Disc grinding / polishing equipment

Abstract

The present invention relates to a disc grinding / polishing device (10) for planar grinding and / or polishing, by means of a rotating grinding / polishing disc (18), particularly of the lower sample surface of an embedded and / or unembedded sample, in particular for sample preparation for material structural analysis, comprising: a grinding / polishing head (30) having a sample holder (34) for receiving one or more samples; a lower housing (12) having a collection vessel (16) for collecting the abrasive and / or polishing suspension; a polishing / polishing disk (18) in the collection tank (16), on whose upper surface (18a) different polishing pads, polishing pads and / or polishing cloths can be removably fixed in order to planarly polish and / or polish the underside of a sample pressed against the polishing / polishing disk (18) from above with the respective polishing pads, polishing pads or polishing cloths; a first electric drive motor (60) for the sample holder (34) disposed within the grinding / polishing head (30); a second electric drive motor (160) for the abrasive / polishing disc (18) disposed within the lower housing (12); a first drive spindle (66) for rotationally driving the sample holder (34), the first electric drive motor (60) including a first stator (64) and a first rotor (62), the first drive spindle (66) being coaxially connected to the first rotor (62), the first electric drive motor (60) forming together with the first drive spindle (66) a first coaxial direct drive (61) for the sample holder (34); and / or a second drive spindle (166) for rotationally driving the abrasive / polishing disk (18), the second electric drive motor (160) including a second stator (164) and a second rotor (162), the second drive spindle (166) being coaxially connected to the second rotor (162), the second electric drive motor (160) forming together with the second drive spindle (166) a second coaxial direct drive (161) for the abrasive / polishing disk (18); It relates to things that include.

Description

[Technical Field]

[0001] The present invention relates to a disc grinding / polishing device for planar grinding and / or polishing of the lower sample surface of embedded and / or unembedded samples by means of a grinding / polishing disc in a collection vessel, in particular for sample preparation for material structural analysis. [Background technology]

[0002] A disc polishing / polishing machine typically has two drives. One drive is located below and drives the polishing / polishing disc. The other drive is located above in the polishing / polishing head and drives the sample holder. The polishing / polishing disc typically runs for 50 min -1 ~500 min -1 The power output is approximately 0.75kW to 1.5kW for a 300mm grinding / polishing disc diameter, or 2.2kW for a 350mm grinding / polishing disc diameter.

[0003] Overall, known disc abrasive / polishing devices have been very reliable in practice, however, the inventors have found room for further improvement in the circumstances described below.

[0004] In known disc grinding / polishing machines, the drive is typically about 1450 min for a four-pole design, for example. -1 This is done by a one- or three-phase asynchronous electric motor that achieves a rated speed of 1000 rpm. In order to provide the required speed stably without speed fluctuations, especially in the lower speed ranges, the speed is typically transmitted to the grinding / polishing disc via a belt drive with a relatively large reduction ratio, for example, of about 5:1.

[0005] For the grinding / polishing head, an even lower rotation speed is required, typically around 20 min -1~200 min -1 The grinding / polishing head, like the grinding / polishing disk below, is typically driven by an asynchronous machine. Therefore, the reduction ratio of the belt drive for the grinding / polishing head must be selected more dramatically than for the grinding / polishing disk, typically about 8:1 to 10:1. However, this disadvantageously results in the motor drive pulley having to be very small due to limited installation space. Furthermore, this results in a relatively small pulley wrap angle.

[0006] A further drawback of this high-speed asynchronous machine is that in order to achieve a large torque, particularly in the lower speed ranges, very large magnetizing currents are required, which is inefficient and generates a lot of heat.

[0007] A further drawback of the belt drives used is that the mass inertia of the drive increases quadratically with each transmission: in the event of a sudden interruption of the grinding / polishing disc or of the grinding / polishing head, slippage of the belt drive can result, which can lead to accelerated wear and even failure.

[0008] Furthermore, due to the above-mentioned unfavorable wrap angle and small drive pulley diameter, the belt must be oversized to be able to transmit the required moment, which again causes large deformations and therefore bending actions, which again can accelerate belt wear.

[0009] Furthermore, the belt tension recommended by the manufacturer should be precisely adhered to, and this should be ensured, for example, using a frequency measuring device. If the belt tension is too high, this can lead to bearing damage in the drive motor. If the belt tension is too low, the belt may slip, which can again lead to wear and complete failure. In disc grinding / polishing machines, the belt should be periodically retightened, which is typically assumed to be done at the customer's site. However, in most cases, customers do not have available measuring devices for checking the belt tension, and as a result, in practice, the belt is often tightened too much. This can result in the bearings being overloaded to the point where drive motor failure due to bearing damage can occur, which leads to expensive on-site maintenance visits at the customer's site.

[0010] In the practice of using grinding / polishing machines, belt drives are repeatedly replaced at specific time cycles, which is not without problems in the field: on the one hand, the machine needs to be partially disassembled, and on the other hand, measuring devices are often not available in the field to accurately determine the belt tension, which can again lead to the aforementioned consequential damage.

[0011] Structurally, known belt drives also have drawbacks. First, they require the possibility of tension adjustment, which is typically achieved by laterally offsetting the electric motor. In this case, the belt drives used require a corresponding amount of installation space in the device for the electric motor and the belt tension adjustment area.

[0012] A further drawback is that belt tension, even when properly adjusted, generates constant lateral forces on the drive shafts of the abrasive / polishing discs and abrasive / polishing heads.

[0013] Furthermore, in known disk grinding / polishing devices (either with individual or central pressing), the sample is pressed against the rotating grinding / polishing disk with a defined pressing force, thereby ensuring a corresponding removal of the sample to be prepared. The strength of the pressing force varies depending on the preparation method and can typically be 5N to 100N per sample for the individual pressing method and 20N to 750N for the central pressing method. The force is typically generated pneumatically via a defined piston surface. Due to their design, packings, guides, etc. used for pneumatic systems generate friction, which is not always constant. Friction can vary, for example, between static and sliding friction, due to temperature changes or contamination.

[0014] All of these can impair the precision of the abrasive removal or, in general, the quality of the abrasive and polishing result. Summary of the Invention [Problem to be solved by the invention]

[0015] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a disc grinding / polishing apparatus that ensures high quality grinding / polishing results.

[0016] Another aspect of the problem is to provide a disc grinding / polishing apparatus that provides a reliable and quality-valuable pressing method at the grinding / polishing head, ensuring precise control of grinding removal.

[0017] Another aspect of the object is to provide a disk grinding / polishing device that avoids the drawbacks of pneumatic feeding for applying abrasive forces and allows compressed air supply within the grinding / polishing head for individual pressing of samples with high reproducibility and less damage caused by temperature fluctuations.

[0018] Another aspect of the problem is to provide a disc grinding / polishing apparatus that uses all available mounting space, especially in the grinding / polishing head, in an optimal manner and, if necessary, allows reliable measurement of the pressing force during grinding and / or polishing, as well as precise and adjustable grinding removal.

[0019] Another aspect of the problem is to provide a disc abrading / polishing device that is reliable, requires less wear and maintenance, and generates less noise during operation. [Means for solving the problem]

[0020] The problem of the invention is solved by the subject matter of the independent claims. Advantageous developments of the invention are defined in the subclaims.

[0021] According to the present invention, there is provided a disc grinding / polishing device, in particular for preparing samples for material structural analysis, for example for subsequent hardness testing or textural investigations on the ground and polished underside, in particular of embedded samples, and in particular for flat grinding and / or polishing the underside of embedded and / or non-embedded samples by means of a rotating grinding / polishing disc.

[0022] The disk grinding / polishing apparatus includes a grinding / polishing head having a sample holder for receiving one or more embedded or non-embedded samples. The sample holder may include, for example, a receiving plate having a plurality of, e.g., six, sample receiving portions symmetrically distributed about the axis of rotation for receiving each one of the embedded or non-embedded samples.

[0023] Grinding and polishing of embedded samples is performed in materialographic analysis, for example, after separating the sample pieces with a separator and subsequently embedding them in an embedding material for forming more or less standardized shapes of the embedded samples, for example, cylindrical shapes with diameters in the range of 25 mm to 50 mm. This is also referred to as metallographic embedding among experts. Disc grinding / polishing devices are particularly suitable as laboratory equipment for such embedded samples. However, disc grinding / polishing devices can also be used with unembedded samples. For this purpose, the unembedded sample can be directly inserted into a special sample holder adapted to the sample.

[0024] The disc grinding / polishing device further includes a lower housing having a collection vessel for collecting the abrasive suspension and / or polishing suspension. During grinding, cooling with water is typically performed, so that the suspension and water resulting from the grinding removal are collected in the collection vessel and can be discharged through the drain port of the collection vessel. Polishing is performed, inter alia, with a polishing suspension, such as a diamond suspension, which is applied onto a polishing plate or polishing cloth before and / or during the polishing process. The polishing suspension is also collected in the collection vessel and can be discharged through the drain port.

[0025] Within the collection tank, a horizontal abrasive / polishing disk rotates around a vertical axis of rotation. Optionally, different abrasive pads, such as abrasive paper with different grit sizes, abrasive foil, or thin abrasive plates, and different abrasive particles, such as corundum or diamond, can be removably attached to the upper side of the abrasive / polishing disk for successively more precisely polishing the surface of the sample with different abrasive pads. Subsequently, polishing pads and / or polishing cloths can be removably attached to the abrasive / polishing disk for subsequent polishing of the same sample. The abrasive and polishing pads or polishing cloths can be attached to the upper side of the abrasive / polishing disk, for example, magnetically, by vacuum bonding, and optionally, by an additional adhesive layer. In this way, the lower surface of the sample pressed against the abrasive / polishing disk from above is polished and / or polished with the respective abrasive pads, polishing pads, or polishing cloths.

[0026] Preferably, with the same disc grinding / polishing device, embedded and non-embedded samples can be first ground (with different abrasive grits, if desired) and immediately polished (with polishing suspensions having different finenesses, if desired) without the need to remove the samples from the respective adapted sample holders. If desired, a washing station can also be provided.

[0027] The disc polishing / polishing apparatus includes an upper first electric drive motor disposed within the polishing / polishing head for rotationally driving the sample holder.

[0028] The disc abrasive / polishing apparatus further includes a lower second electric drive motor disposed within the lower housing for rotationally driving the abrasive / polishing disc.

[0029] The sample holder is driven by a first drive spindle, and a first electric drive motor comprises a first stator and a first rotor. The first drive spindle is connected to the first rotor coaxially, in particular by a positive or frictional connection, and extends particularly coaxially through the first rotor and the first stator in such a way that the first electric drive motor, together with the first drive spindle, forms a first coaxial direct drive for the sample holder. The sample holder is attached, in particular coaxially, preferably separably, to the lower end of the first drive spindle.

[0030] Alternatively or additionally, the abrasive / polishing disk is driven by a second drive spindle, and the second electric drive motor comprises a second stator and a second rotor. The second drive spindle is coaxially connected to the second rotor, particularly by a positive or frictional connection, and extends particularly coaxially through the second rotor and the second stator in such a manner that the second electric drive motor, together with the second drive spindle, forms a second coaxial direct drive for the abrasive / polishing disk. The abrasive / polishing disk is attached, particularly coaxially, and preferably separably, to the upper end of the second drive spindle.

[0031] That is, the disk polishing / polishing apparatus may have one individual coaxial direct drive, as defined above, for the sample holder for the polishing / polishing head, or for the polishing / polishing disk, or preferably for both.

[0032] The rotational speed of the first electric drive motor is preferably 20 min -1 ~200 min -1 The rotational speed of the second electric drive motor is preferably in the range of 50 min -1 ~600 min -1 The rotation speed may in particular be adjustable.

[0033] According to a preferred embodiment, the first and / or second electric drive motor is designed as a synchronous motor, in particular as a multi-pole or four-pole torque motor. Preferably, the electric drive motor is designed as an internal rotor.

[0034] That is, instead of a conventional asynchronous motor with a belt drive, for example, a torque motor is used as the direct drive. The torque motor can be designed as an encoder-less synchronous motor (Permanent Magnet Synchronous Motor (PMSM)) with a permanent magnet in the rotor. Each stator can consist of several coils, which generate a magnetic field through the corresponding current flow, which the associated rotor follows. The torque motor can be rotated from standstill to the maximum rotational speed required here (approximately 200 min -1 or 600 min -1 ), they can generate very large torques and are used as direct drives without belt drives or gearing. Each rotor can be directly and coaxially attached to the drive shaft of the grinding / polishing disc or grinding / polishing head, thus transmitting only the drive torque. The connection between each rotor and the associated drive spindle can be made, for example, by a positive key or by a frictional connection. The lateral forces applied to the spindle via the belt in conventional disc grinding / polishing devices are eliminated, significantly reducing bearing loads and therefore wear. Furthermore, the drive is virtually silent and completely maintenance-free, which eliminates on-site maintenance work at the customer's premises. The drive unit as a whole can be constructed compactly, resulting in a slim design despite the large torque.

[0035] Preferably, the disk polishing / polishing apparatus includes a motor-driven vertical lift mechanism that lowers the polishing / polishing head, including the first drive motor, onto the polishing / polishing disk for planar polishing and / or polishing the sample, advantageously allowing for high accuracy in the desired removal.

[0036] Preferably, the lift mechanism includes at least one, preferably at least two, vertical guides, e.g., a recirculating spindle such as a ball screw, and a recirculating spindle drive motor. Preferably, the recirculating spindle drive motor rotates the recirculating spindle and spindle nut or recirculating guide (e.g., a ball recirculating guide of a ball screw) relative to each other to cause vertical lifting movement of the polishing / polishing head along the vertical guide. This moves the polishing / polishing head up and down, thereby allowing the sample in the sample holder to be accurately positioned during polishing and / or polishing.

[0037] The circular spindle drive motor can be designed, for example, as a stepper motor with a rotary encoder.

[0038] According to a preferred embodiment, the grinding / polishing head is suspended on an L-shaped suspension having a vertical tower section and a horizontal bridge section. The vertical tower section is fixed to the device legs within the lower housing and can extend vertically upward from the device legs, particularly from the rear side of the lower housing. The horizontal bridge section is also suspended from the vertical tower section, and the grinding / polishing head, which extends horizontally above the lower housing to the grinding / polishing head or to an area above the grinding / polishing disk, is suspended from the front end of the bridge section opposite the tower section. As a result, the suspension, together with the grinding / polishing head, is configured in a substantially U-shape. Preferably, a vertical lift mechanism is disposed within the vertical tower section and raises and lowers the horizontal bridge section together with the grinding / polishing head and the first coaxial direct drive. Preferably, the first drive spindle is suspended from a rigid area of ​​the grinding / polishing head with an axially elastic force applied thereto.

[0039] The first drive spindle can be supported above and below the first rotor, in particular by rolling bearings, preferably ball bearings. The lower bearing of the first drive spindle can be designed as a fixed bearing, in particular with at least one angular contact ball bearing or deep groove ball bearing, and can be preloaded by a wave spring to eliminate bearing play.

[0040] Furthermore, the upper bearing of the first drive spindle may be designed as a floating bearing, in particular as a cylindrical roller bearing, to accommodate axial movement of the first drive spindle with the first rotor relative to the suspension of the first stator and grinding / polishing head.

[0041] The second drive spindle is also preferably supported above and below the second rotor, in particular by angular contact ball bearings or deep groove ball bearings.

[0042] For surface grinding and / or polishing by central pressing, the sample is fitted particularly tightly in the sample holder. By feeding the entire grinding / polishing head, which includes a first electric drive motor, a defined pressing force F is applied via the first drive spindle. A is applied to the sample holder as a central pressure.

[0043] In other words, central pressing can be achieved via the sample holder by a motorized lift mechanism for the grinding / polishing head, which allows for precise control of the abrasive removal.

[0044] Preferably, the pressing force acting on the first drive spindle of the direct drive against the grinding / polishing head is measured by a force measuring device, particularly in the grinding / polishing head. Furthermore, the force measuring device can determine the zero point of contact of the sample with the grinding / polishing disk during the lowering of the grinding / polishing head onto the grinding / polishing disk. The force measuring device measures the pressing force F between the first drive spindle and the rigid region of the suspension of the grinding / polishing head in response to an axial movement of the first drive spindle applying an elastic force caused by the pressing force, particularly against the rigid region of the suspension. A Measure.

[0045] That is, in central pressing, the force is preferably not applied to the sample by a pneumatic piston, but rather electrically, for example, using a spindle drive. In this case, the force can be measured by a force measuring device, and via this signal, the drive motor for the lift mechanism can be adjusted in a closed loop, so that the lift mechanism can apply the exact correct load feed movement, for example, via a ball screw. Similarly, the electric spindle drive of the lift mechanism can output the exact path length through calculation of the motor position, for example, using a rotary encoder. This allows for the removal of an exactly defined amount of sample under an exactly defined feed force.

[0046] The polishing / polishing apparatus preferably further comprises a device for determining the zero point, which can detect contact of the lower sample surface with the polishing / polishing disc or polishing pad. This allows for accurate determination of the zero point, i.e., the surface of the sample from which material removal measurements are made. To determine the zero point, the collision of the sample with the polishing / polishing disc is detected when the polishing / polishing head is lowered. This advantageously allows for accurate determination of the amount of material removed from the sample during the polishing process. This can be determined or adjusted as needed within a range of a few hundredths to a few thousandths of a millimeter, which can be advantageous for penetrating a specific layer of the sample.

[0047] Accurate adjustment of the material removal rate is possible especially with an electric lift mechanism, since, compared to pneumatic force application, a tight feed drive can be achieved, which avoids unknown frictional forces in the system and inaccuracies due to, for example, the compressibility of air. Thus, zero-point determination has a special synergistic effect in combination with an electric lift mechanism.

[0048] For the zero point determination, i.e. for the detection of contact with the sample surface, a force measuring device, as mentioned above, can in particular be used, since the force measuring device outputs a measurable signal already at the minimum contact of the sample with the abrasive / polishing disk.

[0049] The force measuring device can include one or more force sensors, such as strain gauges, that change their electrical resistance when stretched. At least one force sensor or strain gauge can be mounted on a spring element, such as a leaf spring element, of the force measuring device. The leaf spring element can be arranged around the first drive spindle, preferably below the first drive motor.

[0050] The force measuring device may be annular and preferably extends around the first drive spindle of the first direct drive. The force measuring device may include a force distribution ring extending coaxially around the first drive spindle. In the central pressing, a reaction force F generated by the sample holder acting upwards towards the first drive spindle is G can be transmitted to the force distribution ring via, for example, a bearing (e.g., two ball bearings) below the first drive spindle. The force distribution ring receives the pressing force F via the elongation of the strain gauges caused by the axial movement of the first drive spindle relative to the suspension during central pressing. A In order to measure the force by means of strain gauges, for example, at least one or more force sensors, in particular having strain gauges, can be mounted thereon, which are connected to the suspension of the grinding / polishing head with an axially elastic force, in particular by means of radial leaf spring elements.

[0051] That is, preferably, the motor shaft of the first electric drive motor, i.e., the first drive spindle, together with the first rotor, is suspended on the suspension of the polishing / polishing head under an axially elastic force. In this case, the axially elastic suspension of the first electric drive motor or the first drive spindle on the rigid member of the polishing / polishing head is preferably performed by a force measuring device. The force measuring device is preferably generally annular in shape and forms a force measuring flange that can be annularly arranged around the motor shaft of the first electric drive motor or the first drive spindle. The motor shaft of the first electric drive motor or the first drive spindle extends coaxially through a central opening in the force measuring flange. That is, the force measuring device or the force measuring flange is preferably arranged coaxially with respect to the first electric drive motor. More preferably, the force measuring device and / or the force measuring flange are arranged coaxially with respect to the first rotor of the first electric drive motor and with respect to the sample holder. The first motor shaft or the first drive spindle preferably extends coaxially through the force measuring device or through the force measuring flange.

[0052] According to a preferred embodiment, the first rotor is suspended axially displaceably and coaxially elastically relative to the first stator, a (center) push causes a coaxial displacement of the first rotor relative to the first stator against the spring force of the elastic suspension, and a force measuring device measures the force exerted on the elastic suspension by the coaxial displacement of the first rotor relative to the first stator.

[0053] In particular, the first drive spindle and the first rotor form a first motor shaft of the first drive motor. The first motor shaft, including the first drive spindle and the first rotor, is suspended on the polishing / polishing head, in particular in a resilient manner. The force measuring device can measure the pressing force directly on the first motor shaft, in particular coaxially with the first drive spindle and with the first rotor or the first motor shaft of the first drive motor. In particular, in central pressing, when the sample holder with the inserted sample is pressed against the polishing / polishing disk, the first motor shaft is axially displaced in a resilient manner against the first stator or against a rigid member of the polishing / polishing head against the spring tension of the resilient suspension of the first motor shaft, and the force measuring device measures the force applied by the first motor shaft to the resilient suspension of the first motor shaft.

[0054] The suspension or force measuring device that applies the elastic force of the first motor shaft is preferably arranged axially between the first drive motor and the lower bearing of the first drive spindle or first motor shaft.

[0055] To ensure that the force measuring device receives a signal of unimpaired quality, it is highly advantageous that no lateral forces, for example from the drive belt, are introduced into the force measuring device. This can be achieved in particular by a first coaxial direct drive, for example by a torque motor, which introduces a drive torque only into the shaft and does not affect the force measuring device. Axial direct drives therefore offer special synergistic effects, especially in combination with coaxial force measuring devices.

[0056] That is, the rotor and stator of the first direct drive motor are preferably axially displaceable relative to each other to absorb the axial elastic movement of the first drive spindle when the sample is pressed against the abrasive / polishing disc, particularly in the central pressing method.

[0057] The rotary bearing of the first drive spindle may likewise be, for example, a cylindrical roller bearing, to absorb the elastic axial movements when the sample is pressed against the grinding / polishing disc.

[0058] Preferably, a user can input a pressing force target value into a control device that controls the lift mechanism, in particular the circulating spindle drive motor or stepper motor, and defines a closed control circuit, which then actively adjusts the pressing force applied by the lift mechanism to the sample holder against the abrasive / polishing disc during the polishing and / or polishing process to the set pressing force target value in response to the pressing force measurements measured by the force measuring device.

[0059] Preferably, the sample holder is designed as a multiple sample holder having a plurality of sample receiving portions arranged symmetrically around the rotation axis of the first drive spindle. Optionally, in addition to the electric motor-driven feed in the central pressing, the grinding / polishing head may comprise a plurality of individual pressing pistons, each of which individually applies a force to the sample inserted into the associated sample receiving portion.

[0060] The sample holder is designed to receive, for example, six samples arranged symmetrically around the rotation axis of the first drive motor or the first drive spindle for simultaneously planar grinding and / or polishing multiple samples. For individual pressing, the samples are inserted into the sample receiving portion from above. For central pressing, the samples are additionally firmly fixed into the sample holder so that the desired pressing force for planar grinding and / or polishing can be applied to all inserted samples in the center via the first drive spindle and the sample holder.

[0061] The individual pressing pistons can be operated pneumatically. For this purpose, compressed air can be introduced into the first drive spindle, particularly via a compressed air connection rotatable relative to the first drive spindle. The compressed air connection is preferably arranged at the upper end of the first drive spindle or above the first electric drive motor. For example, an axial compressed air channel can extend through the first drive spindle, which can guide the compressed air axially through the first rotor and the first stator to an air distributor below the first electric drive motor and rotating together with the first drive spindle. The air distributor can distribute the compressed air radially through the distributor channel to the individual pressing pistons for pneumatic operation. The air pressure can be adjusted by a pressure regulating valve so that the required pressing force is applied to the grinding / polishing disk.

[0062] The present invention also provides a disk polishing / polishing device for planar polishing and / or polishing of the lower sample surface of a sample, in particular of an embedded and / or non-embedded sample, by means of a horizontally rotating polishing / polishing disk, in particular for sample preparation as a substep of sample preparation for material structural analysis, for example. The disk polishing / polishing device according to this aspect comprises: a lower housing having a collection vessel for collecting the abrasive and / or polishing suspension; a horizontal abrasive / polishing disk disposed in a collection tank and rotating around a vertical rotation axis, on whose upper surface different abrasive pads, polishing pads and / or polishing cloths, such as abrasive paper, abrasive foil, thin abrasive plates having different grain sizes, such as corundum, diamond, etc., can be selectively fixed in order to planarly abrade and / or polish the underside of a sample pressed against the abrasive / polishing disk from above with the respective abrasive pad, polishing pad or polishing cloth, and during operation, the abrasive suspension and / or polishing suspension is collected in the collection tank and can be discharged through a suspension outlet of the collection tank; a grinding / polishing head having a sample holder for fitting one or more samples; a first drive spindle extending vertically within the grinding / polishing head, the sample holder being coaxially connected to a lower end of the first drive spindle for centrally rotating the sample holder together with the first drive spindle; A first electric drive motor, having a variable rotational speed as needed, for driving the rotation of a first drive spindle arranged in the grinding / polishing head, the first electric drive motor including a first stator and a first rotor, the first drive spindle being coaxially connected to the first rotor, for example by a form-fit or friction-fit connection, and the first electric drive motor extending coaxially within the first rotor and first stator in such a manner that, together with the first drive spindle, the first electric drive motor forms a first coaxial direct drive for the sample holder.

[0063] Preferably, a second electric drive motor for the abrasive / polishing disk is located within the lower housing if the abrasive / polishing disk is to rotate simultaneously with the sample holder, either in the same direction or in opposite directions.

[0064] Preferably, the second electric drive motor also forms a direct drive for the grinding / polishing disk. To this end, a second drive spindle is included that extends vertically from the lower housing through the bottom opening of the collection tub into the collection tub, and the grinding / polishing disk is connected at its upper end to the second drive spindle for rotating the grinding / polishing disk together with the second drive spindle. The second electric drive motor includes a second stator and a second rotor, the second drive spindle being coaxially connected to the second rotor, for example, by a positive or frictional connection, and extending coaxially within the second rotor and second stator, such that the second electric drive motor, together with the second drive spindle, forms a second coaxial direct drive for the grinding / polishing disk.

[0065] There are also simple disk polishing / polishing devices that do not have a polishing / polishing head and an automatic pressing mechanism, in which the sample is polished and ground manually. It is conceivable to use the above-mentioned drive for the polishing / polishing disk in such simple disk polishing / polishing devices as well. The subject of the present invention is therefore a disk polishing / polishing device for flat-grinding and / or polishing the lower sample surface of a sample, in particular an embedded or non-embedded sample, using a horizontally rotating polishing / polishing disk, in particular as a partial step of sample preparation for material structural analysis. The disk polishing / polishing device comprises: a lower housing having a collection vessel for collecting the abrasive and / or polishing suspension; a horizontal abrasive / polishing disk disposed in a collection tank and rotating around a vertical rotation axis, on whose upper surface different abrasive pads, polishing pads and / or polishing cloths, such as abrasive paper, abrasive foil, thin abrasive plates having different grain sizes, such as corundum, diamond, etc., can be selectively fixed in order to planarly abrade and / or polish the underside of a sample pressed against the abrasive / polishing disk from above with the respective abrasive pad, polishing pad or polishing cloth, and during operation, the abrasive suspension and / or polishing suspension is collected in the collection tank and can be discharged through a suspension outlet of the collection tank; a second drive spindle extending vertically from the lower housing through the bottom opening of the collection tank into the collection tank, the grinding / polishing disc in the collection tank being connected at its upper end to the second drive spindle for rotating the grinding / polishing disc together with the second drive spindle from below; A second electric drive motor for driving the rotation of a second drive spindle, the second drive spindle having a variable rotational speed as required, arranged within the lower housing, the second electric drive motor including a second stator and a second rotor, the second drive spindle being coaxially connected to the second rotor, for example by a positive or frictional connection, and the second electric drive motor extending coaxially inside the second rotor and the second stator so that, together with the second drive spindle, the second electric drive motor forms a second coaxial direct drive for the grinding / polishing disc.

[0066] In the following, the invention will be described in detail based on embodiments and with reference to the drawings, in which identical and similar elements are partly provided with the same reference numerals and in which the features of the various embodiments can be combined with one another. [Brief explanation of the drawings]

[0067] [Figure 1]1 shows a three-dimensional view of a disk grinding / polishing apparatus according to one embodiment of the present invention with the grinding / polishing head cut away. [Figure 2] 2 is a vertical cross-sectional view of the grinding / polishing head of the disc grinding / polishing apparatus of FIG. 1. [Figure 3] 1 shows a three-dimensional representation of a force measuring device according to an embodiment of the invention; [Figure 4] FIG. 4 is a top view of the force measuring device of FIG. 3. [Figure 5] 5 is a cross-sectional view of the force measuring device taken along line AA in FIG. 4. [Figure 6] FIG. 2 is an exploded view of the grinding / polishing head and suspension. [Figure 7] FIG. 2 is a vertical cross-sectional view of a lift mechanism for a grinding / polishing head. [Figure 8] 2 shows the disc grinding / polishing apparatus of FIG. 1 from the front in a partially cut-away state. [Figure 9] 2 is a vertical cross-sectional view of the abrasive / polishing disc with collection reservoir and drive of the disc abrasive / polishing apparatus of FIG. 1. [Figure 10] FIG. 1 is an exploded view of an abrasive / polishing disc with a collection trough and drive portion. DETAILED DESCRIPTION OF THE INVENTION

[0068] Referring to FIG. 1, a disk polishing / polishing apparatus 10 comprises a base housing 12 having a display and / or input device 14, in the form of a touch display in this example, through which a user can input desired operating parameters, such as the rotation speed of the sample holder, the rotation speed of the polishing / polishing disk, the pressing force, the amount of polishing removal, etc., into a control device (not shown). A collection reservoir 16 for the polishing and polishing suspensions is embedded in the lower housing 12 at its upper surface 12a. A polishing / polishing disk 18 is disposed in the collection reservoir 16 and rotates around a vertical rotation axis 20 (FIG. 9). On the upper surface 18a of the polishing / polishing disk 18, a user can selectively attach various polishing pads, polishing pads, or polishing cloths. The polishing pads can be designed, for example, as silicon carbide polishing plates or diamond polishing plates, as abrasive paper, or as abrasive foil. If necessary, a magnetic foil can be used as an attachment carrier. For polishing, a polishing pad or polishing cloth can be attached to the upper surface 18a, which can be used for polishing in combination with a polishing suspension, such as a diamond suspension. Through the water cock 22, water can be supplied onto the polishing pad or polishing pad or polishing cloth, for example for wet polishing or cleaning.

[0069] The polishing / polishing head 30 is suspended on a suspension 32 above the polishing / polishing disk 18. At the lower end of the polishing / polishing head 30, a central sample holder 34, in this example a sextuple sample holder, is fixed to a drive spindle 66 of the polishing / polishing head 30. The sample holder 34 is rotated around the rotation axis 21 (FIG. 2) of the polishing / polishing head 30. This sample holder 34 is illustratively designed for embedded samples. Material-structural samples (not shown), particularly embedded samples in this case, to be polished and polished are individually inserted from above into the sample receptacles 36 of the sample holder 34. For polishing and / or polishing by individual pressing, individual pressing pistons 38 operated by air pressure are provided above each sample receptacle 36, by which the samples inserted in the sample holder 34 are individually pressed from above. For grinding and / or polishing by central pressing, the sample is fixed in the attached sample receiver 36 and pressed against the sample with a defined pressing force F A In order to press the sample holder 34 against the grinding / polishing disk 18 or to move the grinding / polishing head 30 axially, particularly to achieve a specified removal amount in the grinding process, the entire sample holder 34 is subjected to the application of force via a drive spindle 66 above the rotary drive within the grinding / polishing head 30.

[0070] The suspension 32 for the polishing / polishing head 30 includes a vertical tower section 42 having a lift mechanism 44, which raises and lowers a horizontal bridge section 46, from whose front end the polishing / polishing head 30 is suspended. For center-pressure polishing and / or polishing, the bridge section 46 suspended by the lift mechanism 44 is moved downward by the lift mechanism 44 to apply a pressing force for the polishing or polishing process. That is, the lift mechanism 44 moves the entire polishing / polishing head 30 together with the suspension 32 in the vertical direction. For this purpose, the lift mechanism 44 in this embodiment includes a stepper motor 48 with a rotary encoder, which generates vertical lift via rotation of a ball screw 50. In this case, the suspension 32 or bridge section 46 is guided by two vertical linear guides 52a, 52b, which are subjected to a bending moment. The lift mechanism 44 is located within the rear vertical tower section 42, so that the tower section 42, the horizontal bridge section 46, and the grinding / polishing head 30, which may be housed within a head housing 47, form a U-shaped arm.

[0071] 2-6 , the upper stator 64 and the upper rotor 62 form an upper electric direct drive motor, in this example in the form of an upper synchronous or torque motor 60, for the sample receiver 34. That is, the rotational drive of the sample holder 34 is performed by the upper synchronous or torque motor 60 in the grinding / polishing head 30. The upper torque motor 60 is designed as an internal rotor with four poles, so that the upper rotor 62 rotates within the upper stator 64. The upper rotor 62 is hollow and coaxially accommodates an upper drive spindle 66, which is connected to the upper rotor 62 in a form-locking or friction-locking manner, in this example by a key 68. The upper torque motor 60, together with the upper drive spindle 66 coaxially connected to the upper rotor 62, thus forms an upper coaxial direct drive 61 for the sample holder 34, which is coaxially connected at its lower end to the upper drive spindle 66.

[0072] The upper drive spindle 66 is supported above and below the rotor 62. The lower bearing 70 is designed as a fixed bearing and can include an angular contact ball bearing or a conventional deep groove ball bearing. In this case, the lower fixed bearing 70 consists of two deep groove ball bearings 70a, 70b. The lower bearing 70 is arranged in a bearing housing 71 and is preloaded by a wave spring 72. The preload helps to eliminate bearing play. The two ball bearings 70a, 70b are separated by an intermediate ring 74 and fixed inward by a clamping nut 76.

[0073] A force measuring device 80 is arranged on the upper drive spindle 66, which in this example is designed as an annular force measuring flange 81 and extends around the upper drive spindle 66. The annular force measuring device 80 comprises an inner force distribution ring 82, which in the central compression measures the pressing force F A Reaction force F GWhen the force acting axially on the upper drive spindle 66 via the sample holder 34 is applied by the upper drive spindle 66, in this example via the lower bearing 70. The force measuring device 80 includes a leaf spring section 84 that radially connects the inner force distribution ring 82 with the outer force dissipation ring 86. The leaf spring section 84 includes, for example, four radially extending leaf springs 85 that connect the inner force distribution ring 82 with the outer concentric force dissipation ring 86 under axial elastic force. The individual leaf springs 85 can be particularly uniformly distributed around the upper drive spindle 66 of the upper coaxial direct drive 61. The outer force dissipation ring 86 is supported, for example, on a rigid region of the grinding / polishing head 30. On the leaf spring section 84, in this embodiment on one of the leaf springs 85, a force sensor 87 is mounted, e.g., a strain gauge 88 glued, which changes its electrical resistance when stretched, so that the stretch of the associated leaf spring 85 or leaf spring section 84 can be measured relative to a rigid part of the grinding / polishing head 30 or relative to the spring tension when the upper drive spindle 66 is displaced axially. Strain gauges can also be mounted or glued on several, e.g., two or all (here, four) leaf springs 85, which can further improve the accuracy of the force measurement. The measurement signal of the strain gauge 88 can be amplified by a measuring amplifier 89, whereby the pressing force F A , can be transmitted to the control device of the disc grinding / polishing machine 10 for adjusting the force. The measuring amplifier 89 can be mounted directly on the force measuring device 80. For example, the measuring amplifier 89 can be fitted into a recess 101 in the force measuring flange 81, and cast therein if necessary. In other words, the force measuring flange 81, or the inner force distribution ring 82, the leaf spring section 84 and the outer concentric force dissipation ring 86, form an axially elastic suspension of the upper motor shaft formed by the upper drive spindle 66 and the upper rotor 62 of the upper synchronous or torque motor 60.

[0074] That is, in the central pressing, the grinding / polishing head 30 is moved axially downward by the lift mechanism 44 until the sample fitted in the sample holder 34 contacts the grinding / polishing disk 18. During further vertical feeding by the central pressing, the sample is moved with a pressing force F A against the grinding / polishing disc 18 with a corresponding reaction force F G acts axially or vertically upward on the upper drive spindle 66. This reaction force F G causes deformation of the leaf spring 85 and therefore elongation of the strain gauge 88, thereby increasing the pressing force F A can be measured.

[0075] Instead of central pressing, the samples can also be pressed individually by individual pressing pistons 38. The individual pressing pistons 38 are pneumatically operated and are moved downward against the preload of return springs 39 toward the upper surface of each sample (not shown). For pneumatic operation of the individual pressing pistons 38, compressed air can be introduced centrally into the upper drive spindle 66 via a compressed air connection 90. The compressed air connection 90 is rotatable relative to the upper drive spindle 66 and directs compressed air downward through an axial compressed air channel 92 that extends through the upper drive spindle 66 as a central axial hole. An intermediate piece 94 having a radial air distributor 96 is fixed to the lower end of the upper drive spindle 66. The air distributor 96 transfers compressed air to the individual pressing pistons 38 via the axial connecting channel 98 and respective radial distributor channels 102 in order to operate the individual pressing pistons 38 and press them against the embedded sample. That is, the compressed air is led to the air distributor 96 through the compressed air connection 90 passing through the upper drive spindle 66 and distributed to, for example, six individual pressing pistons 38 via the radial air distributor channels 102.

[0076] In operation, the upper drive spindle 66, which is rigidly connected to the upper rotor 62, rotates together with the air distributor 96 and the individual thrust pistons 38, as well as the sample holder 34, which is fixed to the lower end of the upper drive spindle 66. The sample holder 34 may be fixed to the lower part of the upper drive spindle 66, for example, by a quick lock 104.

[0077] In the central pressing, the sample is firmly fitted into the sample holder 34 and a pressing force F A is applied to the sample holder 34 through the movement of the grinding / polishing head 30 by the upper drive spindle 66, and a pressing force A is measured by the force measuring device 80 during the grinding and / or polishing process. The measurement results of the force measuring device 80, in this example in the form of a change in resistance of the strain gauge 88, are transmitted to the control device of the grinding / polishing device 10, which reacts to this measurement signal in a closed circuit to calculate the pressing force F A In other words, the pressing force F A is measured by the force measuring device 80 or the force sensor 87 and adjusted to a target value of the pressing force, which can be input via the input device 14, through feedback to the control device in a closed loop.

[0078] The upper bearing 106 of the upper drive spindle 66, by virtue of its free axial mobility, forms a floating bearing and is designed in this example as a cylindrical roller bearing in order to equalize the axial deformations of the force measuring device 80 in the central compression. A sealing ring 108 seals the upper drive spindle 66 or the upper rotor 62 against a non-rotating cover plate 110.

[0079] 7 and 8, the tower section 42 is suspended, for example, on the rear side of the machine legs 112, which form the machine base within the lower housing 12. Two vertical guide rods 53a, 53b are suspended from the machine legs 112 as part of linear guides 52a, 52b. The bridge section 46, to whose front end the grinding / polishing head 30 is rigidly fixed, is provided with vertically sliding guide sleeves 54a, 54b on the guide rods 52a, 52b at the ends facing the grinding / polishing head 30. The vertical lift drive of the lift mechanism 44 is driven by a stepper motor 48. The vertical lift drive may be designed as a spindle drive 49. The stepper motor 48 drives, via a coupling 116, a ball screw 50 that rotates in a spindle nut or ball circulation guide 118 to more precisely cause vertical movement of the suspension 32 and, therefore, the grinding / polishing head 30. To enable precise control of the vertical lift movement of the grinding / polishing head 30, the stepper motor 48 is equipped with a rotary encoder (not shown).

[0080] The tower section 42 may further be suspended from the apparatus legs 112 so as to be horizontally displaceable. To this end, the tower section 42, particularly including the lift mechanism 44, may be connected to the apparatus legs 112 so as to be horizontally displaceable linearly with horizontal linear guides 252a, 252b. In this example, the tower section 42 is suspended on guide sleeves 254a, 254b that slide horizontally on guide rods 253a, 253b. As a result, the tower section 42, including the lift mechanism 44, performs horizontal movement parallel to the polishing / polishing plate 18. The horizontal displacement mechanism 244 is driven by, for example, a ball screw 250 with an electric motor 248 via a spindle drive 249. The horizontal movement may be performed, for example, transverse to the horizontal bridge section 46. As a result, for example, horizontal pendulum movement of the sample may be generated during polishing of the sample on the polishing / polishing disk 18. This has the advantage that wear of the polishing or polishing plate occurs uniformly.

[0081] Generally defined, the disc grinding / polishing apparatus 10 includes a horizontal motion mechanism for the grinding / polishing head 30, by which the grinding / polishing head 30, including the first drive motor 60 and / or force measuring device 80, and the lift mechanism 44, can be moved laterally relative to the grinding / polishing disc 18 by a motor.

[0082] 9 and 10, the lower stator 164 and the lower rotor 162 form a lower electric direct drive motor for the grinding / polishing disk 18, in this example in the form of a lower synchronous or torque motor 160. That is, the rotational drive of the grinding / polishing disk 18 is provided by the lower synchronous or torque motor 160. The lower torque motor 160 is designed as an internal rotor, so that the lower rotor 162 rotates within the lower stator 164. The lower rotor 162 is hollow and coaxially accommodates a lower drive spindle 166, which is connected to the lower rotor 162 in a form-locking or friction-locking manner, in this example by a key 168. As such, the lower torque motor 160, together with the lower drive spindle 166 coaxially connected to the lower rotor 162, forms a lower coaxial direct drive 161 for the grinding / polishing disk 18, which is coaxially connected at its upper end to the lower drive spindle 166.

[0083] The abrasive / polishing disk 18 rests on a lower coaxial direct drive 161 for being rotationally driven about the lower rotation axis 20 by a lower drive spindle 166. The lower drive spindle 166 extends axially through a lower rotor 162. That is, the lower rotor 162 and the lower drive spindle 166 are driven by a lower stator 164. In this manner, the lower torque motor 160, together with the lower drive spindle 166, form a lower coaxial direct drive 161 for the abrasive / polishing disk 18, which is coaxially connected to the lower drive spindle 166.

[0084] The abrasive / polishing disk 18 rotates to collect the abrasive or polishing suspension in the collection reservoir 16. The abrasive / polishing disk 18 may be sealed to the collection reservoir 16 by a sealing ring, such as a lip seal, to keep the abrasive and polishing suspension away from the drive 161.

[0085] The lower drive spindle 166 is supported axially above and below the lower torque motor 160 by a lower bearing 170 and an upper bearing 172. The bearings 170, 172 can be designed, for example, as deep groove ball bearings or angular contact ball bearings.

[0086] The grinding / polishing disc 18 rests on a disc receiving part 19 which is further threaded coaxially from above onto a drive spindle 166 and allows easy removal of the grinding / polishing disc 18. The grinding / polishing disc 18 can be held on the disc receiving part 19, for example, magnetically and form-fittingly.

[0087] Optionally, an annular splash guard may also be attached to the upper edge of the collection basin 16 (not shown). A lower drive spindle 166 extends through a central bottom opening 176 of the collection basin 16. A lower electric drive motor 160 may be flange-connected to the collection basin 16 from below, coaxially with the bottom opening 176. The collection basin 16 may be emptied through a drain port 178 and a drain pipe 180.

[0088] It is clear to those skilled in the art that the above-described embodiments should be understood as exemplary, and that the invention is not limited thereto, but can be modified in many ways without departing from the scope of protection of the claims. Furthermore, it is clear to those skilled in the art that features individually define essential elements of the invention, even if they are described together with other features, whether or not they are disclosed in the description, claims, drawings or otherwise.

Claims

1. 1. A disk grinding / polishing device (10) for planar grinding and / or polishing, by means of a rotating grinding / polishing disk (18), in particular of the lower sample surface of an embedded and / or non-embedded sample, in particular for sample preparation for material structural analysis, comprising: a grinding / polishing head (30) having a sample holder (34) for receiving one or more samples; a lower housing (12) having a collection vessel (16) for collecting the abrasive and / or polishing suspension; a polishing / polishing disk (18) in the collection tank (16), on whose upper surface (18a) different polishing pads, polishing pads and / or polishing cloths can be removably fixed in order to planarly polish and / or polish the underside of a sample pressed against the polishing / polishing disk (18) from above with the respective polishing pads, polishing pads or polishing cloths; a first electric drive motor (60) for the sample holder (34) disposed within the grinding / polishing head (30); a second electric drive motor (160) for the abrasive / polishing disc (18) disposed within the lower housing (12); a first drive spindle (66) for rotationally driving the sample holder (34), the first electric drive motor (60) including a first stator (64) and a first rotor (62), the first drive spindle (66) being coaxially connected to the first rotor (62), the first electric drive motor (60) forming together with the first drive spindle (66) a first coaxial direct drive (61) for the sample holder (34); and / or a second drive spindle (166) for rotationally driving the abrasive / polishing disc (18), the second electric drive motor (160) including a second stator (164) and a second rotor (162), the second drive spindle (166) being coaxially connected to the second rotor (162), the second electric drive motor (160) forming together with the second drive spindle (166) a second coaxial direct drive (161) for the abrasive / polishing disc (18); A disc abrading / polishing device (10) comprising:

2. The rotation speed of the first electric drive motor (60) is 20 min -1 ~200 min -1 and / or the rotational speed of the second electric drive motor (160) is in the range of 50 min -1 ~600 min -1 2. The disc abrading / polishing apparatus (10) of claim 1, wherein the disc abrading / polishing apparatus (10) is in the range of

3. 3. The disc grinding / polishing device (10) according to claim 1 or 2, wherein the first electric drive motor (60) and / or the second electric drive motor (160) are designed as synchronous motors, in particular as torque motors.

4. 3. The disk grinding / polishing apparatus (10) of claim 1 or 2, further comprising a vertical lift mechanism (44) by which the grinding / polishing head (30) is lowered onto the grinding / polishing disk (18) for flat grinding and / or polishing of the sample.

5. 5. The disc grinding / polishing apparatus of claim 4, wherein the lift mechanism comprises at least one vertical guide, a circulating spindle, and a circulating spindle drive motor that rotates the circulating spindle within a spindle nut or circulating guide to effect vertical lift movement of the grinding / polishing head along the at least one vertical guide.

6. 6. The disc grinding / polishing apparatus (10) of claim 5, wherein the circulating spindle drive motor (48) is designed as a stepper motor having a rotary encoder.

7. The grinding / polishing head (30) is suspended on a suspension (32) having a vertical tower section (42) and a horizontal bridge section (46); The vertical tower section (42) is secured to and extends vertically upward from the equipment leg (112); the horizontal bridge section (46) is suspended from the vertical tower section (42) and extends horizontally above the lower housing (12) to the grinding / polishing head (30); a grinding / polishing head (30) suspended from the end of the bridge section (46) opposite the tower section (42); and / or the lift mechanism (44) is disposed within the vertical tower section (42) and raises and lowers the horizontal bridge section (46) together with the grinding / polishing head (30) and the first coaxial direct drive (61); The grinding / polishing apparatus (10) of claim 4.

8. 3. The grinding / polishing device (10) according to claim 1 or 2, wherein the first drive spindle (66) is supported above and below the first rotor (62), and the lower bearing (70) is designed as a fixed bearing, in particular having an angular contact ball bearing or a deep groove ball bearing, and is preloaded, in particular by a wave spring (72).

9. 3. The grinding / polishing device (10) according to claim 1 or 2, wherein the first drive spindle (66) is supported above and below the first rotor (62), and the upper bearing (106) is designed as a floating bearing, in particular having a cylindrical roller bearing, to accommodate axial movement of the first drive spindle (66) relative to the first stator (64).

10. 3. The grinding / polishing device (10) according to claim 1 or 2, wherein the second drive spindle (166) is supported above and below the first rotor (62), in particular by angular contact ball bearings or deep groove ball bearings.

11. The sample can be firmly fitted into the sample holder (34) for flat grinding and / or polishing by central pressing, and the entire grinding / polishing head (30) including the first electric drive motor (60) can be fed via the first drive spindle (66) with a defined pressing force (F A 3. The grinding / polishing apparatus (10) of claim 1 or 2, wherein a central pressure is applied to the sample holder (34).

12. 3. The polishing / polishing apparatus (10) of claim 1 or 2, further comprising a device for zero point determination that detects contact of the lower sample surface with the polishing / polishing disc (18).

13. 3. The polishing / polishing apparatus (10) of claim 1, wherein the first drive spindle (66) and the first rotor (62) form a first motor shaft of the first drive motor (60), and the first motor shaft, together with the first drive spindle (66) and the first rotor (62), is suspended from the polishing / polishing head (30) in a state in which an elastic force is applied in the axial direction.

14. 14. The polishing / polishing apparatus (10) of claim 13, wherein the first motor shaft is displaced axially relative to the first stator (64) while applying an elastic force against the spring tension of the elastic suspension of the first motor shaft when the sample holder (34) is pressed against the polishing / polishing disk (18), and a force measuring device (80) is included that measures the force applied from the first motor shaft by the suspension that applies an elastic force in the axial direction of the first motor shaft.

15. 3. The grinding / polishing apparatus (10) of claim 1 or 2, further comprising a force measuring device (80) for measuring the pressing force (FA) acting on the first drive spindle (66) and / or arranged coaxially with respect to the first electric drive motor (60) and / or with respect to the first rotor (62).

16. 3. The polishing / polishing apparatus of claim 1, wherein the first rotor is suspended axially displaceably and elastically relative to the first stator, a pressing force against the polishing / polishing disk causing a coaxial displacement of the first rotor relative to the first stator, and a force measuring device is included that measures the force applied to the elastic suspension by the coaxial displacement of the first rotor relative to the first stator.

17. 15. The grinding / polishing apparatus (10) of claim 14, wherein the force measuring device (80) comprises at least one force sensor (87), in particular at least one strain gauge (88), which is in particular arranged radially outside the first drive spindle (66).

18. The force measuring device (80) includes a force distribution ring (82) extending around the first drive spindle (66) and measures the reaction force (F) acting upward on the first drive spindle (66) generated through the sample holder (34) in a central compression. G ) is transmitted to the force distribution ring (82), particularly via the lower bearing (70) of the first drive spindle (66), and the force distribution ring (82) is axially elastically coupled to the suspension (32) of the grinding / polishing head (30), and the force measuring device (80) includes at least one force sensor (87), by which the pressing force (F A 15. The grinding / polishing apparatus (10) of claim 14, wherein the grinding / polishing apparatus (10) can measure the grinding / polishing distance.

19. A control device is included that can input a pressing force target value, the control device controls the lift mechanism (44) and defines a closed control circuit, in which the pressing force (F) applied by the lift mechanism (44) to the sample holder (34) against the grinding / polishing disk (18) is determined. A 15. The grinding / polishing apparatus (10) of claim 14, wherein the force measuring device (80) actively adjusts the pressing force to a preset target value in response to the pressing force measured by the force measuring device (80).

20. 3. A polishing / polishing apparatus (10) as described in claim 1 or 2, wherein the sample holder (34) is designed as a multiple sample holder having a plurality of sample receiving portions (36) arranged around the rotation axis (21) of the first drive spindle (66), the polishing / polishing disk (30) is provided with individual pressing pistons (38), and the samples inserted into the associated sample receiving portions (36) are individually subjected to force by each one of the individual pressing pistons (38).

21. 21. The grinding / polishing apparatus of claim 20, wherein the individual pressing pistons are pneumatically operated, the first drive spindle having a compressed air connection for introducing compressed air, an axial compressed air channel extending within the first drive spindle for conducting the compressed air axially through the first rotor and the first stator to an air distributor below the first electric drive motor, the air distributor distributing the compressed air radially through distributor channels to the individual pressing pistons for pneumatically operating them.

22. 3. The polishing / polishing apparatus (10) of claim 1 or 2, further comprising a horizontal movement mechanism (244) for the polishing / polishing head (30), by means of which the polishing / polishing head (30) including the first drive motor (60) and / or the force measuring device (80), and in particular a lift mechanism (44) for the polishing / polishing head (30), can be moved laterally relative to the polishing / polishing disk (18) by a motor.

23. 3. A disk grinding / polishing device (10), in particular according to claim 1 or 2, for planar grinding and / or polishing the lower sample surface of a sample, in particular for sample preparation, by means of a rotating grinding / polishing disk (18), comprising: a lower housing (12) having a collection vessel (16) for collecting the abrasive and / or polishing suspension; a horizontal abrasive / polishing disk (18) disposed within the collection tank (16) and rotating about a vertical rotation axis (20), wherein different abrasive pads, polishing pads and / or polishing cloths can be removably fixed to an upper surface (18a) of the abrasive / polishing disk (18) for planarly abrading and / or polishing the lower surface of a sample pressed against the abrasive / polishing disk (18) from above with the respective abrasive pads, polishing pads or polishing cloths; a grinding / polishing head (30) having a sample holder (34) for receiving one or more samples; a first drive spindle (66) extending vertically within the grinding / polishing head (30), the sample holder (34) being connected to a lower end of the first drive spindle (66) for driving the sample holder (34) in rotation together with the first drive spindle (66); a first electric drive motor (60) disposed within the grinding / polishing head (30) for driving rotation of the first drive spindle (66), the first electric drive motor (60) including a first stator (64) and a first rotor (62), the first drive spindle (66) extending coaxially within the first rotor (62), the first electric drive motor (60) forming, together with the first drive spindle (66), a first coaxial direct drive (61) for the sample holder (34); A disc abrading / polishing device (10) comprising:

24. 24. The disc abrasive / polishing apparatus (10) of claim 23, further comprising a second electric drive motor (160) disposed within said lower housing (12) for said abrasive / polishing disc (18).

25. a second drive spindle (166) extending vertically from the lower housing (12) through a bottom opening (176) of the collection basin (16) into the collection basin (16), the second drive spindle (166) being connected to an upper end of the second drive spindle (166) for rotationally driving the grinding / polishing disk (18) together with the second drive spindle (166); 25. The disc grinding / polishing apparatus (10) of claim 24, wherein the second electric drive motor (160) includes a second stator (164) and a second rotor (162), the second drive spindle (166) extends coaxially within the second rotor (162), and the second electric drive motor (160) together with the second drive spindle (166) forms a second coaxial direct drive section (161) for the grinding / polishing disc (18).

26. 3. A disk grinding / polishing device (10), in particular according to claim 1 or 2, for planar grinding and / or polishing the underside of a sample surface by means of a rotating grinding / polishing disk (18), in particular for sample preparation, comprising: a lower housing (12) having a collection vessel (16) for collecting the abrasive and / or polishing suspension; a horizontal abrasive / polishing disk (18) disposed within the collection tank (16) and rotating about a vertical rotation axis (20), wherein different abrasive pads, polishing pads and / or polishing cloths can be removably fixed to an upper surface (18a) of the abrasive / polishing disk (18) for planarly abrading and / or polishing the lower surface of a sample pressed against the abrasive / polishing disk (18) from above with the respective abrasive pads, polishing pads or polishing cloths; a second drive spindle (166) extending vertically from the lower housing (12) into the collection tank (16), the abrasive / polishing disc (18) being connected to an upper end of the second drive spindle (166) for driving the abrasive / polishing disc (18) in rotation together with the second drive spindle (166); a second electric drive motor (160) disposed within the lower housing (12) for driving rotation of the second drive spindle (166), the second electric drive motor (160) including a second stator (164) and a second rotor (162), the second drive spindle (166) extending coaxially within the second rotor (162), the second electric drive motor (160) forming together with the second drive spindle (166) a second coaxial direct drive (161) for the abrasive / polishing disk (18); A disc abrading / polishing device (10) comprising:

27. a grinding / polishing head (30) having a sample holder (34) for fitting one or more samples above the grinding / polishing disc (18); a first drive spindle (66) extending vertically within the grinding / polishing head (30), the sample holder (34) being connected to a lower end of the first drive spindle (66) for driving the sample holder (34) in rotation together with the first drive spindle (66); a first electric drive motor (60) disposed within the grinding / polishing head (30) for driving the rotation of the first drive spindle (66), the first electric drive motor (60) including a first stator (64) and a first rotor (62), the first drive spindle (66) being coaxially connected to the first rotor (62), the first electric drive motor (60) forming, together with the first drive spindle (66), a first coaxial direct drive (61) for the sample holder (34); 27. The disc abrading / polishing apparatus (10) of claim 26, further comprising:

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