Graded self-adaptive polishing tool and manufacturing method thereof

Abstract

The invention relates to a polishing tool (1) for treating a technical surface, comprising a polishing base body (1a) and a polishing agent carrier (1b), the polishing agent carrier (1b) having at least one polishing particle, at least one material property of the polishing agent carrier (1b) changing perpendicular or horizontal to an axis of rotation (3a) of the polishing tool, the invention relates to a polishing tool (1) for polishing a workpiece (2) in order to pertinently control the polishing removal function on the surface of the workpiece (2) to be treated, said polishing tool having a built-in cooling channel through which a polishing agent suspension is fed and the effect of at least one polishing particle on the workpiece surface can be influenced by a change in material properties.

Description

Field of the Invention

[0001] The present invention relates to a polishing tool having characteristics suitable for deterministically polishing functional surfaces and a method for manufacturing a polishing tool. Background Art

[0002] Available polishing methods are generally classified according to the geometry of the surface shape to be produced. While so-called shell tools with large-area tool engagement are typically used for flat and spherical surfaces, sub-aperture tools must be used for aspherical and free-form surface geometries. For methods that select large-area tool engagement, the aim is to achieve so-called constant removal, i.e., a constant amount of material is removed at each point on the surface during the polishing period. If successful, very high shape accuracy and a repeatable polishing process can be achieved at this time. For polishing methods using sub-aperture tools, the requirements for axis movement and the synchronization of the axes with each other are very high, and due to the smaller tool engagement area, a longer polishing time is required. In addition, an increase in the influence of mid-frequency errors, which those skilled in the art refer to as so-called mid-spatial frequency errors, is also inevitable.

[0003] The increasing requirements for the shape accuracy of optical surfaces with increasingly complex geometries require a deterministic polishing process with locally predefined removal functions. If successful, targeted shape correction can be achieved while reducing surface roughness. For this reason, precise control of the axis movement required for the polishing tool is needed. In practice, for this, the tool function is determined at a point lens, the locally different material removal rates required are calculated mathematically, and a dwell-time-controlled polishing process is used to targetedly flatten the area to be removed.

[0004] For the above-mentioned large-area and small-area polishing tools based on mechanochemical removal, the design freedom of the polishing tool is restricted. Conventionally, the polishing substrate is covered with a polyurethane film or asphalt for this purpose. In order to increase this design freedom, various inventions and solutions have been disclosed in the prior art, aiming to be able to influence the polishing parameters targetedly.

[0005] Patent publication JPH1199452A proposes a polishing tool in which the edge region of the tool has a different hardness from the inner region of the tool. For this purpose, an iron substrate is used, and a separate pad portion is applied thereon, and the hardness and height of the pad portion are different according to its position. The outer pad portion that first contacts the glass surface has a lower hardness (Brinell hardness ≤ 20) to avoid deep cracks caused by the extrusion of the polishing tool.

[0006] Patent document JP2006231464A proposes a polishing tool for processing large wafers. The polishing tool consists of annular segments with different hardnesses to ensure a uniform polishing rate across the entire workpiece area. The hardness of the segments gradually decreases from the inside to the outside. The disclosed figures show a tool with a larger diameter and a smaller workpiece.

[0007] Similarly, patent publication JP2006140240A also describes a polishing process using polishing pads with different arrangements. This tool is suitable for chemical mechanical polishing in semiconductor technology. The aim is to reduce the negative effects such as delamination, flaking, and erosion of the insulating layer (low-k film, dielectric constant lower than SiO 2 , ε r <3.9). For this purpose, the tool is covered with two plastic pads with different hardnesses. The entire surface is formed by the individual surfaces of the alternately arranged pads. Although the hardness of the polishing tool can be changed according to all the given pad arrangements, these arrangements can only be made discretely and are largely inflexible and not suitable for a deterministic polishing process.

[0008] Patent JP5502542B2 describes a polishing pad with an adaptive tool function. This is to achieve a uniform flatness while avoiding polishing scratches. The substrate is coated on the back of the polyurethane film using a wet coagulation process. The substrate contains two film layer elements with different Shore A hardnesses. Both types can be arranged in different structures, such as a grid, a ring, or stripes. Under a constant polishing pressure, different pressures are generated, making it easier for the polishing particles to move.

[0009] Patent document CN114473855A discloses a complete tool for grinding and polishing. The tool is designed as a grinding and polishing tool and consists of two or more regions with different hardnesses to achieve different removal rates under a constant grinding / polishing pressure. It is suitable for use as a tool for the chemical mechanical polishing plane of semiconductor components. Similarly, patent document CN210139311U proposes a utility model for a polishing brush for glass polishing. The aim is to generate a uniform material removal amount across the entire surface by changing the removal rates of the individual regions. The tool is divided into an inner and an outer circular ring region, and within each circular ring region, a plurality of polishing partitions with a base layer and a polishing layer are arranged correspondingly. The hardness of the polishing layer in the inner region is selected to be lower than that in the outer region.

[0010] However, the use of adaptive polishing tools has also been described for the application field of aspherical polishing and is the subject of current research. For example, the paper (Scheibe 2016 - Scheibe, H.: Aktiv - adaptive Polierwerkzeuge zur Herstellung rotationssymmetrischer Dissertation, TU Ilmenau, 2016 (Method for polishing aspherical surfaces using a fully active adaptive polishing tool, doctoral thesis, TU Ilmenau, 2016) proposed a method for polishing aspherical surfaces using a fully active adaptive polishing tool. The structure of the tool consists of a combination of an adaptive part and an active part of the tool. The two are in a serial arrangement. The full-aperture contact zone between the tool and the workpiece is achieved by active deformation of the basic shape of the tool. A special needle array was proposed for the targeted sequential deformation of the tool.

[0011] Although all the solutions disclosed in the prior art illustrate various solutions for variable hardness values of polishing tools and their designed adaptive functions, these are very limited with respect to the gradability and flexibility of the polishing tool function and for deterministic polishing. Summary of the Invention

[0012] Therefore, the object of the present invention is to provide a polishing tool for deterministic polishing, which is capable of flexibly achieving targeted adjustable polishing removal at any point of the tool in terms of its function, and furthermore, of achieving this function in the entire processing space, so as to be able to process aspherical and complex-shaped structural elements, in particular free-form surfaces, in a targeted manner. Another object of the present invention is to provide a method for manufacturing a tool for graded / gradual and adaptive polishing.

[0013] This object is achieved by the subject matter of the independent claims. Advantageous embodiments are given in the dependent claims. The polishing tool is formed by a polishing substrate and a graded / gradual polishing agent carrier. Depending on the requirements of the polishing task, the polishing substrate can be made of tool steel, aluminum, hard metal or composite materials and synthetic materials. The polishing agent carrier is made of plastic, such as polyurethane, polyamide or light-curing materials, such as acrylates and epoxy resins. Preferably, the polishing agent carrier is adjusted rotationally symmetrically or specifically graded / gradually in the X and Y dimensions in its polishing function. The polishing function is achieved by removing material at the workpiece within a selected polishing period. The object of the present invention is to provide different partitions of the polishing agent carrier, which produce different material removals on one or more workpiece surfaces with different curvatures. In a simple design of the present invention, a polishing agent carrier with two partitions is provided for a rotationally symmetric polishing tool. When the first partition in the central and surrounding regions of the polishing agent carrier has a higher hardness, for example, Shore hardness D of 83, while the second partition in the outer and edge regions has a lower hardness, for example, Shore hardness D of 75, distinct and different material removals can occur on the workpiece surface. This removal function and the resulting difference in material removal can be advantageously used for processing workpieces on a multiple carrier. For example, if there is a workpiece at the center of a multiple carrier and other workpieces (e.g., three) are distributed along the radius at a certain distance from the center, then due to the different circumferential speeds of the workpieces, different removal conditions will occur during polishing. Experience shows that the workpieces located in the edge region are removed more than the workpieces arranged in the middle of the support due to the higher rotational speed and thus the resulting faster cutting speed. Preferably, at this time, the polishing agent carrier is specifically designed in terms of its hardness for the two partitions according to different removal functions. Advantageously, there can be not only two partitions with the required different polishing characteristics, but also a large number of different partitions, so that the required removal profile can be better approximated when polishing the surface.

[0014] If the number of partitions of different polishing agent carriers for the grading, i.e., polishing function, is chosen very high, the removal function approaches a continuous transition from the maximum hardness to the minimum hardness over the selected polishing tool diameter. This continuous transition is also advantageously set in the X - Y plane extension of the polishing agent carrier, where different variations / trends of variation can be selected in the X extension and in the Y direction. Thus, for example, a continuous transition of Shore hardness D from 52 - 77 can be selected in the X extension of the polishing agent carrier, while a continuous transition of Shore hardness D from 75 - 80 can be selected in the Y extension. The different designs of the polishing function in the X and Y directions of the polishing tool allow the removal function to be tailored to off - axis workpieces, strongly curved surfaces, cylindrical lenses and mirrors, and free - form optical elements, so that a constant removal and a deterministic polishing process can be achieved. The continuously varying hardness distribution of the polishing agent carrier can be advantageously used for varying cutting speed conditions. If the workpiece coincides with the rotation axis of the polishing tool, the cutting or rotational speed of the polishing tool varies from the center to the edge of the workpiece. This variation can be converted into a polishing function through mathematical calculation. The polishing function represents the overall trend of variation from the center of the workpiece, where the (theoretical) cutting speed is zero, to the edge of the workpiece, where the cutting speed is maximum. Using the coefficient of friction of the polishing agent carrier material used, this polishing function can be converted into a grading distribution function of the polishing agent carrier. Thus, when the P RESTON coefficient is estimated accurately enough and the continuous hardness distribution of the polishing agent carrier is adjusted, a constant removal can be achieved over the entire surface to be polished. For a workpiece with a polishing area of 100 cm 2 and made of borosilicate crown glass BK7, the P RESTON coefficient C p = 10 -7 cm 2 N -1 . Assuming the normal force is F N = 10 N and the polishing agent carrier is made of polyurethane. The experimentally determined coefficient of friction is μ = 0.622. These continuously varying polishing functions can also be particularly advantageously used for large - area workpieces, such as telescope mirrors, wafers in the semiconductor industry, and cylindrical optical devices.

[0015] Advantageously, the hardness distribution additionally varies in the vertical direction. By means of the adjusted hardness distribution in the horizontal and vertical directions of the polishing agent carrier, the final polishing function can be influenced in a targeted manner. The grading of the hardness distribution in the vertical direction enables the damping function of the polishing agent carrier on the polishing particles acting on the workpiece surface to be adjusted, which generally follows a spring-damping model. For example, if the restoring force of the polishing particles in the interaction zone is low and the polishing agent carrier has a high damping, little material is removed at this part of the workpiece surface. In the opposite case, where the damping of the polishing agent carrier on the polishing particles is very low, a higher material removal can be recorded at this part. In addition, the polishing function varying over time can be changed by changing the hardness distribution in the Z direction. This polishing function varying over time is caused by the wear and removal of the polishing agent carrier in the Z direction. Therefore, depending on the wear and polishing period, different hardness configurations can be provided by changing the hardness distribution along the Z direction. In traditional polishing processes, the polishing tool is usually constructed in such a way that a very hard tool substrate in the form of a steel die or casting die forms the female die to be polished, and the polishing agent carrier acts as a damper, usually made of a polyurethane film or asphalt. Therefore, a clear transition from hard to soft is pre-determined and not affected. However, preferably, a change in the transition between the polishing substrate and the polishing agent carrier is provided. For this purpose, the substrate and the polishing agent carrier can advantageously be connected to form one tool or manufactured integrally, where the grading in the Z direction extends over a larger area. Thereby, a spring-damping model can be designed for the polishing process by specifically changing the hardness and stiffness in the Z extension of the tool, and it can be adapted partitionally to the corresponding polishing function. Therefore, a deterministic polishing process with high repeatability can be achieved.

[0016] A particular advantage of the stepped adaptive polishing tool is the homogenization of the polishing substrate. For conventional polishing processes, a polishing substrate must be provided for each radius to be polished. Due to the large variety of radii of spherical lenses and mirrors used in optical systems and components, a large number of different polishing substrates must be stocked or manufactured. By means of the adaptive function of the proposed polishing agent carrier, this high number can be reduced to a few polishing tools. This is achieved by directly introducing or generating the required radius during the production of the polishing agent carrier. Thus, the polishing substrate can be designed as a simple end face tool onto which the polishing agent carrier is bonded. If the required radius accuracy is not sufficient, the polishing tool is dressed with a diamond tool during the polishing process. The polishing tool can also be dressed to different radii so that different radii can be produced with one polishing tool. This requires the polishing agent carrier to have a certain central thickness so that it can be dressed several times. In addition, it is provided that the polishing agent carrier is provided as a full aperture female mold for aspherical polishing. For this purpose, the aspherical shape is likewise introduced into the polishing agent carrier based on a mathematical aspherical equation. The accuracy of the polishing tool can be increased again by means of a dressing step in the polishing machine. The particular design of the present invention provides for full aperture polishing of free-form optical structural elements using the polishing tool. Due to the discontinuous surface transitions in free-form optical elements, polishing cannot be carried out according to the movement arrangement as is common in rotationally symmetric structural elements. Advantageously, a female mold of the free surface to be polished is produced as the polishing agent carrier. In this case, the transfer of the action energy of the polishing grains in the polishing process is not achieved by the rotational movement of the polishing tool and the workpiece, but by the vibration force of the translational action between the polishing tool and the workpiece. By changing the amplitude and frequency of this periodic oscillatory movement, the removal can be additionally controlled. Depending on the size and shape of the workpiece to be processed, the amplitude can reach several micrometers and the frequency can range from a few hundred hertz to the ultrasonic frequency of 60 MHz.

[0017] The stepped adaptive polishing tool can be particularly advantageously used for polishing with constant removal and deterministic polishing. The present invention is also applicable to targeted corrective polishing of components. In this regard, after the polishing process, the surface is measured, for example by interferometry, and the defects requiring zonal correction are analyzed. Based on the topographical defect representation of the entire surface or the sub-regions of the workpiece surface, a further polishing function is calculated and converted into a hardness distribution function. Based on this analysis and evaluation, another polishing agent carrier is produced that can targetedly eliminate local defects. In the embodiment of the stepped polishing agent carrier, this means that in the zones of the workpiece surface where material still needs to be removed, these regions of the other polishing agent carriers are set to have a higher hardness, while in the regions of the workpiece surface where no material should be removed or only very little material should be removed, the corresponding regions of the polishing agent carrier have a lower hardness, or another polishing agent carrier is omitted. Thus, additionally, certain regions of the other polishing agent carrier can be set to be free of material so that no material is removed at these sites.

[0018] The use of a graded adaptive polishing tool is very suitable for silicate materials (especially glass and ceramics), plastics and composite materials, metals (especially steel, aluminum, copper and hard alloys), and crystals (such as silicon, germanium, zinc selenide, calcium fluoride, sapphire). The range of the required hardness value of the polishing agent carrier is adjusted according to the material-specific grinding or polishing hardness of the workpiece. When designing the corresponding polishing tool, the type and parameters of the polishing agent used are also considered. For example, cerium oxide is used as a polishing agent for glass and ceramics, while alumina is used for plastics and composite materials. For materials with particularly high hardness, emery can also be used for polishing. The typical particle size range for polishing using a graded adaptive polishing tool is an average particle diameter of less than 1 μm. Nano-scale polishing suspensions can also be used.

[0019] Advantageously, cooling channels are introduced into the polishing tool to convey the polishing suspension and remove the removed workpiece material and worn polishing particles. The cooling channels can be implemented in the lateral orientation of the polishing agent carrier, i.e., perpendicular to the rotation axis of the polishing tool, and / or in the vertical direction, i.e., parallel to the rotation axis of the polishing tool. The characteristics of these two cooling channel arrangements are that they are very flexible to use and have a large degree of design freedom. Generally, according to the size and shape of the component, the structural width of the laterally oriented cooling channels is selected to be 10 μm to 5 mm. Therefore, the solution according to the present invention can also be used for processing micro-optical and micro-mechanical components. For example, when the structural width of the lateral cooling channel is 10 μm, a micro-lens with a minimum diameter of 0.3 mm can be polished. The lateral cooling channels can be implemented with a structural depth of 100 μm up to the maximum polishing agent carrier thickness, or the structural width can also be changed in a defined manner in the Z direction. This application is particularly advantageous if the polishing agent carrier needs to be used multiple times and needs to be trimmed for different workpiece geometries. The vertical cooling channels in the polishing substrate and the polishing agent carrier are used to specifically convey the polishing suspension. Therefore, especially for large-area polishing tools, a constant and evenly distributed polishing agent flow can be ensured over the entire area of the workpiece surface. In addition, the present invention provides that the structural design of the cooling channels is designed such that they convey or apply a polishing suspension with a defined pressure to the polishing agent carrier and the workpiece surface through their path length and channel diameter. If the size and shape of the cooling channels on the entire polishing tool surface are specifically changed, different polishing pressures can be applied to different areas of the workpiece surface. This application is particularly suitable for polishing with variable cutting speeds and corrective polishing.

[0020] This object is also achieved by a method for manufacturing a polishing tool. Advantageously, a method of applying the polishing agent carrier in layers is employed. A printing process is used, which can distribute a liquid polymer onto a platform through two print heads. In the print head 16a for component A, a polymer with a lower Shore hardness, i.e., component A, is stored, and in the print head 16b for component B, a polymer with a higher Shore hardness, i.e., component B, is stored. Components A and B can be provided by polymers of different hardnesses, such as acrylate, Shore hardness D 75–83, or also by two different polymers.

[0021] During layer-by-layer printing, the two components can be applied sequentially or in parallel. By providing a mixing unit, components A and B can be mixed in any ratio, so that with another print head for components A and B, it is also possible to variably print polymers with variable percentages of components A and B in each layer. After applying each layer, the layer is hardened using an ultraviolet radiation source. The typical layer thickness ranges from 50 μm to 200 μm. If the component is trimmed again after additive manufacturing, a larger layer thickness can also be selected. The maximum printing area in the X and Y directions of the polishing tool is typically 600 mm x 600 mm. For larger polishing tools, the printing area can be extended by scaling the X and Y axes of the printing system.

[0022] By using a support material, it is also possible to set such areas of the polishing agent carrier during printing where there should be no material after the tool is completed. This particularly relates to cooling channels on the polishing tool or partitions where removal should not occur at the component. The support material used is, for example, a water-soluble polymer, and it is distributed into the layer to be printed through the print head for the support material 16d. The print head for the support material 16d to be set for this purpose can also work sequentially or in parallel with other material print heads. After the polishing agent carrier or the polishing tool is completed, the support material is dissolved / removed from the 3D printed body in a cleaning step. The arrangement and selection of the cooling channel geometry can be designed such that the polishing agent is specifically guided to flow inside the polishing tool in order to additionally generate different pressure distributions on the surface to be polished. For example, if a higher polishing pressure is achieved in the inner area of the polishing tool, more material can be removed from the center of the component than from the edge area.

[0023] The feasibility of applying different materials and material properties in layers provides a prerequisite for fully producing a polishing tool in a single printing process. The polishing substrate is printed from a harder polymer to achieve high rigidity, while the polishing agent carrier is selected to have a lower hardness. In addition, the hardness grading can be set layer by layer in a targeted manner. The overall combination of the polishing substrate and the polishing agent carrier allows the introduction of continuous cooling channels. Therefore, the polishing suspension can be directly transported within the tool to the working area between the polishing agent carrier and the surface of the component. The layered structure allows for the flexible and individual creation of very different geometries. In addition to flat polishing tools, female molds with spherical, aspherical, and free-form surfaces can also be additively manufactured.

[0024] For polishing tasks with high requirements for shape accuracy, the polishing agent carrier can be additionally trimmed after the printing process. For this purpose, the polishing agent carrier is bonded to the substrate and then further processed with a trimming tool (such as a diamond-bonded tool). The trimming can be carried out on a numerically controlled machine tool with path control, or directly on a polishing machine equipped with the polishing tool. By repeating the trimming process, the worn polishing agent carrier can be repaired after the polishing process. If there are polishing agent carriers with a larger central thickness, they can also be used for different polishing tasks. For example, by re-trimming, the radius and other surface geometries can be changed.

[0025] The present invention will be explained in more detail below with reference to the accompanying drawings by means of embodiments, which also disclose the essential features of the present invention. The embodiments are for illustrative purposes only and should not be construed as limiting. For example, the description of an embodiment having multiple elements or components should not be construed as meaning that all of these elements or components are necessary for implementation. On the contrary, other embodiments may also include alternative elements and components, fewer elements and components, or additional elements and components. Unless otherwise stated, the elements and components of different embodiments can be combined with each other. The modifications and variations described for one of the embodiments can also be applied to other embodiments. To avoid repetition, the same or corresponding elements in different figures are denoted by the same reference numerals and will not be explained again. Description of the Drawings

[0026] Figure 1a The assembly of a polishing tool with two polishing zones for polishing a plurality of spherical structural elements on a multiple carrier is shown,

[0027] Figure 1b A polishing tool with two zones is shown in a sectional view,

[0028] Figure 2 A multi-zone tool for deterministic polishing of flat workpieces is shown,

[0029] Figure 3a A top view of a rotationally symmetric polishing agent carrier with three different hardness zones is shown,

[0030] Figure 3b shows a top view of a square polishing agent carrier, which correspondingly has a hardness distribution varying in the X and Y directions,

[0031] Figure 3c shows a cross-section of a polishing agent carrier, which has a hardness distribution varying in the Z direction,

[0032] Figure 4a shows a top view of a rotationally symmetric polishing agent carrier, which has a horizontally arranged cooling channel structure,

[0033] Figure 4b shows a cross-section of a polishing tool having a polishing substrate and a polishing agent carrier and an arrangement of a vertically distributed cooling channel structure,

[0034] Figure 5a shows a side view of a rotationally symmetric aspherical polishing assembly, which has a full-aperture polishing tool,

[0035] Figure 5b shows a side view of a rotationally symmetric aspherical polishing assembly, which has a two-part stepped sub-aperture polishing tool for sequential pre-polishing and finishing,

[0036] Figure 6 shows a side view of a freeform geometry polishing assembly, which has a full-aperture polishing tool and multiple zoned polishing functions,

[0037] Figure 7a shows a diagram of an assembly for printing a stepped polishing agent carrier, more precisely a polishing tool having two print heads for components A and B; and

[0038] Figure 7b shows a diagram of an assembly for printing a stepped polishing agent carrier, more precisely a polishing tool having two print heads for a material mixture containing components A and B and a support material. Detailed Description

[0039] Figure 1a and Figure 1bA first embodiment is shown. This arrangement shows a polishing tool 1 below, which has two different hardness zones 11.a and 11.b. The polishing tool is used to polish twelve convex lenses on a multiple carrier. The first lens 2a and the second lens 2b are arranged at two different distances from the rotation axis 3b of the workpiece carrier 22. Due to the different circumferential speeds, the first lens 2a has a lower cutting speed than the second lens 2b. This results in the second lens 2b experiencing a higher removal than the first lens 2a. Using a selected area division of the polishing agent carrier 1b corresponding to the geometric arrangement of the lenses, the different removals can be compensated. Accordingly, the hardness and coefficient of friction of zone 11.a are set higher than those of zone 11b, and additive manufacturing is used.

[0040] Figure 2 Another embodiment for processing flat components is shown. The polishing tool 1 is formed by a base body 1a and a multi-zone polishing agent carrier 1b. For this polishing assembly, the rotation axis of the workpiece 3b is offset from the rotation axis of the polishing tool 3a by the radius of the workpiece 2. Zone 11.a is set to have a Shore D hardness of at most 82.5, where zone 11.b has a minimum Shore D hardness value of 71.5. Other zones are provided between the two zones and have a continuous transition. The continuous change in the selected coefficient of friction is proportional to the changed cutting speed distribution. Thus, a constant removal can be ensured over the entire surface of the construction.

[0041] Figures 3a to 3c A selected polishing agent carrier arrangement is shown. The illustration of three exemplary selections only shows the form of the hardness distribution in principle, where the design diversity of the method used can significantly increase the number of zones. In addition, the selected printing method can enable a grading close to a continuous transition from the selected maximum to the minimum. In Figure 3a A top view of a rotationally symmetric polishing agent carrier 1b is shown, which has three different hardness zones. For the three selected zones 11a, 11b, 11c, the hardness distribution is from hard to soft outward from the center of the polishing agent carrier 1b. If the surface to be polished has an edge support (Randauflage) after the pre-treatment stage, i.e., the edge must be removed vigorously, the hardness distribution can also be selected in the other direction. In Figure 3b A top view of a square polishing agent carrier 1b is shown, which has a hardness distribution changing accordingly in the X and Y directions. This arrangement illustrates that the zoning trend of the resulting polishing function can be selected. For example, the same hardness distribution is selected in the X and Y directions. The solution according to the invention also allows the selection of different hardness distribution shapes in the two axial directions. Within the resolution limit of the printing method, the number of adjustable zones can be selected infinitesimally. This is usually 160 dpi. This zoning into cylindrical surfaces and free-form surfaces presents a feasible polishing tool arrangement. Figure 3cShows a cross-section of the polishing agent carrier 1b, which has a hardness distribution that changes along the Z direction. Depending on the layer sequence, the trend of the hardness in each layer or a targeted change in hardness can occur in the Z direction. The limiting factor for the sectional resolution is the layer thickness. The typical layer thickness of the additive manufacturing process is in the range of 50 - 200 μm. The combination of the hardness functions in the X, Y, and Z directions simultaneously allows for a prescribed change in the polishing pressure 21 within the partitioned area of the polishing tool surface.

[0042] Figures 4a to 4b Exemplarily shows the introduction of a prescribed cooling channel. In principle, two arrangements of the cooling channel structure can be achieved. Figure 4a Shows the feasibility of introducing cooling channels, which can be distributed over the entire surface at the surface of the polishing agent carrier 1b, or can also be introduced only in a partitioned manner. Generally, the cooling channels near the surface ensure the uniform distribution of the polishing suspension and the removal of the removed glass residues. In this case, a linear cooling channel structure 7a, a concentric cooling channel structure 7b, or a free-form cooling channel structure 7c is introduced using the additive manufacturing process. However, if a constant removal is not desired at the surface, in the case of partitioned polishing, the distribution of the channel structure on the polishing tool surface can also be selected irregularly. The channel depth is between 1 - 5 mm, but when the polishing agent carrier 1b is used multiple times or when the polishing suspension is transported within the polishing tool 1, it can also be implemented to reach the entire depth of the polishing agent carrier, as Figure 4b shown. In this arrangement, the polishing suspension is transported in the tool and guided through the substrate into the polishing agent carrier 1b. By selecting the cooling channel parameters, especially the selected diameter and the number of cooling channel outlets at the tool carrier, the polishing pressure 21 can be adjusted specifically according to the polishing particles. In this arrangement, different polishing pressure values can also be generated partitioned on the polishing tool surface. In Figure 4b the number of built-in cooling channels in the center of the tool is selected to be higher than that in the edge region. When the rotation axis of the polishing tool 3a coincides with the rotation axis of the workpiece 3b, the increase in the polishing pressure at the center of the polishing tool 1 can be advantageously used for polishing. Similarly, Figure 4a The arrangement example of Figure 4b can be combined with the arrangement example of

[0043] Figure 5a and 5b show two feasible arrangement solutions for deterministic polishing of aspherical surfaces. In Figure 5aIn this case, the polishing tool 1 is designed for full-aperture polishing. The inverse aspherical equation of the aspherical shape to be polished is used as the target geometry for the additive process. After printing, the polishing agent carrier 1b is glued or adhered to the substrate and trimmed with a diamond tool in a polishing machine. For the orientation of the polishing function, three partition regions 11a, 11b, 11c are selected, which match the change in arrow height and the distance from the tool center. Additionally, an edge support 12 is provided, which reacts against the edge drop. Thus, the complicated arrangement of the support ring at the aspherical blank as required for traditional aspherical polishing can be dispensed with. The assembly shown is particularly suitable for aspherical pre-polishing. Even after aspherical fine polishing, an additional polishing step with the Figure 5a assembly in can be carried out in order to minimize the generated intermediate frequency error component. The polishing time for this intermediate step is selected to be very short to avoid deviation from the target shape. Figure 5b Aspherical polishing using a hierarchical adaptive sub-aperture polishing tool 1 is shown. The polishing agent carrier 1b is divided into two partitions 11a, 11b. A typical feature of this assembly is that the partition 11a has a larger diameter and a larger depth. This part of the polishing tool 1 is used for pre-polishing. After the corresponding wear of the partition 11.a, the depths of the two partitions approach each other. Thereafter, the second partition 11.b is used for fine polishing. If the wear during the polishing period is not high enough, the polishing tool 1 can be trimmed to the required target depth. In Figure 5b the assembly of, the sub-aperture polishing tool 1 can also be guided meanderingly over the surface, so that aspherical and free-form shapes without rotational symmetry can be processed.

[0044] Figure 6The component shown is suitable for polishing free-form surfaces. An exemplary freely shaped workpiece simply selected has a square bottom area of 50 mm x 50 mm and a maximum component height of 40 mm. In this example, additive manufacturing is also used as the polishing die required for the polishing tool 1. Different hardness zones are assigned according to the arrow height in the transformation of the free form. In total, the tool supports six different loaded zones. For larger arrow heights, the harder zone 11a is assigned, and for smaller arrow heights, zone 11b is assigned. According to the free-form function, an exemplary assignment may also require a significantly larger number of different zones, which can be assigned to the additive process. In this component, the required action energy is transferred to the polishing grains by a vibration component acting perpendicular to the polishing tool 1. The polishing grains are located in the effective gap 13 in a manner dissolved in the suspension. In the figure, for clarity, they are not shown. Thus, the polishing grains obtain their energy to release the required spark potential at the workpiece surface. The required vibration energy can be provided, for example, by an ultrasonic generator coupled to a synchronous electrode or by two oscillators that generate an imbalance and generate a vibration force component 14. By adjusting the amplitude and frequency of the vibration motion, the polishing pressure 21, the coefficient of friction, and the grain motion in the effective gap 13 can be adjusted. Thus, by selecting and grading the polishing agent carrier 1b, the resulting spring-damping model can be adjusted specifically.

[0045] Figure 7a and Figure 7b respectively show exemplary examples of a method for manufacturing a graded adaptive polishing tool 1. In Figure 7a , two printing systems 16a, 16b are used, which can meter and apply very small amounts of liquid polymer. Two different components are stored in these printing systems. In this case, component A has a higher hardness, while component B has a lower hardness. Both printing systems can work sequentially or in parallel and apply the corresponding printing volume required for each layer. After a layer is successfully generated, the processing platform 15 is lowered and the next layer is produced. In order to provide material properties that require a continuous conversion of parameters, the printing system in Figure 4b is used. With the mixing system 19, the starting components A and B stored in the containers 18a, 18b can be mixed in different volume percentages. The prepared mixture can be metered and applied using the print head 16c for component A + B. Additionally, Figure 7b also shows another print head 16d for the support material. The support material is metered and applied by this other print head, which can be dissolved / removed again after the construction process. Advantageously, a water-soluble polymer is used as the support material. It is necessary to introduce the support material in order to set the necessary cooling channels 8 in the polishing tool 1. After each layer is produced, the polymer is UV-hardened using a UV radiation source 20.

[0046] List of reference numerals

[0047] 1 Polishing tool

[0048] 1a Polishing substrate

[0049] 1b Polishing agent carrier

[0050] 2 Workpiece

[0051] 2a First lens

[0052] 2b Second lens

[0053] 3a Axis of rotation (polishing tool)

[0054] 3b Axis of rotation (workpiece)

[0055] 7a Cooling channel (linear)

[0056] 7b Cooling channel (concentric)

[0057] 7c Cooling channel (free form)

[0058] 8 Cooling channel (vertical)

[0059] 9a Region of higher hardness – translation, horizontal

[0060] 9b Region of medium hardness - translation, horizontal

[0061] 9c Region of lower hardness - translation, horizontal

[0062] 10a Region of higher hardness – translation, vertical

[0063] 10b Region of medium hardness - translation, vertical

[0064] 10c Region of lower hardness - translation, vertical

[0065] 11a Region of higher hardness - radial

[0066] 11b Region of medium hardness - radial

[0067] 11c Region of lower hardness - radial

[0068] 12 Edge support

[0069] 13 Effective clearance

[0070] 14 Translational periodic force component

[0071] 15 Machining platform

[0072] 16a Print head for component A

[0073] 16b Print head for component B

[0074] 16c Print head for components A + B

[0075] 16d Print head for support material

[0076] 17 Printed layer

[0077] 18a Container for component A

[0078] 18b Container for component B

[0079] 19 Mixing unit

[0080] 20 Ultraviolet radiation source

[0081] 21 Polishing pressure

[0082] 22 Workpiece carrier

Claims

1. A polishing tool (1) for treating a technical surface, the polishing tool comprising a polishing base (1a) and a polishing agent carrier (1b), in, The polishing agent carrier (1b) has at least one polishing particle, - at least one material property of the polishing medium carrier (1b) is varied vertically or horizontally to the axis of rotation (3a) of the polishing tool in order to be able to control the polishing removal function on the surface to be treated of the workpiece (2) in a targeted manner, - the polishing tool has an integrated cooling channel, through which the polishing agent suspension is conveyed, and The effect of at least one polishing particle on the workpiece surface can be influenced by changing the material properties.

2. The polishing tool (1) according to claim 1, It is characterized in that The modified material property of the polishing agent carrier (1b) is the hardness of the polishing agent carrier material, whereby the coefficient of friction of the polishing agent carrier (1b) is adjusted.

3. The polishing tool (1) according to claim 2, It is characterized in that The hardness of the polishing carrier material varies rotationally symmetrically with respect to the axis of rotation (3a) of the polishing tool (1).

4. The polishing tool (1) according to any one of claims 1 to 3, It is characterized in that The at least one material property varies locally only in individual regions of the polishing agent carrier (1b).

5. The polishing tool (1) according to any one of claims 1 to 3, It is characterized in that The at least one material property varies over the entire polishing medium carrier (1b).

6. The polishing tool (1) according to any one of claims 2 to 5, It is characterized in that The polishing agent carrier (1b) has different hardnesses in different regions (9a, 9b, 9c) arranged along a predetermined direction or two predetermined directions perpendicular to each other within a plane.

7. The polishing tool (1) according to any one of claims 1 to 6, It is characterized in that Cooling channels (7a, 7b, 7c) for conveying the polishing suspension are formed perpendicularly to the axis of rotation (3a) in the polishing medium carrier (1b) in a linear, concentric and / or freely formed structure.

8. The polishing tool (1) according to any one of claims 1 to 7, It is characterized in that Cooling channels (8) for conveying polishing suspension are formed horizontally with respect to the rotation axis (3a) in the polishing base body (1a) and the polishing agent carrier (1b).

9. The polishing tool (1) according to any one of claims 1 to 8, It is characterized in that The polishing tool (1) is designed to vary the polishing pressure.

10. The polishing tool (1) according to any one of claims 1 to 9, It is characterized in that The polishing base (1a) and the polishing agent carrier (1b) are connected to each other.

11. The polishing tool (1) according to any one of claims 1 to 10, It is characterized in that The polishing tool (1) has an edge support portion (12) having a suitable hardness for edge polishing.

12. Use of the polishing tool (1) according to any one of claims 1 to 11 for surface polishing and sub-aperture polishing of technical surfaces.

13. A method for producing a graded adaptive polishing tool (1) for polishing with loose particles, the polishing tool comprising a polishing base (1a) and a polishing agent carrier (1b), the method The following steps are involved: - providing a negative mold of the polishing agent carrier (1b), - delivering at least one polymer to at least one print head, - producing at least one layer on the negative mold by means of the print head, thereby forming a polishing agent carrier, wherein: - producing at least two regions of the polishing agent carrier (1b) having different material properties.

14. The method according to claim 13, It is characterized in that The polymer is supplied via two print heads separated from one another, which operate sequentially or in parallel during the production of at least one layer.

15. The method according to claim 13 or 14, It is characterized in that Each polymer contains at least two components, wherein the different components are mixed with one another by means of a mixer and are fed to the print head in a metered manner.

16. The method according to any one of claims 13 to 15, It is characterized in that The at least one layer is hardened by UV radiation.

17. The method according to any one of claims 13 to 16, It is characterized in that At least one layer has a continuous hardness profile.

18. The method according to any one of claims 13 to 17, It is characterized in that An additional polymer is introduced into each layer as a supporting material which is removed by dissolution after the respective layer has been produced.

19. The method according to any one of claims 13 to 18, It is characterized in that In a subsequent step after the production of the at least one layer, the shape of the polishing medium carrier (1b) is corrected in order to minimize shape deviations.

20. The method according to any one of claims 13 to 19, It is characterized in that In a subsequent step after the at least one layer has been produced, the shape of the polishing agent carrier (1b) is modified, wherein the shape of the polishing agent carrier (1b) is adapted to the surface to be polished.

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