DOUBLE-SIDE OR ONE-SIDE MACHINE TOOL

Abstract

A machine tool includes a first support disk and a first working disk. The first working disk defines a clamping surface and is fastened to the first support disk. A counter bearing element is positioned relative to the first working disk such that a working gap is formed between the first working disk and the counter bearing element and is dimensioned to accept a flat workpiece. A first clamping arrangement clamps the clamping surface of the first working disk to the first support disk such that the clamping surface faces away from the working gap. At least one decoupling element is positioned to at least one decoupling element configured to reduce friction between the first support disk and the first working disk.

Claims

1. A machine tool comprising: a first support disk; a first working disk fastened to the first support disk, wherein the first working disk comprises a clamping surface; a counter bearing element, wherein a working gap dimensioned to accept a flat workpiece is defined between the first working disk and the counter bearing element; a first clamping arrangement configured to clamp the clamping surface of the first working disk to the first support disk, wherein the clamping surface of the first working disk faces away from the working gap; and at least one decoupling element configured to reduce friction between the first support disk and the first working disk, wherein the first working disk and the counter bearing element are configured to be driven to rotate relative to each other by at least one drive shaft, and wherein the first working disk and the counter bearing are configured to machine at least one side of the flat workpiece.

2. The machine tool according to claim 1, wherein the at least one decoupling element comprises at least one bearing arranged between the clamping surface of the first working disk and the first support disk.

3. The machine tool according to claim 2, wherein the at least one bearing comprises at least one rolling bearing.

4. The machine tool according to claim 1, wherein the at least one decoupling element comprises an elastic prestressing means configured to elastically prestress the first clamping arrangement.

5. The machine tool according to claim 4, wherein the first clamping arrangement comprises a plurality of clamping screws.

6. The machine tool according to claim 5, wherein the elastic prestressing means comprises elastic spring washers each arranged between a screw head of each of the plurality of clamping screws and a surface of the first support disk facing away from the first working disk.

7. The machine tool according to claim 1, wherein the at least one decoupling element comprises a decoupling intermediate layer located between the first working disk and the first support disk.

8. The machine tool of claim 7, wherein the decoupling intermediate layer comprises one of: (1) a sliding intermediate layer; and (2) an intermediate layer for thermal decoupling.

9. The machine tool according to claim 1, wherein the first working disk comprises a first material and the first support disk comprises a second material, wherein the first material comprises a lower coefficient of thermal expansion than the second material.

10. The machine tool according to claim 1, wherein the counter bearing element is a second working disk, wherein the first and second working disk are arranged coaxially relative to each other, and wherein the working gap is defined between the first and second working disk.

11. The machine tool according to claim 10, wherein: the second working disk defines a clamping surface; the second working disk is fastened to a second support disk using at least one second clamping element such that the clamping surface faces away from the working gap; and at least one decoupling element is configured to at least partially decouple the second working disk from the second support disk.

12. The machine tool according to claim 1, further comprising a pressure volume defined between the first support disk and the first working disk, wherein the pressure volume is connected to a pressure fluid supply, and wherein the pressure fluid supply is configured to generate a pressure is build up in the pressure volume to cause a predetermined deformation of the first working disk.

13. The machine tool according to claim 12, further comprising temperature-controlling channels configured to control a temperature of the first working disk, wherein the temperature-controlling channels are connected to a temperature-controlling fluid supply.

14. The machine tool according to claim 13, wherein the temperature-controlling channels are arranged within the first working disk at a position that is closer to the working gap than the pressure volume, and wherein that the temperature-controlling channels are not connected to the pressure volume.

15. The machine tool according to claim 13, wherein the first working disk is formed from two annular disks which are connected to one another, wherein the temperature-controlling channels are formed between the two annular disks, and wherein a first of the two annular disks borders the working gap and a second of the two annular disks comprises the clamping surface for clamping to the clamping surface of the first support disk.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Exemplary embodiments of the invention are explained in greater detail below based on figures. Schematically:

[0036] FIG. 1 illustrates a sectional view of an embodiment of a portion of a double-side machine tool;

[0037] FIG. 2 illustrates a sectional view of an embodiment of a first working disk and an embodiment of a first support disk of an embodiment of a double-side machine tool;

[0038] FIG. 3 illustrates a sectional view of another embodiment of the first working disk and the first support disk of a double-side machine tool; and

[0039] FIG. 4 illustrates a sectional view of still another embodiment of the first working disk and the first support disk of a double-side machine tool.

[0040] The same reference signs refer to the same objects in the figures unless indicated otherwise.

DETAILED DESCRIPTION OF THE INVENTION

[0041] The double-side machine tool depicted merely as an example in FIG. 1 has an annular first, bottom support disk 100 and a second, top support disk 120 that is also annular. An annular first, bottom working disk 140 is fastened to the bottom support disk 100, and a second, top working disk 160 that is also annular is fastened to the top support disk 120. Between the annular working disks 140, 160, an annular working gap 180 is formed in which flat workpieces such as wafers are machined on both sides during operation. The double-side machine tool can for example be a polishing machine, lapping machine, or a grinding machine.

[0042] The top support disk 120, and with it the top working disk 160, and/or the bottom support disk 100 and with it the bottom working disk 140, can be rotatably driven relative to each other by a suitable drive apparatus comprising for example a top drive shaft, and/or a bottom drive shaft, as well as at least one drive motor. The drive apparatus is known per se and will not be described further for reasons of clarity. In a manner which is also known per se, the workpieces to be machined can be held to float in rotor disks in the working gap 180. By suitable kinematics, for example planetary kinematics, it can be ensured that the rotor disks also rotate through the working gap 180 during the relative rotation of the support disks 100, 120, or respectively working disks 140, 160. A control and/or regulation apparatus 200 controls, or respectively regulates the operation of the double-side machine tool.

[0043] In the example shown in FIG. 1, labyrinth-like temperature-controlling channels 220 are provided within the bottom working disk 140. The temperature-controlling channels 220 are connected by a feed 240 and a discharge 260, for example via a drive shaft driving the bottom support disk 100 and the bottom working disk 140, to a temperature-controlling fluid supply. The control and/or regulation apparatus 200 can be used, for example, to regulate to a predetermined temperature value of the temperature-controlling fluid at the inlet and/or at the outlet of the temperature-controlling channels or to a predetermined temperature difference between the temperature present at the inlet and the temperature present at the outlet of the temperature-controlling channels by correspondingly adjusting the temperature of the temperature-controlling fluid. In the shown example, labyrinthine temperature-controlling channels 280 are also formed in the top working disk 160 that are also connected to a temperature-controlling fluid supply via a feed and discharge (not shown). This temperature-controlling fluid supply is also controlled by the control and/or regulation apparatus 200. By supplying the temperature-controlling channels 220, or respectively 280 with a temperature-controlling fluid, for example a coolant such as water, heating of the working disks 140, 160 and transfer of heat into the support disks 100, 120 can be effectively counteracted so that corresponding changes in geometry are reduced.

[0044] Moreover, a pressure volume 300 that is annular in the example shown is formed between the bottom support disk 120 and the bottom working disk 160 and is connected via a feed 320, for example also via a drive shaft driving the bottom support disk 100 and the bottom working disk 140, to a pressure fluid supply. The pressure fluid supply is also actuated by the control and/or regulation apparatus 200. By correspondingly introducing pressure fluid into the pressure volume 300, a local deformation of the bottom working disk 140 can be created, in particular a local concave or convex deformation as described in principle in DE 10 2016 102 223 A1.

[0045] As can be seen in FIG. 1, the temperature-controlling channels 220 are arranged closer to the working gap 180 than the pressure volume 300. Moreover, the duct systems of the pressure volume 300 and the temperature-controlling channels 220 are not connected to each other, but are instead separately controllable, or respectively regulatable.

[0046] FIGS. 2 to 4 each show a first support disk and a first working disk which can be used in the double-side machine tool shown in FIG. 1. For reasons of illustration, FIGS. 2 to 4 do not show the temperature-controlling channels 220 and the pressure volume 300 as shown in FIG. 1, including the associated feed and discharge lines. It goes without saying that the working disks and support disks shown in FIGS. 2 to 4 can also have corresponding temperature-controlling channels and pressure volumes, including the feed and discharge lines. In addition, FIGS. 2 to 4 show only a first support disk and a first working disk for the sake of illustration. The second support disks and second working disks, which are provided in addition, can be designed accordingly.

[0047] FIG. 2 shows a first exemplary embodiment of a first, bottom support disk 10 and a first, bottom working disk 14, which can be used, for example, in the double-side machine tool shown in FIG. 1. In the exemplary embodiment shown, a plurality of clamping screws 20 are provided, which are inserted through the first support disk 10 from a side facing away from the working gap 18 and are screwed into a corresponding threaded bore in the first working disk 14. The clamping screws are arranged along two partial circles via the annular support and working disks 10, 14, namely a radially outer partial circle and a radially inner partial circle. The clamping screws 20 each have a screw head 22. The first support disk 10 has a clamping surface 24 facing the first working disk 14 and the first working disk 14 has a clamping surface 26 facing the first support disk 10. During the screwing-in of the clamping screws 20, the first support disk 10 and the first working disk 14 are braced against one another. In the illustrated exemplary embodiment according to FIG. 2, the clamping surfaces 24, 26 lie directly against one another in the braced state and are braced against one another.

[0048] In the exemplary embodiment according to FIG. 2, elastic spring washers 30 are disposed between the screw heads 22 of the clamping screws 20 and a surface 28 of the first support disk 10 facing away from the first working disk 14, which spring washers are elastically compressed in the screwed-in state of the clamping screws 20 and thus elastically prestress the clamping means 20. As a result, in the case of a thermally induced relative movement between the first support disk 10 and the first working disk 14 over the clamping surfaces 24, 26, the frictional force provided by the clamping means 20 is reduced, such that, for example, after a thermal expansion of the first working disk 14 and a relative movement caused thereby with respect to the first support disk 10, the first working disk 14 moves back completely into its original position. FIG. 3 shows a further exemplary embodiment which largely corresponds to the exemplary embodiment according to FIG. 2. In addition to the elastic spring washers 30, in the exemplary embodiment according to FIG. 3, rolling bearings 32 arranged around the clamping screws 20 are provided between the clamping surfaces 24, 26 of the first support disk 10 and the first working disk 14. By means of these rolling bearings 32, the first support disk 10 and the first working disk 14, in particular their clamping surfaces 24, 26, are mechanically decoupled from one another. Accordingly, the frictional force between the first support disk 10 and the first working disk 14 which is caused by the clamping screws 20 is further reduced.

[0049] FIG. 4 shows a further example for seeking to avoid the effects of thermal changes in size explained above. The example according to FIG. 4 differs from the exemplary embodiment according to FIG. 2 on the one hand in that no decoupling means or decoupling elements are provided in the form of the elastic spring washers 30. On the other hand, it differs in that relief grooves 34, 36 are formed around the clamping screws 20 in the first support disk 10′ and the first working disk 14′. Attempts have been made to counteract the disadvantageous effects of the thermal change in size explained above by means of such relief grooves 34, 36. However, it has been found that this measure does not yield the success associated with the decoupling means according to FIGS. 2 and 3.

LIST OF REFERENCE SIGNS

[0050] 10, 10′, 100 Bottom support disk [0051] 12, 120 Top support disk [0052] 14, 14′, 140 Bottom working disk [0053] 16, 160 Top working disk [0054] 18, 180 Working gap [0055] 20 Clamping screw [0056] 22 Screw head [0057] 24 Clamping surface [0058] 26 Clamping surface [0059] 28 Surface [0060] 30 Spring washer [0061] 32 Rolling bearing [0062] 34 Relief grooves [0063] 36 Relief grooves [0064] 200 Control and/or regulation apparatus [0065] 220 Temperature-controlling channels [0066] 240 Feed [0067] 260 Discharge [0068] 280 Temperature-controlling channels [0069] 300 Pressure volume [0070] 320 Feed