26 in their diverging state when coaxially aligned. As illustrated in Figure 10, this results in a misalignment 38 of the drive shaft 28 when the working discs 18 and 26 are moving towards each other under load. Figures 11 and 12 show how this misalignment 38 under load can be pre-compensated by a deliberate misalignment 46 when unloaded. Reference sign

[0054] 10 Machine base part

[0055] 12 feet

[0056] 14 Floor

[0057] 16 first carrier disc

[0058] 18 first working disc

[0059] 20 swivel housings

[0060] 22 Swivel arm

[0061] 24 second carrier disc

[0062] 26 second working disc

[0063] 28 Drive shaft

[0064] 30 dampers

[0065] 32 Evaluation unit

[0066] 34 Curved tooth coupling

[0067] 36 Distance sensor

[0068] 38 Misalignment 40 Screw connections

[0069] 42 Rotary drive

[0070] 44 adjustable threaded rods

[0071] 46 Misalignment

Claims

Claims:

1. Double- or single-sided machining machine comprising a preferably annular first working disk (18) and a counter bearing element (26), and comprising a rotary drive (42) with a drive shaft (28) for rotating the first working disk (18) and / or the counter bearing element (26), wherein a working gap is formed between the first working disk (18) and the counter bearing element (26) for machining flat workpieces on both or one side, characterized in that a sensor (36) is provided which is designed to monitor the alignment of the drive shaft (28) during operation of the double- or single-sided machining machine.

2. Double- or single-sided machining machine according to claim 1, characterized in that the counter bearing element (26) is formed by a preferably annular second working disk (26), wherein the working gap for double- or single-sided machining of flat workpieces is formed between the first and second working disk (18, 26).

3. Double- or single-sided machining machine according to one of the preceding claims, characterized in that the first working disk (18) is attached to a first carrier disk (16) and / or that the second working disk (26) is attached to a second carrier disk (24).

4. Double- or single-sided machining machine according to one of the preceding claims, characterized in that the first working disk (18) or the counter bearing element (26) is arranged on a pivoting arm (22) and is pivotable with the pivoting arm (22) relative to the other of the first working disk (18) or counter bearing element (26).

5. Double- or single-sided machining machine according to claim 4, characterized in that the rotary drive (42) and the drive shaft (28) are arranged on the swivel arm (22).

6. Double- or single-sided machining machine according to one of the preceding claims, characterized in that the double- or single-sided machining machine further comprises a machine base part (10) with feet (12) with which the machine base part (10) rests on a floor (14) of a production room in the assembled state of the double- or single-sided machining machine, wherein the machine base part (10) carries the first working disk (18) and the counter bearing element (26).

7. Double- or single-sided machining machine according to one of the preceding claims, characterized in that the sensor (36) comprises a distance sensor (36) for measuring a distance to the drive shaft during the operation of the double- or single-sided machining machine.

8. Double- or single-sided machining machine according to claim 7, characterized in that the distance sensor (36) comprises a mechanical distance sensor (36) and / or an inductive distance sensor (36) and / or an optical distance sensor (36).

9. Double- or single-sided machining machine according to one of the preceding claims, characterized in that an evaluation device (32) is provided which receives the measurement data of the sensor (36).

10. Double- or single-sided machining machine according to claim 9 and one of claims 7 or 8, characterized in that the evaluation device (32) is configured to derive from a vibration amplitude of the ,.. / 22 Distance sensor (36) detected distance measurement signals to infer the orientation of the drive shaft (28).

11. Double- or single-sided machining machine according to one of claims 9 or 10, characterized in that the evaluation device (32) is designed to issue a warning signal when a deviation of the orientation of the drive shaft (28) from a predetermined orientation is detected.

12. Double- or single-sided machining machine according to claim 11, characterized in that the predetermined orientation is an orientation of the drive shaft (28) set within a device of the double- or single-sided machining machine for operation.

13. Double- or single-sided machining machine according to one of claims 9 to 12, characterized in that the evaluation device (32) is designed to control the double- or single-sided machining machine in such a way that the orientation of the drive shaft (28) corresponds again to the predetermined orientation when a deviation of the drive shaft (28) from a predetermined orientation is detected.

14. Double- or single-sided machining machine according to claim 13, characterized in that the drive shaft (28) and / or a support element supporting the first drive shaft (28) and / or the first working disk (18) and / or a first support disk (16) supporting the first working disk (18) and / or the counter bearing element (26) and / or a second support disk (24) supporting the counter bearing element (26) are provided with an adjusting device which is controlled by the evaluation device (32) It is possible to control the alignment of the drive shaft (28) so that it corresponds to the specified alignment.

15. Double- or single-sided machining machine according to claim 14, characterized in that the adjusting device comprises at least one adjusting element (44) which is translationally movable by means of an adjusting drive, in particular an adjusting threaded rod (44), by the translational movement of which the drive shaft (28) and / or a support element supporting the first drive shaft (28) and / or the first working disk (18) and / or a first support disk (16) supporting the first working disk (18) and / or the counter bearing element (26) and / or a second support disk (24) supporting the counter bearing element (26) are height-adjustable and / or laterally adjustable and / or tiltable.

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