Machining device for shaping optical lenses by material removal, having a pre-machining machine and a finishing machine

Abstract

The invention relates to a machining device (1) for shaping optical lenses (100) by material removal, having a pre-machining machine (10) and a finishing machine (30). The pre-machining machine (10) has a data output unit (12) which is configured to assign lens-specific geometry data (D) resulting from the pre-machining to the machined optical lens (100) and to output said data. The finishing machine (30) is controlled by a process controller (32) which is configured to design a finishing strategy of the finishing machine (30) on the basis of the output geometry data (D) for this optical lens (100) and to control the finishing machine (30) on the basis of this finishing strategy. The invention also relates to a method for the shaping finishing an optical lens (100).

Description

[0001] Machining device for the shaping of optical lenses by material removal with a pre-machining machine and a finishing machine

[0002] The invention relates to a processing device for the shaping processing of optical lenses by material removal according to the preamble of claim 1. Furthermore, the invention relates to methods for the shaping processing of optical lenses by material removal according to claims 11 and 14.

[0003] The production of an ophthalmic lens through shaping machining usually begins with a lens blank and involves removing material from one or both sides. For economic reasons, this material removal is usually carried out in several steps. Rough pre-machining is performed, for example, by milling or pre-turning with high removal rates, followed by a precise finishing process step, such as diamond turning with a small infeed, and a final finishing process, such as polishing to smooth the previously created regular surface structure.

[0004] It is known to perform the first two process steps of rough and fine machining, in particular milling and turning, on a single machine, for example, as described in DE 10 2006 050425 A1. The finishing process, in particular a smoothing polishing process, is performed on a separate machine. High material removal during rough pre-machining requires correspondingly high machining forces, which in turn lead to machine vibrations, making a parallel fine machining process on the same machine impossible to achieve sufficient quality. In combined milling and turning machines, fine machining should therefore be performed during breaks in rough machining. Furthermore, the known machining strategies are inefficient, and both pre-machining and fine machining take a long time.

[0005] The object of the invention is therefore to optimize the efficiency of the pre-processing and finishing of optical lenses, in particular in the production of spectacle lenses.

[0006] Main features of the invention are set forth in the characterizing part of claim 1 and claims 11 and 14. Embodiments are the subject of claims 2 to 10, 12, 13, and 15.

[0007] The invention relates to a processing device for the shaping of optical lenses (including optical lens blanks) by material removal, comprising a pre-processing machine and a finishing machine. The pre-processing machine should, in particular, be designed to achieve higher material removal rates than the finishing machine.

[0008] One possible aspect of the invention is that the pre-processing machine has a data output device which is designed to assign lens-specific geometry data resulting from the pre-processing to the processed optical lens and to output said data, wherein the fine processing machine is controlled by a process control which is designed to design a fine processing strategy of the fine processing machine based on the output geometry data for this optical lens and to control the fine processing machine based on this fine processing strategy.

[0009] This allows the finishing process or finishing strategy to be optimized with regard to processing time and manufacturing quality based on knowledge of the lens-specific geometry data. By outputting and utilizing the geometry data, the finishing strategy can be precisely adapted to the actual input geometry (the geometry data), thus significantly reducing process time. According to the invention, information about the surface shape actually produced in pre-processing and thus, at least indirectly, also the surface allowance is available as an input variable for designing the finishing strategy. The geometry actually produced in the pre-processing machine depends on the target design to be manufactured, the installed tool geometry, tool wear, the pre-processing strategy, and the process parameters, such as feed, speeds, minimum allowance, and machine accuracy.

[0010] Without the output and utilized geometry data, during sequential machining on the pre- and finish-machining machine, the finish-machining machine would have to operate without knowledge of the actual surface allowance or the allowance distribution on the machining surface of the optical lens after pre-machining. In the simplest case, the machining strategy is then started with a sufficiently large safety distance from the optical lens and executed regardless of whether the tool is engaged or still at a distance from the optical lens. At the very least, it must be relied upon that a sufficient surface allowance is available.As soon as one wishes to approach the optical lens further in rapid traverse to shorten the machining strategy, one must be sure that the maximum permissible surface allowance relative to the finishing target surface to be machined is not exceeded and that one does not collide with the optical lens in rapid traverse. If there are doubts about these assumptions, special macros with multiple finishing overpasses could be used. However, this would result in an extended process time and would not be necessary in many cases. The decision as to whether to use such a macro with multiple overpasses could at best be made based on a simulation calculation of the pre-machining process prior to the finishing process, assuming standardized parameters.Due to the geometry data output according to the invention, the design of the finishing strategy is much more precise than solutions with such macros and the finishing strategy is shortened in time.

[0011] Furthermore, feedback on the geometry produced during pre-processing also ensures that pre-processing has actually taken place. If an optical lens enters the finishing machine without pre-processing, e.g., due to a logistics error in order control, a machine malfunction, an interrupted pre-processing, an operator error, or an unexpectedly large surface allowance, further processing can be excluded to avoid scrap, tool breakage, and productivity losses due to necessary machine adjustments, etc.

[0012] The machining device can be designed as an integrated combination machine comprising the pre-machining machine and the finishing machine, or it can comprise the pre-machining machine and the finishing machine as individual machines that can be used and / or installed independently of one another. Intermediate configurations in which the pre-machining machine and the finishing machine share individual machine components are also possible, for example, a common machine housing and / or a common control unit and / or a common machine bed.

[0013] In an integrated combination machine, the pre-processing machine should comprise at least one material-removing pre-processing tool and the data output device, while the finishing machine should comprise a material-removing finishing tool and the process control system. The data output device and process control system can be implemented by a common control unit. The data output device is then preferably a purely digital data interface, in particular between different software modules for controlling the pre-processing machine and the finishing machine.It is possible for the pre-machining machine and the finishing machine to share the machine bed, and / or a work area, and / or a workpiece holder, and / or a machine axis, and / or a coolant circuit, and / or a loading / unloading unit, and / or a user interface. In particular, the work areas of the pre-machining machine and the finishing machine can be combined or structurally separated from one another. In a design of the machining device with a shared machine bed, for example, the workpiece holder can also be shared between the pre-machining machine and the finishing machine.

[0014] The advantages of the invention are particularly evident in a design with independent individual machines, because the fine machining strategy of the fine machining machine can be designed using the data output device, taking into account the resulting, lens-specific geometric data, although the latter can also be used independently. For this purpose, the pre-machining machine and the fine machining machine preferably have separate machine beds and / or separate control units. The workpiece holders and / or machine axes and / or work spaces and / or coolant circuits and / or a loading / unloading unit and / or a user interface are then preferably designed independently of one another. The data output device is then preferably a physical interface for data output, e.g. a cable connection or an antenna. The individual machines can be installed adjacent to one another.However, installation at different locations is also possible.

[0015] The advantage of separate machine beds is that pre- and fine-machining processes can run in parallel without the fine-machining being affected by vibrations from the rougher pre-machining. The time required for pre- and fine-machining for each optical lens can vary greatly and depends primarily on the material, the surface geometry to be produced, and the edge or perimeter shape. With regard to series production, this also makes it possible to maintain the installed pre- and fine-machining capacity independently of each other as needed. For example, one pre-machining machine can be combined with two fine-machining machines. Machine design and targeted optimization for the respective process are simplified.

[0016] Separate control units allow the use of individual control software, which is correspondingly less complex. Machines of different generations or even from different manufacturers can also be combined.

[0017] The pre-processing machine preferably has a milling tool, which allows for rapid material removal.

[0018] The precision machining center preferably includes a turning tool. This allows even free-form surfaces to be precisely machined, particularly by coupling the feed rate of the turning tool to the rotation angle of the optical lens.

[0019] Alternatively, the pre-machining machine can also have a turning tool whose tool radius or effective cutting edge geometry is larger than that of the turning tool of the finishing machine. Higher material removal rates can be achieved with a larger radius or larger cutting edge geometry.

[0020] Optical lenses typically have a front surface, an opposite back surface, and a lens circumference that defines the front and back surfaces. The lens circumference may be circular, at least prior to processing.

[0021] Accordingly, it is optionally provided that the lens-specific geometry data describe a front side, a back side, a peripheral surface (also referred to as a lateral surface), and / or a facet of the optical lens. Thus, at least one surface from the group of front side, back side, peripheral surface, and facet is described.

[0022] In ophthalmic lens production, a convex front surface and a concave back surface are typically produced. An optical lens blank can already have a convex front surface and a concave back surface. In many cases, only the concave back surface is further machined to create the optical effect of the optical lens according to a prescription for correcting a vision defect. Alternatively or additionally, the convex front surface can also be machined to shape the lens.

[0023] The pre-machining machine should essentially be designed to produce a pre-machining target surface from the optical lens. Due to technical constraints or for the sake of process efficiency, the actual machined surface and thus also the geometric data may deviate from this pre-machining target surface. If a defined finishing target surface is desired at the end of the finishing process, it is advisable to indirectly define the pre-machining target surface by applying a nominal allowance relative to the finishing target surface.

[0024] The finishing machine should be designed to produce the finishing target surface based on the lens-specific geometric data resulting from pre-processing. The technically necessary tools are required to achieve this goal. The finishing target surface is ultimately the one that will achieve the desired optical effect in the subsequent application. Accordingly, unlike pre-processing, surface deviations are not permitted here simply because the machining process needs to be faster or the appropriate tools are not available.

[0025] In the case of high surface curvatures of the pre-machining target surface, such as in the case of spectacle lenses veneered to a standard diameter with a strong plus effect, material cannot be removed down to the desired minimum allowance in the areas of strong curvature during the pre-machining process. The specified pre-machining target surface can either not be reached at all by the pre-machining machine, or a decision is made to deliberately allow deviations in order to shorten the process. The actually resulting geometric data then deviate from the pre-machining target surface. The tool geometry, for example, limits the accessibility of the pre-machining target surface. Smaller tools or tool radii expand the area towards more strongly curved surfaces, but reduce the efficiency of the pre-machining process. In extreme cases, the same filigree tool geometry as for fine machining would be necessary for the pre-machining tool.Therefore, it is not economically viable to slow down the pre-machining process by selecting small tools. Rather, it is advisable to equip pre-machining machines with tools of different geometries adapted to the production spectrum, which then inevitably leads to increased variance in the allowance distribution as the input geometry for the finishing process. This is where the advantages of the geometric data output according to the invention come into full effect, because the pre-machining machine makes this geometric data on the actually machined surface available for the subsequent finishing. The machining strategy of the pre-machining machine can therefore be optimized. The limits for the design of the pre-machining machine's machining strategy can be set based on what the finishing machine can efficiently achieve, e.g., by defining a permissible maximum allowance.

[0026] Edge geometry created during the pre-machining process, or feedback indicating whether any edge machining has taken place at all, also allows the tools to be moved at rapid traverse during finishing to a minimum safety clearance before the process-relevant feed rate takes effect. This is usually lower than the rapid traverse rate, resulting in a reduction in process time.

[0027] A preferred solution according to the invention provides that the pre-processing machine assigns the resulting, lens-specific geometry data of the pre-processed optical lens to the order and transmits it to the finishing machine as input parameters along with the usual order and production parameters. Since the actual result of the pre-processing is now the input for the finishing process, a simulation calculation on the finishing machine with reconstruction or approximation of the pre-processing is not necessary.

[0028] The availability of the allowance distribution or the geometry data and the allowance distribution derived from it also offers the opportunity to further optimize and accelerate fine machining. If the surface allowance exceeds the maximum desired or permissible infeed, it is not necessary to set the desired surface allowance for the final fine cut via a corresponding number of preliminary cuts, as the speed and feed curve / track groove width are almost replicated in each overpass with a changed infeed. Instead, according to the invention, if a high but locally limited surface allowance is present, based on knowledge of this local distribution characteristic in areas where no material removal is expected and the fine machining tool is, so to speak, moving in air, the time per overpass can be reduced by increasing the feed / track groove width.Assuming a constant tool feed relative to the spindle center, variable circular, concentric zones are created, which are traversed in the finishing process with differently modified radial feeds. According to the invention, the radial feed per spindle revolution in zones where no material removal occurs can be increased by ten to one hundred times compared to the zones with material removal.

[0029] In the case of ophthalmic lenses veneered to a standard diameter with a strong plus effect, the area with increased surface allowance is only circular in special cases. The previously described division into circular zones with different radial feed values ​​can already lead to a significant reduction in machining time. Further optimization is possible, however, if the zones of different feed rates are not assumed to be circular, but rather they are adapted to the areas of maximum surface allowance in such a way that these areas can be traversed with a minimum number of spindle revolutions. A first approximate variant is, for example, to design these zones elliptically. In this case, the radial tool feed towards the spindle center would no longer be continuous, but superimposed in an oscillating manner. The radial tool feed towards the spindle center is then coupled to the angle of rotation of the optical lens.Fine machining can be divided into a homogenization of the surface allowance with oscillating radial tool feed to the spindle center and a final machining step to remove the homogenized surface allowance. The quality of the final machining is high due to the homogeneous penetration depth of the tool that is then possible.

[0030] According to the invention, the process control of the finishing machine should have a data interface for receiving the geometry data from the data output device of the pre-processing machine. The data interface can be formed directly between the pre-processing machine and the finishing machine. Alternatively, however, an indirect data interface via a host computer system or a data storage device physically assigned to the optical lens is also possible.

[0031] Furthermore, the pre-processing machine should be controlled by a process control system configured to design a pre-processing strategy of the pre-processing machine based on a pre-processing target surface and to control the pre-processing machine based on this pre-processing strategy. The lens-specific geometric data resulting from the pre-processing may deviate from the pre-processing target surface, particularly if the pre-processing strategy intentionally provides for this. In particular, the pre-processing target surface may have an at least essentially or exactly homogeneous surface allowance compared to the fine-processing target surface. The actual surface allowance resulting from the difference between the geometric data and the fine-processing target surface, however, may be inhomogeneous.Accordingly, the lens-specific geometry data can include a surface shape actually produced in the pre-processing machine. This creates a discrepancy between what the pre-processing machine should ideally produce for a surface (the pre-processing target surface) and the surface actually produced (the geometry data), with the pre-processing machine providing information about this using the geometry data. Optionally, the process control of the pre-processing machine is configured to design the pre-processing strategy while maintaining a maximum overrun of the surface allowance compared to the pre-processing target surface and / or the fine-machining target surface. This allows pre-processing time to be reduced through tool selection, because the machining speed can be increased at the expense of pre-processing precision.Up to a maximum exceedance of the local surface allowance, further processing, in particular the equalization of the pre-processing deviation, can be left to the finishing machine.

[0032] Specifically, the finishing strategy designed with the process control of the finishing machine includes tool paths, tool movements and / or movements of the optical lens.

[0033] In a particular embodiment, it is provided that either the lens-specific geometry data comprise information on the surface allowance relative to a finishing target surface of the finishing machine, wherein the information on the surface allowance is output using the data output device of the pre-processing machine, or that information on the surface allowance relative to a finishing target surface of the finishing machine is calculated using the process control of the finishing machine based on the lens-specific geometry data. The surface allowance tells the finishing machine where it still needs to remove material and how much. This information is generally already available to the pre-processing machine, because its pre-processing target surface is preferably determined based on the finishing target surface.Accordingly, the actually produced surface measurement can also be provided to the finishing machine in order to avoid a recalculation on the part of the finishing machine.

[0034] Optionally, the data output device can be configured to output the lens-specific geometry data in the form of a surface point cloud or mathematical formula (e.g., in a Cartesian, cylindrical, or spherical coordinate system). The amount of data increases accordingly with the increasing number of data points. To avoid large data volumes, it may be sufficient for the geometry data to have fewer data points than the finishing target surface. It may be sufficient to approximate the area allowance between the data points.

[0035] Existing minimal deviations in the allowance between the assumed and actual surface are equalized by the finishing machine tool during machining. However, the finishing target surface must be manufactured precisely with regard to its optical effect. Furthermore, the data output device can be configured to output the lens-specific geometry data, including at least one additional piece of information from the group consisting of center thickness, rotational position, decentration, peripheral shape, facet geometry, prism angle, or blocker data. This additional information facilitates the mounting and alignment of the optical lens in the finishing machine. Furthermore, the finishing machine's process control can consider this additional information when designing the finishing strategy.

[0036] Faceting the lens edge is particularly considered as a facet geometry. The transition from the lens edge to the surface to be machined is usually provided with a linear chamfer at a specific angle during the pre-machining process, or with a chamfer tangentially adjacent to the machining surface and / or the lens circumference. This can be achieved in a single movement of the milling tool when pouring it into the surface to be machined after edge machining, after edge machining and before surface machining without direct pivoting, or after edge and surface pre-machining. During the subsequent fine machining, the material removal, usually in the range of 0.1 to 0.2 mm, is so small that the previously machined facet is retained or the expected removal amount is "roughly" maintained. The facet has both cosmetic and technological reasons.With a correctly dimensioned facet, tool wear in the subsequent polishing process can be significantly reduced.

[0037] The blocker data can consist of how an optical lens blank is fixed to a block piece. Ophthalmic lens blanks exist in a wide variety of front curvatures, depending on the desired effect of the finished lens, but also due to material or manufacturer. To easily handle this variety in production, standardized universal block pieces are used. The blank to be machined is fixed to these blocks using alloy, wax, plastic, vacuum, etc., and can thus be machined or measured in different machines using the same clamping reference. By aligning the blank to the axis of the standardized universal block piece, the position and direction of the prism to be manufactured can be adjusted, and the cylinder axis can be defined in conventional toric production.

[0038] The geometry data can optionally be defined by an approximate envelope surface, so that the actual surface machined during pre-machining always lies on the envelope surface (i.e. the local surface allowance can be slightly larger locally than described by the envelope surface) or between the envelope surface and the finish machining surface (i.e. the local surface allowance can be slightly smaller locally than described by the envelope surface). An envelope surface can be used to reduce the amount of data compared to a complete description of the machined surface. The existing surface allowance is calculated by subtracting from the final surface geometry (the finish machining target surface), and the finish machining strategy, including the tool paths, can be calculated for the finish machining machine, regardless of the type of pre-machining strategy used.In this case, it is advisable for the pre-processing machine to output the geometric data for the finished surface shape of the optical lens in the same data format as the pre-processing machine itself receives the target surface to be created. This avoids information loss due to data conversion. If possible, the process control of the finishing machine should also design the finishing strategy without converting the geometric data.

[0039] In another variant, the geometry data includes an actual surface allowance compared to the finishing target surface. This has the advantage that the allowance distribution is immediately visible on the finishing machine. This eliminates the need for repeated calculations of differences at numerous surface points on the finishing machine's process control side, and any necessary cut distribution can be designed more quickly.

[0040] The machines can receive the target surfaces to be machined via a host computer system. A central data interface via the host computer system is therefore also advantageous for transferring the output geometric data to the process control of the finishing machine. It would also be conceivable, however, for the finishing machine to request the geometric data from the preceding pre-machining machine in the process sequence, which would then provide the data via output. Both variants make it easy to reliably determine the surface allowance and cut distribution for the finishing strategy, regardless of the machine, tool, and parameter configuration used for the pre-machining.

[0041] It proves advantageous if the pre-processing machine is designed to produce, based on a pre-processing target surface, a surface allowance that is only essentially homogeneous compared to the finishing target surface to be produced in the finishing machine, whereby a defined minimum allowance is maintained over the entire surface. Pre-processing can thus be carried out quickly and efficiently. Optionally, a defined maximum allowance can be maintained over the entire surface. This avoids inefficient rework on the finishing machine, which is not designed for large material removal. The invention also relates to a method for the shaping of optical lenses (including optical lens blanks) by material removal, comprising the following steps:

[0042] (a) Material removal machining of an optical lens with a pre-machining machine;

[0043] (b) outputting lens-specific geometry data resulting from the pre-processing to the optical lens using a data output device of the pre-processing machine and assigning the geometry data to the pre-processed optical lens;

[0044] (c) designing a finishing strategy of a finishing machine for producing a finishing target surface with a process control based on the output geometry data of the data output device of the pre-processing machine for this optical lens; and

[0045] (d) Controlling the finishing machine according to the finishing strategy and producing a finishing target surface, in particular by material removal.

[0046] This ensures that the finishing strategy is designed efficiently with knowledge of the geometry data, rather than simply assuming that the pre-machining machine would have actually met a target specification.

[0047] This method is particularly advantageous when the pre-machining machine and the finishing machine have separate machine beds and / or separate control units. Despite the machine separation, the pre-machining machine and the finishing machine can then operate efficiently.

[0048] The method can be implemented, in particular, with all optional design variants of the previously described processing device. The usage specifications and described effects for the processing device are also to be understood as features that can be implemented in the process technology. The optional design variants of the processing device are therefore also optional developments of the method.

[0049] Conversely, it is within the scope of the invention that the above-mentioned design variants of the machining device are further developed by a design for carrying out the method. The invention also relates to a method for the fine-machining of an optical lens (including optical lens blanks) by removing material with a turning tool in a turning process, wherein the optical lens is driven to rotate about a spindle axis, and wherein a starting surface with an inhomogeneous surface allowance relative to a fine-machining target surface is machined with the turning tool, in which the following steps are carried out:

[0050] (a) at least one step of homogenizing the machining allowance by traversing the starting surface with the turning tool in a non-circular orbit around the spindle axis by modulating a radial infeed (i.e., transverse to the spindle axis) of the turning tool, wherein zones of inhomogeneous surface allowance comprising an increased surface allowance relative to the finishing target surface are located on the non-circular orbit, and modulating the axial infeed (i.e., along the spindle axis) of the turning tool to produce a homogeneous target allowance relative to the finishing target surface, wherein the penetration depth of the turning tool into the optical lens varies over the orbit; and

[0051] (b) a finishing step in which the target stock is removed from the finishing target surface with at least a substantially constant penetration depth of the turning tool over the orbit up to the finishing target surface.

[0052] This ensures that the surface can be machined homogeneously during the final machining step, with continuous grooves and constant groove widths. This finishing strategy is particularly successful when the initial surface is the result of a pre-machining strategy that only provides an inhomogeneous allowance compared to the final machining target surface.

[0053] In this process, the starting surface can correspond to the geometric data of the previously described process, and in particular, this process can be applied within the previously described process. It then forms the basis for the finishing strategy.

[0054] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. They show:

[0055] Fig. 1 shows a schematic representation of a machining device with a pre-machining machine and a finishing machine; Fig. 2 shows a schematic cross-section of an optical lens with a pre-machining target surface and a finishing target surface;

[0056] Fig. 3a is a schematic representation of a spiral machining path over an optical lens;

[0057] Fig. 3b is a schematic representation of a non-circular machining path over an optical lens;

[0058] In Fig. 1, a processing device 1 for the shaping processing of optical lenses 100 by material removal, which has a pre-processing machine 10 and a fine processing machine 30, is shown in outline.

[0059] The pre-processing machine 10 has two milling tools 13, 13' for processing the optical lens 100. The optical lens 100 has a front side 101, an opposite rear side 102, and a lens periphery 103, which delimits the front side 101 and rear side 102 at their respective peripheries. One of the milling tools 13 is used here to process the rear side 102, the lens periphery 103, or a facet at the transition of the lens periphery 103 to the rear side 102. The other of the milling tools 13' is used, at least primarily, to process the lens periphery 103. The milling tools 13, 13' are each driven in rotation. Furthermore, the optical lens 100 is driven by a spindle drive 16, which drives the optical lens 100 in rotation about a spindle axis 15. This spindle drive 16 is mounted on a cross slide so that the optical lens 100 can be moved transversely and longitudinally to the spindle axis 15.In this case, the spindle axis 15 is aligned parallel to the rotational axes of the milling tools 13, 13'. However, different kinematics are also possible. The milling tools 13, 13' and the spindle drive 16 are mounted on a common machine bed 11.

[0060] The pre-machining machine 10 is controlled by a process controller 14, which is designed to define a pre-machining strategy for the pre-machining machine 10 based on a pre-machining target surface ZF1 and to control the pre-machining machine 10 based on this pre-machining strategy. The process controller 14 can be mounted on the machine bed 11, but is preferably vibration-decoupled and, if necessary, mounted separately from the machine bed 11.

[0061] The pre-processing machine 10, in particular its process control 14, has a data output device 12 configured to assign lens-specific geometry data D resulting from the pre-processing to the processed optical lens 100 and to output said data. The geometry data D should, in particular, remain physically or logically linked to the processed optical lens 100 even after leaving the pre-processing machine 10. In ophthalmic lens manufacturing, it is common practice for the optical lens 100 to be further transported after its pre-processing as a pair of lenses for the spectacles in a transport container 110 (also called a tray).

[0062] Following pre-processing in the pre-processing machine 10, the optical lens 100 is fed to the finishing machine 30, in this case with the sketched transport container 110.

[0063] The precision machining machine 30 has a turning tool 33 that is driven in an oscillating manner by a servo or oscillation drive 37 (also referred to as a fast tool). The optical lens 100 is driven in rotation about a spindle axis 35 by a spindle drive 36. The spindle drive 36 is mounted on a cross slide to move the optical lens 100 axially toward or away from the turning tool 33 along the spindle axis 35, and to move the optical lens 100 past the turning tool 33 transversely to the spindle axis 35. The turning tool 33 can be used, for example, to produce free-form surfaces by coupling the feeds of the turning tool 33 to the angle of rotation of the optical lens 100. The spindle drive 36 and the servo or oscillation drive 37 are mounted on a common machine bed 31.

[0064] The machine bed 11 of the pre-machining machine 10 and the machine bed 31 of the finishing machine 30 are physically separated from each other, particularly to isolate vibrations. In this case, the pre-machining machine 10 and the finishing machine 30 are independently operable machines.

[0065] The finishing machine 30 is controlled by a process controller 32, which is designed to define a finishing strategy for the finishing machine 30 based on the output geometric data D for this optical lens 100 and to control the finishing machine 30 based on this finishing strategy. The process controller 32 is also preferably vibration-decoupled and, if necessary, mounted separately from the machine bed 31. The process controllers 14 and 32 are implemented in separate control units of the pre-processing machine 10 and the finishing machine 30.

[0066] Furthermore, the process control 32 of the finishing machine 30 has a

[0067] Data interface 34 for receiving the geometry data D from the data output device

[0068] 12 of the pre-processing machine 10. As an alternative to the direct data connection shown, in which the fine processing machine 30 preferably queries the pre-processing machine 10 for the geometric data D of the optical lens 100 to be processed, communication via a host computer system or data transfer via a data carrier assigned to the optical lens 100 or its transport container 110 is also possible.

[0069] The finishing machine 30 thus receives precise geometric data D resulting from the pre-processing. As a result, it does not have to rely on the pre-processing machine 10 having reached the pre-processing target surface ZF1 or approximating any deviations therefrom. Rather, the pre-processing machine 10 is even given the freedom to deviate from the pre-processing target surface ZF1 in a process-economical manner. The pre-processing target surface ZF1 is ultimately only an intermediate working stage, without requiring any optical applications of the optical lens 100 to be performed.Specifically, the pre-machining machine 10, in particular its process control 14, can be configured to produce, based on the pre-machining target surface ZF1, a surface allowance A that is only substantially homogeneous compared to the finishing target surface ZF2 to be produced in the finishing machine 30, wherein a defined minimum allowance is maintained over the entire surface. At the same time, a defined maximum allowance should be maintained over the entire surface, since this must subsequently be removed by the finishing machine 30.

[0070] The finishing strategy designed by the process control 32 of the finishing machine 30 determines tool paths, tool movements, and / or movements of the optical lens, particularly taking into account the obtained geometric data D. The lens-specific geometric data D should describe at least the front side 101, the back side 102, and / or the peripheral surface 103 of the optical lens 100. In particular, the surfaces machined by the pre-processing machine 10 should be part of the geometric data D. Unchanged surfaces can also be provided from another data source, e.g., a machine database for the optical lens 100 or a host computer system.

[0071] Additionally, the lens-specific geometry data D can include, for example, information on the surface allowance A relative to the finishing target surface ZF2 of the finishing machine 30, wherein the information on the surface allowance A is output by the data output device 12 of the pre-processing machine 10. Alternatively, information on the surface allowance A relative to the finishing target surface ZF2 of the finishing machine 30 could be calculated by its process control 32 based on the lens-specific geometry data D. Optionally, the data output device 12 can be configured to output the lens-specific geometry data D including at least one further piece of information from the group consisting of center thickness, rotational position, decentration, peripheral shape, facet geometry, prism angle, or blocker data.

[0072] The data output device 12 can be designed to output the lens-specific geometry data D in the form of a surface point cloud or mathematical formula.

[0073] With this processing device 1, a method for shaping optical lenses 100 by material removal can now be carried out, comprising the following steps:

[0074] (a) Material removal machining of the optical lens 100 with the pre-processing machine 10;

[0075] (b) outputting lens-specific geometry data D resulting from the pre-processing to the optical lens 100 with a data output device 12 of the pre-processing machine 10 and assigning the geometry data D to the pre-processed optical lens 100;

[0076] (c) designing a finishing strategy of the finishing machine 30 for producing the finishing target surface ZF2 with the process controller 32 based on the output geometry data D of the data output device 12 of the pre-processing machine 10 for this optical lens 100;

[0077] (d) Controlling the finishing machine 30 according to the finishing strategy and producing the finishing target surface ZF2.

[0078] The material removal can be carried out with the turning tool 33 in a turning process, wherein the optical lens 100 is driven in rotation about the spindle axis 35. A starting surface F defined by the geometric data D with an inhomogeneous surface allowance A relative to the fine machining target surface ZF2 can then be machined in two stages. In particular, an allowance homogenization step can first be carried out by traversing the starting surface F with the turning tool 33. In this case, the axial feed of the turning tool 33 is modulated to produce a homogeneous target allowance relative to the fine machining target surface ZF2, wherein the penetration depth of the turning tool 33 into the optical lens 100 varies over the orbit.Optionally, this can be done in a non-circular orbit around the spindle axis 35 by modulating a radial infeed of the turning tool 33, wherein zones of the inhomogeneous surface allowance A, comprising an increased surface allowance A1 relative to the finishing target surface ZF2, are located on the non-circular orbit. A final machining step can then be performed in which the target allowance relative to the finishing target surface ZF2 is removed with an at least substantially constant penetration depth of the turning tool 33 over the orbit up to the finishing target surface ZF2. The orbit is preferably circular (this should also include a spiral shape).

[0079] Fig. 2 shows a sketchy cross-section of an optical lens 100, of which a partial section of the rear side 102 is included, and the front side 101 and the periphery 103 are only indicated. Starting from the rear side 102, which is produced, for example, in a previous machining operation or in a casting process, a fine machining target surface ZF2 is to be achieved by two-stage, material-removing machining. A pre-machining target surface ZF1 can be specified for a pre-machining machine 10 as described above, or the pre-machining target surface ZF1 is determined by the pre-machining machine 10 based on the fine machining target surface ZF2 and, for example, a minimum allowance.Due to the tool geometry or restrictions regarding the freedom of movement of the tool relative to the optical lens 100, it may be necessary to deviate from the pre-machining target surface ZF1 with a homogeneous surface allowance A relative to the finishing target surface ZF2. The actually machined surface of the pre-machining then corresponds to the geometric data D and maintains both the minimum surface allowance A relative to the finishing target surface ZF2 and a maximum surface allowance. This then results in zones A2 of the inhomogeneous surface allowance A, which have a small surface allowance, and zones A1, which have an increased surface allowance, as shown.

[0080] The inhomogeneous surface dimension A must then be further processed using a finishing machine, such as that described above.

[0081] For this purpose, Fig. 3a shows a schematic representation of a spiral machining path above an optical lens 100. It can be seen that in two concentric rings, zones A1 with increased surface allowance lie within a zone A2 with low, homogeneous surface allowance. With the sketched spiral machining path, which can be achieved by constant transverse movement of the tool and constant rotation speed of the optical lens 100, the entire rear side 102 is traversed, whereby, depending on the infeed, only the zones A1 with inhomogeneous, increased surface allowance are removed and the turning tool hovers above the surface in between. The machining path could be restricted to the area between the concentric rings with the zones A1 with inhomogeneous, increased surface allowance by means of rapid traverse, in order to first remove the zones A1 with inhomogeneous, increased surface allowance.However, it proves particularly efficient if the radial infeed of the tool is modulated as a function of the rotation angle, as outlined in Fig. 3b, whereby a non-circular machining path is traversed. Compared to the spiral path shown in Fig. 3a, the path of the procedure outlined in Fig. 3b is not only shortened but also compressed into an elliptical shape in order to traverse all zones A1 with an inhomogeneous, increased surface allowance with fewer revolutions. This initially allows a homogeneous surface allowance to be created. Only during the final machining should the entire relevant surface of the optical lens 100 be traversed again in a spiral manner and with a constant penetration depth of the turning tool.

[0082] The invention is not limited to one of the embodiments described above, but can be modified in many ways.

[0083] All features and advantages arising from the claims, the description and the drawings, including design details, spatial arrangements and method steps, can be essential to the invention both individually and in a wide variety of combinations.

[0084] Reference symbol list

[0085] Machining device 103 peripheral surface

[0086] Pre-processing machine 110 T ransport container (tray) Machine bed

[0087] Data output device A Surface measurement milling tool A1 Zones of the inhomogeneous process control surface measurement comprising a spindle axis increased surface measurement spindle drive A2 Zones of the inhomogeneous surface measurement comprising a

[0088] Finishing machine small surface allowance Machine bed D Geometry data (resulting from the process control pre-machining and turning tool lens-specific) Data interface F Starting surface Spindle axis ZF1 Pre-machining target surface Spindle drive ZF2 Finishing target surface

[0089] Servo drive / oscillation drive / Fast-Tool optical lens

[0090] front

[0091] back

Claims

Patent claims 1. Processing device (1) for the shaping processing of optical lenses (100) by material removal, with a pre-processing machine (10) and with a fine processing machine (30), characterized in that the pre-processing machine (10) has a data output device (12) which is designed to assign lens-specific geometry data (D) resulting from the pre-processing to the processed optical lens (100) and to output these, - wherein the finishing machine (30) is controlled by a process controller (32) which is designed to design a finishing strategy of the finishing machine (30) based on the output geometric data (D) for this optical lens (100) and to control the finishing machine (30) based on this finishing strategy.

2. Machining device (1) according to claim 1, characterized in that the process control (32) of the fine machining machine (30) has a data interface (34) for receiving the geometric data (D) from the data output device (12) of the pre-machining machine (10).

3. Machining device (1) according to one of claims 1 or 2, characterized in that the pre-machining machine (10) is controlled by a process control (14) which is designed to design a pre-machining strategy of the pre-machining machine (10) based on a pre-machining target surface (ZF1) and to control the pre-machining machine (10) based on this pre-machining strategy.

4. Machining device (1) according to one of the preceding claims, characterized in that the finishing strategy designed with the process control (32) of the finishing machine (30) includes tool paths, tool movements and / or movements of the optical lens (100).

5. Processing device (1) according to one of the preceding claims, characterized in that the lens-specific geometry data (D) are a front side (101), a back side (102), a peripheral surface (103) and / or facet of the optical lens (100).

6. Processing device (1) according to one of the preceding claims, characterized in that a) the lens-specific geometric data (D) comprise information on the surface allowance (A) relative to a finishing target surface (ZF2) of the finishing machine (30), wherein the information on the surface allowance (A) is output by the data output device (12) of the pre-processing machine (10); or b) information on the surface allowance (A) relative to a finishing target surface (ZF2) of the finishing machine (30) is calculated by the process control (32) of the finishing machine (30) based on the lens-specific geometric data (D).

7. Processing device (1) according to one of the preceding claims, characterized in that the data output device (12) is designed to output the lens-specific geometry data (D) in the form of a surface point cloud or mathematical formula.

8. Processing device (1) according to one of the preceding claims, characterized in that the data output device (12) is designed to output the lens-specific geometry data (D) including at least one further item of information from the group of center thickness, rotational position, decentration, peripheral shape, facet geometry, prism angle or blocker data.

9. Machining device (1) according to one of the preceding claims, characterized in that the pre-machining machine (10) is designed to produce, based on a pre-machining target surface (ZF1), a surface allowance that is only substantially homogeneous compared to the fine-machining target surface (ZF2) to be produced in the fine-machining machine (30), wherein a defined minimum allowance is maintained over the entire surface.

10. Processing device (1) according to claim 9, characterized in that a defined maximum allowance is maintained over the entire surface.

11. A method for shaping optical lenses (100) by material removal, comprising the following steps: (a) material-removing machining of an optical lens (100) with a pre-machining machine (10); (b) outputting lens-specific geometry data (D) resulting from the pre-processing to the optical lens (100) with a data output device (12) of the pre-processing machine (10) and assigning the geometry data (D) to the pre-processed optical lens (100); (c) designing a finishing strategy of a finishing machine (30) for producing a finishing target surface (ZF2) with a process control (32) based on the output geometric data (D) of the data output device (12) of the pre-processing machine (10) for this optical lens (100); (d) controlling the finishing machine (30) according to the finishing strategy and producing a finishing target surface (ZF2).

12. The method according to claim 11, wherein the pre-machining machine (10) and the finishing machine (30) have separate machine beds (11, 31) and / or separate control units.

13. Method according to one of claims 11 or 12, characterized in that it is carried out with a processing device (1) according to one of claims 1 to 11.

14. Method for the fine-machining of an optical lens (100) by material removal with a turning tool (33) in a turning process, wherein the optical lens (100) is driven to rotate about a spindle axis (35), and wherein a starting surface (F) with an inhomogeneous surface allowance (A) relative to a fine-machining target surface (ZF2) is machined with the turning tool (33), characterized by the following steps: (a) At least one allowance homogenization step by traversing the starting surface (F) with the turning tool (33) in a non-circular orbit around the spindle axis (35) by modulating a radial infeed of the turning tool (33), wherein zones of the inhomogeneous surface allowance (A) comprising an increased surface allowance (A1) relative to the finishing target surface (ZF2) are located on the non-circular orbit, and modulating the axial infeed of the turning tool (33) to produce a homogeneous target allowance relative to the finishing target surface (ZF2), wherein the penetration depth of the turning tool (33) into the optical lens (100) varies over the orbit; and (b) a finishing step in which the target allowance relative to the finishing target surface (ZF2) is removed with an at least substantially constant penetration depth of the turning tool (33) over the orbit up to the finishing target surface (ZF2).

15. Method according to claim 14, characterized in that it is part of the Finishing strategy of claim 11, wherein the initial surface (F) corresponds to the geometric data (D).

Images