Integration of leaky optical fibers in 3D printed articles

Abstract

The invention provides a method for manufacturing a 3D article by means of fused deposition modeling, wherein the 3D article further at least partially comprises an optical fiber; the method comprises: (A) a 3D printing stage comprising layer-by-layer deposition of a 3D printable material to provide a multi-layer 3D printed material wherein the multi-layer comprises n sets of two stacked layers wherein each set comprises a first layer and a second layer; wherein n > = 1; (B) k1 integration stages wherein each integration stage comprises (a) after providing a first layer of one of the n groups, providing an optical fiber on the first layer such that the optical fiber extends from the first layer and at least partially protrudes into the first layer, thereby forming at least a portion of the via, and (b) subsequently providing a second layer on the first layer and the portion of the optical fiber, causing portions of the optical fibers to reside in vias formed in the layers of the set; (C) performing a 3D printing stage and k integration stages such that the optical fiber forms p external loops, where k1 > = 2, and where 1 < = p < = k1-1.

Description

Technical Field

[0001] The present invention relates to a method for producing a 3D (printed) object. Furthermore, the present invention may relate to a software product for executing such a method. Furthermore, the present invention relates to a 3D (printed) object obtainable by such a method. Furthermore, the present invention relates to a lighting device including such a 3D (printed) object. Furthermore, the present invention may relate to a 3D printer, such as a 3D printer for use in such a method. Background Art

[0002] Methods of 3D printing parts that incorporate fibers are known in the art.

[0003] US2017157851A1 describes a method and apparatus for 3D printing parts that incorporate long fiber reinforcements in advanced composite materials. A nozzle for a 3D printing device receives a polymer material and reinforcing fibers through separate inlets. A passageway from the reinforcing fiber inlet cuts through a passageway containing the polymer material to create a gap cavity into which the reinforcing fibers are introduced. The polymer material closes in on itself and encapsulates the reinforcing fibers, then drags the fibers with it as it flows and exits the nozzle for deposition on the work surface or part being manufactured.

[0004] EP3363619A1 discloses a method comprising 3D printing a 3D object. The method comprises depositing a 3D printable material and an optical fiber during a printing phase to provide a 3D object having the optical fiber at least partially embedded in the 3D printing material. During at least a portion of the printing phase, the 3D printable material comprises a light-transmitting material. The method further comprises providing a light escape portion during the printing phase, the light escape portion comprising the 3D printing material, the 3D printing material comprising the light-transmitting material, wherein visible light propagating through the optical fiber can escape from the optical fiber to the exterior of the 3D object via the 3D printing material comprised by the light escape portion. Summary of the Invention

[0005] Over the next 10 to 20 years, digital manufacturing will increasingly transform the nature of global manufacturing. One aspect of digital manufacturing is 3D printing. Currently, many different technologies have been developed to produce a variety of 3D-printed objects using a variety of materials, such as ceramics, metals, and polymers. 3D printing can also be used to produce molds, which are then used to replicate objects.

[0006] To create the mold, polymer jetting techniques have been proposed. This type of technique utilizes the deposition of layer-by-layer photopolymer material, which is cured after each deposition to form a solid structure. While this technique produces a smooth surface, photocurable materials are not very stable and have relatively low thermal conductivity, which is useful for injection molding applications.

[0007] The most widely used additive manufacturing technology is the process known as fused deposition modeling (FDM). FDM is an additive manufacturing technique commonly used for modeling, prototyping, and production applications. FDM lays down material layer by layer according to an "additive" principle: a plastic filament or metal wire is unwound from a coil and applied to produce the part. Optionally (for thermoplastics, for example) the filament is melted and extruded before being laid down. FDM is a rapid prototyping technique. Other terms for FDM are "fused filament fabrication" (FFF) or "filament 3D printing" (FDP), which are considered equivalent to FDM. Generally speaking, an FDM printer uses a thermoplastic filament, which is heated to its melting point and then extruded layer by layer (actually, one filament at a time) to create a three-dimensional object. FDM printers are relatively fast, low-cost, and can be used to print complex 3D objects. These printers are used to print a wide variety of shapes using a variety of polymers. The technology has also been further developed in the production of LED lamps and lighting solutions.

[0008] It is desirable to further control the structure and appearance of 3D printed objects, such as for optical properties, tactile properties, mechanical properties, aesthetic properties, etc. In particular, it is desirable to have methods that can incorporate optical fibers into 3D objects to create improved lighting surfaces. However, current methods do not provide such options, or provide them only in a limited and often unreliable manner.

[0009] Therefore, one aspect of the present invention is to provide an alternative 3D printing method and / or 3D (printed) article, which preferably further at least partially alleviates one or more of the above-mentioned disadvantages. The present invention aims to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0010] Thus, in a first aspect, the present invention provides a method for producing a 3D object by means of fused deposition modeling. The 3D object at least partially comprises an optical fiber. The optical fiber is a leaky optical fiber partially integrated into the 3D object. The method comprises a 3D printing stage. The 3D printing stage comprises layer-by-layer deposition of an extrudate, the extrudate comprising a 3D printable material. Such layer-by-layer deposition provides a multilayer 3D printed material. The multilayer comprises n groups of two stacked layers, for example, two adjacent stacked layers. Each group comprises a first layer and a second layer. The multilayer printed material comprises at least one group of two stacked layers, i.e., n≥1. The method comprises k1 integration stages, where k1≥2. Each integration stage comprises: (a) after providing a first layer of one of the n groups, providing an optical fiber on the first layer such that the optical fiber extends from the first layer and at least partially protrudes into the first layer, thereby forming at least a portion of a through-hole, and (b) subsequently providing a second layer on the first layer and a portion of the optical fiber such that a portion of the optical fiber resides in the through-hole formed in the layer of the group. The method comprises performing a 3D printing phase and k1 integration phases such that the optical fiber forms p external loops, ie, external loops extending to multiple layers of 3D printed material, where 1≤p≤k1-1.

[0011] Therefore, the present invention provides a method for producing a 3D object by means of fused deposition modeling, wherein the 3D object also includes, at least in part, a leaky optical fiber; the method comprises: (A) a 3D printing stage, which comprises depositing 3D printable material layer by layer to provide a multilayer 3D printed material, wherein the multilayer comprises n groups of two stacked layers, wherein each group comprises a first layer and a second layer; wherein n≥1; (B) k1 integration stages, wherein each integration stage comprises: (a) after providing a first layer of one of the n groups, providing an optical fiber on the first layer so that the optical fiber can extend from the first layer and can at least partially protrude into the first layer, thereby forming at least a portion of a through hole, and (B) subsequently providing a second layer on the first layer and a portion of the optical fiber so that a portion of the optical fiber can reside in the through hole formed in the layer of the group; (C) performing the 3D printing stage and k1 integration stages so that the optical fiber forms p external loops, wherein k≥2, and wherein 1≤p≤k1-1.

[0012] Using this type of method, 3D objects with integrated leaky optical fibers can be provided in a reliable manner without showing defects in the 3D printing. In addition, the method can provide 3D objects with improved lighting surfaces. Using the present invention, it is also possible to control the spatial distribution of the optical fibers while printing relatively easily. In particular, the optical fibers can be maintained in the desired position while being firmly integrated into the 3D object in a reliable manner. Light can escape from the optical fibers, where the light generating device is produced by a technique such as 3D printing. In addition, the present invention can provide improved material efficiency because a relatively small part of the optical fiber can be surrounded by the 3D printed layer. Therefore, a large part of the optical fiber can be uncovered, so that light can be provided with relatively high efficiency.

[0013] As indicated above, the present invention provides a method for producing 3D (printed) objects by means of fused deposition modeling. In this context, the 3D object at least partially comprises a leaky optical fiber. The term "leaky optical fiber" or similar terms may refer to an optical fiber that, when light is provided (entered) into the optical fiber during an operational mode, may suffer from propagation losses over at least part of its length due to some light escaping from the optical fiber. For example, light may escape into the cladding of the fiber (i.e., leak into the cladding of the fiber), for example by distortion of the total internal reflection of the fiber by reflective particles (see also below), and / or the cladding may be interrupted to allow light to escape. As a result, the light decays slowly in the direction of propagation, and the fiber may provide a glowing appearance.

[0014] Through the method described herein, an optical fiber is partially integrated into a 3D object. The method includes a 3D printing phase. The 3D printing phase generally includes feeding a 3D printable material, forming an extrudate, and depositing the 3D printable material to provide a 3D object comprising the 3D printable material. The 3D printing phase includes depositing the 3D printable material layer by layer to provide multiple layers of the 3D printable material.

[0015] In one embodiment, 3D printable material may be provided to a 3D printer, specifically a print head of the 3D printer. The 3D printable material may then be extruded by the print head through a nozzle onto a receiver object. For example, in one embodiment, the 3D printable material may be deposited onto a printing platform. Specifically, in one embodiment, the 3D printable material may be deposited in a single direction, thereby providing a stream of 3D printable material. Through deposition, the 3D printable material becomes 3D printing material.

[0016] Furthermore, the printing direction of the 3D printable material may be in particular along the longitudinal axis (A X In this article, the longitudinal axis (A X) may refer to an axis that is aligned with the length of the corresponding 3D printed layer (and therefore aligned with the printing path of the corresponding 3D printed layer). In embodiments, the corresponding 3D printed layer may not be straight in length, for example, the layer may include curves or corners, and thus, the 3D printed layer may include a local direction of its length at a particular location. Thus, in such embodiments, the longitudinal axis (A) may be aligned with the length of the corresponding 3D printed layer (and therefore aligned with the printing path of the corresponding 3D printed layer). X ) can include curvature (like the average center circle of a ring).

[0017] Thus, in an embodiment, the 3D printable material may be deposited layer by layer, thereby providing multiple layers of 3D printable material. Thus, by depositing multiple layers of 3D printable material in a stacked manner, a 3D object may be provided.

[0018] A multilayer (of a 3D printed object) comprises n groups of two (adjacent) stacked layers. Each group comprises a first layer and a second layer. The second layer (of the first group) may be the first layer of another group (i.e., the first layer of the second group). For example, in an embodiment, a multilayer may comprise three layers (e.g., layer a, layer b, and layer c) and two groups (i.e., n=2). In such embodiments, layer a may be the first layer of the first group, layer b may be the second layer of the first group and the first layer of the second group, and layer c may be the second layer of the second group. However, in other embodiments, the second layer of the first group may be different from the first layer of the second group. It should be noted that in principle a single group may be sufficient, however, in practice a multilayer may comprise multiple groups.

[0019] The multilayer comprises at least one group, such as at least two groups, like at least five groups, and in particular at least ten groups. Thus, n ≥ 1. However, in an embodiment, the multilayer may comprise at most 5 groups, such as at least 10 groups, like selected from the range of 5 to 200 groups. However, other values ​​are also possible.

[0020] In addition to 3D printing multiple layers of 3D printable material during the printing phase to provide the 3D object, leaky optical fibers are also partially integrated into the 3D object.

[0021] Therefore, the method further comprises an integration phase. In particular, the method comprises k1 integration phases, wherein k1 is equal to 2 or more than 2, such as at least 4, like at least 10. Therefore, k1 ≥ 2. Furthermore, in embodiments, k1 may be at least 10, such as selected from the range of 2 to 1000, such as 5 to 500, in particular from 4 to 100, or from 3 to 50. However, other values ​​are also possible.

[0022] Each integration stage includes: (a) after providing a first layer of one of the n groups, providing an optical fiber on the first layer, and (b) subsequently providing a second layer on the first layer and a portion of the optical fiber. The optical fiber extends from the first layer and partially protrudes into the first layer. Thus, the optical fiber forms at least a portion of the through-hole (through the first layer). Furthermore, in an embodiment, the optical fiber may (also) extend from the first layer and the second layer and partially protrude into the first layer and the second layer. Thus, the optical fiber forms at least a portion of the through-hole (through the first layer and the second layer). In particular, a portion of the optical fiber resides in the through-hole formed in the layer of the group. In this document, the phrase "the optical fiber may extend from x" or similar terms may refer to an optical fiber protruding from x. For example, the optical fiber may extend from the first layer and partially protrude into the first layer, i.e., the portion of the optical fiber protruding into the first layer is in contact with the first layer, while the portion of the optical fiber protruding from the first layer is not in contact with the first layer.

[0023] As mentioned above, the optical fiber may be arranged on the first layer (of a set of stacked layers). In particular, in embodiments, the optical fiber may not be (anti-)parallel to the longitudinal axis (A) of the first (and second) layer. X For example, in an embodiment, the (local) longitudinal axis (A) of the first (and second) layer may be perpendicular to the (local) longitudinal axis (A) of the first (and second) layer. X ) provides optical fibers. Thus, in an embodiment, the optical fibers may be arranged at a fiber angle (α F ) provides the fiber angle (α F ) can be relative to the longitudinal axis (A X ) is defined. In particular, in the embodiment, 10°≤α F ≤90, such as 45°≤α F ≤85, like 10°≤α F ≤45. More particularly, in the embodiment, α F ≠0°. Thus, in embodiments, the optical fibers may be arranged non-parallel with respect to the first (and second) layer.

[0024] As mentioned above, in embodiments, the optical fiber may be perpendicular to the local longitudinal axis (A) of the first layer. X) is provided. Here, perpendicular does not necessarily mean that the optical fiber is never parallel to the first layer. In embodiments, a portion of the one or more outer loops of the optical fiber may be parallel to the first layer, as long as the optical fiber is not completely parallel to the first layer. In embodiments, only a relatively small portion of the one or more outer loops of the optical fiber may be parallel to the first layer, such as <10% of the loop, like <5%. However, in other embodiments, a relatively large portion of the one or more outer loops of the optical fiber may be parallel to the first layer, such as >50% of the loop, like >75%, excluding 100% (because in this case there are no outer loops, i.e. outer loops of multiple layers of 3D printed material (see also below), like selected from the range of 55% to 98%).

[0025] As described above, after providing the optical fiber on the first layer, the second layer is provided over the first layer and a portion of the optical fiber. In particular, in embodiments, the optical fiber can be recessed into the first layer such that the optical fiber and the first layer provide a smooth contact surface for the second layer, i.e., the optical fiber can be completely recessed into the first layer. In other embodiments, the optical fiber can be partially recessed into the first layer such that the optical fiber protrudes from the first layer to provide a (slightly) textured contact surface for the second layer. In other embodiments, the optical fiber can be provided on the first layer without being recessed into the first layer. In such embodiments, the second layer can be provided over the first layer and the optical fiber such that the optical fiber is (substantially completely) recessed into the second layer.

[0026] In embodiments, the layers of the 3D printed material may each have a layer height (H), see also below. In particular, the layer height (H) may be individually selected for each layer in a multilayer 3D printed material. In embodiments, the multilayers may have essentially the same layer height (H). However, in other embodiments, two or more layers in the multilayer may differ in their individually selected layer height (H). Furthermore, in embodiments, the optical fiber may have a fiber diameter (D f ), in particular the fiber diameter (D) defined in a plane perpendicular to the fiber length (L1) of the optical fiber f ) (See also below). Fiber diameter (D f ) may be selected from the range of 50 μm to 2000 μm, such as the range of 100 μm to 1000 μm, like the range of 100 μm to 500 μm. In particular, in an embodiment, the fiber diameter (D f ) can be smaller than two layers of 3D printing material, i.e. the fiber diameter (D f ) can be less than twice the layer height (H). In an embodiment, 0.05*H≤D f <2*H, especially 0.1*H≤D f <2*H, such as 0.2*H≤D f ≤1.5*H, like 0.5*H≤D f ≤1*H.

[0027] Furthermore, as described above, the method includes performing a 3D printing phase and k1 integration phases, such that the optical fiber forms p external loops. Thus, the method includes performing two or more integration phases, i.e., k1 ≥ 2. For example, in one embodiment, k1 = 2, such that the optical fiber can pass through the layers of the group in a first direction (through a through-hole), forming a loop, and then pass through the layers of the group in a second direction (different from the first direction) (through another through-hole), such as a layer of the same group. In such an example, k1 = 2 and p = 1. Thus, the number of loops can be fewer than the number of integration phases. In particular, 1 ≤ p ≤ k1 - 1. In another example, in one embodiment, k1 = 3, such that the optical fiber can pass through the layers of the group in a first direction (through a first through-hole), forming a first loop, and then pass through the layers of the group in a second direction (different from the first direction) (through a second through-hole), such as a layer of the same group. Subsequently, in such an embodiment, the optical fiber can form a second loop and then pass through the layers of the group in a third direction (different from the second direction) (through a third through-hole), such as a layer of the same group. In an embodiment, the method may comprise forming at least one loop, such as at least five loops, like at least ten loops. Thus, the method may comprise forming p loops such that p ≥ 1. In particular, p may be selected from the range of 1 to 100, such as the range of 4 to 100, in particular the range of 3 to 50, such as the range of 1 to 15.

[0028] Thus, in an embodiment, each loop can be defined between a group of two through-holes. In particular, the optical fiber can form a loop outside the multilayer (i.e., can form an external loop) and can be secured to the multilayer via a group of two through-holes (i.e., the optical fiber can protrude from the multilayer twice to form a loop). Thus, in an embodiment, the optical fiber can (i) extend from the first through-hole, i.e., protrude from the first through-hole, (ii) form a loop (or curve), and (iii) protrude into the second through-hole. Similarly, it can be said that the optical fiber can (i) extend from the second through-hole, i.e., protrude from the second through-hole, (ii) form a loop (or curve), and (iii) protrude into the first through-hole. Because the optical fiber forms a loop outside the multilayer but is secured to the multilayer via the integration of two through-holes, the optical fiber is partially integrated into the multilayer. In other words, portions of the optical fiber, rather than the entire optical fiber, are bonded between the multiple layers of 3D printed material.

[0029] In an embodiment, the two through holes of a single loop may be configured in layers of the same group, i.e., the first layer and the second layer may be the same layer for the two through holes of a single loop. However, in an embodiment, the two through holes of a single loop may also be configured in layers of different groups, i.e., the first layer and the second layer may be different for the two through holes of a single loop. For example, in an embodiment, the first through hole of a loop may be configured between the main first layer and the main second layer (i.e., the layers of the main group), while the second through hole of the same loop may be configured between the secondary first layer and the secondary second layer (i.e., the layers of the secondary group). In an embodiment, the main first layer and the secondary first layer may be the same layer, and similarly, the main second layer and the secondary second layer may be the same layer, i.e., the first through hole and the second through hole of a loop may be configured in layers of the same group. However, in other embodiments, for example, the main second layer may be the same layer as the secondary first layer, while the main first layer and the secondary second layer may both be different layers. In other embodiments, the primary first layer, the primary second layer, the secondary first layer and the secondary second layer may all be different (separate) layers, ie the first through-hole and the second through-hole of the loop may be arranged in different groups of layers.

[0030] As indicated above, the method includes depositing a 3D printable material during the printing phase. As used herein, the term "3D printable material" refers to the material to be deposited or printed, and the term "3D printed material" refers to the material obtained after deposition. These materials can be fundamentally the same, as 3D printable material can specifically refer to material in a printer head or extruder that is exposed to high temperature, and 3D printed material refers to the same material, but at a later stage in deposition. In embodiments, the 3D printable material can be printed as a filament and deposited as such. The 3D printable material can be provided as a filament or can be formed into a filament. Thus, regardless of the starting material used, a filament comprising the 3D printable material can be provided by the printer head and 3D printed. The term "extrudate" can be used to define 3D printable material downstream of the printer head but not yet deposited. The latter can be referred to as "3D printed material." In fact, the extrudate can be considered to include 3D printable material because it has not yet been deposited. When depositing 3D printable materials or extrudates, the materials may therefore be indicated as 3D printing materials. Fundamentally, these materials may be the same material as the thermoplastic material upstream of the print head, downstream of the print head, and may be the same material(s) when deposited.

[0031] In this document, the term "3D printable material" may also be indicated as "printable material". The term "polymeric material" may refer to a mixture of different polymers in embodiments, but may also refer to a single polymer type with fundamentally different polymer chain lengths in embodiments. Thus, the term "polymeric material" or "polymer" may refer to a single type of polymer, but may also refer to a plurality of different polymers. The term "printable material" may refer to a single type of printable material, but may also refer to a plurality of different printable materials. The term "printed material" may refer to a single type of printed material, but may also refer to a plurality of different printed materials.

[0032] Therefore, the term "3D printable material" can also refer to a combination of two or more materials. Generally speaking, these (polymeric) materials have a glass transition temperature (T g ) and / or melting temperature (T m ). The 3D printable material will be heated by the 3D printer to a temperature of at least the glass transition temperature, and generally at least the melting temperature, before exiting the nozzle. Thus, in certain embodiments, the 3D printable material comprises a 3D printable material having a glass transition temperature (T g ) and / or melting point (T m ) of a thermoplastic polymer, and the printer head action may include heating the 3D printable material above the glass transition temperature, and in embodiments above the melting temperature (particularly when the thermoplastic polymer is a semi-crystalline polymer). In yet another embodiment, the 3D printable material includes a thermoplastic polymer having a melting point (T m ) of a (thermoplastic) polymer, and the 3D printing stage may comprise heating the 3D printable material to be deposited on the receiver item to a temperature of at least the melting point. The glass transition temperature is generally different from the melting temperature. Melting is a transition that can occur in crystalline polymers. Melting can occur when the polymer chains break away from their crystal structure and become a disordered liquid. The glass transition can be a transition that occurs in amorphous polymers; that is, the chains of the polymer are not arranged into ordered crystals, but are scattered around in any way, even if they are in the solid state. Polymers can be amorphous, essentially having a glass transition temperature but no melting temperature, or can be (semi-)crystalline, generally having a glass transition temperature and a melting temperature, where the latter is generally greater than the former. The glass temperature can be determined, for example, using differential scanning calorimetry. The melting point or melting temperature can also be determined using differential scanning calorimetry.

[0033] The printable material can be printed onto a receiver object. In particular, the receiver object can be a build platform or can be included in the build platform. During 3D printing, the receiver object can also be heated. However, during 3D printing, the receiver object can also be cooled.

[0034] The phrase "printing on a receiver item" and similar phrases include printing directly on the receiver item, or printing on a coating on the receiver item, or printing on 3D printing material previously printed on the receiver item. The term "receiver item" may refer to a printing platform, print bed, substrate, support, build plate, or build platform, etc. ... The term "substrate" may also be used instead of the term "receiver item". The phrase "printing on a receiver item" and similar phrases also include printing on a separate substrate on or comprised by a printing platform, print bed, support, build plate, or build platform, etc. ... Therefore, the phrase "printing on a substrate" and similar phrases include printing directly on a substrate, or printing on a coating on a substrate, or printing on 3D printing material previously printed on a substrate. Hereinafter, the term "substrate" is also used, which substrate may refer to a printing platform, print bed, substrate, support, build plate, or build platform, etc., or a separate substrate on or comprised thereby.

[0035] The printable material may be deposited layer by layer, thereby generating a 3D printed object (during a printing phase). The 3D printed object may display a characteristic ribbed structure (deriving from the deposited filaments). However, it is also possible that after the printing phase, further phases, such as a finishing phase, are performed. This phase may include removing the printed object from the receiver object and / or one or more post-processing actions. One or more post-processing actions may be performed before removing the printed object from the receiver object, and / or one or more post-processing actions may be performed after removing the printed object from the receiver object. Post-processing may include, for example, one or more of polishing, coating, adding functionalized features, etc. Post-processing may include smoothing the ribbed structure, which may result in a substantially smooth surface.

[0036] In particular, the 3D object comprises one or more layers of 3D printed material. More particularly, the 3D object comprises multiple layers of 3D printed material. The 3D object may comprise two or more layers of 3D printed material, such as at least 5 layers, such as at least 10 layers, and in an embodiment at least 20 layers.

[0037] A 3D-printed object can include multiple layers stacked on top of each other, i.e., a stack. The width (thickness) (W) and height (H) of a (separately 3D-printed) layer can, for example, be selected from a range of 100 μm to 5000 μm, such as 200 μm to 2500 μm, in embodiments, where the height (H) is generally smaller than the width (W). For example, the ratio of height (H) to width (W) can be equal to or less than 0.8, such as equal to or less than 0.6.

[0038] Layers can be core-shell layers or can be composed of a single material. Within a layer, there can also be variations in composition, such as when a core-shell printing process is applied and during the printing process it changes from printing a first material (and not printing a second material) to printing a second material (and not printing the first material).

[0039] At least a portion of the 3D printed article may include a coating.

[0040] Referring back to the optical fiber, the optical fiber can transmit light. Specifically, in embodiments, light provided to the optical fiber (by a light source) can propagate through the optical fiber. More specifically, light propagating through the optical fiber (leaking) can escape from the optical fiber to the exterior of the multi-layer 3D printed material. Specifically, the light can include visible light, i.e., light having one or more wavelengths within the wavelength range of 380 nm to 780 nm. For example, the light can be white light, while in other embodiments, the light can be colored light. However, other embodiments, such as color-controllable embodiments, are also possible.

[0041] Because the method includes k1 integration stages, optical fibers can be integrated into multiple layers of 3D printed material multiple times. In one embodiment, optical fibers can be provided to the multiple layers of 3D printed material in a fundamentally identical manner for each of the k1 integration stages. However, in other embodiments, optical fibers can be provided to the multiple layers of 3D printed material in different manners for each of the k1 integration stages.

[0042] In certain embodiments, at least one of the k1 integration stages may include: (a) after providing a first layer of one of the n groups, providing an optical fiber on the first layer such that the optical fiber extends from the first layer and protrudes into the first layer, thereby forming a through-hole, and (b) subsequently providing a second layer on the first layer and a portion of the optical fiber such that the portion of the optical fiber resides in the through-hole formed in the layer of the group. Thus, in such embodiments, the optical fiber may be recessed in the first layer such that the optical fiber and the first layer provide a smooth contact surface for the second layer. Thus, in such embodiments, the through-hole may be entirely contained in the first layer.

[0043] In other specific embodiments, at least one of the k1 integration stages may include subsequently providing a second layer over the first layer and portion of the optical fiber, such that the optical fiber also extends from the second layer and also protrudes at least partially into the second layer, thereby forming another portion of the through-hole, and such that a portion of the optical fiber resides in the through-hole provided by the set of layers. Thus, in such embodiments, the optical fiber may be partially recessed in the first layer, such that the optical fiber may protrude from the first layer to provide a (slightly) textured contact surface for the second layer. Thus, in such embodiments, the through-hole may be partially included in the first layer and partially included in the second layer.

[0044] Such methods can provide the benefit of securely integrating optical fibers into 3D objects. In particular, during the printing process, the optical fibers can be securely held in place due to their recessing into adjacent layers, i.e., movement of the optical fibers can be reduced.

[0045] Furthermore, in embodiments, printing conditions may be selected to achieve specific results. In particular, in embodiments, during at least one of the k1 integration stages, printing conditions may be selected such that, when providing the first layer with an optical fiber, the temperature of the 3D printed material of the first layer at the location where the optical fiber contacts the 3D printed material may be higher than the melting temperature (T m More specifically, the temperature of the first layer of 3D printing material at the location where the optical fiber contacts the 3D printing material may be higher than the melting temperature (T m ) is at least 5°C higher, such as higher than the melting temperature (T m ) is at least 10°C higher than the melting temperature of the 3D printing material (T m ) at least 20°C higher, especially higher than the melting temperature (T m ) at least 30℃ higher.

[0046] Thus, in a particular embodiment, the method may include selecting printing conditions during at least one of the k1 integration stages such that, when providing the optical fiber on the first layer, the temperature of the 3D printed material of the first layer at the location where the optical fiber contacts the 3D printed material may be higher than the melting temperature (T m ).

[0047] Such embodiments can be beneficial in preventing defects in 3D-printed articles due to the integration of fibers during the printing process. Furthermore, such printing conditions can improve adhesion between layers of 3D-printed material. Furthermore, during the integration phase with the conditions described herein, the 3D-printed material can be relatively soft, making it easier to integrate (e.g., press) the optical fibers into the layers of the 3D-printed material. Thus, such methods described herein can provide an improved method for incorporating optical fibers into 3D-printed articles.

[0048] In embodiments, the printing conditions may be specifically selected so that the 3D printed material can begin to anneal and still remain ductile enough to compress the optical fiber into the first layer. Thus, in embodiments, the temperature of the 3D printed material of the first layer at the location where the optical fiber contacts the 3D printed material may be lower than the glass transition temperature (T G ) is at least 30-50°C higher. However, the glass transition temperature (T G ) is generally lower than the melting temperature of the 3D printing material (T m ). Therefore, in particular so that the optical fiber can be at least partially pressed in the first layer, in an embodiment, the temperature of the 3D printed material of the first layer can be lower than the melting temperature (T m ) is at least 10°C higher. Thus, in an embodiment, for a 3D printing material, at least one of the following may apply: (i) the temperature of the 3D printing material is within the glass transition temperature (T G ) and melting temperature (T m ), and (ii) the temperature of the 3D printing material is higher than the melting temperature of the material (T m ) (at least 10°C). In particular, when the temperature of the 3D printing material is higher than the melting temperature (T m ) embodiments, pressing the optical fiber into the 3D printing material may require lower force.

[0049] For example, the conditions (i.e., temperatures) described herein can be achieved by controlling (over time) the temperature of the nozzle of the 3D printing device being used. In another example, in an embodiment, the conditions (i.e., temperatures) can be achieved by (additional) use of a cooling device, see also below. Alternatively or additionally, a heating device can be applied, such as a hot air device or an infrared radiator.

[0050] In an embodiment, the printing device may specifically include a fused deposition modeling 3D printer. Therefore, in an embodiment, the method may further include: using a fused deposition modeling 3D printer, the printer including (a) an optical fiber providing system and (b) a substrate.

[0051] In particular, in an embodiment, the optical fiber providing system may be configured to provide optical fibers to the 3D printed material. As mentioned above, the optical fibers may be provided in a direction different from the printing direction, in particular not in the direction of the (local) longitudinal axis (A). X ) overlap. Therefore, in embodiments, the fiber provisioning system may include a fiber positioning device configured to control the orientation and position of the optical fiber relative to the 3D printed material. For example, in embodiments, the fiber positioning system may include a robotic arm configured to position the optical fiber in a desired orientation and position relative to the 3D printed material. In embodiments, the fiber positioning system may also be configured to provide the optical fiber to the 3D printed material by operating in a manner similar to a sewing machine, i.e., implementing a sewing machine mechanism.

[0052] Furthermore, in embodiments, the fused deposition modeling 3D printer may include a substrate (see also below). The substrate may be configured to support 3D printing material (and integrated optical fiber). In embodiments, the substrate may include (a portion of) a 3D object. Other embodiments regarding the substrate are further described below.

[0053] Thus, in an embodiment, a fused deposition modeling 3D printer may be configured to provide an optical fiber to a 3D printing material. In particular, in an embodiment, the fused deposition modeling 3D printer may be configured to provide p external loops of optical fiber. More particularly, the method may include providing the p external loops by one or more of (i) an optical fiber positioning device and (ii) a substrate. In an embodiment, one or more of (i) the optical fiber positioning device and (ii) the substrate may be movable in a horizontal plane. Thus, in a particular embodiment, the method may include using a fused deposition modeling 3D printer comprising (a) an optical fiber provision system configured to provide an optical fiber; wherein the optical fiber provision system may include an optical fiber positioning device, and (b) a substrate configured to support the 3D printing material; wherein the method may include providing the p external loops by moving one or more of (i) the optical fiber positioning device and (ii) the substrate.

[0054] For example, in an embodiment, the fiber optic positioning device can be configured to move relative to the substrate (in a horizontal plane), while the substrate remains stationary. Therefore, in such embodiments, the optical fiber can be moved to achieve its desired position. In another example, the fiber optic positioning device and the substrate can both move relative to each other (in a horizontal plane), for example, in an embodiment, the fiber optic positioning device can include a substrate. In yet another example, in an embodiment, the substrate can be configured to move relative to the fiber optic positioning device (in a horizontal plane), while the fiber optic positioning device remains stationary. Therefore, in such embodiments, the substrate can be moved to achieve placement of the optical fiber in its desired position. In particular, the fiber optic positioning device and / or the substrate can also move in a vertical direction. For example, the fiber optic positioning device can be moved in a vertical direction to position the optical fiber.

[0055] In embodiments, the fiber delivery system may include a robotic arm configured to deliver and / or position the optical fiber. Thus, in embodiments, the fiber positioning device may (also) include a robotic arm. In particular, in embodiments, the fiber positioning device may essentially be a robotic arm. However, those skilled in the art will appreciate that other (types of) devices may also be suitable.

[0056] In embodiments, the optical fibers may be integrated into the multi-layer 3D printed material in a random manner, for example, in a (randomized) cross configuration. However, in other embodiments, the optical fibers may be integrated into the multi-layer 3D printed material in an ordered manner, such as arranged in a pattern. In particular, in embodiments, the optical fibers may be arranged in one or more of a coil pattern, a braid pattern, or a spiral pattern. In particular, in some embodiments, the method may include integrating the optical fibers in a (ir) regular pattern by configuring one or more of a fiber positioning device and a substrate to obtain said patterned integration of the optical fibers.

[0057] Movements of the type described herein may be controlled by a control system of a 3D printer, which in embodiments may be programmed to perform the method. In embodiments, the 3D printer may include a motor controlled by the control system and configured to convert electrical energy into mechanical movement (in a horizontal direction) of one or more of the aforementioned components (of the 3D printer).

[0058] Furthermore, the optical fiber can not only be placed in a horizontal desired position, but, as described above, the optical fiber can also be recessed into the first layer in which it can be placed. Therefore, in an embodiment, the fused deposition modeling 3D printer may further include a printer nozzle, see also below. In an embodiment, the method may include (vertically) pressing the optical fiber at least partially into the first layer. In a specific embodiment, the method may (even) include pressing the optical fiber (fundamentally) completely into the first layer. In particular, by controlling the vertical position of one or more of (i) the printer nozzle, (ii) the optical fiber positioning device, and (iii) the substrate, the optical fiber can be at least partially pressed into the first layer. Therefore, in a specific embodiment, the fused deposition modeling 3D printer may further include a printer nozzle; wherein the method may include: by controlling the vertical position of one or more of (i) the printer nozzle, (ii) the optical fiber positioning device, and (iii) the substrate, the optical fiber can be at least partially pressed into the first layer.

[0059] With such embodiments, the optical fiber can be securely recessed into at least a portion of the surrounding layer so that the optical fiber can be maintained at a desired location. Thus, such embodiments can provide the benefit of securing the optical fiber at a desired location.

[0060] For example, in an embodiment, the printer nozzle may be configured to move (in a vertical direction) relative to the substrate while the substrate remains stationary. Thus, in such embodiments, the optical fiber may be pressed into the first layer (or layers) of the 3D-printed material (printed on the substrate) by the printer nozzle to achieve recessing of the optical fiber into the first layer (or layers) of the 3D-printed material. Similarly, in another embodiment, the substrate may be configured to move (in a vertical direction) relative to the printer nozzle while the printer nozzle remains stationary. Thus, in such embodiments, the optical fiber may be pressed into the first layer (or layers) of the 3D-printed material to achieve recessing of the optical fiber into the first layer (or layers) of the 3D-printed material. In yet another example, in an embodiment, the optical fiber positioning device may be configured to move (in a vertical direction) relative to the stationary substrate (and printer nozzle). Thus, in such embodiments, the optical fiber may be pressed into the first layer (or layers) of the 3D-printed material (printed on the substrate) by the optical fiber positioning device to achieve recessing of the optical fiber into the first layer (or layers) of the 3D-printed material (printed on the substrate). Furthermore, in embodiments, a combination of one or more of (also) the printer nozzle, the fiber positioning device, and the substrate may be configured to move relative to each other (in a vertical direction) such that the optical fiber may be pressed into the first layer (or layers) of the 3D printed material.

[0061] Movements of the type described herein may be controlled by a control system of a 3D printer, which in embodiments may be programmed to perform the method. In embodiments, the 3D printer may include a motor controlled by the control system and configured to convert electrical energy into mechanical movement (in a vertical direction) of one or more of the aforementioned components (of the 3D printer).

[0062] In embodiments, the term “pressing the optical fiber into the first layer of 3D printed material” and similar terms may refer to applying pressure on the optical fiber or one or more other components such that the optical fiber is forced (slightly) into the first layer of 3D printed material.

[0063] The pressure with which the optical fiber is pressed into the first layer (or layers) of the 3D printed material may depend at least on the desired amount of depression of the optical fiber into the first layer. As described above, the optical fiber may have a (cross-sectional) fiber diameter (D) defined in a plane perpendicular to the fiber length (L1) of the optical fiber. F In an embodiment, the optical fiber may be pressed into the first layer (layers) of the 3D printed material so that the fiber diameter (D F ) can be recessed into the first layer so that the fiber diameter (D F ) can be recessed into the first layer, similar to the fiber diameter (D F ) can be recessed into the first layer. In particular, in an embodiment, the optical fiber can be pressed into the first layer (layers of the group) of 3D printed material so that the fiber diameter (D F ) can be recessed into the first layer so that the fiber diameter (D F ) can be recessed into the first layer, similar to the fiber diameter (D F ) can be recessed in the first layer. In certain embodiments, (even) 100% of the fiber diameter (D F ) can be recessed into the first layer (or layers of the group) of 3D printed material. It should be noted that when a higher percentage of the fiber diameter (D F ) is recessed into the first layer (layer of the group) of 3D printed material, the required pressure can be higher. On the other hand, when a lower percentage of fiber diameter (D F ) is recessed into the first layer (or layers of the group) of 3D printing material, the required pressure can be relatively low.

[0064] Furthermore, the aforementioned positioning of the optical fiber by horizontal and / or vertical movement may (also) require a change in the printing speed. In particular, in an embodiment, during the 3D printing phase, multiple layers (of 3D printed material) may be provided at a first printing speed (V1). In an embodiment, the first printing speed (V1) may be selected from a range of 15 mm / s to 150 mm / s, such as from a range of 50 mm / s to 150 mm / s. Additionally or alternatively, in an embodiment, during the k1 integration phases, one or more of the first and second layers may be provided at a second printing speed (V2). In an embodiment, the second printing speed (V2) may be selected from a range of 15 mm / s to 150 mm / s, such as from a range of 20 mm / s to 100 mm / s. In particular, in an embodiment, V1 ≥ V2, such as V1 ≥ 2V2, such as V1 ≥ 3V2.

[0065] Since the optical fiber can be at least partially pressed into the first layer (layer of the group) of 3D printing material, in an embodiment, the optical fiber can have a recessed portion. In particular, in an embodiment, the optical fiber can have k1 recessed portions. In an embodiment, the k1 recessed portions can each have a recessed portion length (L q ). Length of recessed portion (L q ) can depend on the fiber angle (α F ). The fiber is perpendicular to the (local) longitudinal axis (A X ) integration (i.e. α F =90°), the length of the recessed portion (L q ) can be (essentially) equal to the layer width (W). F ≠90°) longitudinal axis (A X ) In the embodiment of the integration, for the recessed portion length (L q ) can be applied, L q =W / sine(α F ).

[0066] Furthermore, in an embodiment, the optical fiber may have a (first) fiber length (L1). The fiber length (L1) may therefore in particular comprise k1 recessed portion length (L q ) and p external loop length (L p ), see also below. Therefore, in the embodiment, L1=k1*L q +p*L p. In particular, in an embodiment, the fiber length (L1) can be selected from the range of 5 sides to 300 cm, such as the range of 10 cm to 200 cm. In some embodiments, the optical fiber can have a relatively large fiber length (L1), such as a fiber length (L1) of at least 100 cm, such as at least 150 cm. In particular, in such embodiments, (only) one optical fiber can be integrated into the 3D object, however, this may not necessarily be the case. In other embodiments, the optical fiber can have a relatively small fiber length (L1), such as a fiber length (L1) of at most 25 cm, such as at most 15 cm. In such embodiments, (even) one or more (separate) optical fibers can be integrated into the 3D object, such as 2 to 20 optical fibers, like 5 to 10 optical fibers. It should be noted that in such embodiments, each of the one or more optical fibers can have a fiber length (L1, L2, L3, etc.).

[0067] Thus, the phrase "a 3D article at least partially comprises an optical fiber" and similar phrases may refer to a 3D article in which the optical fiber is partially integrated in the through hole. Thus, the optical fiber may be at least partially integrated in the through hole. q ) is integrated into the 3D object, and the remainder of the optical fiber can be external to the 3D printed material. In this way, an arrangement comprising a 3D object and an optical fiber is provided, wherein the optical fiber is at least partially integrated into the 3D object. Thus, the present invention provides, in an embodiment, a 3D-printed object having a leaky optical fiber integrated therein.

[0068] As indicated above, the optical fiber can form p outer loops. In particular, in embodiments, the loops can be arranged outside the multi-layer 3D printed material. Thus, in embodiments, the outer loops may not be covered by the 3D printed material.

[0069] In an embodiment, each of the p outer loops may have a (separate) outer loop length (L p ), where the loop can be confined between two groups of vias. Thus, in an embodiment, the outer loop length (L p ) may be defined as the length of the optical fiber from a first through-hole to a second through-hole in a set of through-holes. Furthermore, in an embodiment, each of the p outer loops may have a shortest distance (d2) between the (corresponding) through-holes. In an embodiment, the shortest distance (d2) between the (corresponding) through-holes of the outer loops may be defined in a plane passing through at least the first stack of layers including one or more groups associated with the respective outer loops. In particular, in an embodiment, the outer loop length (L p ) may be greater than the minimum distance (d2). More particularly, in an embodiment, L p ≥1.05*d2, such as L p ≥1.5*d2, image, Lp ≥2*d2. In particular, in the embodiment, 1.05*d2≤L p ≤π*d2. However, larger values ​​are also possible.

[0070] In an embodiment, most of the fiber length (L1) may be arranged outside the multi-layer 3D printed material. In particular, in an embodiment, at least 70% of the fiber length (L1) of the optical fiber may be comprised by the p outer loops, such as at least 80%, like at least 90%, in particular at least 95%. Thus, in an embodiment, p*L p ≥0.7*L1, especially p*L p ≥0.9*L1. In other words, at most 30% of the fiber length (L1) of the optical fiber may be comprised by the k1 recessed portion, such as at most 20%, such as at most 10%, particularly at most 5%, and in other embodiments particularly at least 1%, such as at least about 2%. Thus, in an embodiment, k1*L q ≤0.3*L1, in particular, k1*L q ≤0.1*L1. Therefore, in a particular embodiment, each of the p outer loops may have an outer loop length (L p ), wherein each of the p outer loops can have a shortest distance (d2) between through-holes, wherein the shortest distance (d2) between the through-holes of the outer loops can be defined in a plane passing through at least a first stack of layers including one or more groups associated with the respective outer loops, wherein Lp>1.1*d2; and wherein at least 90% of the fiber length (L1) of the optical fiber can be comprised by the p outer loops.

[0071] As indicated above, the present invention may therefore provide a method comprising providing a filament of 3D printable material, and printing said 3D printable material on a substrate during a printing phase to provide said 3D object.

[0072] Materials particularly suitable as 3D printable materials may be selected from the group consisting of metals, glass, thermoplastic polymers, silicones, and the like. In particular, the 3D printable material includes a group selected from the following: ABS (acrylonitrile butadiene styrene), nylon (or polyamide), acetate (or cellulose), PLA (polylactic acid), terephthalate (such as PET polyethylene terephthalate), acrylic (polymethyl methacrylate, organic glass, polymethyl methacrylate, PMMA), polypropylene (or polypropene), polycarbonate (PC), polystyrene (PS), PE (such as expanded high impact polyethylene (or polyethylene)), low density (LDPE) high density (HDPE)), PVC (polyvinyl chloride) polyvinyl chloride, such as thermoplastic elastomers based on copolyester elastomers, polyurethane elastomers, polyamide elastomers, polyolefin-based elastomers, styrene-based elastomers, etc. Optionally, the 3D printable material may include a 3D printable material selected from the group consisting of: urea-formaldehyde resin, polyester resin, epoxy resin, melamine formaldehyde and thermoplastic elastomer. Optionally, the 3D printable material may include a 3D printable material selected from the group consisting of polysulfones. Elastomers, particularly thermoplastic elastomers, may be particularly interesting because they are flexible and can help to obtain relatively more flexible filaments including thermally conductive materials. Thermoplastic elastomers may include one or more of styrene block copolymers (TPS (TPE-s)), thermoplastic polyolefin elastomers (TPO (TPE-o)), thermoplastic vulcanizates (TPV (TPE-v or TPV)), thermoplastic polyurethanes (TPU (TPU)), thermoplastic copolyesters (TPC (TPE-E)) and thermoplastic polyamides (TPA (TPE-A)).

[0073] Suitable thermoplastic materials, such as those also mentioned in WO2017 / 040893, may include one or more of the following: polyacetals (e.g., polyethylene oxide and polyoxymethylene), poly(C 1-6alkyl) acrylates, polyacrylamides, polyamides (e.g., aliphatic polyamides, polyphthalamides, and polyaramids), polyamideimides, polyanhydrides, polyarylates, polyarylene ethers (e.g., polyphenylene ether), polyarylene sulfides (e.g., polyphenylene sulfide), polyarylsulfones (e.g., polyphenylene sulfide), polybenzothiazoles, polybenzoxazoles, polycarbonates (including polycarbonate copolymers such as polycarbonate-siloxanes, polycarbonate-esters, and polycarbonate-ester-siloxanes), polyesters (e.g., polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyarylates), and polyester copolymers such as polyester-ethers), polyetheretherketones, polyetherimides (including copolymers such as polyetherimide-siloxane copolymers), polyetherketoneketones, polyetherketones, polyethersulfones, polyimides (including copolymers such as polyimide-siloxane copolymers), poly(C 1-6 alkyl) methacrylate, polymethacrylamide, polynorbornene (including copolymers containing norbornene-based units), polyolefins (e.g., polyethylene, polypropylene, polytetrafluoroethylene and copolymers thereof, such as ethylene-α-olefin copolymers), polyoxadiazoles, polyoxymethylene, polyphthalate, polysilazane, polysiloxane, polystyrene (including copolymers such as acrylonitrile-butadiene-styrene (ABS) and methyl methacrylate-butadiene-styrene (MBS)), polysulfide, polysulfoneamide, polysulfonate, polysulfone, polythioester, polytriazine, polyurea, polyurethane, polyvinyl alcohol, polyvinyl ester, polyvinyl ether, polyvinyl halide, polyvinyl ketone, polyvinyl sulfide, polyvinylidene fluoride, etc., or a combination comprising at least one of the foregoing thermoplastic polymers. Examples of polyamides may include, but are not limited to, synthetic linear polyamides such as nylon-6,6; nylon-6,9; nylon-6,10; nylon-6,12; nylon-11; nylon-12 and nylon-4,6, preferably nylon 6 and nylon 6,6, or a combination comprising at least one of the foregoing. Polyurethanes that may be used include aliphatic, alicyclic, aromatic, and polycyclic polyurethanes, including those mentioned above. Also useful are poly(C 1-6 Alkyl) acrylate and poly (C 1-6 The polyolefin may include one or more of polyethylene, polypropylene, polybutene, polymethylpentene (and copolymers thereof), polynorbornene (and copolymers thereof), poly-1-butene, poly(3-methylbutene), poly(4-methylpentene), and copolymers of ethylene with propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 1-octadecene.

[0074] In certain embodiments, the 3D printable material (and 3D printing material) may include one or more of the following: polycarbonate (PC), polyethylene (PE), high-density polyethylene (HDPE), polypropylene (PP), polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), polysulfone (PSU), polyphenylene sulfide (PPS) and semi-crystalline polyethylene terephthalate (PET), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polystyrene (PS) and styrene-acrylic acid copolymer (SMMA).

[0075] The term 3D printable material is also further explained below, but may particularly refer to a thermoplastic material, optionally including additives, whose volume percentage is maximum about 60%, in particular maximum about 30 vol.%, such as maximum 20 vol.% (additives relative to the total volume of thermoplastic material and additives).

[0076] Thus, in an embodiment, the printable material may comprise two phases. The printable material may comprise a phase of a printable polymeric material, in particular a thermoplastic material (see also below), which phase is in particular a substantially continuous phase. In the continuous phase of the thermoplastic material, there may be polymer additives such as one or more of antioxidants, heat stabilizers, light stabilizers, UV stabilizers, UV absorbing additives, near infrared absorbing additives, infrared absorbing additives, plasticizers, lubricants, release agents, antistatic agents, antifogging agents, antimicrobial agents, colorants, laser marking additives, surface effect additives, radiation stabilizers, flame retardants, and anti-drip agents. The additives may have useful properties selected from optical properties, mechanical properties, electrical properties, thermal properties, and mechanical properties (see also above).

[0077] The printable material in an embodiment may comprise a granular material, i.e. particles embedded in a printable polymer material, the particles forming a substantially discontinuous phase. The number of particles in the total mixture is in particular not greater than 60 vol.%, relative to the total volume of the printable material (including the (anisotropically conductive) particles), in particular in applications where the coefficient of thermal expansion is reduced. For optical and surface-related effects, the number of particles in the total mixture is equal to or less than 20 vol.%, such as up to 10 vol.%, relative to the total volume of the printable material (including the particles). Thus, a 3D printable material may in particular refer to a continuous phase of a substantially thermoplastic material, in which other materials, such as particles, may be embedded. Likewise, a 3D printing material may in particular refer to a continuous phase of a substantially thermoplastic material, in which other materials, such as particles, are embedded. The particles may comprise one or more additives as defined above. Thus, in an embodiment, the 3D printable material may comprise a granular additive.

[0078] Furthermore, in embodiments, the 3D printable material (and 3D printing material) may specifically include a light-transmitting polymer. Specifically, the 3D printable material may transmit visible light. For example, in embodiments, the 3D printable material (and 3D printing material) may be a translucent polymer. Specifically, in embodiments, the 3D printable material may be slightly light-scattering. Thus, in embodiments, (visible) light leaking from an optical fiber may be transmitted and / or scattered by multiple layers of 3D printing material.

[0079] Such embodiments may provide decorative and other optical effects in the 3D printed article resulting from performing the method, since light may be partially coupled into the 3D printed article.

[0080] Furthermore, in embodiments, the 3D printable material (and 3D printed material) may include reflective particles. In particular, in embodiments, such reflective particles may be arranged around the through-holes. However, this need not necessarily be the case, i.e., the reflective particles may not necessarily be confined to the through-holes. In embodiments, the reflective particles may be configured to reflect light (leaking from the optical fiber) back into the optical fiber. In particular, in embodiments, the reflective particles may specularly reflect (visible) light (leaking from the optical fiber). Thus, in certain embodiments, the 3D printable material may include reflective particles that are arranged around the through-holes and configured to reflect light back into the optical fiber.

[0081] Such embodiments can be beneficial because the reflective particles can reflect light (leakage) from the optical fiber back into the optical fiber, so that light propagation through the optical fiber can be improved by reducing light losses inside the multi-layer 3D printed material.

[0082] In embodiments, the 3D printed material can diffusely reflect (visible) light (leaking from the optical fiber). However, in embodiments, the 3D printed material can also be diffusely transparent to (visible) light (leaking from the optical fiber). The presence of reflective particles (in the 3D printed material) can contribute to the diffuse effect of the 3D printed material. In embodiments, the reflective particles can specifically specularly reflect the light leaking from the optical fiber, thereby creating a shimmering effect.

[0083] In an embodiment, the reflective particles may have a spherical shape or may have a shape that is approximately spherical. In other embodiments, the reflective particles may (also) have a flake shape. Thus, in an embodiment, the reflective particles may have an average equivalent spherical diameter (D RP In particular, in the embodiment, the average equivalent spherical diameter (D RP ) may be selected from the range of 1 nm to 1 mm, such as 0.01 μm to 1 mm, such as from the range of 0.1 μm to 500 μm, like from the range of 1 μm to 50 μm.

[0084] Furthermore, in embodiments, the reflective particles may include a material that reflects visible light. Specifically, in embodiments, the reflective particles may include one or more materials selected from the group consisting of silver, aluminum, and mica. For example, in embodiments, the reflective particles may be silver nanoparticles. In other embodiments, the reflective particles may be mica flakes.

[0085] The term "approximately" and its variations, such as in "approximately a shape", refer herein to being almost identical to the following terms, in particular identical, for example almost identical to a circle portion or a semi-cylindrical shape. For example, if there are no defects, the reflective particles can be defined as spherical particles. Similarly, for example, the circle defined by the reflective particles may not be a perfect circle, but slightly elliptical. In particular, an object that approximates a first shape may refer herein to: a first shape realization encompassing the object, wherein the first shape realization is defined as the smallest encompassing shape of the (2D or 3D) object, wherein the first shape realization has the shape of the first shape, wherein the ratio of the area (volume) of the first shape realization to the area (volume) of the object is ≤1.2, in particular ≤1.1, such as ≤1.05, in particular ≤1.02. For example, the reflective particles may be approximately spherical, wherein the first shape realization may be defined as the smallest encompassing spherical shape of the reflective particles, wherein the ratio of the volume of the first shape realization to the volume of the reflective particles is ≤1.2, in particular ≤1.1, such as ≤1.05, in particular ≤1.02, including 1. Furthermore, if the dimensions of the first shape are defined, the term "approximately" may mean that the object and the first shape are superimposable (in 2D or 3D, respectively) such that the intersection between the object and the first shape covers at least n% of the object and at least n% of the shape, where n is at least 90%, such as at least 95%, in particular at least 98%, such as at least 99%, including 100%.

[0086] The equivalent spherical diameter (ESD) of a (irregular) three-dimensional shape (or "equivalent spherical diameter") is the diameter of a sphere of equivalent volume. For example, the equivalent spherical diameter of a cube with side length a is SQRT[3]((6*a^3) / π). For a sphere, the diameter is the same as the equivalent spherical diameter. If a sphere with diameter D in the xyz coordinate system is deformed into any other shape (in the xyz coordinate system) without changing its volume, then the equivalent spherical diameter of that shape is D.

[0087] In addition, in an embodiment, it can be expected that the 3D printed material includes more reflective particles at a position (directly) surrounding the optical fiber than in the rest of the 3D printed material, that is, the local concentration of reflective particles is higher at a position closer to the optical fiber than in the rest of the 3D printed material. In such embodiments, light leaking from the optical fiber can be reflected back to the optical fiber by the reflective particles, thereby efficiently utilizing resources. For two filaments with different reflective particle concentrations, the local higher concentration of such reflective particles described herein can be achieved, for example, by 3D printing using two different printer nozzles. In another example, the 3D printer can include two filament providing devices, also see below, for providing two filaments with different concentrations of reflective particles to the printer nozzle.

[0088] Since the reflective particles can be configured to reflect light back into the optical fiber, in embodiments, it may be desirable that the optical fiber include a light-transmitting material. In particular, in embodiments, the optical fiber may be a leaky optical fiber comprising a material that transmits visible light. Thus, in certain embodiments, the optical fiber may include one or more of glass, silica, and a polymer material other than the polymer material defined in claim 8. In embodiments, the polymer material may be different from the polymer material defined above for 3D printable (and 3D printing) materials. However, in embodiments, this may not necessarily be the case. Furthermore, in embodiments, the optical fiber may also include a crystalline material, such as sapphire.

[0089] In an embodiment, the optical fiber may comprise a fiber core and a fiber cladding. In particular, the core may be surrounded by a cladding, or in other words, the cladding may be wrapped around the core. More particularly, in an embodiment, the cladding may comprise a material having a lower refractive index than the material comprised by the core. Thus, in an embodiment, the core and the cladding of the optical fiber may comprise different materials (compositions). In this way, light may escape from the optical fiber via leakage modes. In other embodiments, the cladding may comprise a material having a higher refractive index than the material comprised by the core, but also comprises openings. In this way, light may escape via the openings. In particular, the core and the cladding may comprise different materials (compositions), including one or more of glass, silica, and a polymer material (different from the polymer material described above, see also above).

[0090] Returning to the method, as described above, the method comprises k1 integration stages, wherein the printing conditions can be selected so that the 3D printed material of the first layer (of the group of layers) can have a higher melting temperature (T ) than the 3D printed material at the location where the optical fiber contacts the 3D printed material. m). It may be desirable to reduce the temperature of the 3D printed material after at least one of the k1 integration stages. This may be beneficial in securing the integrated optical fiber in place between the first and second layers of the 3D printed material. Excessively high temperatures of the 3D printed material may cause unnecessary deformation of the 3D printed material and / or displacement of the optical fiber during subsequent stages of the method.

[0091] Thus, in an embodiment, at least one of the k1 integration stages may be followed by a cooling stage, wherein the second (integration) layer may be cooled during the cooling stage. In a particular embodiment, (even) each of the k1 integration stages may be followed by such a cooling stage, i.e., the method may comprise k1 cooling stages.

[0092] In embodiments, cooling of the second (integrated) layer during the cooling phase may refer to active cooling, passive cooling, or a combination thereof. For example, in embodiments, the cooling phase may include leaving the 3D printed material for a period of time (e.g., a preprogrammed period of time) to allow passive cooling of the second (integrated) layer. In other embodiments, the cooling phase may include active cooling, for example, using a cooling device such as a (layer) fan, a water cooling device, or a blower. Thus, in embodiments, the method may include one or more cooling phases.

[0093] The method described herein provides a 3D printed object. Therefore, the present invention also provides, in another aspect, a 3D printed object obtainable by the method described herein.

[0094] In another aspect, a 3D printed article obtainable by the method described herein is provided.

[0095] The present invention provides a 3D object for production by means of fused deposition modeling. The 3D object includes multiple layers of 3D printing material and partially integrated leaky optical fibers. The multiple layers include n groups of two stacked layers, for example, two adjacent stacked layers. Each group includes a first layer and a second layer. The multiple layers include at least one group of two stacked layers, i.e., n≥1. The optical fiber is partially integrated between the first layer and the second layer of one of the n groups, so that the optical fiber extends from the first layer and at least partially protrudes into the first layer. In particular, the optical fiber thereby forms at least a portion of a through-hole. More particularly, a portion of the optical fiber resides in a through-hole formed in a layer of the group. The 3D printed object includes k2 (such) through-holes. In addition, in an embodiment, at least two portions of the optical fiber may reside in at least two of the k2 through-holes. In the 3D item, k2≥2. In addition, the optical fiber forms p external loops, where 1≤p≤k2-1.

[0096] Accordingly, the present invention provides a 3D article, wherein the 3D article comprises multiple layers of 3D printed material and partially integrated leaky optical fibers, wherein the multiple layers comprise n groups of two stacked layers, wherein each group comprises a first layer and a second layer, wherein n≥1; wherein the optical fiber is partially integrated between the first layer and the second layer of one of the n groups such that the optical fiber extends from the first layer and at least partially protrudes into the first layer, thereby forming at least a portion of a through-hole in the layers of the group, wherein the 3D printed article comprises k2 through-holes, wherein at least a portion of the optical fiber resides in the k2 through-holes; wherein the optical fiber forms p external loops, wherein k2≥2, and wherein 1≤p≤k2-1.

[0097] When discussing the method, some specific embodiments related to 3D printing of articles have been described above. Below, some specific embodiments related to 3D printing of articles will be discussed in more detail.

[0098] As indicated above, the optical fiber is partially integrated between the first and second layers of one of the n groups. The optical fiber is integrated so that it extends from the first layer and optionally the second layer. Furthermore, in embodiments, the optical fiber can be integrated so that it protrudes at least partially into the first layer and optionally into the second layer. Thus, the optical fiber can form at least a portion of a through-hole in the layers of the group.

[0099] In particular, the 3D object comprises one or more layers of 3D printed material. More particularly, the 3D object comprises multiple layers of 3D printed material. The 3D object may comprise two or more layers of 3D printed material, such as at least 5 layers, such as at least 10 layers, and in an embodiment at least 20 layers.

[0100] Thus, generally speaking, a 3D-printed object can include multiple layers stacked on top of each other, i.e., a stack. The width (thickness) and height of the (individually 3D-printed) layers can, for example, in embodiments be selected from a range of 100 μm to 5000 μm, such as 200 μm to 2500 μm, with the height generally being smaller than the width. For example, the ratio of height to width can be equal to or less than 0.8, such as equal to or less than 0.6.

[0101] Layers can be core-shell layers or can be composed of a single material. Within a layer, there can also be variations in composition, such as when a core-shell printing process is applied and during the printing process it changes from printing a first material (and not printing a second material) to printing a second material (and not printing the first material).

[0102] At least a portion of the 3D printed article may include a coating.

[0103] As described above, a multilayer 3D printed material may have a layer height (H). Additionally, an optical fiber may have a fiber diameter (D fIn an embodiment, the layer height (H) may be greater than the fiber diameter (D f ). In particular, in the embodiment, 0.05*H≤D f <2*H, such as 0.1*H≤D f <2*H.

[0104] Furthermore, in an embodiment, as described above, the optical fiber may have a (first) fiber length (L1). The fiber length (L1) may in particular comprise the k1 recessed portion length (L q ) and p external loop length (L p ), see also below. Therefore, in the embodiment, L1=k1*L q +p*L p .

[0105] Furthermore, as indicated above, the optical fiber forms p outer loops. In an embodiment, each of the p outer loops may have a (separate) outer loop length (L p ), where a loop may be defined between two groups of vias. In particular, in an embodiment, each of the p outer loops may have a shortest distance (d2) between (corresponding) vias, as described above. In particular, in an embodiment, the outer loop length (L p ) can be greater than the minimum distance (d2), that is, L p ≥1.1*d2.

[0106] In an embodiment, the majority of the fiber length (L1) may be arranged outside the multi-layer 3D printed material. In particular, in an embodiment, p*L p ≥0.9*L1. In other words, in the embodiment, k1*L q ≤0.1*L1. Therefore, in a particular embodiment, each of the p outer loops may have an outer loop length (L p ), wherein each of the p external loops may have a shortest distance (d2) between through-holes, wherein the shortest distance (d2) between through-holes for the external loops may be defined in a plane passing through at least a first stack of layers including one or more groups associated with the respective external loops, wherein Lp>1.1*d2; and wherein at least 90% of the fiber length (L1) of the optical fiber may be affected by the p external loops. In an embodiment, the loop length (L p ) may be at least about 2 mm, such as at least about 5 mm, like at least about 8 mm in an embodiment. Generally speaking, the loop length (L p ) will not be greater than 150 mm, such as a maximum of 100 mm, although other values ​​are not excluded herein.

[0107] In embodiments, the optical fibers may be arranged in a random manner within the multiple layers of 3D printed material, for example, in a (random) cross configuration. However, in other embodiments, the optical fibers may be integrated within the multiple layers of 3D printed material in an ordered manner, such as arranged in a pattern. In particular, in embodiments, the optical fibers may be arranged in one or more of a coil pattern, a braid pattern, or a spiral pattern.

[0108] For example, in an embodiment, the optical fiber can be woven through multiple layers of 3D printed material in a regular pattern such that the shortest distance (d2) and the outer loop length (L p ) can be the same for each of the p loops. However, in other embodiments, the optical fiber can also be woven through the multiple layers of 3D printed material in an irregular manner so that the shortest distance (d2) and the outer loop length (L p ) may be different for p different loops. In another example, the optical fiber may be integrated in multiple layers of 3D printed material such that the optical fiber may form a (partial) coil around the 3D printed material.

[0109] Different configurations of optical fibers in 3D-printed objects can be beneficial because they can provide different decorative effects within the 3D object. Different configurations can also yield a wide range of 3D objects for different needs. For example, a 3D object comprising (tightly) coiled optical fibers can provide a beneficial combination of spatial efficiency and light intensity, while a 3D object comprising braided optical fibers with (varying) outer loop lengths can provide a beneficial combination of decorative appeal and practical utility.

[0110] Decorative and / or optical effects can also be achieved through material selection. The 3D printing material can include a polymer material, as also discussed above. In embodiments, the 3D printing material can specifically include a light-transmitting polymer. In particular, the 3D printable material can transmit visible light, such as when visible light can leak from an optical fiber out of the 3D object during its operational mode.

[0111] Furthermore, in embodiments, the 3D printed material may include reflective particles. In particular, in embodiments, such reflective particles may be disposed around one or more of the k2 through-holes. In embodiments, the reflective particles may be configured to reflect light (leaking from the optical fiber) back into the optical fiber during the operational mode of the 3D article. Thus, in embodiments, the 3D (printed) article may include a higher concentration of reflective particles, particularly at locations in the multiple layers surrounding the optical fiber. Thus, in certain embodiments, the 3D printable material may include reflective particles that are disposed around the through-holes and configured to reflect light back into the optical fiber.

[0112] Thus, in embodiments, the optical fiber may comprise a light-transmitting material such that, in an operational mode of the 3D object, (visible) light provided to the optical fiber may leak out of the optical fiber. In particular, in embodiments, as also described above, the optical fiber may comprise one or more of glass, silica, and a polymer material different from the polymer material defined for 3D printing materials.

[0113] Thus, the leaky optical fiber can be designed such that light propagating through the optical fiber leaks from the fiber over part of its length, in particular over its entire length. In this way, an extended (fiber) light source can be provided.

[0114] As described herein, in embodiments, a 3D object can have an operational mode. Thus, in embodiments, the 3D printed object obtained (using the methods described herein) can itself be functionalized. For example, the 3D printed object can be a lens, a collimator, a reflector, etc. The 3D object thus obtained can (alternatively) be used for decorative or artistic purposes. The 3D printed object can include or be provided with functionalized components. The functionalized components can in particular be selected from the group consisting of optical components, electrical components, and magnetic components. The term "optical component" in particular refers to a component having an optical function, such as a lens, a reflector, a light-transmitting element, a filter, etc. The term "optical component" can also refer to a light source (such as an LED). The term "electrical component" can refer to, for example, an integrated circuit, a PCB, a battery, a driver, and can also refer to a light source (since a light source can be considered both an optical component and an electrical component). The term "magnetic component" can refer to, for example, a magnetic connector, a coil, etc. Alternatively or additionally, the functionalized component can include a thermal component (e.g., configured to cool or heat an electrical component). Thus, the functionalized component can be configured to generate heat or collect heat, etc.

[0115] As indicated above, 3D printed objects can be used for different purposes. Among them, 3D printed objects can be used for lighting.

[0116] Therefore, in a further aspect, the present invention also provides a lighting device comprising a 3D article as defined herein.

[0117] In one particular aspect, the present invention provides an illumination system comprising (a) a light source configured to provide (visible) light source light, and (b) a 3D article as defined herein, wherein the optical fiber is configured to be in a light receiving relationship with the light source.

[0118] Thus, in embodiments, the lighting device may specifically include a light source configured to provide light source light to the optical fiber. In embodiments, the light source may include a solid-state light source, such as a laser light source or an LED light source, however, other types of light sources are not excluded herein. The light source may specifically be configured to provide visible light source light. For example, in embodiments, the light source may be configured to provide white light source light. In other embodiments, the light source may be configured to provide colored light source light. Furthermore, in embodiments, the 3D article may be configured as one or more of (i) at least a portion of a housing, and (ii) at least a portion of a wall of the lighting chamber.

[0119] Thus, in another aspect, the present invention provides a lighting device comprising a 3D article as described herein and a light source configured to provide visible light source light, wherein the optical fiber is configured to be in a light receiving relationship with the light source, and wherein the 3D article is configured as one or more of (i) at least a portion of a lighting device housing and (ii) at least a portion of a wall of a lighting chamber.

[0120] Since a relatively smooth surface can be provided, a 3D printed object can also be used as a mirror or lens, etc. In an embodiment, a 3D object can be configured as a light shield. A device or system can include multiple different 3D printed objects with different functions.

[0121] Returning to the 3D printing process, a specific 3D printer can be used to provide the 3D printed objects described herein.

[0122] Therefore, in another aspect, the present invention also provides a fused deposition modeling 3D printer, comprising (a) a printer head, the printer head comprising a printer nozzle, (b) a 3D printable material providing device, the 3D printable material providing device being configured to provide 3D printable material to the printer head, (c) an optical fiber providing system, the optical fiber providing system being configured to provide optical fiber, the optical fiber providing system comprising an optical fiber positioning device, (d) a substrate, the substrate being configured to support the 3D printing material, and (e) a control system; wherein the control system is configured to perform the method as described herein for printing a 3D object as described herein.

[0123] In particular, a fused deposition modeling 3D printer is configured to provide the 3D printable material to a substrate according to the methods described herein.

[0124] Furthermore, in the operational mode, the fused deposition modeling 3D printer is configured to provide p optical fiber outer loops. For example, the p outer loops can be provided by moving (in a horizontal plane) one or more of (i) the optical fiber positioning device and (ii) the substrate.

[0125] The fused deposition modeling 3D printer is configured to provide an optical fiber to a 3D printing material (according to the methods described herein) such that the optical fiber is at least partially recessed into a first layer of a set of layers of the 3D printing material.

[0126] For example, in an embodiment, the printer nozzle of a fused deposition modeling 3D printer may be configured to apply pressure to the optical fiber such that the optical fiber is (slightly) pressed into said first layer of 3D printing material.

[0127] In embodiments, a printer nozzle may include a single opening. In other embodiments, the printer nozzle may be a core-shell type having two (or more) openings. The term "printer head" may also refer to multiple (different) print heads; thus, the term "printer nozzle" may also refer to multiple (different) printer nozzles. Similarly, the term "optical fiber positioning device" may also refer to multiple (different) optical fiber positioning devices. For example, in embodiments, an optical fiber provisioning system may include a first optical fiber positioning device configured to position an optical fiber in a horizontal plane, and a second optical fiber positioning device configured to position the optical fiber in a vertical direction. In another example, in embodiments, the optical fiber positioning system may include a robotic arm configured to arrange the optical fiber in a desired orientation and position relative to the 3D printing material. In yet another example, in embodiments, the optical fiber positioning system may also be configured to provide the optical fiber to the 3D printing material by operating in a manner similar to a sewing machine, i.e., implementing a sewing machine mechanism.

[0128] Furthermore, in an embodiment, the fused deposition modeling 3D printer is configured to provide the printing conditions (i.e., temperature) required by the method described above. Therefore, the fused deposition modeling 3D printer may further include one or more of the cooling devices or heating devices described above, such as a hot air device or an IR radiator.

[0129] In addition, the 3D printable material providing device can provide filaments comprising 3D printable material to the printer head, or can provide 3D printable material in such a way that filaments comprising 3D printable material are generated by the printer head. In an embodiment, the 3D printable material providing device may include a device for providing filaments comprising 3D printable material to the nozzle, such as a spool or roller. Additionally or alternatively, the 3D printable material providing device may include a supply or storage device, such as a container, in an embodiment, which includes particles comprising 3D printable material that can be provided to the nozzle.

[0130] Accordingly, the present invention provides a fused deposition modeling 3D printer comprising (a) a printer head comprising a printer nozzle, (b) a filament providing device configured to provide a filament comprising a 3D printable material to the printer head, (c) an optical fiber providing system configured to provide an optical fiber, the optical fiber providing system comprising an optical fiber positioning device, (d) a substrate configured to support the 3D printing material, and (e) a control system configured to perform the method described herein.

[0131] Thus, in particular, the 3D printer comprises a controller (or is functionally coupled to a controller) which is configured to perform the method described herein in a control mode (or "operation mode"). Instead of the term "controller", the term "control system" may also be applied (e.g., see above).

[0132] The term "control" and similar terms particularly refer to at least determining the behavior of an element or supervising the operation of an element. Therefore, "control" and similar terms in this document may, for example, refer to applying an action to an element (determining the action or supervising the operation of an element), such as measuring, displaying, activating, opening, moving, changing the temperature, etc. In addition, the term "control" and similar terms may also include monitoring. Therefore, the term "control" and similar terms may include applying an action to an element, as well as applying an action to an element and monitoring the element. Control of the element may be accomplished using a control system, which may also be indicated as a "controller." Therefore, the control system and the element may be functionally coupled, at least temporarily or permanently. The element may include a control system. In embodiments, the control system and the element may not be physically coupled. Control may be accomplished via wired and / or wireless control. The term "control system" may also refer to multiple different control systems, which may be functionally coupled, and in which, for example, one control system may be a master control system and one or more other control systems may be slave control systems. The control system may include or may be functionally coupled to a user interface.

[0133] The control system can also be configured to receive and execute commands from a remote control. In an embodiment, the control system can be controlled via an application (App) on a device, such as a portable device like a smartphone or iPhone or a tablet. Thus, the device does not have to be coupled to the lighting system, but can be (temporarily) functionally coupled to the lighting system.

[0134] Therefore, in embodiments, the control system can (also) be configured to be controlled by an app on a remote device. In such embodiments, the control system of the lighting system can be a slave control system or controlled in slave mode. For example, the lighting system can be identified by a code, in particular a unique code for the respective lighting system. The control system of the lighting system can be configured to be controlled by an external control system that accesses the lighting system based on knowledge of the (unique) code (input via a user interface with an optical sensor (e.g., a QR code reader)). The lighting system may also include equipment for communicating with other systems or devices, such as based on Bluetooth, WiFi, LiFi, ZigBee, BLE, WiMAX, or other wireless technologies.

[0135] A system, device, or apparatus may perform an action in a "mode," "mode of operation," or "mode of operation." Similarly, in a method, an action, phase, or step may be performed in a "mode," "mode of operation," or "operational mode." The term "mode" may also be referred to as a "control mode." This does not exclude that the system, device, or apparatus may also be adapted to provide another control mode, or multiple other control modes. Similarly, this does not exclude that one or more other modes may be performed before and / or after the execution of the mode.

[0136] However, in embodiments, a control system may be available that is adapted to provide at least a control mode. If other modes are available, selection of such modes may in particular be performed via a user interface, although other options are also possible, such as executing a mode dependent on sensor signals or (time) scenarios. In embodiments, an operating mode may also refer to a system, device, or apparatus that can only operate in a single operating mode (i.e., "on," without further tunability).

[0137] Thus, in an embodiment, the control system may be controlled depending on one or more of an input signal from a user interface, a sensor signal (of a sensor), and a timer.The term "timer" may refer to a clock and / or a predetermined time scheme.

[0138] Furthermore, the present invention relates to a software product that can be used to perform the methods described herein.

[0139] Therefore, in yet another aspect, the present invention also provides a computer program product capable of implementing the method described herein when run on a computer functionally coupled to or comprised by a fused deposition modeling 3D printer.

[0140] Thus, in one aspect, the present invention (therefore) provides a software product which, when run on a computer, is capable of implementing the method (one or more embodiments) as described herein (for producing 3D objects by means of fused deposition modeling).

[0141] The term "3D printer," "FDM printer," or "printer" may be used instead of the term "fused deposition modeling (FDM) 3D printer." A printer nozzle may also be indicated as a "nozzle" or sometimes as an "extruder nozzle." BRIEF DESCRIPTION OF THE DRAWINGS

[0142] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference characters indicate corresponding parts, and in which:

[0143] Figures 1A to 1C Some general aspects of a 3D printer and 3D printing materials are schematically depicted.

[0144] Figures 2A to 2B Some aspects of a method and some further aspects of a 3D printer are schematically depicted.

[0145] Figure 3 Some aspects of the 3D article are depicted schematically.

[0146] Figures 4A to 4B A method and some other aspects of the corresponding 3D article are schematically depicted.

[0147] The schematic diagrams are not necessarily drawn to scale. DETAILED DESCRIPTION

[0148] Figure 1A Some aspects of a 3D printer are schematically depicted. Reference numeral 500 denotes a 3D printer. Reference numeral 530 denotes a functionalization unit configured for 3D printing, in particular FDM 3D printing; this reference numeral may also denote a 3D printing stage unit. In this document, a print head for providing 3D printing material, such as an FDM 3D printing head, is depicted only schematically. Reference numeral 501 denotes a print head. The 3D printer of the present invention may in particular include a fiber supply system 602, see also below. Reference numeral 502 denotes a printer nozzle. Reference numeral 320 denotes a filament with which the 3D printable material 201 can be printed.

[0149] Instead of filaments, pellets can also be used as 3D printable material 201. Both can be extruded through the printer nozzle 502.

[0150] For the sake of clarity, not all features of the 3D printer 500 are depicted, only those that are particularly relevant to the present invention (see also below). Reference numeral 321 designates an extrudate (of the 3D printable material 201 ).

[0151] The 3D printer 500 is configured to generate a 3D object 1 by depositing layers 322 layer by layer on a receiver object 550, which in an embodiment may be at least temporarily cooled, wherein each layer 322 comprises a 3D printable material 201, such as a 3D printable material having a melting point T m . 3D printable material 201 can be deposited on substrate 1550 (during the printing phase). Through deposition, 3D printable material 201 has become 3D printing material 202. 3D printable material 201 escaping from nozzle 502 is also indicated as extrudate 321. Reference numeral 401 indicates thermoplastic material.

[0152] The 3D printer 500 can be configured to heat the filament 320 material upstream of the printer nozzle 502. This can be accomplished, for example, using a device that includes one or more of an extrusion and / or heating function. Such a device is indicated by reference numeral 573 and is arranged upstream of the printer nozzle 502 (i.e., before the filament material leaves the printer nozzle 502). The print head 501 can (thus) include a liquefier or heater. Reference numeral 201 indicates a printable material. When deposited, this material is indicated as a (3D) printing material, indicated by reference numeral 202.

[0153] Reference numeral 572 indicates a spool or roller with material, in particular in the form of a thread, which can be indicated as filament 320. The 3D printer 500 converts this into an extrudate 321 downstream of the printer nozzle, which becomes a layer 322 on a receiver or on already deposited printing material. Generally speaking, the diameter of the extrudate 321 downstream of the nozzle 502 is reduced relative to the diameter of the filament 320 upstream of the print head 501. Therefore, the printer nozzle 502 is sometimes (also) indicated as an extruder nozzle. By arranging layer 322 one after another and / or layer 322 on layer 322, a 3D object 1 can be formed. Reference numeral 575 indicates a filament supply device, which includes a spool or roller and a drive wheel indicated by reference numeral 576.

[0154] The reference symbol Ax indicates the longitudinal axis or filament axis. Printing can be performed in particular along a printing direction which can be aligned with the longitudinal axis A. XFurthermore, reference sign S indicates the direction of layer-by-layer deposition (ie, the build direction), such that a stack 340 of layers 322 of the 3D printing material 202 may be provided.

[0155] Reference numeral 300 schematically depicts a control system. The control system can be configured to control the 3D printer 500. The control system 300 can be included in the 3D printer 500 or functionally coupled to the 3D printer 500. The control system 300 can also include or be functionally coupled to a temperature control system configured to control the temperature of the receiver item 550 and / or the print head 501. Such a temperature control system can include a heater capable of heating the receiver item 550 to a temperature of at least 50°C, but particularly in the range of about 350°C, such as at least 200°C.

[0156] Alternatively or additionally, in embodiments, the receiver plate can also be moved in one or both of the xy plane (horizontal plane). Furthermore, alternatively or additionally, in embodiments, the receiver plate can also be rotated about the z axis (vertical). Thus, the control system can move the receiver plate in one or more of the x, y, and z directions.

[0157] Alternatively, the printer 500 may have a head that can also rotate during printing. This type of printer 500 has the advantage that the printed material 202 cannot be rotated during printing.

[0158] Each layer is indicated by reference numeral 322 and has a layer height H and a layer width W.

[0159] It should be noted that the 3D printable material 201 is not necessarily provided to the print head 501 as a filament 320. Furthermore, the filament 320 can also be produced in the 3D printer 500 from multiple pieces of 3D printable material 201. Thus, the nozzle 502 can effectively produce the filament 320 from the granular 3D printable material 201, which is indicated as a layer 322 (comprising the 3D printable material 202) when deposited. It should be noted that the shape of the extrudate 321 can further change during printing, for example due to the nozzle 502 smearing off the 3D printable material 201 / 3D printable material 202. Figure 1B It is schematically depicted that granular 3D printable material 201 may also be used as feed to the printer nozzle 502 .

[0160] Reference numeral D indicates the diameter of the nozzle 502 through which the 3D printable material 201 is forced. However, the nozzle 502 is not necessarily circular.

[0161] Figure 1BThe printing of a 3D object 1 being constructed is schematically depicted in more detail in 3D. Here, in this schematic diagram, the ends of layers in a single plane are not interconnected, although in practice this may be the case in embodiments.

[0162] Reference numeral H indicates the height of the layer. The individual layers are indicated by reference numeral 322. Here, the layers have a substantially circular cross-section. However, in general, they can be flat, such as having an outer shape similar to a flat oval tube or a flat oval conduit (i.e., a round rod having a diameter compressed to a height less than the width, wherein the sides (defining the width) are (still) circular).

[0163] therefore, Figure 1A Some aspects of a fused deposition modeling 3D printer 500 are schematically depicted, including (a) a first printer head 501 comprising a printer nozzle 502, (b) a filament providing device 575 configured to provide a filament 320 comprising a 3D printable material 201 to the first printer head 501, and optionally (c) a receiver item 550 that can be used to provide a layer of 3D printing material 202.

[0164] Figure 1B Some aspects of a fused deposition modeling 3D printer 500 (or portion thereof) are schematically depicted, the printer including a first printer head 501 including a printer nozzle 502 and an optional receiver item (not depicted) that can be used to provide layers of 3D printing material 202. Such a fused deposition modeling 3D printer 500 may also include a 3D printable material supply device configured to provide the 3D printable material 201 to the first printer head.

[0165] exist Figures 1A-1B , downstream of the nozzle 502, the filament 320 of 3D printable material becomes a layer 322 of 3D printing material 202 as it is deposited. Figure 1B In FIG. 5 , by way of example, due to the short distance between the nozzle 502 and the 3D printing material (or receiver item (not shown)), the extrudate is essentially directly a layer 322 of the 3D printing material 202 .

[0166] Figure 1C A stack 340 of 3D printed layers 322 is schematically depicted, each 3D printed layer having a layer height H and a layer width W. It should be noted that in embodiments, the layer width and / or layer height may be different for two or more layers 322. The layer width and / or layer height may also vary within a layer. Figure 1C Reference numeral 252 in the figure indicates an item surface of the 3D item (in Figure 1C(schematically depicted in ).

[0167] refer to Figures 1A-1C , the deposited filaments of 3D printable material result in a layer having a height H (and a width W). Layer 322 is deposited after layer 322 , resulting in the 3D object 1 . Figure 1C A single-walled 3D object 1 is depicted very schematically. Reference numeral 25 may refer to reflective particles, see also above and below.

[0168] Figure 2A Further embodiments of the invention are schematically depicted, which may relate to the method, the 3D article 1 and / or the fused deposition modeling 3D printer 500 .

[0169] In particular, Figure 2A A method for producing a 3D object 1 by means of fused deposition modeling, in particular by using a fused deposition modeling 3D printer 500, can be schematically depicted. In an embodiment, the 3D object 1 can also at least partially include an optical fiber 610. More particularly, the optical fiber 610 can be a leaky optical fiber 610 partially integrated in the 3D object 1.

[0170] In embodiments, the depicted method can include a 3D printing phase. In particular, the 3D printing phase can include layer-by-layer deposition of an extrudate 321 comprising a 3D printable material 201. Such layer-by-layer deposition can provide multiple layers 322 of 3D printed material 202. In particular, in embodiments, multiple layers 322 can include n groups 1322 of two stacked layers 322 (e.g., two adjacent stacked layers 322). In embodiments, each group 1322 can include, in particular, a first layer 322a and a second layer 322b. Multiple layers 322 of printed material 202 can include, in particular, at least one group 1322 of two stacked layers 322, i.e., in embodiments, n ≥ 1.

[0171] In embodiments, the depicted method may further include k1 integration stages. In certain embodiments, the method may include two or more integration stages, i.e., k1 ≥ 2. Specifically, each integration stage may include, after providing the first layer 322a of one of the n groups 1322, providing an optical fiber 610 on the first layer 322a (e.g., as shown in FIG. 2a, panel I). Reference numeral 331 herein may refer to a location where the optical fiber 610 contacts the 3D-printed material 202 of the first layer 322a. In embodiments, the optical fiber 610 may be provided such that the optical fiber 610 extends from the first layer 322a and at least partially protrudes into the first layer 322a, thereby forming at least a portion of the through-hole 330. Subsequently, each integration stage may include providing a second layer 322b (see FIG. 2a, panels I-III) over the first layer 322a and a portion of the optical fiber 610, such that a portion of the optical fiber 610 resides in the through-hole 330 formed in the group 1322 of layers 322.

[0172] Furthermore, in an embodiment, the method may include performing a 3D printing phase and k1 integration phases such that the optical fiber 610 forms p outer loops 615. In particular, in an embodiment, 1≤p≤k1-1.

[0173] In an embodiment, the method may further comprise a cooling phase. In particular, at least one or k1 integration phases may be followed by a cooling phase. During the cooling phase, in an embodiment, the second integration layer 322b may be cooled.

[0174] Furthermore, in an embodiment, during the 3D printing phase, the multiple layers 322 may be provided at a first printing speed V1. Additionally or alternatively, in an embodiment, during the k1 integration phases, one or more of the first layer 322a and the second layer 322b may be provided at a second printing speed (V2). In particular, in an embodiment, V1 ≥ V2.

[0175] Figure 2B Schematically depicts another embodiment of the method and the fused deposition modeling 3D printer 500. In an embodiment, during the method, the optical fiber 610 can form p outer loops 615, in particular, each loop 615 can be defined between two groups 330 of through-holes. In an embodiment, the two through-holes 330 of a single loop 615 can be arranged in the same group 1322 of the layer 322, i.e., the first layer 322a and the second layer 322b can be the same layer 322 for the two through-holes 330 of the single loop 615. However, in an embodiment, the two through-holes 330 of the single loop 615 can also be arranged in different groups 1322 of the layer 322, i.e., the first layer 322a and the second layer 322b can be different for the two through-holes 330 of the single loop 615. Figure 2BAn example of the above two situations is described. In an embodiment, the 3D object 1 may specifically comprise k2 through holes.

[0176] Furthermore, as described above, the optical fiber 610 may be disposed on the first layer 322a (of the group 1322 of stacked layers 322). In particular, in embodiments, the optical fiber 610 may not be (anti-)parallel to the longitudinal axis A of the first layer 322a. X , such as perpendicular to the longitudinal axis A of the first layer 322a X Thus, in an embodiment, the optical fiber 610 may be arranged relative to the longitudinal axis A. X Fiber forming angle α F Provided, where the fiber angle α F can be defined in a plane parallel to the xy plane (or horizontal plane). In other words, the fiber angle α F , and thus the longitudinal axis A X , can be defined in a plane perpendicular to the (building) direction S. In particular, in an embodiment, α F ≠0°, such as 10°≤α F ≤90°.

[0177] like Figure 2A As shown in sub-figure II, the optical fiber 610 can be partially recessed into the first layer 322a so that the optical fiber 610 can protrude from the first layer 322a to provide a (slightly) textured contact surface for the second layer 322b. In other words, the optical fiber 610 protrudes from the first layer 322a so that during deposition of the second layer 322b, the 3D printable material 201 is molded around the protrusion. Thus, the method described herein can be such that at least one of the k1 integration stages can include: (a) after providing a first layer 322a of one of the n groups 1322, providing the optical fiber 610 on the first layer 322a so that the optical fiber 610 extends from the first layer 322a and protrudes into the first layer 322a, thereby forming a through hole 330, and (b) subsequently providing a second layer 322b on the first layer 322a and a portion of the optical fiber 610 so that a portion of the optical fiber 610 resides in the through hole 330 formed in the layer 1322 of the group. However, in embodiments, such as in Figure 2AAs depicted in sub-figure III, optical fiber 610 may also be recessed into first layer 322a such that optical fiber 610 and first layer 322a provide a smooth contact surface for second layer 322b, i.e., optical fiber 610 may be completely recessed into first layer 322a. In other words, optical fiber 610 is recessed into first layer 322a such that, during deposition of second layer 322b, 3D printable material 201 is deposited on a (substantially) horizontal surface formed by first layer 322a and optical fiber 610. Thus, the method described herein may be such that at least one of the k1 integration stages may include subsequently providing second layer 322b over the first layer 322a and portion of optical fiber 610, such that optical fiber 610 also extends from second layer 322b and also at least partially protrudes into second layer 322b, thereby forming another portion of through-hole 330, and such that a portion of optical fiber 610 resides in through-hole 330 provided by layer 322 of group 1 322.

[0178] In particular, in an embodiment, the optical fiber 610 may be smaller than the two layers 322 of the 3D printing material 202. In particular, the optical fiber 610 may have a fiber diameter D f In the embodiment, the fiber diameter (D f ) may be a cross-sectional diameter defined in a plane perpendicular to the fiber length (L1) of the optical fiber 610. In particular, in an embodiment, the fiber diameter D f It can be less than twice the layer height H, such as 0.05*H≤D f <2*H, in particular, 0.1*H≤D f <2*H.

[0179] Furthermore, in an embodiment, during at least one of the k1 integration stages, printing conditions may be selected to achieve a particular result. In particular, in an embodiment, printing conditions may be selected such that when the optical fiber 610 is provided to the first layer 322a, the temperature of the 3D printed material 202 of the first layer 322a at the location 331 where the optical fiber 610 contacts the 3D printed material 202 may be higher than the melting temperature (T m )(See also above).

[0180] like Figure 2BAs shown, the method may include using a fused deposition modeling 3D printer 500, the printer including a fiber providing system 602, the fiber providing system being configured to provide optical fibers 610. In particular, the fiber providing system 602 may include an optical fiber positioning device (not shown here). The 3D printer 500 may also include a base plate 1550 configured to support the 3D printing material 202, such that the method may include providing p outer loops 615 by moving (in a horizontal plane) one or more of (i) the optical fiber positioning device (included by the optical fiber providing system 602), and (ii) the base plate 1550:

[0181] As described above, in embodiments, the method can include at least partially pressing the optical fiber 610 into the first layer 322a (vertically). In certain embodiments, the method can (even) include (substantially) completely pressing the optical fiber 610 into the first layer 322a. In particular, the optical fiber 610 can be at least partially pressed into the first layer 322a by controlling the vertical position of one or more of (i) the printer nozzle 502, (ii) the optical fiber positioning device (included in the optical fiber providing system 602), and (iii) the substrate 1550. Movements such as those described herein (in the horizontal plane and / or vertical position) have been described in greater detail above and will not be repeated here.

[0182] In a further aspect, a 3D printed object 1 obtainable by the method described herein is provided. In particular, the present invention may provide a 3D object 1 comprising a 3D printing material 202. More particularly, the present invention may provide a 3D object 1 produced by means of fused deposition modeling. Figure 3 and Figures 4A to 4B A schematic diagram of the 3D object 1 may be provided. Figure 3 4 discuss an embodiment of a 3D article 1 .

[0183] In an embodiment, a 3D object 1 may include multiple layers 322 of 3D printed material 202 and (partially integrated leaky) optical fibers 610. In an embodiment, multiple layers 322 may include n groups 1322 of two stacked layers 322, as described above. In an embodiment, optical fibers 610 may be partially integrated between a first layer 322a and a second layer 322b of one of the n groups 1322, such that optical fibers 610 may extend from the first layer 322a and may at least partially protrude into the first layer 322a. In particular, optical fibers 610 may thereby form at least a portion of a through-hole 330. More particularly, portions of optical fibers 610 may reside in through-holes 330 formed in layers 322 of group 1322. Because optical fibers 610 may be at least partially pressed into first layer 322a, in an embodiment, optical fibers 610 may have a recessed portion 616. In particular, in an embodiment, optical fibers 610 may have a k1 recessed portion 616. In an embodiment, the k1 recessed portions 616 may each have a recessed portion length L q In particular, the length L of the recessed portion q It can be (essentially) equal to the layer width W.

[0184] In an embodiment, Figure 4A It is further schematically depicted that the optical fiber 610 may have a (first) fiber length L1. The fiber length L1 may in particular comprise k1 the length L of the recessed portion. q and p external loop length L p , see also below. Therefore, in an embodiment, L1=k1*L q +p*L p . Figure 4A A cross section of a 3D (printed) object 1 can be particularly schematically depicted, while Figure 4B A cross-section of a stack 340 including a layer 322 of optical fibers 610 may be schematically depicted.

[0185] In an embodiment, the outer loop length L p L may be defined as the length of the optical fiber 610 from a first through-hole 330′ to a second through-hole 330″ in a set of through-holes 330. Furthermore, in an embodiment, each of the p outer loops 615 may have a shortest distance d2 between the (corresponding) through-holes 330′, 330″. In an embodiment, the shortest distance d2 between the (corresponding) through-holes 330′, 330″ of the outer loops 615 may be defined in a plane passing through a layer 322 of the first stack 340, the layer 322 including at least one or more groups 1322 associated with the corresponding outer loop 615. In particular, in an embodiment, the outer loop length L p More specifically, in an embodiment, L p ≥1.1*d2.

[0186] Furthermore, in embodiments, at least 90% of the fiber length L1 of the optical fiber 160 may be comprised of p outer loops 615. Thus, in embodiments, p*L p ≥0.9*L1.

[0187] In embodiments, optical fiber 610 may comprise a light-transmitting material. In particular, in embodiments, optical fiber 610 may comprise one or more of glass, silica, and a polymer material. Furthermore, in embodiments, 3D printable material 201 used during the methods described herein and 3D printed material 202 from 3D (printed) articles 1 described herein may comprise a light-transmitting polymer.

[0188] Furthermore, in an embodiment, the 3D printable material 201 (and the 3D printing material 202) may include reflective particles 25 that are disposed around one or more k2 through-holes 330 and configured to reflect the light 11 back into the optical fiber 610. The reflective particles 25 have been described in more detail above and will not be repeated here.

[0189] Figure 3 Some examples of 3D (printed) articles 1 are schematically depicted. In particular, sub-figure 1 schematically depicts a 3D (printed) article 1 obtained by the method described herein, further comprising arranging an optical fiber 610 in a coil pattern. Sub-figure 1 schematically depicts a 3D (printed) article 1 obtained by the method described herein, further comprising arranging at least a portion of the optical fiber 610 in a braid pattern. Thus, in embodiments, the method may further comprise arranging the optical fiber 610 in one or more of a coil pattern, a braid pattern, or a spiral pattern. However, other regular patterns are not excluded herein.

[0190] also, Figure 3 The application of 3D (printed) articles 1 is schematically depicted. In particular, Figure 3 A lighting device 1000 is schematically depicted, comprising a 3D object 1 and a light source 10 as described herein. Light source 10 can be particularly configured to provide visible light source light 11. Thus, in an embodiment, optical fiber 610 is functionally coupled to light source 10 such that light source light 11 can propagate through optical fiber 610. Thus, 3D object 1 can be configured as lighting device 1000. In other embodiments not depicted herein, 3D object 1 can be configured as one or more of (i) at least a portion of a lighting device housing, and (ii) at least a portion of a wall of a lighting chamber.

[0191] The term "plurality" refers to two or more.

[0192] The term "substantially" or "substantially" and similar terms will be understood by those skilled in the art herein. The term "substantially" or "substantially" may also include embodiments with "completely", "completely" or "entirely". Thus, in embodiments, the adjective "substantially" or "substantially" may also be removed. Where applicable, the term "substantially" or the term "substantially" may also relate to 90% or higher, such as 95% or higher, in particular 99% or higher, even more in particular 99.5% or higher, including 100%.

[0193] The term "comprising" also includes embodiments, wherein the term "comprising" means "consisting of.

[0194] The term "and / or" specifically refers to one or more of the items mentioned before and after "and / or". For example, the phrase "item 1 and / or item 2" and similar phrases can refer to one or more of item 1 and item 2. The term "comprising" can mean "consisting of" in one embodiment, but can also mean "including at least the defined categories and optionally one or more additional categories" in another embodiment.

[0195] Furthermore, the terms first, second, third, etc. in the description and claims are used to distinguish similar elements and not necessarily to describe a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0196] While an apparatus, device or system may be described herein during operation, it will be apparent to one skilled in the art that the present invention is not limited to methods of operation, or apparatus, devices or systems in operation.

[0197] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0198] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0199] The use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps not stated in a claim. Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise," "comprising," etc. should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

[0200] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0201] The invention can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, an apparatus claim, or a system claim enumerating several means, several of these means may be embodied by the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0202] The present invention also provides a control system that can control a device, apparatus, or system, or can perform the methods or processes described herein. Furthermore, the present invention also provides a computer program product that, when functionally coupled to a device, apparatus, or system or executed on a computer included in the device, apparatus, or system, controls one or more controllable elements of such a device, apparatus, or system.

[0203] The present invention also applies to an apparatus, device or system comprising one or more of the characteristic features described in the specification and / or shown in the accompanying drawings. The present invention also relates to a method or process comprising one or more of the characteristic features described in the specification and / or shown in the accompanying drawings.

[0204] The various aspects discussed in this patent can be combined to provide additional advantages. In addition, those skilled in the art will understand that the embodiments can be combined, and more than two embodiments can also be combined. In addition, some of the features can form the basis of one or more partitioning applications.

[0205] It goes without saying that one or more of the first (printable or printed) material and the second (printable or printed) material may contain fillers, such as glass and fibers, which have a significant effect on the T of the material(s). g or T m No impact.

Claims

1. A method for producing a 3D object (1) by means of fused deposition modeling, wherein the 3D object (1) further comprises at least partially a leaky optical fiber (610); the method comprising: a 3D printing stage, the 3D printing stage comprising depositing a 3D printable material (201) layer by layer to provide a multilayer (322) 3D printing material (202), wherein the multilayer (322) comprises n groups (1322) of two stacked layers (322), wherein each group (1322) comprises a first layer (322a) and a second layer (322b); wherein n≥1; k1 integration stages, wherein each integration stage comprises: (a) after providing the first layer (322a) of one of the n groups (1322), providing the optical fiber (610) on the first layer (322a) such that the optical fiber (610) extends from the first layer (322a) and at least partially protrudes into the first layer (322a) thereby forming at least a portion of a through hole (330), and (b) subsequently providing the second layer (322b) on the first layer (322a) and the portion of the optical fiber (610) such that a portion of the optical fiber (610) resides in the through hole (330) formed in the layer (322) of the group (1322); The 3D printing stage and the k integration stages are performed such that the optical fiber (610) forms p external loops (615), where k1≥2, and where 1≤p≤k1-1.

2. The method according to claim 1, wherein at least one of the k1 integration stages comprises: After providing the first layer (322a) of one of the n groups (1322), providing the optical fiber (610) on the first layer (322a) such that the optical fiber (610) extends from and protrudes into the first layer (322a) to form the through hole (330), and (b) subsequently providing the second layer (322b) on the first layer (322a) and a portion of the optical fiber (610) such that a portion of the optical fiber (610) resides in the through hole (330) formed in the layer (322) of the group (1322).

3. The method according to claim 1, wherein at least one of the k1 integration stages comprises: The second layer (322b) is then provided over the first layer (322a) and the portion of the optical fiber (610) such that the optical fiber (610) also extends from the second layer (322b) and also protrudes at least partially into the second layer (322b) to form another portion of the through hole (330), and a portion of the optical fiber (610) resides in the through hole (330) provided by the layers (322a, 322b) of the group (1322).

4. The method according to any of the preceding claims, wherein during at least one of the k integration stages, printing conditions are selected such that when the optical fiber (610) is provided on the first layer (322a), the temperature of the 3D printed material (202) of the first layer (322) at the location (331) where the optical fiber (610) contacts the 3D printed material (202) is higher than the melting temperature T of the 3D printed material (202). m .

5. The method according to any one of the preceding claims, further comprising: Using a fused deposition modeling 3D printer (500), the fused deposition modeling 3D printer includes (a) an optical fiber providing system (602), the optical fiber providing system being configured to provide the optical fiber (610); wherein the optical fiber providing system (602) includes an optical fiber positioning device (603); and (b) a substrate (1550) configured to support a 3D printed material (202); wherein the method comprises providing the p outer loops (615) by moving one or more of (i) the fiber positioning device (603) and (ii) the substrate (1550).

6. The method of claim 5, wherein the fused deposition modeling 3D printer (500) further comprises a printer nozzle (502); wherein the method comprises: The optical fiber (610) is at least partially pressed into the first layer (322a) by controlling the vertical position of one or more of (i) the printer nozzle (502), (ii) the optical fiber positioning device (603) and (iii) the substrate (1550).

7. The method according to any one of the preceding claims, wherein each of the p outer loops (615) has an outer loop length (L p ), wherein each of said p external loops (615) has a shortest distance (d2) between said through-holes (330), wherein said shortest distance (d2) between said through-holes (330) of the external loops (615) is defined in a plane passing through a layer (322) of a first stack (340), said layer (322) comprising at least one or more of said groups (1322) associated with the respective external loops (615), wherein L p >1.1*d2; and wherein at least 90% of the fiber length (L1) of the optical fiber (610) is comprised by the p outer loops (615).

8. The method of any one of the preceding claims, wherein the 3D printable material (201) comprises a polymer material, wherein the polymer material comprises a light-transmissive polymer, and wherein the printable material (201) comprises reflective particles (25) arranged around the through-hole (330) and configured to reflect light back into the optical fiber (610).

9. A method according to any one of the preceding claims, wherein the optical fiber (610) comprises one or more of glass, silica and a polymer material different from the polymer material defined in claim 8; and wherein the optical fiber (610) comprises a leaky fiber.

10. A 3D object (1) produced by means of fused deposition modeling, wherein the 3D object (1) comprises multiple layers (322) of 3D printing material (202) and a partially integrated leaky optical fiber (610), wherein; The multilayer (322) includes n groups (1322) of two stacked layers (322), wherein each group (1322) includes a first layer (322a) and a second layer (322b), wherein n≥1; The optical fiber (610) is partially integrated between the first layer (322a) and the second layer (322b) of one of the n groups (1322) such that the optical fiber (610) extends from the first layer (322a) and at least partially protrudes into the first layer (322a), thereby forming at least a portion of k2 through-holes (330), wherein portions of the optical fiber (610) reside in the k2 through-holes (330) formed in the layer (322) of the group (1322); The optical fiber (610) forms p outer loops (615), where k2≥2, and where 1≤p≤k2-1.

11. The 3D article (1) according to claim 10, wherein each of the p outer loops (615) has an outer loop length (L p ), wherein each of said p external loops (615) has a shortest distance (d2) between said through-holes (330), wherein said shortest distance (d2) between said through-holes (330) for an external loop (615) is defined in a plane passing through a layer (322) of a first stack (340), said layer (322) comprising at least one or more of said groups (1322) associated with a respective external loop (615), wherein L p >1.1*d2; and wherein at least 90% of the fiber length (L1) of the optical fiber (610) is comprised by the p outer loops (615).

12. The 3D article (1) according to any one of claims 10 to 11, wherein the 3D printed material (202) comprises a polymer material, wherein the polymer material comprises a light-transmitting polymer, and wherein the 3D printed material (202) comprises reflective particles (25) arranged around the through hole (330) and configured to reflect light back into the optical fiber (610).

13. The 3D article (1) according to any one of the preceding claims 10 to 12, wherein the optical fiber (610) comprises one or more of glass, silica and a polymer material different from the polymer material defined in claim 12.

14. A lighting device (1000) comprising a 3D article (1) according to any one of claims 10 to 13, and a light source (10) configured to provide visible light source light (11), wherein the optical fiber (610) is configured to be in a light receiving relationship with the light source (10); wherein the 3D article (1) is configured as one or more of (i) at least a portion of a lighting device housing and (ii) at least a portion of a wall of a lighting room.

15. A fused deposition modeling 3D printer (500), comprising: (a) a printer head (501), said printer head comprising a printer nozzle (502); (b) a 3D printable material providing device (575), the 3D printable material providing device being configured to provide 3D printable material (201) to the printer head (501); (c) an optical fiber providing system (602) configured to provide optical fiber (610), the optical fiber providing system comprising an optical fiber positioning device (603); (d) a substrate (1550) configured to support a 3D printing material (202); and (e) a control system (300), wherein the control system (300) is configured to perform the method according to any one of the preceding claims 1 to 9.

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