Method for additive manufacturing

Abstract

The invention relates to a component (1) of an eyeglass frame and a method for additive manufacturing of such a component (1) by means of stereolithography, wherein the component (1) comprises at least one eyeglass frame (3) having an inner edge (10), wherein an inner support structure (12) is manufactured together with the eyeglass frame (3) in order to support the eyeglass frame (3), wherein the inner support structure (12) of the manufactured component (1) is connected to the inner edge (10) at at least two opposing points (14) in such a way that these points (14) are supported relative to one another, wherein a surface (5) of the component (1) has at least one connection region (7), wherein the connection region (7) is concealed in the position of use of the finished eyeglass frame, wherein an outer support structure (9) is provided, which is manufactured together with the component (1), wherein a connection between the outer support structure (9) and the component (1) is established in the connection region (7), wherein the manufacturing of the inner support structure (12) is started as soon as the connection between the outer support structure (9) and the component (1) has been established.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for additive manufacturing of a component of a spectacle structure by means of stereolithography, wherein the component comprises at least one spectacle frame with an inner edge, wherein an inner support structure for supporting the spectacle frame is manufactured together with the spectacle frame, wherein the inner support structure of the manufactured component is connected to the inner edge at least at two opposite points, such that these points are supported relative to one another, wherein the surface of the component comprises at least one connection region, wherein the connection region is concealed in the position of use of the finished spectacle structure, wherein an outer support structure is provided which is manufactured together with the component, wherein a connection between the outer support structure and the component is created in the connection region. BACKGROUND

[0002] It has been established to manufacture spectacle structures by means of laser sintering. WO 2011 / 089208 A1 discloses a special surface treatment in this context.

[0003] Numerous attempts have also been made to manufacture spectacle structures or components thereof using stereolithography. In this context, US 2020 / 0164591 Al discloses a special geometry for protecting mechanical components, in particular edges in the temple connection region, during surface treatment.

[0004] One disadvantage of the known methods for additive manufacturing of components of spectacle structures using stereolithography is the finishing process. This is necessary in order to process the connection points that are unavoidable in this printing process so that they no longer hinder and, if possible, are no longer visible on the finished product. However, this requires different local treatments of the surface, which can therefore only be carried out manually. The required manual treatment steps are an obstacle to the popularization of stereolithography in this application. SUMMARY

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

[0006] According to the invention, the manufacturing of the inner support structure is started after the connection between the outer support structure and the component has been created. In other words, the outer support structure is first built to the connection region. Starting from the connection region, the manufacturing of the component is started. The manufacturing of the inner support structure can be started from and connected to this or another point of the inner edge of the at least one spectacle frame at the earliest when the component has been manufactured to at least one point of the inner edge of the at least one spectacle frame, which point is available later.

[0007] Due to this manufacturing sequence, all external support structures connected to the visible surface of the component can be dispensed with. At least one connection region can be located outside the visible surface of the component. It can be provided that the at least one connection region does not overlap one of the visible surfaces of the component. In the position of use of the manufactured eyewear structure, the connection region can be hidden, for example, by a temple or a veneer (for example, an adhesive metal sun visor), so that it does not form part of the visible surface of the component. Visible surface is understood here as a surface that preferably only has to meet aesthetic or physiological requirements. In other words, the surface of the component of the eyewear structure produced by stereolithography is not visible in the connection region, but is veneered or hidden. The connection region can be provided, for example, on a generally functional surface, an interface, an inner surface, a cut surface, a contact surface or a support surface of the component. The connection region serves to connect the support structure to the component of the eyewear. In the finished eyewear structure, the connection region can comprise, for example, the connection to the temple. By enabling complete avoidance of the connection of the visible surface area of the component to the external support structure, the final processing of the component can be significantly simplified and, optionally, fully automated. Since the visible surface thus does not contain irregularities due to process-related support structures, a high-quality surface can be achieved by uniform surface treatment (cleaning and / or rinsing and / or grinding) of the visible surface. The uniform surface treatment can be carried out without manual work steps or interventions.

[0008] In the context of the present disclosure, support structure refers to a structure that is manufactured (for example, printed) together with the component but is not part of the component or the eyewear structure. It is a process-related structure, for example, required due to the layer-by-layer manufacturing when using stereolithography. The support structure can, for example, hold or support component segments that have not yet been connected due to the layer-by-layer structure at the beginning of production. They are also used to connect the components to a possible build platform if they should not be connected directly to the build platform due to their geometry. The support structure can also be referred to as a build geometry, a support geometry or a sacrificial geometry. The fact that the support structure is manufactured together with the component does not necessarily mean that each layer has to be manufactured in a single exposure step. A layer of the component can be exposed in a single exposure process, thus simultaneously with a layer of the support structure, or in several exposure processes, whereby, for example, a layer of the component can first be exposed and then, after a pause (for example, 100 milliseconds), a layer of the support structure is exposed.

[0009] In the present disclosure, an inner support structure refers to a support structure that supports at at least two different points of an object manufactured by additive manufacturing (in this case a component of a spectacle structure) opposite to each other. Thus, forces are transmitted within the manufactured object by the inner support structure. In contrast, an outer support structure refers to a support structure by which the manufactured object or the inner support structure is supported on an outer surface not produced as part of the manufacturing process, typically on a build platform. A coherent support structure can typically form the inner support structure and the outer support structure. Depending on the direction of the forces, forces can act within the manufactured object or on the outer surface, for example. The outer support structure can absorb vertical forces that counteract the force of gravity and act on horizontally spaced points of the manufactured object, for example, so that a horizontal force component can be absorbed within the object. This allows counteracting deformations, in particular different deformations between different sections of the object.

[0010] In this context, it is to be understood that the at least two points at which the inner support structure is connected to the inner edge are arranged opposite to each other. These opposite points are therefore not adjacent. Rather, the tangents at the opposite points of the inner edge should be parallel and spaced apart, or form an angle of at least 30°. The present disclosure is not limited to diametrically opposite points on which these tangents are parallel and spaced apart, but also encompasses inner support structures that are arranged, for example, in an angular strut manner.

[0011] The 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 a support strut between locations in two or more different regions of the inner edge. However, the inner support structure can also be connected to the inner edge continuously, for example along an arc between at least two locations, or even continuously to the entire inner edge. The connection between the inner support structure and the inner edge at the at least two points is present in the manufactured component. The respective connection can have been 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 in certain locations or continuously by material expansion during the manufacturing process.

[0012] After the component of the spectacle structure is finished, the inner support structure can be removed from the spectacle frame. This removal can be done manually or automatically, for example by pressing it out of the spectacle frame. The connection between the inner support structure and the spectacle frame is such that removing the inner support structure does not damage the spectacle frame, so that the entire component is not damaged. Furthermore, the inner support structure does not leave any residues on the visible surface of the component that is not connected. The inner edge of the spectacle frame, at least in the area where the inner support structure is connected, is not a visible surface, but is hidden by the lens in the position of use of the finished spectacle structure with at least one lens. The inner edge may, for example, comprise a recess or groove, whereby the point at which the inner support structure is connected to the inner edge can be located within the recess or groove, for example in the center of the groove or at the edge of the groove. Alternatively, the inner edge may, for example, comprise a step or be flat instead of recessed or grooved. In these cases, the inner support structure can also be connected to the inner edge.

[0013] According to the definition used herein, a spectacle comprises a spectacle structure and at least one spectacle lens. The spectacle lens or lenses are usually framed in the finished 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 the at least one lens. The spectacle frame corresponds to the complete or partial rim that surrounds the at least one lens. The spectacle structure can comprise one or more components.

[0014] For example, the spectacle frame can be manufactured as one component, while the two temples are manufactured as other components, which are then assembled into the spectacle structure. The present disclosure relates to a component of the spectacle structure, which comprises at least one spectacle frame, i.e. for at least one spectacle lens. This can be the only component of the spectacle structure or one of several components. The present disclosure also includes spectacle structures without temples or with only one temple.

[0015] Optionally, the two opposing points can be arranged substantially on a horizontal line during the manufacturing process, or the imaginary connection line can form an angle of less than 60°, in particular less than 45°, with a horizontal line through the two opposing points during the manufacturing process. One object of the present disclosure is to improve the stability of the unfinished component during the manufacturing process. It is advantageous if the layer of the inner support structure that is exposed at a certain point in time during the manufacturing process is connected on both sides to the inner edge. This allows the use of a thin, thus material-saving, support structure, which itself is subjected to as little deformation as possible. The angle to the horizontal line also depends on whether the layer that is exposed during the exposure is arranged horizontally or at an angle. The two opposing points can be arranged at least temporarily on a horizontal line, i.e. at least during a part of the manufacturing process, in particular before the spectacle frame in question is completely manufactured.

[0016] The inner support structure can optionally be connected to the inner edge at a plurality of opposing points, wherein the opposing points are each substantially arranged in a horizontal line during the manufacturing process. For example, the inner support structure can be made of a plurality of parallel support struts or a grid or lattice of support struts.

[0017] Optionally, the inner support structure can be manufactured as a continuous disc. This has the advantage of simplifying the planning of the geometry of the inner support structure. The continuous disc can be connected to the inner edge continuously or comprise connections to the inner edge, for example at regular intervals.

[0018] For example, the inner support structure can substantially occupy the place of a lens which can later be accommodated in the spectacle frame. This is a simple way of ensuring that all points of connection to the inner edge are hidden by the lens in the position of use of the finished spectacle structure.

[0019] Optionally, at least two inner support structures can be provided within the same spectacle frame, the inner support structures being connected to the inner edge at respective further opposing points, the two respective opposing points being substantially arranged in a horizontal line during the manufacturing process. The inner support structures can optionally be connected to each other. Alternatively, the inner support structures can be formed as separate support structures.

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

[0021] The component can optionally comprise two spectacle frames connected by a bridge piece. The bridge piece can also optionally form a nose pad of the spectacle structure. Each of the two spectacle frames is designed to accommodate a lens. For example, the component can be symmetrical with respect to a symmetry plane through the center of the bridge piece and substantially perpendicular to the bridge piece. 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. This connection can be achieved by an outer support structure or by the inner support structures.

[0022] In this case, the bridge piece can be arranged vertically during the manufacturing process or can form an angle of at most 45° with the vertical. Thus, the orientation of the component in space during the manufacturing process can be substantially hanging laterally. In other words, the longest extension axis of the manufactured component can be substantially vertical. For example, the orientation can be such that the axis through the connection area and the (intended) center of gravity of the manufactured component forms an axis angle of at most 45° with the vertical.

[0023] The outer support structure can optionally be manufactured to be connected to the inner support structure. This allows the inner support structure to be supported externally, for example on a build platform. This makes it possible to transfer some of the forces acting on the inner support structure, in particular the force of gravity, to the outside.

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

[0025] The component and the inner support structure can be made of the same material. This material can be a light-curing material, in particular a material that cures under UV light. In general, the inner support structure can be made of a different material than the component. For example, the use of a material that can be dissolved and washed away by a washing process can be considered. For example, the use of the same material can simplify the design and ensure that the plastic and mechanical properties are compatible in any state and no stress or accidental adhesion occurs. The material can optionally be transparent or colored.

[0026] In a similar way and with the same effects and advantages, the present disclosure also relates to a component of a spectacle structure, wherein the component is produced by means of stereolithography, wherein the component comprises at least one spectacle frame having an inner edge, wherein an inner support structure is arranged within the spectacle frame and is connected to the inner edge at least at two opposite points, such that these points are supported relative to each other, wherein the inner support structure is connected to an outer support structure.

[0027] In the disclosed component, the connecting line through the two opposite points can be arranged substantially perpendicular to the longitudinal extension of the outer support structure. For example, the outer support structure is optimized for absorbing the force of gravity, and the inner support structure is optimized for absorbing forces acting transversely thereon, which will be dissipated within the component to minimize the number of connection points of the outer support structure.

[0028] As already described in connection with the method and the similar advantages, in the disclosed component it can also be provided that the inner support structure comprises a continuous disc. Optionally, in the disclosed component, the inner support structure can also substantially occupy the place of a lens, which can later be accommodated in the spectacle frame.

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

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

[0031] The component can be directly connected to the build platform or to the outer support structure to be prefabricated in the connection area. The shaft angle can be at most 40°, in particular at most 35°, in particular at most 22.5°. The smaller the shaft angle, the lower the torque in the connection area when the component is finished. A non-zero shaft angle can be advantageous since the center of gravity of the unfinished component naturally moves during the manufacturing process. In particular, the contact angle can be at most 40°, in particular at most 35°, in particular at most 22.5°. The inner edge area defined by the edge angle at least comprises all perpendiculars during the manufacturing process. The support of the support structure at these points mainly absorbs shear forces. One advantage of the support in this area is that spring deflection by the unfinished (e.g. not yet fully solidified) component is reduced. This can counteract different expansions of the frame parts, which would otherwise occur due to the usually asymmetric shape of the spectacle frame with respect to the perpendiculars. In this variant, the support structure can be an inner support structure or an outer support structure or a combination of both. BRIEF DESCRIPTION OF DRAWINGS

[0032] The application will be further described below with reference to particularly preferred embodiments (to which the application is not limited) and with reference to the accompanying drawings. The drawings show in detail:

[0033] Figure 1 and Figure 2 a component of a spectacle structure according to a first embodiment of the present disclosure is schematically shown after finishing the component manufacturing on a build platform;

[0034] Figure 3 and Figure 4 an extended embodiment of a respective number of components of a number of spectacle structures is schematically shown;

[0035] Figure 5 a front view of a component of a spectacle structure according to a third embodiment is schematically shown;

[0036] Figure 6 a cross-sectional view of the component according to Figure 5 along the section line VI-VI is schematically shown; and

[0037] Figures 7 to 9 is a further view of the component according to Figure 1 without a build platform. DETAILED DESCRIPTION

[0038] Figure 1 and Figure 2A component 1 of a spectacle structure is shown. The component 1 is manufactured using a stereolithography technique. The component 1 comprises two spectacle frames 2, 3. The two spectacle frames 2, 3 are connected by a bridge 4. A surface 5 of the component 1 comprises a visible surface 6 and two connection areas 7, 8. The connection areas 7, 8 are each intended for connection to a temple, for example by means of a hinge. The connection areas 7, 8 are hidden by the connected temples when the finished spectacle structure is in a position of use. An outer support structure 9 is connected to the component in both connection areas 7, 8.

[0039] Each spectacle frame 2, 3 comprises an inner edge 10. Each of the two spectacle frames 2, 3 is provided with an inner support structure 11, 12 in the form of a continuous disc. In each case, the inner support structure 11, 12 occupies the position of a lens which can later be accommodated in the spectacle frame 2, 3. The inner support structure 11, 12 is connected all around to the inner edge 10, although the connection can be interrupted in places due to the manufacturing process. The spectacle frame 2, 3 is thus itself supported on the entire circular edge of the inner edge 10. Each of the two spectacle frames 2, 3 is provided with an inner support structure 11, 12 which is also connected to the outer support structure 9 in each case. The component 1 itself, as well as the outer support structure 9 and the inner support structures 11, 12, are each made of the same light-curing material.

[0040] Due to the two-dimensional continuity of the two inner support structures 11, 12, a number of pairs 13 of opposing points 14 can be identified at which the inner support structures 11, 12 are connected to the inner edge 10. In at least some of these pairs 13 of opposing points 14, an imaginary connecting line 15 can be drawn through the two respective opposing points 14, wherein the imaginary connecting line 15 is arranged substantially perpendicular to a longitudinal extension 16 of the outer support structure 9.

[0041] In the position shown in Figure 1 and Figure 2 , the component 1 is shown hanging or standing on the outer support structure 9 from a build platform 17. In this position, the bridge 4 forms an angle of less than 20° with a vertical line 18. During the manufacturing process, the build platform 17 can be located in a horizontal plane and moved vertically step by step to produce the individual layers. Accordingly, at least some of the pairs of opposing points 14 are arranged on a horizontal line 19 during the manufacturing process.

[0042] In the position shown in Figure 3 and Figure 4 , several components 1 (in this case 9) can be manufactured simultaneously on the build platform 17 in one manufacturing process.

[0043] Figure 5 is shown in the same way as Figure 1A front view of component 20 constructed in a similar manner. It can be clearly seen that inner support structures 23 and 24 are respectively provided in the two eyeglass frames 21 and 22, occupying the positions where lenses are later accommodated in the eyeglass frames 21 and 22. Figure 6 As shown along Figure 5 In the cross-section along line VI-VI, it can be seen that the eyeglass frame 21 includes a groove 26 in the inner edge 25. The inner support structure 23 is connected to the inner edge 25 within the groove 26. Therefore, the visible surface 27 of component 20 is not connected to the inner support structure 23 or any outer support structure (see [reference]). Figures 1 to 4 In addition, in Figure 6 As can be seen, the cross-section of the inner support structure 23 is significantly smaller than the cross-section of the eyeglass frame 21.

[0044] Figures 7 to 9 It shows Figure 1 and Figure 2 A further view of component 1 shown, including its inner support structure and outer support structure. Figure 9 In the middle, the shape of the external support structure 9 and the connection areas 7 and 8 can be clearly identified.

Claims

1. Method for additive manufacturing of a component (1) of a spectacle structure by means of stereolithography, wherein the component (1) comprises at least one spectacle frame (3) having an inner edge (10), wherein an inner support structure (12) for supporting the spectacle frame (3) is manufactured together with the spectacle frame (3), wherein the inner support structure (12) of the manufactured component (1) is connected to the inner edge (10) at least at two opposite points (14) in such a way that these points (14) are supported relative to one another, wherein a surface (5) of the component (1) comprises at least one connection region (7), wherein the connection region (7) is concealed in the position of use of the finished spectacle structure, wherein an outer support structure (9) is provided, which is manufactured together with the component (1), wherein a connection between the outer support structure (9) and the component (1) is created in the connection region (7), characterized in that the manufacturing of the inner support structure (12) is started after the connection between the outer support structure (9) and the component (1) has been created.

2. The method of claim 1, wherein, During the manufacturing process, the two opposite points (14) are arranged essentially on a horizontal line (19), or during the manufacturing process, an imaginary connecting line (15) through the two opposite points (14) forms an angle of less than 60° with a horizontal line (19).

3. The method of claim 1, wherein, The inner support structure (12) is connected to the inner edge (10) at a plurality of opposite points (14), which during the manufacturing process are arranged essentially in pairs on a horizontal line (19).

4. The method of claim 3, wherein, The inner support structure (12) is manufactured as a continuous disc.

5. The method of claim 4, wherein, The inner support structure (12) essentially occupies the position of a spectacle lens, which can later be accommodated in the spectacle frame (3).

6. The method of claim 1, wherein, At least two inner support structures are provided within one and the same spectacle frame, which are connected to the inner edge at different opposite points, which during the manufacturing process are arranged essentially in two opposite positions on a horizontal line.

7. The method of claim 6, wherein, During the manufacturing process, the at least two inner support structures are essentially parallel and are separated by a vertical distance.

8. The method of claim 1 or 2, wherein, The component (1) comprises two spectacle frames (2, 3) which are connected by a bridge piece (4).

9. The method of claim 8, wherein, The bridge piece (4) is arranged perpendicularly during the manufacturing process or forms an angle of at most 45° with a perpendicular line (18).

10. The method of claim 1 or 2, wherein, The outer support structure (9) is manufactured in such a way that it is connected to the inner support structure (12).

11. The method of claim 1 or 2, wherein, The component (1) and the inner support structure (12) are made of the same material, in particular a light-curing material.

12. The method of claim 1, wherein, During the manufacturing process, an imaginary connecting line (15) through the two opposite points (14) forms an angle of less than 45° with a horizontal line (19).

13. Component (1) of a spectacle structure, wherein the component (1) is produced by means of stereolithography, wherein the component (1) comprises at least one spectacle frame (3) having an inner edge (10), wherein an inner support structure (12) is arranged within the spectacle frame (3) and is connected to the inner edge (10) at least at two opposite points (14) in such a way that these points (14) are supported relative to one another, wherein the inner support structure (12) is connected to an outer support structure (9).

14. A component (1) according to claim 13, characterized in that An imaginary connecting line (15) through the two opposite points (14) is arranged essentially perpendicular to a longitudinal extension (16) of the outer support structure (9).

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

16. A component (1) according to claim 13 or 14, characterised in that A surface (5) of the component (1) comprises at least one connection region (7), which is concealed in the position of use of the finished spectacle structure, in which the outer support structure (9) is connected to the component (1).

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