Method for additive manufacturing

Abstract

The present invention relates to a component (1) of an eyeglass frame and a method for the additive manufacturing of such a component (1) by stereolithography, the component (1) comprising at least one eyeglass frame (3) with an inner edge (10), an inner support structure (12) being manufactured together with the eyeglass frame (3) to support the eyeglass frame (3), the inner support structure (12) of the manufactured component (1) being connected to the inner edge (10) at at least two opposing points (14), these points (14) being supported relative to each other, the surface (5) of the component (1) having at least one connection region (7), the connection region (7) being hidden in the use position of the finished eyeglass frame, an outer support structure (9) being provided, the outer support structure (9) being manufactured together with the component (1), the connection between the outer support structure (9) and the component (1) being established at the connection region (7), and the manufacturing of the inner support structure (12) being started when the connection between the outer support structure (9) and the component (1) is established.

Description

Technical Field

[0001] The present invention is a method for additively manufacturing components of an eyewear structure by stereolithography, the components comprising at least one eyewear frame having an inner edge, an inner support structure for supporting the eyewear frame being manufactured together with the eyewear frame, the inner support structure of the manufactured component being connected to the inner edge at at least two opposing points, these points being supported relative to each other, the surface of the component comprising at least one connection region, the connection region being hidden in the use position of the finished eyewear structure, an outer support structure being provided, the outer support structure being manufactured together with the component, and the connection between the outer support structure and the component being generated in the connection region.

Background Art

[0002] Manufacturing eyewear structures by laser sintering has been established. WO2011 / 089208A1 discloses special surface treatments in this context.

[0003] Also, numerous attempts have been made to use stereolithography to manufacture eyewear structures or their components. In this context, US Patent Application Publication No. 2020 / 0164591A1 discloses special geometries for protecting edges in the connection regions of mechanical components, especially temples, during surface treatment.

[0004] One disadvantage of known methods for additive manufacturing of components of an eyewear structure using stereolithography is the finishing process. This is necessary to process the inevitable connection points in this printing process so that they no longer interfere and, if possible, are no longer visible in the finished product. However, this requires the processing of different local surfaces, which can therefore only be carried out manually. The required manual processing steps are an obstacle to the widespread use of stereolithography for this application.

Summary of the Invention

[0005] The object of the present invention is to eliminate or at least reduce the disadvantages of the prior art.

[0006] According to the present invention, the manufacture of the inner support structure is started after the connection between the outer support structure and the component has been generated. In other words, the outer support structure is first built up to the connection area. Starting from the connection area, the manufacture of the component begins. At the earliest point in time when the component has been manufactured up to at least one point on the inner edge of at least one eyewear frame, the manufacture of the inner support structure can start from this point or from another point on the inner edge of at least one eyewear frame that has been manufactured up to this point and is later available and is also connected thereto.

[0007] Due to this sequence of manufacturing, all outer support structures connected to the visible surface of the component can be omitted. At least one connection area can be positioned outside the visible surface of the component. It can be provided that at least one connection area does not overlap with one of the visible surfaces of the component. In the use position of the manufactured spectacle structure, the connection area can be hidden, for example, by a temple or a veneer (e.g., a glued-on metal visor), so that it does not form part of the visible surface of the component. The visible surface is here understood to be a surface that preferably only has to meet aesthetic or physiological requirements. In other words, the surface of the component of the spectacle structure produced by stereolithography cannot be seen in the connection area, but is veneered or hidden. The connection area can be provided, for example, on the general functional surface, interface, inner surface, cut surface, contact surface, or support surface of the component. The connection area is used to connect the support structure to the spectacle component. In the completed spectacle structure, the connection area can, for example, comprise a connection to the temple. By making it possible to completely avoid the connection to the external support structure in the area of the visible surface of the component, the final processing of the component is significantly simplified and can optionally be fully automated. Thus, since the visible surface does not have irregularities due to process-related support structures, a high-quality surface can be achieved by a uniform surface treatment (washing and / or rinsing and / or polishing) of the visible surface. The uniform surface treatment can be carried out without manual steps or interventions.

[0008] In the context of the present disclosure, a support structure refers to a structure that is manufactured (e.g., printed) with a component but is not part of the component or the eyewear structure. It is a process-related structure that is required, for example, due to layer-by-layer manufacturing using stereolithography. The support structure can, for example, hold or support sections of a component that are not yet connected due to the layer-by-layer structure at the start of production. They also serve to connect the component to a possible build platform when the component should not be directly connected to the build platform due to its geometry. The support structure can also be referred to as construction geometry, support geometry, or sacrificial geometry. The fact that the support structure is manufactured with the component does not necessarily mean that each layer must be manufactured in a single exposure step. The layers of the component can be exposed in a single exposure pass and thus simultaneously with the layers of the support structure, or they can be exposed in several exposure passes, such that, for example, the layers of the component can be exposed first, and then, after a pause (e.g., 100 ms), the layers of the support structure are exposed.

[0009] In the present disclosure, an inner support structure refers to a support structure that supports at least two different points of an object (in this case, a component of an eyewear structure) manufactured by additive manufacturing relative to each other. Thus, forces are transmitted through the inner support structure within the manufactured object. In comparison, an outer support structure refers to a support structure by which the manufactured object or the inner support structure is supported thereby against an outer surface (typically, a build platform) that is not created as part of the manufacturing process. A consistent support structure can generally form both an inner support structure and an outer support structure. For example, forces can act within the manufactured object or on the outer surface depending on the direction of the force. For example, the outer support structure can absorb a vertical force that counteracts gravity and can act on horizontally spaced points of the manufactured object such that horizontal force components can be absorbed within the object. This enables different deformations (especially different deformations between different sections of the object) to be counteracted.

[0010] In this context, it is understood that at least two points where the inner support structure is connected to the inner edge are arranged on opposite sides of each other. Thus, such opposing points are not adjacent. Instead, the tangents at the opposing points of the inner edge should either be parallel and spaced apart or include an angle of at least 30°. The present disclosure does not limit itself to diametrically opposed points where these tangents are parallel and spaced apart, but also covers, for example, an inner support structure arranged in the form of an angle strut.

[0011] At least two points can (but need not) correspond to at least two distinguishable structures. For example, the inner support structure can be formed as support struts between locations in two or more individual regions of the inner edge. However, the inner support structure can also be continuously connected to the inner edge, for example, along an arc between at least two locations, or even continuously connected across the entire inner edge. The connection between the inner support structure and the inner edge at at least two points exists in the manufactured component. The corresponding connection can already be provided in the model of the component to be printed, or a small distance between the inner support structure and the inner edge can be provided in the model, which is bridged locally or continuously during manufacture by material expansion.

[0012] The inner support structure can be removed from the spectacle frame after the components of the spectacle structure are completed. This removal can be done manually or automatically, for example, by pushing it out from the spectacle frame. The connection between the inner support structure and the spectacle frame is such that the removal of the inner support structure leaves the spectacle frame (and thus the components) undamaged as a whole. In addition, residues from the inner support structure do not remain on the visible surfaces of components that it was never connected to. The inner edge of the spectacle frame (at least the area where the connection to the inner support structure existed) is not a visible surface and is hidden by the lens at the usage position of the completed spectacle structure with at least one lens. The inner edge can, for example, comprise a recess or a groove, whereby the point at which the inner support structure connects to the inner edge can be positioned, for example, at the center of the groove, or at the edge of the groove, inside the recess or the groove. Alternatively, the inner edge can, for example, comprise a step instead of a recess or a groove, or can be flat. Also, the inner support structure can connect to the inner edge in these cases as well.

[0013] As defined herein, a spectacle comprises a spectacle structure and at least one spectacle lens. One or more spectacle lenses are usually inserted into the frame in the completed spectacle structure. The present disclosure relates only to the manufacture of the spectacle structure. The spectacle structure comprises at least one spectacle frame. The spectacle frame is the part or section of the spectacle structure that at least partially surrounds at least one lens. The spectacle frame corresponds to the complete or partial boundary around at least one lens. The spectacle structure can comprise one or more components.

[0014] For example, a spectacle frame can be manufactured as one component, and two temples can be manufactured as further components and then assembled to form a spectacle structure. The present disclosure relates to components of a spectacle structure comprising at least one spectacle frame (i.e., for at least one spectacle lens). This can be the only component of the spectacle structure or can be one of several components. Spectacle structures without temples or with only one temple are also included in the present disclosure.

[0015] Optionally, the two opposing points can be arranged substantially on a horizontal line during the manufacturing process, or the virtual connection line can form an angle of less than 60°, especially less than 45°, with the horizontal line passing through the two opposing points during the manufacturing process. One aim of the present disclosure is to increase the stability of the unfinished component during the manufacturing process. It is preferred if the layer of the inner support structure that is exposed at a specific point at an appropriate time during the manufacturing process is connected to the inner edge on both sides. This allows for the use of thin and thus material-saving support structures that themselves undergo as little deformation as possible. Also, the angle formed with the horizontal line depends on whether the layer being exposed during the exposure is arranged horizontally or at a predetermined angle. The two opposing points can be arranged at least temporarily, i.e., during at least part of the manufacturing process, especially before the spectacle frame in question is fully manufactured, substantially on the horizontal line.

[0016] The inner support structure can optionally be connected to the inner edge at a plurality of opposing points, and the opposing points are arranged in pairs substantially on a horizontal line during the manufacturing process. For example, the inner support structure can be manufactured from a plurality of parallel support struts or a mesh or grid of support struts.

[0017] Optionally, the inner support structure can be manufactured as a continuous disk. This has the advantage that planning the geometry of the inner support structure is simplified. The continuous disk can be continuously connected to the inner edge, or can be provided with connections to the inner edge, for example, at regular intervals.

[0018] Optionally, the inner support structure can, for example, essentially replace a lens that can later be housed in an eyeglass frame. This is a simple way to ensure that, in the use position of the completed eyeglass structure, all points with connections to the inner edge are hidden by the lens.

[0019] Optionally, at least two inner support structures can be provided in the same eyeglass frame, with the inner support structures connected to the inner edge at respective opposite points, and the two respective opposite points being arranged substantially on a horizontal line during the manufacturing process. The inner support structures can optionally be interconnected. Alternatively, the inner support structures can be formed as separate support structures.

[0020] For example, at least two inner support structures can, in this context, be arranged substantially parallel to each other and separated by a vertical distance during the manufacturing process. This can reduce the loss of material passing through the support structures compared to a continuous disk.

[0021] The component can optionally comprise two spectacle frames connected by a bridge. Also, the bridge can optionally form the nose piece of the spectacle structure. Each spectacle frame is designed to accommodate a lens. The component can be symmetric, for example, with respect to a plane of symmetry that passes through the center of the bridge and is substantially perpendicular to the bridge. Each of the two spectacle frames can be manufactured with a separate inner support structure. The inner support structures of the two spectacle frames can optionally be connected to each other. Such connection can be achieved via the outer support structure or via the inner support structure.

[0022] In this context, the bridge can be arranged vertically during the manufacturing process or can form an angle of at most 45° with the vertical line. Thus, the orientation of the component in the space during the manufacturing process can be essentially horizontally suspended. In other words, the axis having the longest extension of the manufactured component can be essentially vertical. For example, the orientation can be such that the axis passing through the connection region and the (expected) center of gravity of the manufactured component includes an axis angle of at most 45° with the vertical line.

[0023] The outer support structure can optionally be manufactured such that it is connected to the inner support structure. This enables the inner support structure to be supported externally (e.g., on a build platform). This enables some of the forces acting on the inner support structure (especially gravity) to be diverted outwards.

[0024] In this way, the forces that will be absorbed by the component can be reduced.

[0025] The component and the inner support structure can be manufactured from the same material. The material can be, for example, a photocurable material, in particular a material that cures under UV light. Generally, the inner support structure can be manufactured from a material different from that of the component. For example, a material that can be dissolved and washed away by a cleaning process is conceivable. Using the same material simplifies the design, ensures that the plastic and mechanical properties match in all conditions, and that, for example, no stress or unwanted bonding occurs. The material can optionally be transparent or colored.

[0026] In a similar manner and with the same effects and advantages, the present invention relates to a component of an eyewear structure, the component being produced by stereolithography, the component comprising at least one eyewear frame having an inner edge, the inner support structure being disposed within the eyewear frame and connected to the inner edge at at least two opposing points, these points being supported relative to each other, and the inner support structure being connected to an outer support structure.

[0027] In the disclosed component, the connecting line passing through the two opposing points can be arranged substantially perpendicular to the longitudinal extension of the outer support structure. For example, the outer support structure is optimized to absorb gravity, and the inner support structure is optimized to absorb the lateral forces acting within the component that will be dissipated within the component in order to minimize the number of connection points of the outer support structure.

[0028] As already explained in connection with the method and with similar advantages, it is also possible to provide that in the disclosed component the inner support structure comprises a continuous disk. Also optionally, the inner support structure can essentially replace the lens that can later be accommodated within the eyewear frame in the disclosed component.

[0029] Furthermore, the surface of the component can comprise at least one connection region, the connection region being hidden in the use position of the finished spectacle structure, and the outer support structure being connected to the component at the connection region.

[0030] More generally, and independently of the features defined above and in the claims, the present disclosure also relates to a method for additive manufacturing of components of a spectacle structure by stereolithography, the component comprising at least one spectacle frame having an inner edge, the surface of the component comprising at least one connection region, the connection region being hidden in the use position of the finished spectacle structure, the component being manufactured starting from the connection region, during the manufacturing process, the axis passing through the connection region and the (expected) center of gravity of the manufactured component forming an axis angle of at most 45° with the vertical line, the support structure for supporting the spectacle frame being manufactured together with the spectacle frame, the support structure of the manufactured component being connected to the inner edge at at least one point, the tangent of the inner edge at this point forming an edge angle of at most 45° with the axis.

[0031] The component can be directly connected to the build platform in the connection area or can be connected to an outer support structure that will be pre-fabricated. The axial angle can be at most 40°, particularly at most 35°, and particularly at most 22.5°. The smaller the axial angle, the lower the torque in the connection area when the component is completed. Since the center of gravity of the unfinished component moves naturally during the manufacturing process, a non-zero axial angle may be preferred. Particularly, the contact angle can be at most 40°, particularly at most 35°, and particularly at most 22.5°. The area of the inner edge defined by the edge angle includes at least all vertical lines during the manufacturing process. The support by the support structure at these points mainly absorbs shear forces. One advantage of the support in this area is that the spring deflection formed by the unfinished (e.g., not yet fully cured) component is reduced. This can counter different expansions of the frame parts, which may otherwise occur due to the generally asymmetric shape of the spectacle frame with respect to the vertical lines. In this variant, the support structure can be an inner support structure, an outer support structure, or a combination thereof.

[0032] The present invention will be further described below with reference to particularly preferred embodiments (the present invention is not limited thereto) and with reference to the drawings. The drawings show the following in detail.

Brief Description of the Drawings

[0033]

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DETAILED DESCRIPTION OF THE INVENTION

[0034] FIGS. 1 and 2 show a component 1 of a spectacle structure. The component 1 is manufactured using stereolithography. The component 1 includes two spectacle frames 2, 3. The two spectacle frames 2, 3 are connected by a bridge 4. The surface 5 of the component 1 includes a visible surface 6 and two connection regions 7, 8. The connection regions 7, 8 are each used to connect to the temple via, for example, a hinge. The connection regions 7, 8 are hidden by the connected temples when the completed spectacle structure is in the use position. The outer support structure 9 is connected to the component at both connection regions 7, 8.

[0035] Each of the spectacle frames 2, 3 comprises an inner edge portion 10. Inner support structures 11, 12 in the form of continuous disks are arranged within each of the two spectacle frames 2, 3. In each case, the inner support structures 11, 12 serve as a substitute for lenses that can later be accommodated within the spectacle frames 2, 3. The inner support structures 11, 12 are connected to the inner edge portion 10 over their entire circumference, although the connection can be interrupted at various points due to the manufacturing process. Thus, the spectacle frames 2, 3 are self-supporting over the entire peripheral portion of the inner edge portion 10. The inner support structures 11, 12 within each of the two spectacle frames 2, 3 are additionally connected to the outer support structure 9 in each case. Component 1 itself and both the outer support structure 9 and the inner support structures 11, 12 are made from the same photocurable material.

[0036] Due to the two-dimensional continuity of the two inner support structures 11, 12, several pairs 13 of opposing points 14 can be identified, at which locations the inner support structures 11, 12 are connected to the inner edge portion 10. At least some of these pairs 13 of opposing points 14, a virtual connection line 15 can be drawn through each of the two opposing points 14, and the virtual connection line 15 is arranged substantially perpendicular to the longitudinal extension 16 of the outer support structure 9.

[0037] In the positions shown in FIGS. 1 and 2, component 1 is shown as hanging or standing above the outer support structure 9 from the build platform 17. In this position, the bridge 4 forms an angle of less than 20° with the vertical line 18. During the manufacturing process, the build platform 17 can lie in a horizontal plane and can be moved stepwise vertically to create individual layers. Thus, at least some of the opposing points 14 are arranged in pairs above the horizontal line 19 during the manufacturing process.

[0038] In FIGS. 3 and 4, it is shown that several components 1 (nine in this example) can be manufactured simultaneously in one manufacturing process on the build platform 17.

[0039] FIG. 5 shows a front view of a component 20 constructed in a manner similar to that of FIG. 1. The inner support structures 23, 24 are disposed within respective ones of the two spectacle frames 21, 22, and it can be clearly recognized that they serve in place of lenses that will subsequently be received therein. In the cross-section shown in FIG. 6 along line VI-VI in FIG. 5, it can be seen that the spectacle frame 21 has a groove 26 at its inner edge 25. The inner support structure 23 is connected to the inner edge 25 within the groove 26. Thus, the visible surface 27 of the component 20 has no connection to the inner support structure 23 and also has no outer support structure (see FIGS. 1-4). Additionally, in FIG. 6, it can be seen that the inner support structure 23 has a cross-section that is significantly smaller than that of the spectacle frame 21.

[0040] FIGS. 7 through 9 show further views of the component 1 shown in FIGS. 1 and 2, with its inner and outer support structures. In FIG. 9, the shapes of the outer support structure 9 and the connection regions 7, 8 are clearly recognizable.

Claims

1. A method for additive manufacturing of components (1) of an eyewear structure by stereolithography, wherein said component (1) comprises at least one eyewear frame (3) having an inner edge (10), and an inner support structure (12) for supporting said eyewear frame (3) is manufactured together with said eyewear frame (3), and said inner support structure (12) of the manufactured component (1) is connected to said inner edge (10) at at least two opposing points (14), and these points (14) are supported against each other, and the surface (5) of said component (1) comprises at least one connection region (7), said connection region (7) being hidden in the use position of the finished eyewear structure, and an outer support structure (9) is provided, said outer support structure (9) being manufactured together with said component (1), and the connection between said outer support structure (9) and said component (1) is generated at said connection region (7), in the method, The method is characterized in that the manufacturing of said inner support structure (12) is started after the connection between said outer support structure (9) and said component (1) has been generated.

2. The method according to claim 1, characterized in that said two opposing points (14) are arranged substantially above a horizontal line (19) during the manufacturing process, or a virtual connection line (15) passing through said two opposing points (14) forms an angle of less than 60°, especially less than 45°, with the horizontal line (19) during the manufacturing process.

3. The method according to claim 1 or 2, characterized in that said inner support structure (12) is connected to said inner edge (10) at a plurality of opposing points (14), and said opposing points (14) are arranged in pairs substantially above a horizontal line (19) during the manufacturing process.

4. The method according to any one of claims 1 to 3, characterized in that said inner support structure (12) is manufactured as a continuous disk.

5. The method according to any one of claims 1 to 4, characterized in that said inner support structure (12) substantially replaces an eyeglass lens that can later be housed in said eyewear frame (3).

6. At least two inner support structures are provided within the same spectacle frame, the inner support structures being connected to the inner edge at different opposing points, the two opposing points being arranged substantially on a horizontal line during the manufacturing process, the method according to any one of claims 1 to 5.

7. The method according to claim 6, characterized in that the at least two inner support structures are substantially parallel and separated by a vertical distance during the manufacturing process.

8. The method according to any one of claims 1 to 7, characterized in that the component (1) comprises two spectacle frames (2, 3) connected by a bridge (4).

9. The method according to claim 8, characterized in that the bridge (4) is arranged vertically during the manufacturing process or forms an angle of at most 45° with a vertical line (18).

10. The method according to any one of claims 1 to 9, characterized in that the outer support structure (9) is manufactured so that it is connected to the inner support structure (12).

11. The method according to any one of claims 1 to 10, characterized in that the component (1) and the inner support structure (12) are manufactured from the same material, in particular from a photocurable material.

12. A component (1) of a spectacle structure, the component (1) being produced by stereolithography, the component (1) comprising at least one spectacle frame (3) having an inner edge (10), an inner support structure (12) being arranged within the spectacle frame (3) and connected to the inner edge (10) at at least two opposing points (14), these points (14) being supported relative to each other, the inner support structure (12) being connected to an outer support structure (9), component (1).

13. The component (1) according to claim 12, characterized in that a virtual connection line (15) passing through the two opposing points (14) is arranged substantially perpendicular to the longitudinal extension (16) of the outer support structure (9).

14. The component (1) according to claim 12 or 13, characterized in that the inner support structure (12) comprises a continuous disk.

15. The surface (5) of the component (1) comprises at least one connection region (7), the connection region (7) being hidden in the use position of the finished spectacle structure, and the outer support structure (9) being connected to the component (1) in the connection region (7), the component (1) according to any one of claims 12 to 14.

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