DE10314625B3 - Process for post-processing precision surfaces on random workpieces comprises using a rotating polishing tool for fine grinding an polishing having a polishing element which is longitudinally guided in a guiding chamber of a housing - Google Patents

Abstract

Process for post-processing precision surfaces on random workpieces comprises using a rotating polishing tool (1) for fine grinding an polishing having a polishing element (6) which is longitudinally guided in a guiding chamber (5) of a housing (19) impinged with polishing suspension (20). Process for post-processing precision surfaces on random workpieces comprises using a rotating polishing tool (1) for fine grinding an polishing having a polishing element (6) which is longitudinally guided in a guiding chamber (5) of a housing (19) impinged with polishing suspension (20). The rear side of the polishing element is impinged with the polishing suspension under pressure whilst the front surface (10) of the polishing element lies against the precision surface of the workpiece. A gap (16) is maintained between the front surface of the housing and the precision surface of the workpiece during the whole polishing process. An independent claim is also included for a device for carrying out the process.

Description

The The invention relates to a method and to carry out the Appropriate device for reworking precision surfaces those mentioned in the preamble of claim 1 and claim 11 Features. Since with the mentioned method a reworking of the surfaces in limited areas is carried out can also be called correction processing.

The Precision surfaces can on any workpieces made of any materials. These are important applications Reworking such precision surfaces Lenses and optical mirrors. But also molds and injection molds for manufacturing high-precision components can be reworked very advantageously with the correction processing. However, other applications are also possible.

The workpieces are first processed by grinding and polishing edited and the surface with a geometry so precise as possible and with a roughness depth as low as possible. Because of higher Profitability for the corresponding operations Used tools that lie on the workpiece over a large area, which is appropriate huge Material removal allowed per unit of time.

adversely is that with curved workpiece surfaces exact geometric shape can no longer be maintained if it is precision surfaces. This depends on it together that the interfaces between workpiece and tools are too big, to be very precise Geometries on curved surfaces to be able to manufacture. The errors that arise in this way are subsequently processed eliminated.

Right away before the post-processing (correction processing) the pre-made surfaces precise measured and the deviations found as "plus dimensions" in a given coordinate system determined and stored electronically. From these "plus dimensions" and the associated coordinates The geometric locations then arise at which material in the fine area “point for point " got to. With "dot" there are surface elements on the workpiece surface with Dimensions in the millimeter range meant.

Especially important applications arise in the manufacture of high-precision lenses, as they e.g. B. in the manufacture of microchips for exposing the Wafer needed become. The prefabricated lenses (high precision ground and polished) are measured with an interferometer and the "plus dimensions" with the associated coordinates electronically stored. Then the targeted material removal takes place at the points found with the "plus dimensions". The measurement with the interferometer and the post-processing can then repeated a few times until the surface of the Lens of the desired Geometry corresponds exactly.

On Another important area of work for correction processing of workpiece surfaces is in Given mold making. In such forms, e.g. B. lenses in casting or injection molding manufactured. Accordingly, the shapes must be exact. Also here the workpiece surfaces are first precisely ground, polished and then measured. In this case, laser devices are used for measuring, with which the "plus dimensions" are also determined.

On the positions found with "plus dimensions" are then displayed targeted material removal through correction processing using fine grinding or polishing. The success of work is checked by measuring and repeat the steps if necessary. Also in the manufacture Optical mirrors (e.g. concave mirrors) can be used for the molds described Apply procedure.

method and devices of the type mentioned for post-processing (correction processing) high more precise surfaces using fine grinding or polishing methods are already known per se.

One this method is called topographical polishing, at a pen-shaped polishing tool (Polishing pen) with a typical diameter of 5 to 15 mm becomes. For the end surface of the polishing stick is used for the polishing process, to do this with a polishing film (polyurethane film) or a Felt covered is.

The A polishing arm is rotated around its axis by a robot arm Workpiece surface guided or is connected to the tool spindle of a four-axis CNC polishing machine (correction machine).

The The polishing process is running then with the addition of polishing suspension, while the polishing stick in succession all geometric locations with "plus dimensions" the respective dwell time, the material removal is controlled according to the "plus dimension".

• – Da die gesamte Polierleistung von der kleinen Stirnfläche des Polierstifts aufgebracht werden muss, ist der Materialabtrag nur klein und das Werkzeug erfährt eine sehr starke Abnutzung. Die Folge sind hohe Kosten wegen der langen Polierzeiten und wegen des hohen Werkzeugaufwandes.
• – Bei diesen Polierverfahren wird auch eine relativ rauhe Oberflächenstruktur erzeugt, da aus Gründen der Wirtschaftlichkeit mit höheren Anpressdrücken gearbeitet werden muss. Auch dies ist ein erheblicher Nachteil.

All processes that work with a polishing pen have the following disadvantages:

• - Since the entire polishing performance has to be applied from the small end face of the polishing stick, the material removal is only small and the tool is subject to very heavy wear. The result is high costs due to the long polishing times and the high tooling costs.
• - With this polishing process, a relatively rough surface structure is also generated, since higher pressure must be used for reasons of economy. This is also a significant disadvantage.

Used are also inflatable membranes for this correction processing. However, these have the additional Disadvantage that the interface and so that the work area is not clearly defined.

In the US 49 56 944 A describes a "polishing apparatus" in which a type of polishing stick is also used. The resulting disadvantages correspond to those described above.

Also in the EP 0937 542 A1 A "method for polishing optical lenses ..." is described, in which the aforementioned disadvantages also occur.

In the DE 100 31 057 A1 A "method for corrective fine polishing of optical lenses or mirrors and devices for carrying out the method" is described. In this method, an inflatable, rotating polishing wheel is used for correction processing. The circumferential surface of the wheel causes the material removal in cooperation with added suspensions, the fine abrasives The toroidal shape of the polishing wheel creates a relatively small contact area between the polishing wheel and the workpiece on the workpiece surface.

Advantageous This process involves the relatively high material removal with a long service life of the polishing tool used. The disadvantage, however, is that the Size of the contact area is essential of the contact pressure between tool and workpiece as well on the geometry of the workpiece depends. For concave surfaces there is a larger contact area, at convex surfaces a smaller one. This makes targeted material removal difficult at Correction processing.

In the DE 100 38 415 A1 "A method for correcting the geometry of optical lenses ..." is proposed, which has similar disadvantages as previously with the DE 100 31 057 A1 described.

In the DE 101 13 599 A1 describes a "device for the abrasive processing of surfaces of optical elements". Here, a nozzle-like device is used, through which a suspension is pressed, which contains grinding or polishing agents.

This Device comes with its mouth the surface to be machined approached to within a few tenths of a millimeter, so that an annular gap arises from the surface of the workpiece and the front wall of the nozzle-like Device is formed.

By the strong acceleration of the suspension in the annular gap as a result the beam deflection and the high speeds take place on workpiece a material removal due to abrasion. A disadvantage of this method is on the one hand the low material removal (no mechanical contact due to a polishing tool) and on the other hand the change in the removal rate in dependence from the radius (starting from the nozzle axis). With this method, it is not possible to work economically with larger "plus dimensions" targeted material removal is difficult.

In the EP 0 858 381 B1 describes a process with the title "DETERMINISTIC MAGNETORHEOLOGICAL FINISHING". In this process, a suspension containing grinding or polishing bodies and a magnetizable powder is applied to a support body and then solidified with a strong electromagnetic field The suspension body and the magnetic lines can be shaped so that they form only a small contact area with the workpiece.

If the supporting body with the solidified suspension and the workpiece relative movements to each other To run, material is removed from the surface of the workpiece. The disadvantage of this type of correction processing is that the removal rate is only minor. The economical elimination of mistakes in the surface geometry is only for deviations <200 nm possible.

This depends on it together that the suspension by the magnetic fields is not very can be strongly consolidated. Another disadvantage is that the Size and shape the interface between workpiece and the solidified suspension depends on the contact pressure and so that is not clearly defined. It is difficult with that desired Generate corrections during post-processing.

WO 94/04313 A1 describes a method with the title "MAGNETORHEOLOGICAL POLISHING DEVICES AND METHODS". With regard to the disadvantages of this method, the same applies as for the EP 0 858 381 B1 already be wrote.

In the US 50 76 026 A describes a process with the title "MICROSCOPIC GRINDING METHOD AND MICROSCOPIC GRINDING DEVICE". Here, too, a polishing suspension is used which contains magnetizable particles and can therefore be solidified. The disadvantages are as above for the EP 0 858 381 B1 described.

The The present invention was based on the task of post-processing (Correction processing) of precision surfaces by Fine grinding or polishing to make more economical, with simultaneous Improve surface quality and accuracy.

This The task is according to the invention Method, with device for performing the method, the input mentioned type, with the characterizing features of claim 1 and of claim 11 solved. Advantageous configurations result from the features of Dependent claims.

at the inventive method becomes a special small diameter polishing tool on the arm a robot or on the tool spindle of a multi-axis CNC-controlled Polishing machine (correction machine) attached and set in rotation. It is then activated by appropriate control of the machine axes moved to the geometric locations of the "plus dimensions" and there the desired material removal carried out. The polishing tool is guided so that its distance from the surface of the workpiece remains constant. A distance of 0.1 to 0.2 mm is preferably selected are other distances, however intended.

The Polishing tool doing about a cylindrical housing, whose inner cavity has a larger area on one side, creating a lead room, preferably in the form of a guide cylinder, is formed. However, leadership rooms with other cross-sectional shapes are also provided (e.g. square or hexagonal cross-section). In the lead room the actual polishing element is housed in a longitudinally displaceable manner.

On the holding device is located on the opposite side of the housing for fastening the polishing tool to a drive spindle (robot arm) or on a tool spindle (polishing machine).

The Cross section of the polishing element made of polishing felt or another Material with the required Properties, corresponds to that of the management room. Is preferred a cylindrical polishing felt, whose diameter is a few millimeters. However, there are others Diameters, other cross sections and other materials are provided. Even very small diameters are possible because of the polishing element from the lead room enclosed and supported becomes.

To the Fine grinding or polishing as part of the intended correction processing the polishing tool with its holding device on the processing machine attached and in contact with the workpiece surface by controlling the machine axes brought. While the polishing element the workpiece touched, exists between the front of the guide space and the workpiece surface Distance from 0.1 to 0.2 mm. However, other distances are also provided.

In front the start of the rotational movement of the polishing tool becomes the inner one Cavity of the housing over the hollow drilled drive or tool spindle of the processing machine a fluid supplied. This fluid is preferably an aqueous suspension, which contains all the materials required for fine grinding or polishing.

Out establish linguistic simplification is only referred to as suspension below. But it always means a fluid with a different composition.

The Suspension leaves then through the case the narrow annular gap between the polishing element and the guide space. Finds at the same time but also a very advantageous flow through the permeable polishing element with suspension instead. The polishing element is designed accordingly that it has a loosened structure inside or a enough size Has porosity.

There the annular gap between the polishing element and the guide space is relatively narrow Suspension when it flows through a desired one Pressure loss. The same applies the direct flow of the polishing element.

This Pressure loss causes an overpressure in the inner cavity of the housing and therefore on the back the polishing element (facing away from the workpiece) a pressure force.

With this pressure force, the polishing element is pressed against the surface of the workpiece, which creates the required machining pressure. This can be regulated very finely according to the desired work results by using the Flow rate of suspension is varied.

After this the flow of the polishing tool with suspension is ensured Rotation movement switched on. In addition, during the Machining process also rotates the workpiece, whereby the speed preferably in synchronism with that of the polishing tool chosen (same direction of rotation).

By the rotational movement of the workpiece and the axes of the machine tool are then moved Relative movement (feed movement) between the polishing tool and the workpiece instead of. The trajectory corresponds to a mathematically determined function based on the measured surface defects and the process data.

There in the case of fine grinding or polishing, the material removal is proportional to the processing time, the dwell time of the polishing tool be longer in geometric locations with large "plus dimensions", than in places with small "plus dimensions". The feed rate of the polishing tool relative to the surface of the workpiece therefore change constantly, so that these different dwell times can be realized.

By the pressure in the inner cavity of the housing becomes the polishing element pressed against the workpiece surface. The Material removal per unit of time is very much from this pressure affected. The pressure of the suspension is therefore monitored by means of a sensor measured and by varying the amount of suspension flowing through to constant Values adjusted.

There the material removal depends of the working pressure (contact pressure of the polishing element against the Workpiece surface), can the desired one Material removal also through change of the working pressure can be controlled. In this case, the amount of suspension promoted (depends on this the pressure in the internal cavity of the housing depends) changed from the geometric location of the polishing tool on the workpiece surface. With large "plus dimensions" would result a big output and vice versa.

During the The tool also performs fine grinding or polishing processes quickly Oscillatory movements. This will result in the work result regarding the Surface quality (shallow roughness, gradient free) significantly improved. These oscillatory movements are activated by controlling the corresponding machine axis or several Machine axes generated.

• – Es herrschen ideale Schmierverhältnisse, da das Polierelement von der Suspension umströmt und zum Teil auch durchströmt wird. Dies führt zu sehr glatten Oberflächen mit äußerst geringer Rauhtiefe. Man spricht auch von gradientenfreier Oberfläche.
• – Durch die längs verschiebliche, reibungsarme Führung des Polierelements in dem Führungsraum und seine hydrostatische Anprssung an die Werkstückoberfläche, findet eine ideale Anpassung zwischen Polierelement und Werkstückoberfläche statt. Dies führt zu außerordentlich guten Oberflächenqualitäten.
• – Durch die mechanische Berührung des Polierelements mit der Oberfläche des Werkstücks ergibt sich ein wesentlich höherer Materialabtrag pro Zeiteinheit, als dies bei Verfahren der Fall ist, bei denen die Poliersuspension nur mittels Strömungskräften bzw. Magnetkräften mit der Oberfläche in Kontakt ist.
• – Das Polierelement kann auch bei hohen Anpressdrücken nicht seitlich ausweichen, da es von dem Führungsraum bis auf den Überstand von 0,1 bis 0,2 mm umschlossen ist. Dadurch kann mit hohen Bearbeitungsdrücken gearbeitet werden, woraus sich ein großer Materialabtrag pro Zeiteinheit ergibt. Wegen der guten Schmierung des mit Suspension durchströmten Polierelements treten dabei nicht die gefürchteten „Rauhigkeiten" auf, wie sie beim Arbeiten mit den herkömmlichen Polierstiften bekannt sind, wenn der Arbeitsdruck zu groß gewählt wird.
• – Auch bezüglich der Werkzeugabnutzung ergeben sich erhebliche Vorteile. Da das Polierelement in dem Führungsraum geführt wird, kann es eine große Längserstreckung haben, ohne dass sich hieraus Nachteile ergeben (z. B. mechanische Instabilitäten). Wenn sich das Polierelement an seiner Vorderseite abnutzt, so wird es von dem Druck der Poliersuspension weiter nach vorne geschoben, so dass es immer an der Oberfläche des Werkstücks anliegt. So lange noch ein Reststück von einigen Millimetern Länge vorhanden ist, ändern sich die Bearbeitungsparameter nicht.
• – Das Polierelement ist das einzige Verschleißteil. Es kann ausgewechselt werden, ohne dass das Polierwerkzeug aus der Bearbeitungsmaschine ausgebaut werden muss. Ein Kalibrieren des Werkzeugs bzw. sein genaues Ausrichten beim Erneuern des Polierelements kann daher entfallen.
• – Vorteilhaft ist auch, dass das Polierelement durch die Führung in dem Führungsraum seinen Durchmesser behält und nicht im Laufe der Bearbeitung durch den Bearbeitungsdruck breit gedrückt wird. Dies ist eine sehr wichtige Eigenschaft, da der Durchmesser des Polierelements bei der Berechnung der Bearbeitungsparameter naturgemäß eine sehr wichtige Rolle spielt.
• – Der Durchmesser des Polierelements kann sehr klein gewählt werden, da dessen mechanische Festigkeit praktisch keine Rolle spielt. Das Polierelement wird allseitig von dem Führungsraum umschlossen und kann daher in radialer Richtung nicht ausweichen. In axialer Richtung wirkt auf seine eine Stirnseite der statische Druck der Suspension, während seine andere Stirnseite auf dem Werkstück aufliegt.

The advantages of the method according to the invention compared to the known methods for post-processing (correction processing) and in particular compared to the conventional polishing pencils are as follows:

• - There are ideal lubrication conditions, since the polishing element is flowed around by the suspension and partly also flows through. This leads to very smooth surfaces with extremely low roughness. One also speaks of a gradient-free surface.
• - Due to the longitudinally displaceable, low-friction guidance of the polishing element in the guide space and its hydrostatic pressure on the workpiece surface, an ideal adaptation takes place between the polishing element and the workpiece surface. This leads to extremely good surface qualities.
• - The mechanical contact of the polishing element with the surface of the workpiece results in a substantially higher material removal per unit of time than is the case with methods in which the polishing suspension is only in contact with the surface by means of flow forces or magnetic forces.
• - The polishing element cannot deflect laterally even at high contact pressures, since it is enclosed by the guide space up to a protrusion of 0.1 to 0.2 mm. This means that high machining pressures can be used, resulting in a large amount of material being removed per unit of time. Because of the good lubrication of the polishing element through which the suspension flows, the feared “roughness” does not occur, as is known when working with the conventional polishing pins, if the working pressure is chosen too high.
• - There are also considerable advantages with regard to tool wear. Since the polishing element is guided in the guide space, it can have a large longitudinal extent without this resulting in disadvantages (e.g. mechanical instabilities). If the polishing element wears out on its front side, it is pushed further forward by the pressure of the polishing suspension, so that it always lies against the surface of the workpiece. The machining parameters do not change as long as there is a remaining piece of a few millimeters in length.
• - The polishing element is the only wear part. It can be replaced without having to remove the polishing tool from the processing machine. A calibration of the tool or its precise alignment when replacing the polishing element can therefore be omitted.
• It is also advantageous that the polishing element retains its diameter through the guide in the guide space and is not pressed wide during the processing by the processing pressure. This is a very important one shaft, since the diameter of the polishing element naturally plays a very important role in the calculation of the machining parameters.
• - The diameter of the polishing element can be chosen to be very small, since its mechanical strength is practically irrelevant. The polishing element is enclosed on all sides by the guide space and therefore cannot escape in the radial direction. The axial pressure of the suspension acts on its one end face in the axial direction, while its other end face rests on the workpiece.

From this the possibility arises also to eliminate defects on the workpiece surface, the in their area extension are only very small.

The method and the device for carrying out the method are described below using an example and 1 explained in more detail. The processing of a workpiece (lens) with a precision surface is shown using a polishing machine. This is not shown in detail since it is not the subject of the method proposed here. For better clarification of the subject matter of the invention were in the 1 the proportions of the individual components are shown somewhat distorted.

The polishing tool ( 1 ) has at the top of its housing ( 19 ) via a holding device ( 2 ) by means of it on the clamping device ( 21 ) of the rotationally driven tool spindle ( 3 ) a polishing machine (correction machine) is attached. The rotation of the tool spindle ( 3 ) takes place in the usually sloping A / C axis. The polishing machine is not shown in detail.

The housing ( 19 ) of the polishing tool ( 1 ) has an internal cavity ( 4 ), which extends over its entire length. This inner cavity ( 4 ) expands at the bottom of the case ( 19 ) and thus forms a management room ( 5 ) which the polishing element ( 6 ) records.

In the lead room ( 5 ) is the polishing element ( 6 ) arranged longitudinally displaceable. Its dimension transverse to the longitudinal axis is chosen so that it matches the wall of the guide space ( 5 ) an annular gap ( 7 ) that allows fluid to flow through. In the example shown, the fluid is a polishing suspension ( 20 ).

The tool spindle ( 3 ) has a central hole inside ( 13 ) and is on a swivel head ( 8th ) attached to the polishing machine. This can perform swivel movements (rotary movements) in the B axis. This makes it possible to rotate the tool spindle ( 3 ) relative to the axis of rotation (C-axis) of the workpiece spindle ( 9 ) deliver at an angle. This means that the end face ( 10 ) of the polishing element ( 6 ) is always arranged parallel to the machined surface element of the workpiece surface during the polishing process.

At its upper end is the tool spindle ( 3 ) with a rotating union ( 11 ), which allows a pipe ( 12 ) added polishing suspension ( 20 ) to the central hole ( 13 ) of the rotating tool spindle ( 3 ) forward. The central hole ( 13 ) is connected to the inner cavity ( 4 ) of the polishing tool ( 1 ) so that the polishing suspension ( 20 ) in this cavity ( 4 ) can flow in.

The workpiece to be machined ( 14 ) is in a workpiece holder ( 15 ) clamped of conventional design, which in turn with the workpiece spindle driven in rotation in the C-axis ( 9 ) connected is. The workpiece spindle ( 9 ) is attached to two guide slides (not shown), which allow her translatory movements in the X and Z axes.

The procedure is as follows: First, the polishing tool ( 1 ) by swiveling the tool spindle ( 3 ) swiveled around the B axis into the intended angular position and then by moving the workpiece spindle ( 9 ) in the X and Z axes contact between the workpiece ( 14 ) and the polishing element ( 6 ) of the polishing tool ( 1 ) manufactured. A gap ( 16 ) from 0.1 to 0.2 mm between the end face ( 17 ) of the housing ( 19 ) and the precision surface ( 18 ) complied with. This gap ( 16 ) during the entire machining of the workpiece ( 14 ) with the polishing tool ( 1 ) maintained.

After contact between the polishing element ( 6 ) and the precision surface ( 18 ) the conveyor (not shown) for the polishing suspension ( 20 ) started and the inner cavity ( 4 ) over the central hole ( 13 ), as well as the rotating union ( 11 ) and the pipeline ( 12 ) loaded with suspension. The pressurized polishing suspension ( 20 ) flows through the annular gap ( 7 ) and to a small extent also the polishing element that is permeable to liquids ( 6 ).

The resulting excess pressure depends on the pressure loss in the area of the polishing element ( 6 ). Since the pressure drop not only depends on the geometric conditions there, but also on the volume flow of the polishing suspension ( 20 ), it is regulated so that the pressure in the inner cavity ( 4 ) remains constant. A pressure sensor ( 22 ) available, which generates a pressure-dependent electrical signal that processes in a controller the suspension pump or an actuator in the pipeline ( 12 ) controlled accordingly.

Due to the overpressure in the inner cavity ( 4 ) the polishing element ( 6 ) against the precision surface ( 18 ) pressed. The resulting working pressure between the face ( 10 ) of the polishing element ( 6 ) and the precision surface ( 18 ) is selected so that there is maximum material removal with an optimal surface quality.

Due to the overpressure, the 10 ) constantly polishing suspension ( 20 ) from the annular gap ( 7 ) or from the polishing element ( 6 ) itself pushed out. The emerging polishing suspension ( 20 ) an ideal lubricating effect and an optimal material removal in the work area is generated. In this way, very good surface qualities can be produced with maximum material removal.

Then the rotary movement of the workpiece spindle ( 9 ) with the workpiece ( 14 ) started in the C axis and at the same time the tool spindle ( 3 ) with the polishing tool ( 1 ) set in rotation in the A / C axis. To improve the polishing result, the polishing tool ( 1 ) relative to the precision surface ( 18 ) Oscillatory movements.

This oscillation can be generated by small swiveling movements of the tool spindle ( 3 ) in the B axis or by moving several machine axes simultaneously. Eccentric storage of the polishing tool ( 1 ) on the tool spindle ( 3 ) is possible.

After starting the rotary movements on the tool spindle ( 3 ) and the workpiece spindle ( 9 ) the polishing tool ( 1 ) by moving the workpiece spindle ( 9 ) in the X and Z axes according to a mathematically specified function on the precision surface ( 18 ) guided.

This feed movement and above all the rotation of the workpiece spindle ( 9 ) in the C-axis are controlled in such a way that the calculated dwell times result, which are used to eliminate the errors in the geometry of the precision surface ( 18 ) are required at the individual geometrical locations (elimination of the "plus dimensions").

All of the above-mentioned rotary and translatory machine axes are controlled axes and are controlled by a computer. It is therefore possible to measure the "plus dimensions" of the precision surface ( 18 ), together with the associated coordinates of the geometric locations as well as the process parameters in the machine control, which then calculates the motion sequence of all machine axes and then executes them. The dwell times of the polishing tool ( 1 ) at the different geometric locations on the precision surface ( 18 ) are controlled in such a way that the required material removal to eliminate the "plus dimensions" results.

1

polishing tool

2

holder

3

tool spindle

4

internal cavity

5

guide space

6

polishing

7

annular gap

8th

swivel head

9

Workpiece spindle

10

face

11

Rotary union

12

pipeline

13

drilling

14

workpiece

15

Workpiece holder

16

gap

17

face

18

precision surface

19

casing

20

polishing suspension

21

jig

22

pressure sensor

Claims (20)

Process for reworking precision surfaces on any workpieces made of any materials, the existing dimensional deviations with respect to the desired geometry being determined by measurement technology as "plus dimensions" in a given coordinate system and these "plus dimensions" together with the coordinates of the associated geometric locations electronically saved as a data record and then a targeted material removal takes place at these geometric locations by fine grinding or polishing using a CNC-controlled processing machine and a polishing tool using the data record, characterized in that a rotating polishing tool for fine grinding or polishing ( 1 ) is used, the polishing element ( 6 ) in a with polishing suspension ( 20 ) loaded management room ( 5 ) of a housing ( 19 ) is guided to be longitudinally displaceable, the back of the polishing element ( 6 ) of the pressurized polishing suspension ( 20 ) is applied while the end face ( 10 ) of the polishing element ( 6 ) against the precision surface ( 18 ) of the workpiece ( 14 ), whereby between the end face ( 17 ) of the housing ( 19 ) and the precision surface ( 18 ) of the workpiece ( 14 ) during the entire polishing process A gap ( 16 ) is complied with and that the polishing suspension ( 20 ) through an annular gap ( 7 ) and to a lesser extent also through the polishing element ( 6 ) flows through and into the working area of the polishing element ( 6 ) on the precision surface ( 18 ) of the workpiece ( 14 ) arrives. A method according to claim 1, characterized in that the polishing tool ( 1 ) for processing the precision surface ( 18 ) is attached to a robot arm that holds the polishing tool ( 1 ) according to a given mathematical function on the precision surface ( 18 ) of the workpiece ( 14 ) leads. A method according to claim 1, characterized in that the polishing tool ( 1 ) for processing the precision surface ( 18 ) on a tool spindle ( 3 ) is attached to a CNC-controlled polishing machine (correction machine), the polishing tool rotating in the A / C axis ( 1 ) by controlled and coordinated movement of the X and Z axes (translatory) and the C and B axes (rotary) over the precision surface ( 18 ) of the workpiece ( 14 ) to be led. Method according to one of claims 1 to 3, characterized in that the polishing tool ( 1 ) relative to the precision surface ( 18 ) performs oscillating movements during the fine grinding or polishing process. Method according to one of claims 1 to 4, characterized in that that when using a CNC controlled polishing machine the oscillation movements by generating the B axis. Method according to one of claims 1 to 5, characterized in that the material removal by changing the residence time of the polishing tool ( 1 ) with the polishing element ( 6 ) at the different geometric locations of the precision surface ( 18 ) is controlled. Method according to one of claims 1 to 5, characterized in that the material removal by constant change in the pressure of the polishing suspension ( 20 ) at the different geometric locations of the precision surface ( 18 ) is controlled. Method according to one of claims 1 to 7, characterized in that a workpiece spindle ( 9 ) with the workpiece ( 14 ) and the tool spindle ( 3 ) with the polishing tool ( 1 ) rotate in the same direction. Method according to one of claims 1 to 8, characterized in that the rotationally driven and hollow-bored tool spindle ( 3 ) of the processing machine that the polishing tool ( 1 ) carries, via a rotating union ( 11 ) during the polishing process 20 ) is supplied. Method according to one of claims 1 to 9, characterized in that the pressure of the polishing suspension ( 20 ) during the polishing process using a pressure sensor ( 22 ) is regulated to a certain value or to different values. Apparatus for carrying out the method according to claim 1, consisting of a CNC-controlled processing machine, to the rotationally driven and hollow-drilled tool spindle of which a polishing tool is attached, the processing machine having devices with which the polishing tool can be guided over the surface of the workpiece, characterized that a polishing tool ( 1 ) at the top of its housing ( 19 ) via a holding device ( 2 ) by means of which it is attached to a tool spindle ( 3 ) of the processing machine and that the housing ( 19 ) through an internal cavity ( 4 ) which is located in the lower area of the housing ( 19 ) in a leadership room ( 5 ) expanded and that in the lead room ( 5 ) a polishing element ( 6 ) is longitudinally displaceable and that a bore ( 13 ) in the tool spindle ( 3 ) with the inner cavity ( 4 ) and a pressurized polishing suspension ( 20 ) towards the polishing tool ( 1 ) is flowed through. Device according to claim 11, characterized in that an annular gap ( 7 ) is present, which has a flow with polishing suspension ( 20 ) enables. Device according to claim 11 or 12, characterized in that the polishing element ( 6 ) has an elongated shape. Device according to claim 11 or 13, characterized in that the guide space ( 5 ) and the polishing element ( 6 ) have a round cross-section. Device according to claim 11 or 13, characterized in that the guide space ( 5 ) and the polishing element ( 6 ) have a polygon as a cross section. Device according to one of claims 11 to 15, characterized in that the polishing element ( 6 ) consists of a polishing felt. Device according to one of claims 11 to 15, characterized in that the polishing element ( 6 ) consists of polyurethane. Device according to one of claims 11 to 17, characterized in that the bore ( 13 ) the tool spindle ( 3 ) with a rotating union ( 11 ) is connected. Device according to one of claims 11 to 18, characterized in that in the flow path of the polishing suspension ( 20 ) a pressure sensor ( 22 ) is available. Device according to one of claims 11 to 19, characterized in that when a polishing machine is used as the processing machine, a workpiece ( 14 ) with a workpiece holder ( 15 ) connected to a workpiece spindle ( 9 ) which can perform controlled rotational movements in the C-axis and controlled translational movements in the X- and Z-axes, while the polishing tool ( 1 ) with a tool spindle rotatably driven in the A / C axis ( 3 ) connected by means of a swivel head ( 8th ) Can perform pivoting movements around the B axis.