DE19846260A1 - Device for grinding and polishing optical lenses connects to a cast metal machine frame with feeder channels for heating and cooling agents while operating slides for grinding tools - Google Patents

Abstract

A Z-slide (13) for carrying a grinding tool (37) in a grinding and polishing machine for optical lenses (9) is connected to a cast metal machine frame (1) by a connecting element (10), containing feeder channels (11) for heating and cooling agents. Driving mechanisms with and without play or with low elastic deformation are used to move X-(2) and Z-slides fitted in the upper and lower parts. One of two spindles is connected to a swinghead (4).

Description

The aim of the present invention is to improve the devices for processing optical To design lenses (grinding and polishing machines) so that there are cost advantages their manufacture and the accuracy of the generated Lenses can be increased. This objective relates in particular to devices for producing large diameter optical lenses. The fiction appropriate device can also be used in the manufacture of smaller lenses with insert part.

According to the prior art, optical lenses are made by several grinding processes gears and at least one polishing process. The corresponding grinding and polishing machines have a machine frame made of metal and min at least a workpiece spindle and a tool spindle, their geometrical Axes lie in the same vertical plane (spindle plane), which is perpendicular to the operator's line of sight. One of these spindles is arranged vertically net while the other spindle opposite the vertical axis and in the Spindle plane can be inclined so that the axes of the two spindles one  can include adjustable angle. This inclination of one of the two spindles is a prerequisite for the usual grinding and polishing processes, in particular in the manufacture of spherical lenses. The usual pots are used tools for grinding or molds for polishing.

So that one of the two spindles can be inclined, it is attached to a so-called called swivel head attached, which can be rotated about the B axis, which intersects the geometric spindle axis and is perpendicular to the spindle plane. The swivel head is usually located in the upper part of the machine, it can but can also be arranged below.

To align the two spindles in a horizontal as well as in a vertical direction other, the grinding and polishing machines also have the latest technology about linear feed systems called X-slide and Z-slide and to which the spindles are attached. With one of the two spindles the swivel head interposed. The X-slide allows linear movements in X-directions (horizontal movements in the spindle plane), during the Z slide linear movements in the Z direction (vertical movements in the Spindle level).

The arrangement or assignment of swivel head, X and Z slide and the Spindles on the machines and each other are different. They are construct tions become known in which the upper spindle with the swivel head and this is connected to the X-slide, while the lower spindle with the Z slide is connected. In other constructions, the upper spindle is with the Connected swivel head and stored directly on the machine frame, weh rend the lower spindle is attached to the Z-slide, which in turn with the X-slide communicates.  

Which of the possible combinations of swivel head, X and Z slide or Spindles chosen depends on the specific use of the machine and the resulting requirements. In any case, it must be possible be the workpiece and the tool spindle relative to each other in X and To adjust the Z direction and also to incline the spindle axes against each other.

This applies to both lens grinding machines and lens polishing machines.

The known machines for producing optical lenses have one relatively high level of development, but still have some disadvantages that be especially when large diameter lenses and to be manufactured with high precision.

These disadvantages in prior art lens manufacturing machines are as follows:

• 1. Conventional grinding and polishing machines have a machine frame made of metal (e.g. gray cast iron). While the thermal expansion of the machine frame can still be accepted in many cases with smaller machines, there are quality deviations with large machines and / or the manufacture of high-precision lenses because the metal frame expands and heats up unevenly when heated (environmental influences, heat loss from the drives) the machine geometry thereby changed in an undesirable manner. The large coefficient of thermal expansion and the good thermal conductivity of the metals make it practically impossible to remedy this without changing the material for the machine frame. Also the air conditioning of the production rooms is only a partial solution to the thermal expansion problem, because the good thermal conductivity of the metals means that the heat loss generated in the machine itself flows to components where heating is undesirable, since their thermal expansion then leads to the problems mentioned .
  Special connecting elements which serve to dissipate this heat and are arranged between the components in which heat loss is generated and the machine frame are not known. Connecting elements with which specific thermal expansions are generated by different heating in order to compensate for deformations on the machine frame have just not become known.
  Cooling devices on the machine frame and other components of the machine, to avoid undesired thermal expansion, have not previously been used. In the optical industry in particular, there are no machines in which cooling elements have been integrated into the machine frame.
  For manufacturing reasons and because of the high strength of the metals, the machine frames that are common today are relatively thin-walled and of low mass. While this has certain advantages, e.g. B. during transport, but also leads to a low heat storage capacity. This combined with the good heat conduction of the metals also requires that the temperature of the machine frame made of metal changes relatively quickly when heat is supplied (environment, heat loss), which in turn leads to the undesired thermal expansions mentioned.
• 2. A disadvantage of machine frames made of metal are also vibrations which are excited by the spindles and can move practically undamped in the machine frame, since metals, and here in particular also gray cast iron or steel, have only poor damping properties. However, machine vibrations are extremely harmful in the manufacture of high-precision components such as lenses.
  The elastic properties of the relatively thin-walled machine frames made of metal also have an unfavorable effect. So z. B. machine frames made of gray cast iron or steel to elastic deformations under the action of loading workers. This changes the geometry of the machine, which also has an adverse effect on the accuracy of the lenses produced.
• 3. There is a known machine for the production of lenses Another disadvantage is that the drives for the X and Z slides are rotating Electric motors are used that have appropriate gears and threads have spindles and ensure the linear feed movement. Although these Drives have reached a high technical level today, they are for the Manufacture of high-precision lenses too imprecise. This is necessary on the wise existing play and / or the elasticity between the moving construction parts of the gearbox and the threaded spindles. This game and / or the elasticities in the conventional drives and guidance minimized, but not avoided entirely.
• 4. Conventional lens making machines have Precise For reasons of economy and cost, usually not via linear Y feed systems for one of the two spindles with which these in the Y direction, d. h: perpendicular to Spindle level, could be adjusted. However, this would be desirable since today positioning accuracy can be achieved with special feed systems those that are significantly larger than the feasible production and assembly accuracies in precision engineering. This means that an exact Align the upper to the lower spindle, d. H. to the spindle plane, with a special Y feed system can be achieved sooner than by precise loading work and assemble the components involved.  
• 5. A particular problem with the usual machines for producing optical Lenses consist in the precise mounting of the swivel head. In particular if, as usual, it is supported on one side and with a linear feed system is connected, there is often an inadmissibly large game and / or too casually large elasticities due to the addition of the individual deformations. This does is particularly noticeable when the swivel head, accordingly the prior art, is arranged at the top of the machine, since then the weight forces of the machine components acting at rest in the idle state Play and "push out" the elastic deformations down while when operating the machine, the upward reaction force between Tool and lens up the game and the elastic deformations "push out". The game and the elastic deformations involved Components therefore act between the idle state and the operating state of the Machine fully off. In addition, if the swivel is mounted on one side head the game and the elastic deformations into one slight inclination of the upper spindle with the Swivel head is connected.

In the device for processing optical lenses according to the invention The disadvantages mentioned in points 1-5 are avoided as follows:

To 1.

To avoid the thermal expansion problems mentioned here, the Ma Rail frame made of mineral casting or grown stone instead of metal blocks made.

The mineral casting consists of suitable minerals in specified grains gene and is plastic-bound. However, they are also mineral binders intended. Instead of minerals, others can also be used advantageously  Fabrics are used, such as. B. broken quartz glass in different Fractions or quartz sand, which have a particularly low thermal expansion point. In connection with this patent application, however, is always from Mineral casting is spoken, regardless of the composition.

Machine frames made of mineral casting are characterized by low heat conduction and thermal expansion and also have a due to their mass good heat storage capacity, since they are used for reasons of strength large wall thicknesses or massive, d. H. who made without internal cavities the. Because of the low heat conduction and thermal expansion and above all because of the large heat storage capacity experienced machine frames Mineral casting therefore only a small, un harmful deformation. The heat loss generated in the machine itself can essentially due to the low heat conduction locations are limited. In this context, too, the big one affects Heat storage capacity of the machine frames made of mineral casting cheap.

It can also be advantageous to naturally wax the machine frame stone blocks that are particularly tension-free and mecha nically stable. The connection of the individual blocks from which the Machine frame then can be either by gluing and / or Ver dowels are manufactured. Tie rods can also advantageously be inserted be set. Cooling tubes can also be provided in bores with which the machine frame can be kept at a constant temperature. The connection between the machine elements made of metal and the Machine frame made of stone can e.g. B. by dowels or tie rods be put. In the rest of the text, only mineral casting is used Chen, the same applies analogously to machine frames from naturally grown stone blocks.  

A further embodiment of the device according to the invention provides between between the components in which heat loss is generated and the others Components such as B. machine frame and other structural elements, heat lower order. This can e.g. B. fasteners with inner Be flow channels through which cooling water or another cooling medium is passed through. These connecting elements are advantageous e.g. B. made of gray cast iron and cooled with water. However, it also comes other materials in question. The heat loss in the one component is created, then gets into the connecting element and is from the cooling water drained without the other components being heated. To everyone Heating or cooling of these other components (machine frames, To avoid structural elements), their temperature can be measured and the average cooling water temperature can be adjusted to this value. An un Desired heat flow to the machine frame or other structural elements then no longer takes place.

There is also provision for the machine frame to be insulated with heat provided (e.g. foaming with PU foam). Temperature changes the environment, the temperature and thus the thermal expansion of the No longer significantly affect the machine frame. In the case of heat iso However, it must be ensured that all sources of Heat loss and the machine frame cooled connecting elements be ordered and the coolant temperature is regulated. If so too nor the coolant for the grinding process or the polishing suspension in their Temperature can be regulated, so air conditioning of the work largely be dispensed with.

Since components such. B. machine frames, from mineral casting in a casting process be produced using ambient temperatures,  it is easily possible to insert cooling or heating pipes in the mold and in pour the components. These pipes are located after the Casting material inside the component, e.g. B. the machine frame, and he possible to temper this by adding a cooling medium through the pipes is passed through. A machine frame manufactured in this way can also be used be kept at a constant temperature regardless of the order ambient temperature or the heat loss generated. It is particularly advantageous it to combine some of the aforementioned features of the invention to the Keep the machine frame and other components at a constant temperature and thus to avoid undesirable warpage due to thermal expansion.

To correct the finest inaccuracies, e.g. B. in the axial position (angularity) of lower and upper machine spindles to each other, the above Connecting elements also acted upon with a cooling or heating medium be that the resulting different thermal expansions in the connecting element to the desired corrections in the machine lead geometry. For this purpose, the connecting element z. B. above and below via separate flow channels that are mixed with media of different temperatures temperature can be applied. The targeted warmth expansions become quasi a linear feed in the desired sense used. These corrections can then be carried out particularly effectively if there are deviations from the ideal geometry through measurements (mechanical / optical) are detected and the temperature of the media ent is regulated accordingly.

The optimal corrections regarding the relative position of tool and Workpiece to each other are achieved if additional measuring probes for Ab scan the grinding lip and query the workpiece surfaces finally edge are used and their measurement data in the sense of the he  generating geometry can be included. This allows the desired Achieve machining accuracy. These probe designs are here not shown in detail since they are state of the art (see Akz 197 51 750.1-14 - Method and device for producing optical lenses with min at least three grinding tools and a swivel head at the bottom).

The thermal expansions mentioned for the correction of machine inaccurate speeds can also be generated using electrical heating. About who the electrical heating elements in corresponding connecting elements or di installed directly in the affected machine parts and pre- switched control heated. These connections are advantageous elements or parts thereof made of materials with high thermal expansion provides such. B. made of aluminum or copper, which is electrically heated and corresponds be isolated accordingly. As a reference variable for the regulation, the aforementioned geometry data can be measured. To minimize costs in Connection with electricity consumption is provided, the heated construction isolate parts thermally.

One way to quickly correct the smallest deviations in the Machine geometry also consists of that in the flow channels of the Connection elements circulating cooling or heating medium by means of a high bring the pressure pump to an increased pressure. As a result of the mecha The resulting stresses can be used for the desired Corrections can be used.

The inventive concept, thermal expansions and / or expansions as a result of To use compressive stresses for corrections in the machine geometry not limited to the connecting elements mentioned, but can be any machine part can be used.  

Preferably, the connecting elements mentioned in the invention according device between the Z-slide of the upper spindle and the Machine frame arranged and by targeted loading with a Cooling or heating medium generates thermal expansions with which the axis of the Spindle can be aligned exactly vertically. It is then axially parallel to the lower spindle. However, other applications are also envisaged.

The connecting elements are also used for geometric reasons the machine frame and the other components switched. The verb The element then has an area that is appropriate for the machine frame fits, while a second surface is designed so that it opens up to the taking components fits. Components can be different Dimensions can be combined with the machine frame without this must be changed.

To 2.

The known problems with mechanical vibrations are in the machine frames according to the invention made of mineral casting or ge growing stone blocks because of the larger mass avoided. The generated in the device according to the invention excitation energies for mechanical vibrations are not sufficient to Large mass of the machine frame made of the mineral mate mentioned vibrate rialien. They also have mineral casting materials due to their composition from different materials much better damping behavior than is the case with metals.

Elastic deformations also occur in machine frames from the ge mentioned mineral materials only to a very small extent. This depends  with the large cross sections of the machine frames of this type and also with the favorable elongation behavior of the mineral materials.

The geometry of the machine frames made of mineral materials remains largely unchanged with thermal, dynamic and static loads changes get precise. This is an essential requirement for the manufacturer provide more precise optical lenses with the device according to the invention.

To 3.

The accuracy problems when positioning the X and Z slides in the Connection with the game and the elastic deformations in the ge driven and the threaded spindles of the rotating electric motors can largely avoid according to the invention, if instead linear motors for the drive of the two slides can be used. Generate linear motors translatory movements and can therefore be done without any intermediate gear can be used directly to drive the X and Z slides. Inaccurate due to play and elastic deformations in mechanical components ten are largely eliminated when using the linear motors.

In German patent application 196 53 233.7-14 and in European Patent application EP 0849 038-A2 already uses linear motors in connection with high-speed lathes for Manufacture of optically effective surfaces mentioned. With these two called However, the ten registrations are not machines for manufacturing spherical lenses, in which the lens rotates without any adjustment movement, while the tool from the linear motors in the radial and axial directions (related to the axis of rotation of the lens) is moved during processing. The In this case, both linear motors form a feed unit, the linear one Allows movement in two mutually perpendicular directions.  

In contrast, the device according to the invention X-slide and the Z-slide, each carrying at least one spindle (in one Case with interposition of the swivel head) independently moved by a linear motor, with the X-slide during machining usually does not perform a feed movement. In this case, they are driving two linear motors on two separate carriages that are not are connected.

However, versions with rotating position drives are also featured see, with special design measures to minimize the Game and the elastic deformations is achieved. One of these construct tive measures consist of using two drives for each slide are controlled by the CNC control so that they ar against each other work, d. H. the associated sled in opposite directions want to move. By tightening the two drives, the "Pushed out" existing game. The same applies to the elastic Deformations so that the slides can be moved practically without play. If the sled is to be at rest, the rotating electric motors are positioned below tension locked, but if the feed carriage is to be moved, then the feed force of one of the two drives increases until the movement begins. The second drive is then moved backwards against its force.

To 4.

For precise alignment of the vertical geometric axis of one of the two Spindles (upper or lower spindle) on the Vorrich invention device an adjustment device in the Y direction, d. H. perpendicular to the spindle plane (= perpendicular to the X and Z axes) (Y feed system). With this The Y feed system can ver the connected spindle in the fine area drive that their geometric axis lies exactly in the plane of the spindle,  specified by the other spindle. This is with accuracy possible, which is due to mechanical processing or alignment processes can not be achieved in the assembly of the device according to the invention.

Preferably, the special Y feed system is designed so that the cylindrical housing of the corresponding spindle with an eccentric Boh tion to accommodate the spindle and rotate about a vertical axis is stored in bar. The geometric central axis of the outer cylindrical um beginning of the housing on which it is rotatably mounted and the Rotati on axis of the spindle are thus against each other by the mentioned eccentricity postponed. If the housing is then powered by an auxiliary drive for some win is rotated, the spindle leads, due to the eccentricity of its Location hole in the housing, an arcuate pivoting movement made up of movements in the X and Y directions can think. The movement in the Y direction becomes the adjustment mentioned the geometrical spindle axis in the spindle plane, while the Movement in the X direction is compensated for by moving the X carriage. By choosing a suitable eccentricity and also its rotational position to Machine frame can make the finest movements in the Y direction with the spindle be performed. In contrast to other known adjustment drives in the fine range (e.g. with piezo crystal) are drives with eccentrics less limited in terms of power delivery and possible travel. Due to the very precise alignment of the upper and lower spindle in the ge lenses with the highest precision can be manufactured on the same spindle plane.

However, other feed systems are also provided for the correction movement in the Y direction. Such feed systems have to yet be able to respond to the reaction forces during lens processing  increase so there are no shifts and hence inaccuracies the workpieces.

To 5.

To the problems with the game and the elastic deformations in the one side storage of the usually arranged swivel head and the corresponding deformations in the associated feed system to avoid the swivel head in the invention arranged below d. H. the spindle attached to it shows with theirs Tools up. In addition, the swivel head is supported on both sides, which gives additional stability.

Because they hit the swivel head and its linearly movable carriage weight forces act vertically downwards, and that of the Bear reaction in the direction of the lens the play in the bearings, guides and drives does not more out. The same applies to the elastic deformations. All deformations are already "pushed out" by the weight forces, so that when the reaction forces acting in the same direction occur, no movement conditions in the fine range due to the play or the elastic deformations more can take place. Due to the double-sided mounting of the swivel head is also the load distribution of the reaction forces and the weight forces on the both camps the same, so that when the reaction forces occur, not uncommon Desired tilting moments arise, as is the case with one-sided storage is. Such tilting moments can also lead to undesired movements due to bearing play and the elastic deformations.

The swivel head is preferably pivotally connected to the X-slide the one that then also in the lower part of the device according to the invention  is attached, since there are structural advantages with this arrangement. So z. B. the X-slide on two relatively far apart line Guides are supported, regarding weight and machining tion forces are arranged symmetrically. A tipping moment caused by these forces is avoided, which increases the machining accuracy. The Zu too Accessibility of the tools (machining tool and clamping tool for the lens) remains fully intact. In addition, the one below offers X-slide is a great way to make the swivel head double and symmetrical to store for the central introduction of force, with the advantages mentioned above.

In the above-mentioned version with an X slide and swivel at the bottom the Z-carriage becomes head in the upper part of the device according to the invention attached and carries the second spindle. Here is also the Y feed system arranged with which the upper spindle can be adjusted in the Y direction.

A further embodiment of the device according to the invention is also provided a tool magazine and / or a workpiece magazine with storage facilities for Arrange several tools or workpieces in the lower machine area. These magazines are advantageously designed as circular disks, who carry the storage facilities mentioned in their scope. By The storage facilities can also be CNC-controlled by rotating the magazine disks the parts located in the respective intended removal position become. In a particularly advantageous variant, the magazines on the X-carriage attached so that it moves through the same with its removal position tion can be positioned exactly under the upper spindle, which can then be The tool or lens can be moved in the Z direction. The The X-carriage is then moved back so far until the one with it over the Swivel head connected lower spindle is aligned with the upper spindle and the process can begin.  

It is also provided that the axis of rotation of one of the two spindles or both spin to be executed as a C-axis. In this case the spindle in question can be from their drives are not only set in continuous rotation, but their rotation movement takes place in a controlled manner with regard to angular speed and bevel angle d. H. the angular velocity can be varied depending on the bevel angle that, to a standstill. This makes it possible to pre-process the lenses increase that lead to surfaces that are not arranged rotationally symmetrically. So z. B. bevelled bevels on the circumference of the lenses that are not rotationally symmetrical and for the rotation-proof fixing of the lenses in the serve optical systems in which they are installed after their completion.

Regardless of the design of the spindles as a C axis, it is also possible with to install the device according to the invention with rotationally symmetrical bevels. These can be cut through the center of the lens and parallel to the optical Represent axis as a straight line or also have a curvature, which is why be special software is used. So z. B. made spherical bevels to whom the lenses will later rest in the optical system and with regard to the correct ones Angular position of their optical axis can be aligned more easily.

It is also possible to center the lenses on their outer circumference d. H. grind the circumference so that it takes the exact shape of a circular cylinder, whose geometric axis coincides with the optical axis of the lens. Such centerings are e.g. B. advantageous when clamping the lenses in the corre spond tools for grinding or polishing the lenses.

The inventive device for processing optical lenses is preferred wise equipped with a CNC control that controls the movements of all axes controls or regulates. These are the X, Y and Z axes which all three are perpendicular to each other the B-axis with which the swivel head is at a certain angle  range can be rotated, the axis of rotation running parallel to the Y axis, and at least one C-axis to monitor the rotary movement at least a spindle. Also the rotating movement of the magazine disc (s) and other auxiliary functions are controlled and checked by the CNC control. The software the CNC control is designed so that collisions during traversing different machine parts can be safely avoided.

The device according to the invention for processing optical lenses is to be explained in more detail below using two examples and FIGS. 1 to 3. However, there are also plans other than the versions shown here and in particular it is also provided to apply the inventive features mentioned in claim 1 independently of one another. For linguistic simplification, the X and Z slides, the Y feed system, the swivel head and the spindles are referred to as active components in the claims.

Example 1 is the embodiment of the device according to the invention as a grinding machine for larger diameter lenses with a tool spindle arranged at the top and a workpiece spindle arranged at the bottom. This includes Figs. 1 and 2.

Example 2 is the embodiment of the device according to the invention as a polishing machine for lenses of larger diameter with a workpiece spindle arranged at the top and a tool spindle arranged at the bottom. This includes Fig. 3.

example 1

In example 1, the device according to the invention for processing optical lenses is designed as a grinding machine. The upper spindle is in this case designed as a tool spindle ( 18 ), while the lower spindle serves as a workpiece spindle ( 7 ).

Fig. 1 shows a side view of the grinding machine,

Fig. 2 shows a top view of the grinding machine with a horizontal section through the upper part corresponding to section AA in Fig. 1.

In the side view of the grinding machine according to Fig. 1 you can see all important movement systems in connection with the tool spindle ( 18 ) and the workpiece spindle ( 7 ). The assemblies and machine elements are attached to a machine frame ( 1 ), which is made of mineral casting and has large wall thicknesses. The machine frame ( 1 ) has an L-shape in the side view with some recesses, for. B: for receiving the X-slide ( 2 ), which is mounted so that it can be moved vertically to the image plane using two linear guides ( 3 ). The drive for moving the X-slide ( 2 ) was not drawn for the sake of clarity. The swivel head ( 4 ) is connected to the X-slide ( 2 ) so that it can rotate about the B-axis ( 5 ). The geared motor ( 6 ) is used to drive the rotary movement of the swivel head ( 4 ). The swivel head ( 4 ) carries the workpiece spindle ( 7 ) located at the bottom, at the upper end of which the workpiece holder ( 8 ) is attached, which carries the lens ( 9 ).

At the upper part of the machine frame (1), the connecting element (10) is connected to the flow channels (11) attached to the the guides (12) bears for the Z-carriage (13). By supplying heating or cooling media to the flow channels ( 11 ) of the connecting element ( 10 ), thermal expansion can be generated in this, which can be used to correct the vertical alignment of the tool spindle ( 18 ). These correction movements take place in the drawing plane as right / left inclinations, with which the geometric axis of the tool spindle ( 18 ) can be set exactly vertically. Such corrections are not necessary perpendicular to the plane of the drawing, since in this plane (spindle plane) the position of the spindles relative to one another can be corrected by tilting the swivel head ( 4 ). The same effect can be generated by different pressurization of the media mentioned in the flow channels ( 11 ). In this case, the elastic expansion of the connecting element ( 10 ) under the action of the pressure load is used for the desired corrections.

The connecting element ( 10 ) can be acted upon in its flow channels ( 11 ) with a cooling medium in such a way that the heat generated by the tool spindle ( 18 ) is dissipated via the connecting element ( 10 ) and the machine frame ( 1 ) does not heat up. This cooling medium, but also the above-mentioned heating medium, can be transported in a circuit with a pump, with corresponding coolers or heaters being switched on in this circuit (not drawn).

What is preferably used for cooling or heating the connecting element ( 10 ). But there are also other liquids, such as. B. heat carrier oil. If work is carried out with increased pressure, the said circuit can be put under increased pressure overall, the combination of thermal expansion and pressure expansion also being provided. The flow channels ( 11 ) at the top and bottom of the connecting element ( 10 ) can be connected to separate flow circuits.

In places where the attachment of a connecting element ( 10 ) is inappropriate, the heat generated by the drives can be dissipated by means of cooling pipes ( 21 ) cast into the machine frame ( 1 ). These cooling tubes ( 21 ) are inserted into the casting mold during the manufacturing process of the machine frame ( 1 ) and closed during the casting process by the cold cast mineral casting. Through these cooling tubes ( 21 ), a cooling medium, for. B. water, are passed through in a closed circuit. This cooling water absorbs the heat and removes it via an interposed cooler (not shown).

The Z-slide ( 13 ) is guided vertically in the guides ( 12 ), which in turn are attached to the connecting element ( 10 ). The drive device for the vertical movement (Z-direction) of the Z-carriage ( 13 ) was executed in the example shown as a spin del drive with an electric motor ( 14 ) and threaded spindle ( 15 ), care being taken to ensure zero backlash and low elastic deformations. However, it can also be designed as a linear motor. The threaded spindle ( 15 ) of the spindle drive for the vertical movements of the Z-carriage ( 13 ) is connected by means of the two toothed wheels ( 17 ) and the toothed belt ( 16 ) to an electric motor ( 14 ). This is controlled by the CNC control and drives the threaded spindle ( 15 ).

The spindle housing ( 19 ), which carries the tool spindle ( 18 ), which is fastened eccentrically in the spindle housing ( 19 ), is rotatably mounted on the Z-slide ( 13 ). The electric motor ( 20 ) is used to drive the tool spindle ( 18 ). The stated eccentricity exists between the axis of rotation of the tool spindle ( 18 ) and the geometric central axis of the cylindrical, outer circumference of the spindle housing ( 19 ). By rotating the spindle housing (19) the tool spindle (18) leads as a result of their eccentric mounting in the spindle housing (19) the required correction movements in the Y-direction. On the underside of the tool spindle ( 18 ) is designed as a pot tool grinding tool ( 37 ) be fastened, with which the lens ( 9 ) can be machined.

Fig. 2 shows a top view with a horizontal section through the upper part of the grinding machine. On the machine frame ( 1 ), the connecting element ( 10 ) is fixed, in which the flow channels ( 11 ) are located, to which the cooling / heating medium is supplied via the supply connection ( 22 ). From the line connection ( 23 ), the heating / cooling medium leaves the connecting element ( 10 ) again. The guides ( 12 ) on which the Z-slide ( 13 ) can be moved up and down vertically (ie perpendicular to the plane of the drawing) are fastened to the connecting element ( 10 ). The threaded spindle ( 15 ) is used to drive this movement.

For the correction movement in the Y direction, an electric motor ( 24 ) is used which drives the spindle housing ( 19 ) via the toothed wheel ( 25 ), the toothed belt ( 26 ) and the toothing ( 27 ). When the spindle housing ( 19 ) rotates, the tool spindle ( 18 ), due to its eccentric bearing in it, performs the desired correction movement in the Y direction. Unwanted movements in the X direction, which also occur here, are compensated for by moving the X carriage.

The X-slide ( 2 ) carries the swivel head ( 4 ), which can be rotated about the B-axis ( 5 ), with the workpiece spindle ( 7 ), which in the drawing is covered by the Z-slide ( 13 ). However, one can see the workpiece holder ( 8 ) with the lens ( 9 ) fixed therein and also a part of the grinding tool ( 37 ).

The tool magazine ( 28 ) with the storage devices ( 29 ) for several tools is also connected to the X-slide ( 2 ). By rotating the tool magazine ( 28 ), each tool stored in the storage devices ( 29 ) can be brought into the removal position ( 30 ). By moving the X-slide ( 2 ), this removal position ( 30 ) and thus the corresponding tool can then be positioned exactly under the tool spindle ( 18 ). By vertically moving the Z-slide ( 13 ) with the tool spindle ( 18 ), the latter can be brought into contact with the tool and removed from the removal position ( 30 ) of the tool magazine ( 28 ). The tool is thus available for the machining processes in the grinding machine. Alternatively or additionally, a workpiece magazine in a similar arrangement could also be attached to the X-slide ( 2 ).

Example 2

In example 2, the device according to the invention for processing optical lenses is designed as a polishing machine. In this case, the upper spindle is designed as a work spindle ( 31 ), while the lower spindle serves as a tool spindle ( 32 ).

Fig. 3 shows a side view of the polishing machine.

A workpiece holder ( 33 ), which receives the lens ( 34 ) to be polished, is attached to the workpiece spindle ( 31 ) arranged at the top. The holding forces for securely fixing the lens ( 34 ) in the workpiece holder ( 33 ) during transport from the tool magazine ( 28 ) to the working position are applied in part by vacuum, which is created via a central bore ( 35 ), which can be found both in the workpiece spindle ( 31 ) and in the workpiece holder ( 33 ). Compressed air can also be applied to the lens ( 34 ) via the same bores during processing, with the result that the required working pressure is applied between the lens ( 34 ) and the polishing tool ( 36 ). In the case of large lenses ( 34 ), the weight of the lens ( 34 ) also acts in the same direction in the chosen arrangement of the spindles and is taken into account when pressure is applied.

The tool spindle ( 32 ) arranged at the bottom bears the polishing tool ( 36 ) formed as a forming tool and is connected as described above to the swivel head ( 4 ), which is also arranged at the bottom. The assignment of the spindles described here has the advantage that the lens ( 34 ), with its own weight, applies part of the required working pressure in the polishing tool ( 36 ). Because of the uniformity of the weight forces, this leads to a higher precision of the lenses he produces ( 34 ).

Otherwise, the basic structure of the polishing machine corresponds to that of Grinding machine. In this respect, what has been said for example 1 applies accordingly.  

Reference list

1

Machine frame (

1

)

2nd

X-slide (

2nd

)

3rd

Linear guides (

3rd

)

4th

Swivel head (

4th

)

5

B axis (

5

)

6

Gear motor (

6

)

7

Workpiece spindle (

7

)

8th

Workpiece holder (

8th

)

9

Lens (

9

)

10th

Connecting element (

10th

)

11

Flow channels (

11

)

12th

Guides (

12th

)

13

Z slide (

13

)

14

Electric motor (

14

)

15

Threaded spindle (

15

)

16

Timing belt (

16

)

17th

Gears (

17th

)

18th

Tool spindle (

18th

)

19th

Spindle housing (

19th

)

20th

Electric motor (

20th

)

21

Cooling pipes (

21

)

22

Supply connection (

22

)

23

Discharge connection (

23

)

24th

Electric motor (

24th

)

25th

Gear (

25th

)

26

Timing belt (

26

)

27

Gearing (

27

)

28

Tool magazine (

28

)

29

Storage facilities (

29

)

30th

Removal position (

30th

)

31

Workpiece spindle (

31

)

32

Tool spindle (

32

)

33

Workpiece holder (

33

)

34

Lens (

34

)

35

Drilling (

35

)

36

Polishing tool (

36

)

37

Grinding tool (

37

)

Claims (30)

1. Device for processing optical lenses by grinding and polishing, characterized in that it has a CNC control and the machine frame ( 1 ) is made of mineral casting or naturally grown stone blocks and carries at least one connecting element ( 10 ) with which Heat can be dissipated and targeted thermal expansion can be generated and the device has at least one X-slide ( 2 ) and a Z-slide ( 13 ) as well as a swivel head ( 4 ), with drives for moving these active components without or with little Clearance and / or slight elastic deformation are used and also at least two spindles are present, one of which is arranged in the upper part and the other in the lower part of the device, one of the two spindles being connected to the swivel head ( 4 ) and In addition, one of the spindles has a Y feed system and facilities are available with which the internal generated heat loss can be dissipated and also a tool magazine ( 28 ) and / or a workpiece magazine is available. 2. Apparatus according to claim 1, characterized in that it is designed as a grinding machine, with an overhead Z-slide ( 13 ) and associated tool spindle ( 18 ), which carries the grinding tool ( 37 ), and an underlying X-slide ( 2nd ) and associated swivel head ( 4 ), where the swivel head ( 4 ) receives the workpiece spindle ( 7 ), which carries the workpiece holder ( 8 ) with the lens ( 9 ). 3. Apparatus according to claim 1, characterized in that it is designed as Po liermaschine, with overhead Z-slide ( 13 ) and thus a related workpiece spindle ( 31 ) which carries the workpiece holder ( 33 ) with the lens ( 9 ) and X-slide ( 2 ) and swivel head ( 4 ) connected below, the swivel head ( 4 ) accommodating the tool spindle ( 32 ) which carries the polishing tool ( 36 ). 4. Apparatus according to claim 1 to 3, characterized in that a or several spindles are designed as a C axis, the rotation of which CNC control with regard to angular velocity and phase angle becomes. 5. Apparatus according to claim 1 to 4, characterized in that a connecting element ( 10 ) is arranged between the machine frame ( 1 ) and the Z-slide ( 13 ), which the guides ( 12 ) for the Z-slide ( 13 ) carries and also receives the electric motor ( 14 ) which drives the threaded spindle ( 15 ) via the gears ( 17 ) and the toothed belt ( 16 ). 6. The device according to claim 1 to 5, characterized in that the connecting element ( 10 ) has connection surfaces or parts which are adapted to the geometry of the machine frame ( 1 ) and do not change, ie are fixed, and also via connection surfaces or -Has parts that can be designed as desired and thus can be adapted to the intended add-on parts. 7. The device according to claim 1 to 6, characterized in that the connecting element ( 10 ) or other components have internal flow channels ( 11 ) which are connected to devices by means of which they acted on with a heating and / or cooling medium can be. 8. The device according to claim 1 to 7, characterized in that in the connecting element ( 10 ) or in other components several mutually un dependent flow channels ( 11 ) are present, which form separate flow systems with the connected heating and / or cooling devices that can flow through media of the same or different temperature. 9. The device according to claim 1 to 8, characterized in that measuring and Control devices are available with which the temperature of the heating and / or Cooling medium depending on the component temperature or Component geometry can be regulated. 10. The device according to claim 1 to 9, characterized in that a directions are available with which the heating and / or cooling medium in the flow channels ( 11 ) can be brought to increased pressure. 11. The device according to claim 1 to 10, characterized in that the machine frame ( 1 ) has cooling tubes ( 21 ). 12. The apparatus of claim 1 to 11, characterized in that the machine frame ( 1 ) and / or other machine parts have a thermal insulation tion. 13. The apparatus according to claim 1 to 12, characterized in that the connecting elements ( 10 ) and / or other machine parts for generating targeted thermal expansions are provided with electrical heating devices. 14. The apparatus according to claim 1 to 13, characterized in that measuring and Control devices are available with which the performance of the electri heating devices depending on the desired machines geometry can be regulated. 15. The apparatus according to claim 1 to 14, characterized in that the connecting elements ( 10 ) made of materials with large thermal expansion, z. B. are made of aluminum or copper and are electrically heated or contain components made of such materials that are electrically heated and have thermal insulation. 16. The apparatus according to claim 1 to 15, characterized in that to form the Y feed system, the workpiece spindle ( 31 ) is mounted eccentrically in the spindle housing ( 19 ), which in turn is rotatably connected to the Z-slide ( 13 ), wherein as Drive is an electric motor ( 24 ) which transmits its kinetic energy via the gear ( 25 ), the toothing ( 27 ) and the toothed belt ( 26 ) to the spindle housing ( 19 ). 17. The apparatus according to claim 1 to 16, characterized in that the X-slide ( 2 ) is supported on both sides on linear guides ( 3 ) which allow movements in the X-directions. 18. The apparatus according to claim 1 to 17, characterized in that the linear guides ( 3 ) of the X-carriage ( 2 ) are arranged symmetrically to the spindle plane. 19. The apparatus according to claim 1 to 18, characterized in that the swivel head ( 4 ) is mounted on both sides and can be rotated about the B-axis ( 5 ) by means of a geared motor ( 6 ). 20. The apparatus according to claim 1 to 19, characterized in that the two bearings of the swivel head ( 4 ) are arranged symmetrically to the spindle plane. 21. The apparatus according to claim 1 to 20, characterized in that the X-slide ( 2 ) and the Z-slide ( 13 ) are driven by a linear motor. 22. The apparatus of claim 1 to 21, characterized in that the X-slide ( 2 ) and the Z-slide ( 13 ) are each driven by a rotating electric motor with a threaded spindle, which are either particularly low backlash and / or low deformation or per slide arranged in pairs who are then switched with their force against each other. 23. The device according to claim 1 to 22, characterized in that the machine frame ( 1 ) is made of mineral casting, which consists of broken natural minerals with a binder. 24. The device according to claim 1 to 23, characterized in that the mineral casting of the machine frame ( 1 ) consists of broken quartz glass with a binder. 25. The device according to claim 1 to 24, characterized in that the mineral casting of the machine frame ( 1 ) contains a plastic as a binder. 26. The device according to claim 1 to 25, characterized in that the mineral casting of the machine frame ( 1 ) contains a mineral binder. 27. The apparatus according to claim 1 to 22, characterized in that the machine frame ( 1 ) consists of naturally grown stone blocks. 28. The apparatus according to claim 1 to 27, characterized in that a directions are available with which the coolant for the grinding process or the polishing suspension for the polishing process to a predetermined constant Temperature can be regulated. 29. The device according to claim 1 to 28, characterized in that a tool magazine ( 28 ) and / or a workpiece magazin is attached to the X-slide ( 2 ). 30. The device according to claim 1 to 29, characterized in that the magazine is designed as a rotatable circular disc, which on its circumference has storage devices ( 29 ) which can be rotated one after the other into the removal position ( 30 ) by rotating the tool magazines ( 28 ) .